Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Hamed Esfandiari; Mohammad Pakravan; Nils A. Loewen; Mehdi Yaseri

doi:10.12688/f1000research.12904.2

Home Browse Predictive value of early postoperative IOP and bleb morphology in...

ALL Metrics

Views

Downloads

Get PDF

Get XML

Export

▬

✚

Research Article

Revised

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

[version 2; peer review: 2 approved]

Hamed Esfandiari^1,2, Mohammad Pakravan³, Nils A. Loewen ², Mehdi Yaseri⁴

PUBLISHED 19 Dec 2017

Author details Author details

¹ Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
² Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
³ Ophthalmic Epidemiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
⁴ Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

Hamed Esfandiari
Roles: Conceptualization, Formal Analysis, Investigation, Methodology, Project Administration, Resources, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing

Mohammad Pakravan
Roles: Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Supervision, Validation

Nils A. Loewen
Roles: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Methodology, Resources, Software, Validation, Writing – Original Draft Preparation, Writing – Review & Editing

Mehdi Yaseri
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Software, Validation, Visualization, Writing – Original Draft Preparation

OPEN PEER REVIEW

REVIEWER STATUS

This article is included in the Eye Health gateway.

Abstract

Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy.
Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC).
Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%).
Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy. An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

Keywords

trabeculectomy, mitomycin C, bleb morphology, Indiana bleb appearance grading scale, intraocular pressure

Corresponding author: Nils A. Loewen

Competing interests: HE, MP, and MY have no financial disclosure. NAL has received honoraria for trabectome wet labs and lectures from Neomedix Corp.

Grant information: This study was funded in part by the Initiative to Cure Glaucoma, of the Eye and Ear Foundation of Pittsburgh, and by the Ophthalmic Research Center of the Shahid Beheshti University of Medical Sciences, and by unrestricted grant from Research to Prevent Blindness, New York, NY.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Copyright: © 2017 Esfandiari H et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).

How to cite: Esfandiari H, Pakravan M, Loewen NA and Yaseri M. Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy [version 2; peer review: 2 approved]. F1000Research 2017, 6:1898 (https://doi.org/10.12688/f1000research.12904.2) First published: 27 Oct 2017, 6:1898 (https://doi.org/10.12688/f1000research.12904.1) Latest published: 19 Dec 2017, 6:1898 (https://doi.org/10.12688/f1000research.12904.2)

Revised Amendments from Version 1

The reviewer’s suggestions helped us improve this manuscript by including the following changes:

The discrepancy between early postoperative visits (1 week versus 2 weeks) has been corrected. As we have confirmed by going back to the original SPSS files, intraocular pressures were checked at the 1-week postoperative visit mistakenly listed as week 2 in Table 2. The discrepancy was corrected throughout the manuscript.
We clarified the criteria when sutures were released, bleb needling performed and that prostaglandin analogs were avoided during the postoperative period. Releasable sutures were removed within the first month of the surgery based on the IOP and the surgeons’ assessment of bleb function. Highly vascularized as well as contracting blebs were indications for needling. The same medications that were effective and safe before the surgery were resumed if necessary except prostaglandin analogs which were avoided.
We updated our conclusion in the Abstract by adding the importance of a vascularized bleb in predicting the failure and the need for a prompt intervention depending on the vascularization.
We also now state in the Abstract the exact average of the age of analyzed patients and p-value for gender differences: the mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911).

See the authors' detailed response to the review by Ding Lin
See the authors' detailed response to the review by Frances Meier-Gibbons

Introduction

For several reasons, the number of trabeculectomies has sharply declined in the last decades in many developed countries^1,2. More surgeons are now trained in microincisional glaucoma surgeries^3,4 which can be performed sooner due to a superior risk profile⁵; laser trabeculoplasty devices have become more affordable and are used as the first line of treatment^6,7; and prostaglandin analogues are now available as generic, less expensive eye medications, further reducing the number of trabeculectomies⁶. However, in economies categorized as developing by the International Monetary Fund⁸ and countries not in the upper quartile of the Human Development Index⁹, trabeculectomies remain the leading surgeries for moderate and severe glaucomas^10,11. Although trabeculectomies have a considerable complication rate¹², they remain a common primary procedure for advanced glaucoma because they lower intraocular pressure (IOP) effectively and are not as expensive as epibulbar glaucoma drainage devices¹³, which involve a comparable surgical effort and risk profile.

Careful patient selection and postoperative management are key to making trabeculectomies successful. Recognized risk factors are, among others, younger age, a higher baseline IOP, and inflammation^14,15. While meticulous preoperative planning, intraoperative use of antifibrotics, and the surgical technique impact the outcome, the postoperative period plays an equally important role^16,17 including adjustment of the frequency of postoperative visits, adjustment of steroid frequency, release or lasering of scleral flap sutures, bleb massage, and bleb needling. Yet, even with the most personalized postoperative care, the individual wound healing and tissue remodeling make predicting a successful outcome difficult. Several recent studies have tried to capture the specific wound healing by correlating the early postoperative IOP or the bleb morphology with long-term outcomes, and found a low early postoperative IOP produces favorable long-term outcomes^18–21. In comparison, bleb grading systems are more complex, less objective but hold promise to describe data otherwise difficult to quantify; they have not been widely adopted^22,23.

The purpose of our study was to validate in our patient population the accuracy of the early postoperative IOP and bleb morphology (Indiana Bleb Appearance Grading Scale (IBAGS)) as a test to predict a failure of trabeculectomy at 12 months. In contrast to prior studies, we also examined the role of an IOP increase during the first 30 postoperative days in predicting such failure.

Methods

Study design

Eighty eyes of 80 consecutive patients diagnosed with primary open angle glaucoma were included in this prospective observational study. In patients who had trabeculectomies in both eyes, the eye was chosen by randomization²⁴. The study was performed at the glaucoma clinic of the Labbafinejad Medical Center of the Shahid Beheshti University of Medical Sciences, Tehran, Iran, from September 2013 to March 2015. It was approved by the ethics committee and the institutional review board at the Ophthalmic Research Center (protocol number: IR.SBMU.ORC.REC.1393.2) and followed the tenets of the Declaration of Helsinki. Informed written consent was obtained from each participant. Inclusion criteria were equal to or above 30 years of age and progressive primary open angle glaucoma (glaucomatous optic neuropathy, retinal nerve fiber layer loss and corresponding visual field defect on standard automated perimetry) that could not be controlled medically. Exclusion criteria consisted of prior ocular surgery, manipulation of the conjunctiva, a necessity for combining trabeculectomy with cataract extraction, ocular or systemic comorbidities that could affect the procedure and study outcomes including immunodeficiency, connective tissue disease, and uncontrolled diabetes. At baseline, all patients underwent a comprehensive ophthalmic examination including determination of best-corrected visual acuity (BCVA), slit lamp examination, Goldmann applanation tonometry, gonioscopy, and fundus examination.

Surgical technique and postoperative management

All trabeculectomies were performed by two surgeons in equal numbers (HE and MP), as described in the following²⁵. After administration of intravenous sedation, a peribulbar block was placed using 2 milliliters (ml) of 2% lidocaine (Lignidic 2%, Caspian Tamin Pharmaceutical Co., Rasht, Iran). Following lid speculum insertion and cul de sacs irrigation with povidone-iodine and normal saline solution, a 7-0 silk traction suture was placed through the superior peripheral cornea. A superior peritomy was fashioned over 1-½ clock hours, and Tenon’s capsule was dissected with Westcott scissors. A 3.0 × 4.0 mm trapezoidal half-thickness scleral flap was fashioned using a crescent knife followed by lamellar dissection of the flap 1mm into the clear cornea. After creating the scleral flap, pieces of 0.02% MMC (Mitomycin-C, Kyowa, Kogyo Company, Tokyo, Japan) soaked cellulose sponges were placed under the Tenon and conjunctiva over the scleral flap for 3 minutes. After removing the sponges and vigorously irrigating the area with 50 ml of balanced salt solution (BSS), the anterior chamber was entered with a small keratome, and a block of clear cornea was removed with a 1 mm Kelly punch followed by a peripheral iridectomy using Vannas scissors. The scleral flap was then secured using two 10-0 nylon releasable sutures. The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures. The conjunctiva was closed using 10-0 nylon wing sutures. Cefazolin 50 mg (Cefazolin 500, Exir Pharmaceutical Co, Tehran, Iran) and betamethasone 2 mg (Betazone, Caspian Tamin Pharmaceutical CO., Rasht, Iran) were injected subconjunctivally into the inferior fornix, and the eye was patched.

The postoperative regimen consisted of chloramphenicol 0.5% eye drops (Sina Darou Lab. Co., Tehran, Iran) 4 times a day for 1 week and betamethasone 0.1% eye drops (Sina Darou Lab. Co., Tehran, Iran) 6 times a day, which was tapered over 8 to 12 weeks depending on the inflammation. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs. Thirty minutes after injecting 0.1 ml of 0.02% Mitomycin-C into the bleb-adjacent subtenon space a 27-gauge needle was used to reform the bleb and dissect adhesions at the slit lamp.

Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months.

We saw our patients on a weekly basis for one month and then monthly for 12 months. At each postoperative visit, BCVA, IOP, bleb morphology, glaucoma medications, and complications were noted. A slit lamp photograph of the blebs was obtained at each visit (Haag-Streit BX 900 slit lamp, Haag-Streit Diagnostics, Köniz, Switzerland). Two glaucoma surgeons, masked to surgeon and patient, graded the bleb images on the Indiana Bleb Appearance Grading Scale (IBAGS). The IBAGS variables included the bleb height (H0-H3), extent (E0-E3), vascularity (V0-V4), and leakage (S0-S2)²³. A trabeculectomy was considered successful if IOP was equal or less than 15 mmHg and more than 5 mmHg with or without glaucoma medications¹⁸.

Statistical analysis

Data was described as mean ± standard deviation (SD), median, range, 95% confidence interval (95% CI) and frequency (percentage). To evaluate for difference between the two groups we used the t-test, Mann-Whitney, Chi-square and Fisher exact test. A change in visual acuity before and after surgery was evaluated by the Wilcoxon signed-rank test. The predictive power of bleb variables was measured with the area under the receiver operator characteristic curve (AUC). To find the relative risk (RR, Supplementary Table 1) of failure by bleb morphology and IOP at the 1-month visit, a Cox regression with defined constant time was used. Youden’s J statistic was used to capture the performance of variables (bleb morphology, IOP) as a diagnostic test. All statistical analyses were done with the SPSS software package (IBM Corp. Released 2016. IBM SPSS Statistic for Windows, Version 24.0, Armonk, NY).

Results

A total of 80 patients were enrolled in this study. This sample size and ratio of success and failure provided an above 90% power to detect an AUC difference of 0.5²⁶. Forty-four eyes would have provided a power of 80% to detect an IOP change of 3 mmHg while 80 eyes allowed for a 97% power. The mean age of study participants was 62.3±13.1 years, and 51.3% of the patients were male (P=0.911). The characteristics of participating patients are presented in Table 1. The procedure was considered successful in 64 patients (80%) at 12 months follow-up.

Table 1. Baseline characteristics of participants (mean±SD, median (range)).

	Total	Success		P
	Total	No (n=16)	Yes (n=64)	P
age	62.3±13.1	63.2±16.3	62±12.3	0.430†
male	41 (51.3%)	8 (50.0%)	33 (51.6%)	0.911*
female	39 (48.8%)	8 (50.0%)	31 (48.4%)
BCVA	0.47±0.47	0.37±0.37	0.49±0.49	0.334‡
IOP	21.8±5.0	20.4±3.3	22.1±5.3	0.171‡
preoperative medications	1.2±1.6	1.4±1.9	1.2±1.6	0.785‡
HVF MD	16.9 ± 5.8	-16.2 ± 5	-17 ± 6	0.645‡
VCD-ratio	0.91 ± 0.93	0.84 ± 0.12	0.92 ± 1	0.666‡

BCVA: Best Corrected Visual Acuity. Medications: topical glaucoma medications. IOP: Intraocular Pressure. HVF MD: Humphrey visual field mean deviation. VCD: vertical cup disc ratio.

† Based on t-test.

‡ Based on Mann-Whitney test.

*Based on Chi-Square test.

Preoperative medications in the no success group were 1.4±1.9 and in the success group were 1.2±1.6 (p=0.785), while the postoperative medications were 1.4 ± 0.5 in the no success group and 1.0±0.0 in the success group (p=0.04). There were no significant differences between the success and failure groups in terms of age, the number of preoperative glaucoma medications, preoperative IOP, visual field mean deviation or vertical cup-disc ratios (Table 1). The postoperative IOP was not different between these groups at any time (Table 2) because an IOP of lower than 5 mmHg was also counted as no success in accordance to prior bleb rating studies. When such a low IOP was considered a success in the absence of hypotony maculopathy, the average IOPs was higher at month 12 (18.9 ± 2.3 [no success] and 9.8 ± 2.1 [success], p<0.001, Supplementary Table 1).

Table 2. Intraocular pressure at each pre- and postoperative visit.

The mean and standard deviation, median and range and area under the receiver operating characteristic curve (AUC) with lower and upper confidence interval (CI) are shown for all timepoints. A higher AUC indicates a better ability to distinguish between the two groups.

Time	No success		Success		P‡	AUC	95% CI
Time	Mean±SD	Median (range)	Mean±SD	Median (range)	P‡	AUC	Lower	Upper
Baseline	21.2±3.4	20 (17 - 28)	21.9±5.2	21 (11 - 32)	0.654	0.473	0.297	0.65
Day 1	6±2.4	6.5 (3 - 9)	7.4±2.5	8 (2 - 13)	0.193	0.355	0.147	0.562
Week 1	7.1±2.1	7 (3 - 10)	7.8±2.5	8 (4 - 18)	0.639	0.452	0.239	0.664
Month 1	9.3±4.6	10 (2 - 16)	8.4±2.4	9 (3 - 19)	0.238	0.8	0.581	1
Month 3	12.6±6.8	14 (2 - 21)	9.5±2.5	10 (5 - 17)	0.143	0.85	0.635	1
Month 6	14.1±7.7	17 (4 - 23)	9.9±2	10 (5 - 15)	0.133	0.875	0.646	1
Month 12	13.7±7.3	17 (4 - 23)	10.1±1.7	10 (6 - 15)	0.143	0.875	0.646	1

‡ Based on Mann-Whitney test.

The best corrected visual acuity did not change significantly (0.47±0.47 logMAR at baseline, 0.48±0.48 postoperatively, P=0.492). Mean IOP decreased significantly from 21.8±5 mmHg at baseline to 10.6±3.8 mmHg at 12 months (p<0.001), and 25 patients needed glaucoma medications to have their IOP within the target range. There were no intraoperative complications. The most common postoperative complication was a shallow anterior chamber, followed by bleb leakage and hyphema as summarized in Table 3.

Table 3. List of postoperative interventions and complications.

	Total	Success		P
	Total	No	Yes	P
Bleb leakage	6 (7.5%)	3 (18.8%)	3 (4.7%)	0.091**
Bleb resuturing	1 (1.3%)	0 (0.0%)	1 (1.6%)	>0.99**
Hyphema	6 (7.5%)	2 (12.5%)	4 (6.3%)	0.594**
Shallow anterior chamber	8 (10.0%)	3 (18.8%)	5 (7.8%)	0.194**
Hypotony	1 (1.3%)	0 (0.0%)	1 (1.6%)	>0.99**
Bleb needling	10 (12.5%)	7 (100.0%)	2 (3.1%)	<0.001**

** Based on Fisher exact test.‡ Based on Mann-Whitney test.

The difference between success and failure groups in a leak, repeat suture, hyphema and shallow anterior chamber were insignificant (P=0.09, 0.99, 0.59, and 0.18, respectively). Bleb needling was more frequently performed in the group that failed (P<0.001). A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001). One eye experienced hypotony maculopathy. Patients with a final IOP of ≤15 mmHg had a mean day 1 IOP of 7.4±2.5 mmHg compared with 6±2.4 mmHg in those with an IOP above 15 mmHg at final follow-up (P=0.193). Respective values for day 7 14 were 7.8±2.5 and 7.1±2.1 mmHg (P=0.639), and for day 30 values were 8.4±2.4 and 9.3±4.6 mmHg (P=0.238). The AUC for IOP at day 1, day 7 and 30 as a predictor of success was 0.355, 0.452, and 0.80 respectively. The bleb morphology parameters according to the IBAGS are detailed in Table 4.

Table 4. Bleb morphologic characteristics at each postoperative visit.

Parameter	Time	No success		Success		P‡	AUC	95% CI
Parameter	Time	Mean±SD	Median (range)	Mean±SD	Median (range)	P‡	AUC	Lower	Upper
Bleb H	Week 2	2.45±0.69	3 (1 to 3)	2.17±0.54	2 (1 to 3)	0.098	0.368	0.172	0.564
	Month 1	2.27±0.65	2 (1 to 3)	2.12±0.53	2 (1 to 3)	0.35	0.428	0.233	0.624
	Month 3	1.64±0.67	2 (1 to 3)	1.96±0.4	2 (1 to 3)	0.024	0.652	0.444	0.859
	Month 6	1.36±0.5	1 (1 to 2)	1.78±0.54	2 (1 to 3)	0.017	0.691	0.523	0.859
	Month 12	1.36±0.5	1 (1 to 2)	1.74±0.56	2 (1 to 3)	0.038	0.669	0.5	0.838
Bleb E	Week 2	2.55±0.52	3 (2 to 3)	2.36±0.48	2 (2 to 3)	0.25	0.408	0.224	0.592
	Month 1	2.18±0.4	2 (2 to 3)	2.3±0.49	2 (1 to 3)	0.41	0.563	0.391	0.734
	Month 3	1.73±0.65	2 (1 to 3)	2.12±0.4	2 (1 to 3)	0.012	0.669	0.47	0.869
	Month 6	1.55±0.52	2 (1 to 2)	2.09±0.37	2 (1 to 3)	<0.001	0.744	0.568	0.92
	Month 12	1.82±0.75	2 (0 to 2)	1.95±0.53	1 (0 to 1)	0.002	0.749	0.57	0.928
Bleb V	Week 2	2.18±0.6	2 (1 to 3)	2.3±0.49	2 (1 to 3)	0.53	0.549	0.357	0.74
	Month 1	1.82±0.6	2 (1 to 3)	2.19±0.52	2 (1 to 3)	0.045	0.654	0.474	0.834
	Month 3	1.64±0.67	2 (0 to 2)	1.86±0.49	2 (1 to 3)	0.368	0.565	0.38	0.751
	Month 6	1.55±0.69	2 (0 to 2)	1.54±0.53	2 (0 to 2)	0.76	0.475	0.282	0.668
	Month 12	1.36±0.67	1 (0 to 2)	1.46±0.53	1 (0 to 2)	0.702	0.532	0.338	0.725

H: height. E: extension. V: vascularization.

‡ Based on Mann-Whitney test.

The AUC for bleb morphology parameters of bleb height, extension, and vascularization on day 14 were 0.368, 0.408 and 0.549, respectively. The AUC values for day 30 were 0.428, 0.563, and 0.654. Based on the AUCs, there was no single bleb variable at month 1 to predict success at month 12.

Surprisingly, the AUC of the IOP change from day 1 to day 30 was a good predictor of success (AUC=0.838, 95% CI: 0.704 to 0.971, Supplementary Table 1). Based on Youden’s J index, the change in IOP less than or equal to 3 mmHg could predict the success in month 12 with the sensitivity of 82.5% (95% CI: 68 to 91%) and specificity of 87.5% (95% CI: 53 to 98%).

Dataset 1.Raw data collected from all study participants.

Discussion

Trabeculectomy remains a common surgery to lower IOP in glaucoma patients and has a long history. In 1958, Grant was the first one to describe a guarded filtering procedure in enucleated eyes with subsequent facility measurements which he termed trabeculectomy²⁷. Sugar followed by performing the first such trabeculectomy in patients in 1961²⁸ and Cairns finally popularized the term and technique by providing detailed drawings and figures²⁹. The procedure was eventually made more effective by adding Mitomycin-C as an antifibrotic³⁰ and somewhat titratable by using sutures that can be lasered or manually released^31,32. The variable success rate of this procedure can be improved by careful patient selection, surgical technique³³, and postoperative management¹⁵. Identifying patients at risk is critical because a timely intervention can improve the outcomes of trabeculectomy¹⁶; preoperative factors including high baseline IOP, number of glaucoma medications, young age, aphakia or pseudophakia and prior surgery with conjunctival scarring are known risk factors for failure³³. The success and failure groups in our study have similar baseline IOP, medications, visual field loss and optic nerve damage indicating that any risk factors related to those were relatively equal in both.

Several recent studies found a low early postoperative IOP produces favorable long-term outcomes^18–21,34 but also causes more frequent and more severe complications that include a shallow anterior chamber, choroidal effusion, hypotony maculopathy, and vision loss³⁵. Although we did observe that the IOP change during the first month was a good predictor of failure, we found only a weak relationship between absolute IOP at day 1, 7, and 30 and long term success. This is similar to Polikoff et al.³⁶ who also reported that early post-trabeculectomy IOP is a poor predictor of success at one year follow-up. The accuracy of a test depends on how well it separates groups under study into those with and without the issue in question. Accuracy is measured by the area under the ROC curve and is commonly classified into .90-1 = excellent, .80-.90 = good, .70-.80 = fair, .60-.70 = poor and .50-.60 = fail²⁶. In our study, the AUC for IOP was the highest on day 30 with 0.8, making it a fair to good predictor²⁶. Early post-trabeculectomy IOP is affected by various factors that include reduced aqueous production, inflammation, the amount of TGF-beta and other growth factors³⁷, and breakdown of the blood-aqueous barrier, over filtration, and choroidal detachment. In our study, the IOP appears to summarize these and other factors reasonably well to a single variable that can be used as a predictor.

An advantage of this study is that approximately 75% more patients participated than in prior bleb grading studies^22,23,38,39. Different from those, we also examined the change in IOP during the first 30 days and found that it served as a good predictor of success that performs better than the IOP itself. The cutoff for an at-risk IOP elevation was only 3 mmHg. Our study was not designed to discover causality, however. It is likely that this finding identifies patients at risk of failure who experienced an IOP increase despite an intensified treatment. It could also indicate that these were patients who received a suboptimal postoperative management. An elevated IOP will increase the stretch of the bleb wall and incite a reactive fibrosis. Stretch is a well-established activator of fibroblast proliferation and fibrosis^40,41. This may lead to a cycle of auto-enhancing IOP increase with further increase of stretch and fibrosis that again elevates pressure as the bleb wall becomes thicker and the bleb contracts. In this model, IOP drives the morphological changes of the bleb. This order matches our AUC findings better (the AUC was better for IOP change than for bleb morphology) than a primary morphological change that is followed by increased IOP. Our observation is supportive of the practice to inject or needle with postoperative 5-fluorouracil or Mitomycin-C to reduce the fibrosis^42,43.

Like IOP, a bleb’s morphology is a reflection of a patient’s specific wound healing that is directly observable but more difficult to quantify. The development of bleb grading scales was an attempt to approach this problem systematically^22,23. While grading systems can be useful teaching tools of bleb features, its inherently subjective nature and categorical data weaken the predictive power. Accordingly, we found only low AUC values for bleb morphology that ranged from 0.368 to 0.549 on day 14 and would be interpreted as a test failure. The day 30 features would be interpreted only slightly better, as poor. Of the variables bleb height, extension and vascularization, vascularization had the highest accuracy. These findings match Picht et al.⁴⁴ who concluded an early vascularization indicates a poor prognosis with higher IOP at 12 months and may support use of anti-VEGF agents^45,46. The above reasons and recent reports of ab interno trabeculectomy results with a reduced complication rate, considerable range of glaucoma indications, and results that can rival traditional glaucoma surgery^47–55 suggest a conventional trabeculectomy with Mitomycin-C may be more appropriately used as a secondary procedure when microincisional surgical modalities are available or only be used in advanced glaucoma with a rather low IOP target.

In conclusion, we found that the IOP change during the first month, rather than the IOP at each visit, was a good predictor of failure. The bleb morphological features did not predict failure except for bleb vascularity which performed poorly to fairly. These finding highlight how important it is to carefully observe for IOP and bleb vascularity changes and to intervene swiftly if necessary.

Data availability

Dataset 1: Raw data collected from all study participants. DOI, 10.5256/f1000research.12904.d181288⁵⁶.

Competing interests

HE, MP, and MY have no financial disclosure. NAL has received honoraria for trabectome wet labs and lectures from Neomedix Corp.

Grant information

This study was funded in part by the Initiative to Cure Glaucoma, of the Eye and Ear Foundation of Pittsburgh, by the Ophthalmic Research Center of the Shahid Beheshti University of Medical Sciences, and by unrestricted grant from Research to Prevent Blindness, New York, NY.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Supplementary material

Supplementary Table 1: Intraocular pressure at each pre- and postoperative visit when success included IOPs below 5 mmHg without complications.

Click here to access the data.

F1000 recommended

References

1. Ramulu PY, Corcoran KJ, Corcoran SL, et al.: Utilization of various glaucoma surgeries and procedures in Medicare beneficiaries from 1995 to 2004. Ophthalmology. 2007; 114(12): 2265–2270.e1. PubMed Abstract | Publisher Full Text
2. Arora KS, Robin AL, Corcoran KJ, et al.: Use of Various Glaucoma Surgeries and Procedures in Medicare Beneficiaries from 1994 to 2012. Ophthalmology. 2015; 122(8): 1615–24. PubMed Abstract | Publisher Full Text
3. Dang Y, Waxman S, Wang C, et al.: Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery. Sci Rep. 2017; 7(1): 1605. PubMed Abstract | Publisher Full Text | Free Full Text
4. Fallano K, Bussel I, Kagemann L, et al.: Training strategies and outcomes of ab interno trabeculectomy with the trabectome [version 2; referees: 2 approved]. F1000Res. 2017; 6: 67. PubMed Abstract | Publisher Full Text | Free Full Text
5. Kaplowitz K, Bussel II, Honkanen R, et al.: Review and meta-analysis of ab-interno trabeculectomy outcomes. Br J Ophthalmol. 2016; 100(5): 594–600. PubMed Abstract | Publisher Full Text
6. Fraser SG, Wormald RP: Hospital Episode Statistics and changing trends in glaucoma surgery. Eye (Lond). 2008; 22(1): 3–7. PubMed Abstract | Publisher Full Text
7. Rachmiel R, Trope GE, Chipman ML, et al.: Laser trabeculoplasty trends with the introduction of new medical treatments and selective laser trabeculoplasty. J Glaucoma. 2006; 15(4): 306–9. PubMed Abstract | Publisher Full Text
8. International Monetary Fund, Research Dept: World Economic Outlook, October 2016: Subdued Demand: Symptoms and Remedies. International Monetary Fund. 2016; 288. Reference Source
9. UNDP: Human Development Report 2015. 2016. Reference Source
10. Anand A, Negi S, Khokhar S, et al.: Role of early trabeculectomy in primary open-angle glaucoma in the developing world. Eye (Lond). 2007; 21(1): 40–5. PubMed Abstract | Publisher Full Text
11. Thomas R, Sekhar GC, Kumar RS: Glaucoma management in developing countries: medical, laser, and surgical options for glaucoma management in countries with limited resources. Curr Opin Ophthalmol. 2004; 15(2): 127–31. PubMed Abstract | Publisher Full Text
12. Gedde SJ, Herndon LW, Brandt JD, et al.: Postoperative complications in the Tube Versus Trabeculectomy (TVT) study during five years of follow-up. Am J Ophthalmol. 2012; 153(5): 804–14.e1. PubMed Abstract | Publisher Full Text | Free Full Text
13. Kaplan RI, De Moraes CG, Cioffi GA, et al.: Comparative Cost-effectiveness of the Baerveldt Implant, Trabeculectomy With Mitomycin, and Medical Treatment. JAMA Ophthalmol. 2015; 133(5): 560–7. PubMed Abstract | Publisher Full Text
14. AGIS: The Advanced Glaucoma Intervention Study (AGIS): 4. Comparison of treatment outcomes within race. Seven-year results. Ophthalmology. 1998; 105(7): 1146–64. PubMed Abstract | Publisher Full Text
15. Landers J, Martin K, Sarkies N, et al.: A twenty-year follow-up study of trabeculectomy: risk factors and outcomes. Ophthalmology. 2012; 119(4): 694–702. PubMed Abstract | Publisher Full Text
16. Marquardt D, Lieb WE, Grehn F: Intensified postoperative care versus conventional follow-up: a retrospective long-term analysis of 177 trabeculectomies. Graefes Arch Clin Exp Ophthalmol. 2004; 242(2): 106–13. PubMed Abstract | Publisher Full Text
17. Kirwan JF, Lockwood AJ, Shah P, et al.: Trabeculectomy in the 21st century: a multicenter analysis. Ophthalmology. 2013; 120(12): 2532–9. PubMed Abstract | Publisher Full Text
18. Alwitry A, Moodie J, Rotchford A, et al.: Predictive value of early IOP in mitomycin-C augmented trabeculectomy. J Glaucoma. 2007; 16(7): 616–21. PubMed Abstract | Publisher Full Text
19. Rong SS, Feng MY, Wang N, et al.: Can early postoperative intraocular pressure predict success following mitomycin-C augmented trabeculectomy in primary angle-closure glaucoma. Eye (Lond). 2013; 27(3): 403–9. PubMed Abstract | Publisher Full Text | Free Full Text
20. Okimoto S, Kiuchi Y, Akita T, et al.: Using the early postoperative intraocular pressure to predict pressure control after a trabeculectomy. J Glaucoma. 2014; 23(6): 410–4. PubMed Abstract | Publisher Full Text
21. Rong SS, Meng HL, Fan SJ, et al.: Can intraoperative intraocular pressure during primary trabeculectomy predict early postoperative pressure? J Glaucoma. 2014; 23(9): 653–7. PubMed Abstract | Publisher Full Text
22. Wells AP, Ashraff NN, Hall RC, et al.: Comparison of two clinical Bleb grading systems. Ophthalmology. 2006; 113(1): 77–83. PubMed Abstract | Publisher Full Text
23. Cantor LB, Mantravadi A, WuDunn D, et al.: Morphologic classification of filtering blebs after glaucoma filtration surgery: the Indiana Bleb Appearance Grading Scale. J Glaucoma. 2003; 12(3): 266–71. PubMed Abstract | Publisher Full Text
24. Haahr M: RANDOM.ORG - True Random Number Service. [cited 2017 Feb 6]. Reference Source
25. Spaeth GL: Ophthalmic Surgery: Principles and Practice. Saunders; 1982; 775. Reference Source
26. Hanley JA, McNeil BJ: The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 1982; 143(1): 29–36. PubMed Abstract | Publisher Full Text
27. Grant WM: Further studies on facility of flow through the trabecular meshwork. AMA Arch Ophthalmol. 1958; 60(4 Part 1): 523–33. PubMed Abstract | Publisher Full Text
28. Saul Sugar H: Experimental Trabeculectomy in Glaucoma. Am J Ophthalmol. 1961; 51(4): 623–7. Publisher Full Text
29. Cairns JE: Trabeculectomy: Preliminary Report of a New Method. Am J Ophthalmol. 1968; 66(4): 673–9. PubMed Abstract | Publisher Full Text
30. Chen CW, Huang HT, Bair JS, et al.: Trabeculectomy with simultaneous topical application of mitomycin-C in refractory glaucoma. J Ocul Pharmacol. 1990; 6(3): 175–82. PubMed Abstract | Publisher Full Text
31. Aykan U, Bilge AH, Akin T, et al.: Laser suture lysis or releasable sutures after trabeculectomy. J Glaucoma. 2007; 16(2): 240–5. PubMed Abstract | Publisher Full Text
32. Liang YB, Feng MY, Meng HL, et al.: Early efficacy and complications of releasable sutures for trabeculectomy in primary angle-closure glaucoma: a randomized clinical trial. J Glaucoma. 2014; 23(3): 136–41. PubMed Abstract | Publisher Full Text
33. Edmunds B, Thompson JR, Salmon JF, et al.: The National Survey of Trabeculectomy. II. Variations in operative technique and outcome. Eye (Lond). 2001; 15(Pt 4): 441–8. PubMed Abstract | Publisher Full Text
34. Asamoto A, Yablonski ME, Matsushita M: Predicting long-term results of trabeculectomy from early postoperative intraocular pressure levels. Ophthalmic Surg Lasers. 1996; 27(5): 355–60. PubMed Abstract
35. Hara T, Araie M, Shirato S, et al.: Conditions for balance between lower normal pressure control and hypotony in mitomycin trabeculectomy. Graefes Arch Clin Exp Ophthalmol. 1998; 236(6): 420–5. PubMed Abstract | Publisher Full Text
36. Polikoff LA, Taglienti A, Chanis RA, et al.: Is intraocular pressure in the early postoperative period predictive of antimetabolite-augmented filtration surgery success? J Glaucoma. 2005; 14(6): 497–503. PubMed Abstract | Publisher Full Text
37. CAT-152 Trabeculectomy Study Group, Grehn F, Holló G, et al.: Factors affecting the outcome of trabeculectomy: an analysis based on combined data from two phase III studies of an antibody to transforming growth factor β₂, CAT-152. Ophthalmology. 2007; 114(10): 1831–1838.e4. PubMed Abstract | Publisher Full Text
38. Furrer S, Menke MN, Funk J, et al.: Evaluation of filtering blebs using the 'Wuerzburg bleb classification score' compared to clinical findings. BMC Ophthalmol. 2012; 12: 24. PubMed Abstract | Publisher Full Text | Free Full Text
39. Sacu S, Rainer G, Findl O, et al.: Correlation between the early morphological appearance of filtering blebs and outcome of trabeculectomy with mitomycin C. J Glaucoma. 2003; 12(5): 430–5. PubMed Abstract | Publisher Full Text
40. Wang JH, Thampatty BP, Lin JS, et al.: Mechanoregulation of gene expression in fibroblasts. Gene. 2007; 391(1–2): 1–15. PubMed Abstract | Publisher Full Text | Free Full Text
41. Chiquet M, Renedo AS, Huber F, et al.: How do fibroblasts translate mechanical signals into changes in extracellular matrix production? Matrix Biol. 2003; 22(1): 73–80. PubMed Abstract | Publisher Full Text
42. Anand N, Khan A: Long-term outcomes of needle revision of trabeculectomy blebs with Mitomycin C and 5-fluorouracil: a comparative safety and efficacy report. J Glaucoma. 2009; 18(7): 513–20. PubMed Abstract | Publisher Full Text
43. Broadway DC, Bloom PA, Bunce C, et al.: Needle revision of failing and failed trabeculectomy blebs with adjunctive 5-fluorouracil: survival analysis. Ophthalmology. 2004; 111(4): 665–73. PubMed Abstract | Publisher Full Text
44. Picht G, Grehn F: Classification of filtering blebs in trabeculectomy: biomicroscopy and functionality. Curr Opin Ophthalmol. 1998; 9(2): 2–8. PubMed Abstract | Publisher Full Text
45. Nilforushan N, Yadgari M, Kish SK, et al.: Subconjunctival bevacizumab versus Mitomycin C adjunctive to trabeculectomy. Am J Ophthalmol. 2012; 153(2): 352–7.e1. PubMed Abstract | Publisher Full Text
46. Kahook MY: Bleb morphology and vascularity after trabeculectomy with intravitreal ranibizumab: a pilot study. Am J Ophthalmol. 2010; 150(3): 399–403.e1. PubMed Abstract | Publisher Full Text
47. Roy P, Loewen RT, Dang Y, et al.: Stratification of phaco-trabectome surgery results using a glaucoma severity index in a retrospective analysis. BMC Ophthalmol. 2017; 17(1): 30. PubMed Abstract | Publisher Full Text | Free Full Text
48. Parikh HA, Bussel II, Schuman JS, et al.: Coarsened Exact Matching of Phaco-Trabectome to Trabectome in Phakic Patients: Lack of Additional Pressure Reduction from Phacoemulsification. PLoS One. 2016; 11(2): e0149384. PubMed Abstract | Publisher Full Text | Free Full Text
49. Neiweem AE, Bussel II, Schuman JS, et al.: Glaucoma Surgery Calculator: Limited Additive Effect of Phacoemulsification on Intraocular Pressure in Ab Interno Trabeculectomy. PLoS One. 2016; 11(4): e0153585. PubMed Abstract | Publisher Full Text | Free Full Text
50. Bussel II, Kaplowitz K, Schuman JS, et al.: Outcomes of ab interno trabeculectomy with the trabectome by degree of angle opening. Br J Ophthalmol. 2015; 99(7): 914–9. PubMed Abstract | Publisher Full Text | Free Full Text
51. Loewen RT, Roy P, Parikh HA, et al.: Impact of a Glaucoma Severity Index on Results of Trabectome Surgery: Larger Pressure Reduction in More Severe Glaucoma. PLoS One. 2016; 11(3): e0151926. PubMed Abstract | Publisher Full Text | Free Full Text
52. Akil H, Chopra V, Huang A, et al.: Clinical results of ab interno trabeculotomy using the Trabectome in patients with pigmentary glaucoma compared to primary open angle glaucoma. Clin Exp Ophthalmol. 2016; 44(7): 563–569. PubMed Abstract | Publisher Full Text
53. Dang Y, Kaplowitz K, Parikh HA, et al.: Steroid-induced glaucoma treated with trabecular ablation in a matched comparison with primary open-angle glaucoma. Clin Exp Ophthalmol. 2016; 44(9): 783–788. PubMed Abstract | Publisher Full Text
54. Dang Y, Roy P, Bussel II, et al.: Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity [version 2; referees: 3 approved]. F1000Res. 2016; 5: 762. PubMed Abstract | Publisher Full Text | Free Full Text
55. Wang C, Dang Y, Waxman S, et al.: Angle stability and outflow in excisional ab interno trabeculectomy with active versus passive chamber management. Peer J Preprints. 2017; 5: e2762v2. Publisher Full Text
56. Esfandiari H, Pakravan M, Loewen N, et al.: Dataset 1 in: Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy. F1000Research. 2017. Data Source

Comments on this article Comments (0)

Version 2

VERSION 2 PUBLISHED 27 Oct 2017

Author details Author details

Mohammad Pakravan
Roles: Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Supervision, Validation

Mehdi Yaseri
Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Resources, Software, Validation, Visualization, Writing – Original Draft Preparation

Competing interests

HE, MP, and MY have no financial disclosure. NAL has received honoraria for trabectome wet labs and lectures from Neomedix Corp.

Grant information

This study was funded in part by the Initiative to Cure Glaucoma, of the Eye and Ear Foundation of Pittsburgh, and by the Ophthalmic Research Center of the Shahid Beheshti University of Medical Sciences, and by unrestricted grant from Research to Prevent Blindness, New York, NY.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Article Versions (2)

version 2

Revised

Published: 19 Dec 2017, 6:1898

https://doi.org/10.12688/f1000research.12904.2

version 1

Published: 27 Oct 2017, 6:1898

https://doi.org/10.12688/f1000research.12904.1

© 2017 Esfandiari H et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).

Download

Export To

metrics

	Views	Downloads
F1000Research	-	-
PubMed Central Data from PMC are received and updated monthly.	-	-

Citations

SEE MORE DETAILS

CITE

how to cite this article

Esfandiari H, Pakravan M, Loewen NA and Yaseri M. Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy [version 2; peer review: 2 approved] F1000Research 2017, 6:1898 (https://doi.org/10.12688/f1000research.12904.2)

NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article.

track

receive updates on this article

Track an article to receive email alerts on any updates to this article.

Open Peer Review

Current Reviewer Status: ?

Key to Reviewer Statuses VIEW HIDE

ApprovedThe paper is scientifically sound in its current form and only minor, if any, improvements are suggested

Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit.

Not approvedFundamental flaws in the paper seriously undermine the findings and conclusions

Version 2

VERSION 2

PUBLISHED 19 Dec 2017

Revised

Views

Reviewer Report 27 Dec 2017

Frances Meier-Gibbons, Eye Center Rapperswil, Rapperswil, Switzerland

Approved

https://doi.org/10.5256/f1000research.14499.r29149

Thanks for the changes and addition, I ... Continue reading

CITE

Report a concern

Respond or Comment

Version 1

VERSION 1

PUBLISHED 27 Oct 2017

Views

Reviewer Report 28 Nov 2017

Frances Meier-Gibbons, Eye Center Rapperswil, Rapperswil, Switzerland

Approved with Reservations

https://doi.org/10.5256/f1000research.13988.r27865

The study is carefully done and the topic is interesting for clinicians.

Comments/remarks:

You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering

The study is carefully done and the topic is interesting for clinicians.

Comments/remarks:

You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
You state that you used postoperative needling with Mitomycine C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.

Is the work clearly and accurately presented and does it cite the current literature?

Yes
Is the study design appropriate and is the work technically sound?

Yes
Are sufficient details of methods and analysis provided to allow replication by others?

Yes
If applicable, is the statistical analysis and its interpretation appropriate?

Yes
Are all the source data underlying the results available to ensure full reproducibility?

Yes
Are the conclusions drawn adequately supported by the results?

Yes

Competing Interests: No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

CITE

Report a concern

Author Response 19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

19 Dec 2017

Author Response

The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in ... Continue reading The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
Authors: We very much appreciate the reviewer’s time and care reviewing our manuscript. Thank you for allowing us to clarify this point. We now state in Methods: "Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months."

2. You state that you used postoperative needling with Mitomycin C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
  Authors: Thank you for allowing us to clarify this point. We needled only highly vascularized and contracting blebs when the IOP was uncontrolled. We now state: "A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001)."

3. In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.
  Authors: This is a good point. We have modified the Conclusions in the Abstract based on the reviewer’s comments:
“Conclusions: The postoperative IOP on day 30 had a fair to good accuracy while the bleb features failed to predict a successful outcome except for bleb vascularity that predicted success with poor to fair accuracy. An IOP increase by as little as more than 3 mmHg during the first 30 days was a good predictor of failure. It is important to carefully observe for IOP changes and bleb vascularity to intervene if necessary.”
The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
Authors: We very much appreciate the reviewer’s time and care reviewing our manuscript. Thank you for allowing us to clarify this point. We now state in Methods: "Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months."

2. You state that you used postoperative needling with Mitomycin C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
  Authors: Thank you for allowing us to clarify this point. We needled only highly vascularized and contracting blebs when the IOP was uncontrolled. We now state: "A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001)."

3. In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.
  Authors: This is a good point. We have modified the Conclusions in the Abstract based on the reviewer’s comments:
“Conclusions: The postoperative IOP on day 30 had a fair to good accuracy while the bleb features failed to predict a successful outcome except for bleb vascularity that predicted success with poor to fair accuracy. An IOP increase by as little as more than 3 mmHg during the first 30 days was a good predictor of failure. It is important to carefully observe for IOP changes and bleb vascularity to intervene if necessary.”
Competing Interests: No competing interests were disclosed. Close
Report a concern
Respond or Comment

COMMENTS ON THIS REPORT

Author Response 19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

19 Dec 2017

Author Response

The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in ... Continue reading The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
Authors: We very much appreciate the reviewer’s time and care reviewing our manuscript. Thank you for allowing us to clarify this point. We now state in Methods: "Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months."

2. You state that you used postoperative needling with Mitomycin C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
  Authors: Thank you for allowing us to clarify this point. We needled only highly vascularized and contracting blebs when the IOP was uncontrolled. We now state: "A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001)."

3. In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.
  Authors: This is a good point. We have modified the Conclusions in the Abstract based on the reviewer’s comments:
“Conclusions: The postoperative IOP on day 30 had a fair to good accuracy while the bleb features failed to predict a successful outcome except for bleb vascularity that predicted success with poor to fair accuracy. An IOP increase by as little as more than 3 mmHg during the first 30 days was a good predictor of failure. It is important to carefully observe for IOP changes and bleb vascularity to intervene if necessary.”
The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
Authors: We very much appreciate the reviewer’s time and care reviewing our manuscript. Thank you for allowing us to clarify this point. We now state in Methods: "Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months."

2. You state that you used postoperative needling with Mitomycin C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
  Authors: Thank you for allowing us to clarify this point. We needled only highly vascularized and contracting blebs when the IOP was uncontrolled. We now state: "A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001)."

3. In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.
  Authors: This is a good point. We have modified the Conclusions in the Abstract based on the reviewer’s comments:
“Conclusions: The postoperative IOP on day 30 had a fair to good accuracy while the bleb features failed to predict a successful outcome except for bleb vascularity that predicted success with poor to fair accuracy. An IOP increase by as little as more than 3 mmHg during the first 30 days was a good predictor of failure. It is important to carefully observe for IOP changes and bleb vascularity to intervene if necessary.”
Competing Interests: No competing interests were disclosed. Close
Report a concern

Views

Reviewer Report 08 Nov 2017

Ding Lin, Aier School of Ophthalmology, Central South University, Changsha, China

Approved

https://doi.org/10.5256/f1000research.13988.r27402

This is a carefully done study containing interesting results which merit indexing. It is very useful and can provide a proof for ophthalmologist to decide how long the patient should be re-visit postoperation according to IOP change. For the benefit of the reader, however, a number of points need clarifying and certain statements require further justification. A few minor revisions are list below.

There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.

1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
There are some misunderstanding in the article.

2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.(Page 3).
The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.

Is the work clearly and accurately presented and does it cite the current literature?

Yes
Is the study design appropriate and is the work technically sound?

Yes
Are sufficient details of methods and analysis provided to allow replication by others?

Yes
If applicable, is the statistical analysis and its interpretation appropriate?

Yes
Are all the source data underlying the results available to ensure full reproducibility?

Yes
Are the conclusions drawn adequately supported by the results?

Yes

Competing Interests: No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

CITE

Report a concern

Author Response 19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

19 Dec 2017

Author Response

1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the ... Continue reading 1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.
Authors: We very much appreciate taking the time and effort to assess our manuscript. We are grateful for the many good suggestions.
There was indeed a discrepancy in the Results section. It should be week 1 in the table as we now write correctly. We have confirmed this in our source SPSS database file.

Regarding the P values in the abstract, we replaced >0.2 in the sentence:
“IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (all P≥0.2).“ with specific P values for each time point: “IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (P= 0.193, 0.639, and 0.238, respectively.)”

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
Authors: That is correct but there is no real contradiction. The reason for this is that we talk about that a change in IOP less than or equal to 3 can predict the success at month 12. In contrast, we talk about failure when a change of more than 3 mmHg was observed.

2. There are some misunderstanding in the article.
2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)
  Authors: Thank you for pointing this out. We changed the sentence "Age and gender were equally distributed" to "The mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911)".

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.
Authors: We apologize and have changed the sentence to state “The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures “to “The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures".

3. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.
Authors: We changed Methods to state: "In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during at the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs".
1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.
Authors: We very much appreciate taking the time and effort to assess our manuscript. We are grateful for the many good suggestions.
There was indeed a discrepancy in the Results section. It should be week 1 in the table as we now write correctly. We have confirmed this in our source SPSS database file.

Regarding the P values in the abstract, we replaced >0.2 in the sentence:
“IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (all P≥0.2).“ with specific P values for each time point: “IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (P= 0.193, 0.639, and 0.238, respectively.)”

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
Authors: That is correct but there is no real contradiction. The reason for this is that we talk about that a change in IOP less than or equal to 3 can predict the success at month 12. In contrast, we talk about failure when a change of more than 3 mmHg was observed.

2. There are some misunderstanding in the article.
2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)
  Authors: Thank you for pointing this out. We changed the sentence "Age and gender were equally distributed" to "The mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911)".

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.
Authors: We apologize and have changed the sentence to state “The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures “to “The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures".

3. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.
Authors: We changed Methods to state: "In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during at the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs".
Competing Interests: No competing interests were disclosed. Close
Report a concern
Respond or Comment

COMMENTS ON THIS REPORT

Author Response 19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

19 Dec 2017

Author Response

1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the ... Continue reading 1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.
Authors: We very much appreciate taking the time and effort to assess our manuscript. We are grateful for the many good suggestions.
There was indeed a discrepancy in the Results section. It should be week 1 in the table as we now write correctly. We have confirmed this in our source SPSS database file.

Regarding the P values in the abstract, we replaced >0.2 in the sentence:
“IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (all P≥0.2).“ with specific P values for each time point: “IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (P= 0.193, 0.639, and 0.238, respectively.)”

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
Authors: That is correct but there is no real contradiction. The reason for this is that we talk about that a change in IOP less than or equal to 3 can predict the success at month 12. In contrast, we talk about failure when a change of more than 3 mmHg was observed.

2. There are some misunderstanding in the article.
2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)
  Authors: Thank you for pointing this out. We changed the sentence "Age and gender were equally distributed" to "The mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911)".

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.
Authors: We apologize and have changed the sentence to state “The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures “to “The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures".

3. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.
Authors: We changed Methods to state: "In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during at the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs".
1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.
Authors: We very much appreciate taking the time and effort to assess our manuscript. We are grateful for the many good suggestions.
There was indeed a discrepancy in the Results section. It should be week 1 in the table as we now write correctly. We have confirmed this in our source SPSS database file.

Regarding the P values in the abstract, we replaced >0.2 in the sentence:
“IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (all P≥0.2).“ with specific P values for each time point: “IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (P= 0.193, 0.639, and 0.238, respectively.)”

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
Authors: That is correct but there is no real contradiction. The reason for this is that we talk about that a change in IOP less than or equal to 3 can predict the success at month 12. In contrast, we talk about failure when a change of more than 3 mmHg was observed.

2. There are some misunderstanding in the article.
2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)
  Authors: Thank you for pointing this out. We changed the sentence "Age and gender were equally distributed" to "The mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911)".

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.
Authors: We apologize and have changed the sentence to state “The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures “to “The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures".

3. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.
Authors: We changed Methods to state: "In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during at the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs".
Competing Interests: No competing interests were disclosed. Close
Report a concern

Comments on this article Comments (0)

Version 2

VERSION 2 PUBLISHED 27 Oct 2017

Open Peer Review

Reviewer Status

Reviewer Reports

	Invited Reviewers
	1	2
Version 2 (revision) 19 Dec 17		read
Version 1 27 Oct 17	read	read

Ding Lin, Central South University, Changsha, China
Frances Meier-Gibbons, Eye Center Rapperswil, Rapperswil, Switzerland

Comments on this article

All Comments(0)

Add a comment

Browse by related subjects

Back to all reports

Reviewer Report

5 Views

27 Dec 2017 | for Version 2

Frances Meier-Gibbons, Eye Center Rapperswil, Rapperswil, Switzerland

5 Views Cite this report Responses(0)

Approved

Thanks for the changes and addition, I approve the manuscript in the revised version.

Competing Interests

No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

Respond to this report

Responses (0)

Back to all reports

Reviewer Report

12 Views

28 Nov 2017 | for Version 1

Frances Meier-Gibbons, Eye Center Rapperswil, Rapperswil, Switzerland

12 Views Cite this report Responses(1)

Approved With Reservations

The study is carefully done and the topic is interesting for clinicians.

Comments/remarks:

You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
You state that you used postoperative needling with Mitomycine C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.

Is the work clearly and accurately presented and does it cite the current literature?

Yes
Is the study design appropriate and is the work technically sound?

Yes
Are sufficient details of methods and analysis provided to allow replication by others?

Yes
If applicable, is the statistical analysis and its interpretation appropriate?

Yes
Are all the source data underlying the results available to ensure full reproducibility?

Yes
Are the conclusions drawn adequately supported by the results?

Yes

Competing Interests

No competing interests were disclosed.

Respond to this report

Responses (1)

Author Response

19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

The study is carefully done and the topic is interesting for clinicians.
Comments/remarks:
1. You write the exact number of preoperative and postoperative medications the patients used. As there are differences in the IOP-lowering effects of the different types of these drugs, it would be interesting to see what type of IOP-lowering drugs the patients applied and if there was a difference in the type of drugs used pre- and postoperatively.
Authors: We very much appreciate the reviewer’s time and care reviewing our manuscript. Thank you for allowing us to clarify this point. We now state in Methods: "Before the surgery patients used glaucoma medications from all four major classes, including beta-blockers, prostaglandin analogous, alpha-2 agonists, and carbonic anhydrase inhibitors. Postoperatively, patients received the same drops that had proved effective and safe before surgery if the target IOP was not achieved. The only exception was prostaglandins analogous that we tried to avoid during the first three postoperative months."

2. You state that you used postoperative needling with Mitomycin C, but you do not clarify when exactly ("impending failure from a contracting bleb" is not specific). Please give a comment in which patients you used the needling and add also in how many patients a needling was necessary.
Authors: Thank you for allowing us to clarify this point. We needled only highly vascularized and contracting blebs when the IOP was uncontrolled. We now state: "A total of ten eyes (12.5%) underwent needling, including two eyes in the success group and eight eyes in the failure group (P=0.001)."

3. In the "Conclusions" of the abstract you state that "the bleb features failed to predict a successful outcome" while in the "Conclusions" at the end of the manuscript you say that an augmented vascularity in the bleb should be carefully observed. Please add this sentence in the "Conclusions" of the abstract.
Authors: This is a good point. We have modified the Conclusions in the Abstract based on the reviewer’s comments:
“Conclusions: The postoperative IOP on day 30 had a fair to good accuracy while the bleb features failed to predict a successful outcome except for bleb vascularity that predicted success with poor to fair accuracy. An IOP increase by as little as more than 3 mmHg during the first 30 days was a good predictor of failure. It is important to carefully observe for IOP changes and bleb vascularity to intervene if necessary.”

View more View less

Competing Interests

No competing interests were disclosed.

Back to all reports

Reviewer Report

10 Views

08 Nov 2017 | for Version 1

Ding Lin, Aier School of Ophthalmology, Central South University, Changsha, China

10 Views Cite this report Responses(1)

Approved

There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.

1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
There are some misunderstanding in the article.

2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.(Page 3).
The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.

Is the work clearly and accurately presented and does it cite the current literature?

Yes
Is the study design appropriate and is the work technically sound?

Yes
Are sufficient details of methods and analysis provided to allow replication by others?

Yes
If applicable, is the statistical analysis and its interpretation appropriate?

Yes
Are all the source data underlying the results available to ensure full reproducibility?

Yes
Are the conclusions drawn adequately supported by the results?

Yes

Competing Interests

No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

Respond to this report

Responses (1)

Author Response

19 Dec 2017

Nils Loewen, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

1. There are mistakes in the study results and we listed some examples in the following and you should revised it in your paper carefully and discreetly.
1.1 In the article, they describe that collect IOP outcomes on Day 7, but it was Week 2 in table 2. In the results part of Line 3 Page 1 (All P≥0.2), but it was 0.193 in day 1 in table 2.
Authors: We very much appreciate taking the time and effort to assess our manuscript. We are grateful for the many good suggestions.
There was indeed a discrepancy in the Results section. It should be week 1 in the table as we now write correctly. We have confirmed this in our source SPSS database file.

Regarding the P values in the abstract, we replaced >0.2 in the sentence:
“IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (all P≥0.2).“ with specific P values for each time point: “IOP of patients with a successful outcome did not differ from unsuccessful ones on day 1, 7 and 30 (P= 0.193, 0.639, and 0.238, respectively.)”

1.2 IOP change more than 3mmHg in Page 1, but it was less than or equal than 3 mmHg in Page 6.
Authors: That is correct but there is no real contradiction. The reason for this is that we talk about that a change in IOP less than or equal to 3 can predict the success at month 12. In contrast, we talk about failure when a change of more than 3 mmHg was observed.

2. There are some misunderstanding in the article.
2.1 The first sentence in the results of page 1. (Age and gender were equally distributed (62.3±13.1 years, P=0.911).)
Authors: Thank you for pointing this out. We changed the sentence "Age and gender were equally distributed" to "The mean age of the study participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911)".

2.2 The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures.
Authors: We apologize and have changed the sentence to state “The anterior chamber was formed by injection of BSS a paracentesis, and the filtration was titrated by adjusting the tension of the scleral flap sutures “to “The anterior chamber was formed by injection of BSS through a sideport, and the filtration was titrated by adjusting the tension of the scleral flap sutures".

3. The releasable sutures were removed as needed after 72 hours depending on bleb appearance to achieve IOPs near 10 mmHg. (Page 3, Marked in yellow and underline). In what time the releasable suture were removed for most of them (for example 7-10 days or something else for 70%(or ?%) patient), and you removed the two releasable suture for one time or two time respectively. If you removed the suture for two times, how much time will pass between them.
Authors: We changed Methods to state: "In most cases, the releasable sutures were removed within 4 weeks after the surgery. One removed first and if the IOP was not within the target range the other one was released during at the follow up one week later. Needling was done during the postoperative period for impending failure from highly vascularized and contracting blebs".

View more View less

Competing Interests

No competing interests were disclosed.

Alongside their report, reviewers assign a status to the article:

Approved - the paper is scientifically sound in its current form and only minor, if any, improvements are suggested

Approved with reservations - A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit.

Not approved - fundamental flaws in the paper seriously undermine the findings and conclusions

Click here to access the data.

Downloaded data do not display as expected? Download the data

[1] 1. Ramulu PY, Corcoran KJ, Corcoran SL, et al.: Utilization of various glaucoma surgeries and procedures in Medicare beneficiaries from 1995 to 2004. Ophthalmology. 2007; 114(12): 2265–2270.e1. PubMed Abstract | Publisher Full Text

[2] 2. Arora KS, Robin AL, Corcoran KJ, et al.: Use of Various Glaucoma Surgeries and Procedures in Medicare Beneficiaries from 1994 to 2012. Ophthalmology. 2015; 122(8): 1615–24. PubMed Abstract | Publisher Full Text

[3] 3. Dang Y, Waxman S, Wang C, et al.: Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery. Sci Rep. 2017; 7(1): 1605. PubMed Abstract | Publisher Full Text | Free Full Text

[4] 4. Fallano K, Bussel I, Kagemann L, et al.: Training strategies and outcomes of ab interno trabeculectomy with the trabectome [version 2; referees: 2 approved]. F1000Res. 2017; 6: 67. PubMed Abstract | Publisher Full Text | Free Full Text

[5] 5. Kaplowitz K, Bussel II, Honkanen R, et al.: Review and meta-analysis of ab-interno trabeculectomy outcomes. Br J Ophthalmol. 2016; 100(5): 594–600. PubMed Abstract | Publisher Full Text

[6] 6. Fraser SG, Wormald RP: Hospital Episode Statistics and changing trends in glaucoma surgery. Eye (Lond). 2008; 22(1): 3–7. PubMed Abstract | Publisher Full Text

[7] 7. Rachmiel R, Trope GE, Chipman ML, et al.: Laser trabeculoplasty trends with the introduction of new medical treatments and selective laser trabeculoplasty. J Glaucoma. 2006; 15(4): 306–9. PubMed Abstract | Publisher Full Text

[8] 8. International Monetary Fund, Research Dept: World Economic Outlook, October 2016: Subdued Demand: Symptoms and Remedies. International Monetary Fund. 2016; 288. Reference Source

[9] 9. UNDP: Human Development Report 2015. 2016. Reference Source

[10] 10. Anand A, Negi S, Khokhar S, et al.: Role of early trabeculectomy in primary open-angle glaucoma in the developing world. Eye (Lond). 2007; 21(1): 40–5. PubMed Abstract | Publisher Full Text

[11] 11. Thomas R, Sekhar GC, Kumar RS: Glaucoma management in developing countries: medical, laser, and surgical options for glaucoma management in countries with limited resources. Curr Opin Ophthalmol. 2004; 15(2): 127–31. PubMed Abstract | Publisher Full Text

[12] 12. Gedde SJ, Herndon LW, Brandt JD, et al.: Postoperative complications in the Tube Versus Trabeculectomy (TVT) study during five years of follow-up. Am J Ophthalmol. 2012; 153(5): 804–14.e1. PubMed Abstract | Publisher Full Text | Free Full Text

[13] 13. Kaplan RI, De Moraes CG, Cioffi GA, et al.: Comparative Cost-effectiveness of the Baerveldt Implant, Trabeculectomy With Mitomycin, and Medical Treatment. JAMA Ophthalmol. 2015; 133(5): 560–7. PubMed Abstract | Publisher Full Text

[14] 14. AGIS: The Advanced Glaucoma Intervention Study (AGIS): 4. Comparison of treatment outcomes within race. Seven-year results. Ophthalmology. 1998; 105(7): 1146–64. PubMed Abstract | Publisher Full Text

[15] 15. Landers J, Martin K, Sarkies N, et al.: A twenty-year follow-up study of trabeculectomy: risk factors and outcomes. Ophthalmology. 2012; 119(4): 694–702. PubMed Abstract | Publisher Full Text

[16] 16. Marquardt D, Lieb WE, Grehn F: Intensified postoperative care versus conventional follow-up: a retrospective long-term analysis of 177 trabeculectomies. Graefes Arch Clin Exp Ophthalmol. 2004; 242(2): 106–13. PubMed Abstract | Publisher Full Text

[17] 17. Kirwan JF, Lockwood AJ, Shah P, et al.: Trabeculectomy in the 21st century: a multicenter analysis. Ophthalmology. 2013; 120(12): 2532–9. PubMed Abstract | Publisher Full Text

[18] 18. Alwitry A, Moodie J, Rotchford A, et al.: Predictive value of early IOP in mitomycin-C augmented trabeculectomy. J Glaucoma. 2007; 16(7): 616–21. PubMed Abstract | Publisher Full Text

[19] 19. Rong SS, Feng MY, Wang N, et al.: Can early postoperative intraocular pressure predict success following mitomycin-C augmented trabeculectomy in primary angle-closure glaucoma. Eye (Lond). 2013; 27(3): 403–9. PubMed Abstract | Publisher Full Text | Free Full Text

[20] 20. Okimoto S, Kiuchi Y, Akita T, et al.: Using the early postoperative intraocular pressure to predict pressure control after a trabeculectomy. J Glaucoma. 2014; 23(6): 410–4. PubMed Abstract | Publisher Full Text

[21] 21. Rong SS, Meng HL, Fan SJ, et al.: Can intraoperative intraocular pressure during primary trabeculectomy predict early postoperative pressure? J Glaucoma. 2014; 23(9): 653–7. PubMed Abstract | Publisher Full Text

[22] 22. Wells AP, Ashraff NN, Hall RC, et al.: Comparison of two clinical Bleb grading systems. Ophthalmology. 2006; 113(1): 77–83. PubMed Abstract | Publisher Full Text

[23] 23. Cantor LB, Mantravadi A, WuDunn D, et al.: Morphologic classification of filtering blebs after glaucoma filtration surgery: the Indiana Bleb Appearance Grading Scale. J Glaucoma. 2003; 12(3): 266–71. PubMed Abstract | Publisher Full Text

[24] 24. Haahr M: RANDOM.ORG - True Random Number Service. [cited 2017 Feb 6]. Reference Source

[25] 25. Spaeth GL: Ophthalmic Surgery: Principles and Practice. Saunders; 1982; 775. Reference Source

[26] 26. Hanley JA, McNeil BJ: The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 1982; 143(1): 29–36. PubMed Abstract | Publisher Full Text

[27] 27. Grant WM: Further studies on facility of flow through the trabecular meshwork. AMA Arch Ophthalmol. 1958; 60(4 Part 1): 523–33. PubMed Abstract | Publisher Full Text

[28] 28. Saul Sugar H: Experimental Trabeculectomy in Glaucoma. Am J Ophthalmol. 1961; 51(4): 623–7. Publisher Full Text

[29] 29. Cairns JE: Trabeculectomy: Preliminary Report of a New Method. Am J Ophthalmol. 1968; 66(4): 673–9. PubMed Abstract | Publisher Full Text

[30] 30. Chen CW, Huang HT, Bair JS, et al.: Trabeculectomy with simultaneous topical application of mitomycin-C in refractory glaucoma. J Ocul Pharmacol. 1990; 6(3): 175–82. PubMed Abstract | Publisher Full Text

[31] 31. Aykan U, Bilge AH, Akin T, et al.: Laser suture lysis or releasable sutures after trabeculectomy. J Glaucoma. 2007; 16(2): 240–5. PubMed Abstract | Publisher Full Text

[32] 32. Liang YB, Feng MY, Meng HL, et al.: Early efficacy and complications of releasable sutures for trabeculectomy in primary angle-closure glaucoma: a randomized clinical trial. J Glaucoma. 2014; 23(3): 136–41. PubMed Abstract | Publisher Full Text

[33] 33. Edmunds B, Thompson JR, Salmon JF, et al.: The National Survey of Trabeculectomy. II. Variations in operative technique and outcome. Eye (Lond). 2001; 15(Pt 4): 441–8. PubMed Abstract | Publisher Full Text

[34] 34. Asamoto A, Yablonski ME, Matsushita M: Predicting long-term results of trabeculectomy from early postoperative intraocular pressure levels. Ophthalmic Surg Lasers. 1996; 27(5): 355–60. PubMed Abstract

[35] 35. Hara T, Araie M, Shirato S, et al.: Conditions for balance between lower normal pressure control and hypotony in mitomycin trabeculectomy. Graefes Arch Clin Exp Ophthalmol. 1998; 236(6): 420–5. PubMed Abstract | Publisher Full Text

[36] 36. Polikoff LA, Taglienti A, Chanis RA, et al.: Is intraocular pressure in the early postoperative period predictive of antimetabolite-augmented filtration surgery success? J Glaucoma. 2005; 14(6): 497–503. PubMed Abstract | Publisher Full Text

[37] 37. CAT-152 Trabeculectomy Study Group, Grehn F, Holló G, et al.: Factors affecting the outcome of trabeculectomy: an analysis based on combined data from two phase III studies of an antibody to transforming growth factor β₂, CAT-152. Ophthalmology. 2007; 114(10): 1831–1838.e4. PubMed Abstract | Publisher Full Text

[38] 38. Furrer S, Menke MN, Funk J, et al.: Evaluation of filtering blebs using the 'Wuerzburg bleb classification score' compared to clinical findings. BMC Ophthalmol. 2012; 12: 24. PubMed Abstract | Publisher Full Text | Free Full Text

[39] 39. Sacu S, Rainer G, Findl O, et al.: Correlation between the early morphological appearance of filtering blebs and outcome of trabeculectomy with mitomycin C. J Glaucoma. 2003; 12(5): 430–5. PubMed Abstract | Publisher Full Text

[40] 40. Wang JH, Thampatty BP, Lin JS, et al.: Mechanoregulation of gene expression in fibroblasts. Gene. 2007; 391(1–2): 1–15. PubMed Abstract | Publisher Full Text | Free Full Text

[41] 41. Chiquet M, Renedo AS, Huber F, et al.: How do fibroblasts translate mechanical signals into changes in extracellular matrix production? Matrix Biol. 2003; 22(1): 73–80. PubMed Abstract | Publisher Full Text

[42] 42. Anand N, Khan A: Long-term outcomes of needle revision of trabeculectomy blebs with Mitomycin C and 5-fluorouracil: a comparative safety and efficacy report. J Glaucoma. 2009; 18(7): 513–20. PubMed Abstract | Publisher Full Text

[43] 43. Broadway DC, Bloom PA, Bunce C, et al.: Needle revision of failing and failed trabeculectomy blebs with adjunctive 5-fluorouracil: survival analysis. Ophthalmology. 2004; 111(4): 665–73. PubMed Abstract | Publisher Full Text

[44] 44. Picht G, Grehn F: Classification of filtering blebs in trabeculectomy: biomicroscopy and functionality. Curr Opin Ophthalmol. 1998; 9(2): 2–8. PubMed Abstract | Publisher Full Text

[45] 45. Nilforushan N, Yadgari M, Kish SK, et al.: Subconjunctival bevacizumab versus Mitomycin C adjunctive to trabeculectomy. Am J Ophthalmol. 2012; 153(2): 352–7.e1. PubMed Abstract | Publisher Full Text

[46] 46. Kahook MY: Bleb morphology and vascularity after trabeculectomy with intravitreal ranibizumab: a pilot study. Am J Ophthalmol. 2010; 150(3): 399–403.e1. PubMed Abstract | Publisher Full Text

[47] 47. Roy P, Loewen RT, Dang Y, et al.: Stratification of phaco-trabectome surgery results using a glaucoma severity index in a retrospective analysis. BMC Ophthalmol. 2017; 17(1): 30. PubMed Abstract | Publisher Full Text | Free Full Text

[48] 48. Parikh HA, Bussel II, Schuman JS, et al.: Coarsened Exact Matching of Phaco-Trabectome to Trabectome in Phakic Patients: Lack of Additional Pressure Reduction from Phacoemulsification. PLoS One. 2016; 11(2): e0149384. PubMed Abstract | Publisher Full Text | Free Full Text

[49] 49. Neiweem AE, Bussel II, Schuman JS, et al.: Glaucoma Surgery Calculator: Limited Additive Effect of Phacoemulsification on Intraocular Pressure in Ab Interno Trabeculectomy. PLoS One. 2016; 11(4): e0153585. PubMed Abstract | Publisher Full Text | Free Full Text

[50] 50. Bussel II, Kaplowitz K, Schuman JS, et al.: Outcomes of ab interno trabeculectomy with the trabectome by degree of angle opening. Br J Ophthalmol. 2015; 99(7): 914–9. PubMed Abstract | Publisher Full Text | Free Full Text

[51] 51. Loewen RT, Roy P, Parikh HA, et al.: Impact of a Glaucoma Severity Index on Results of Trabectome Surgery: Larger Pressure Reduction in More Severe Glaucoma. PLoS One. 2016; 11(3): e0151926. PubMed Abstract | Publisher Full Text | Free Full Text

[52] 52. Akil H, Chopra V, Huang A, et al.: Clinical results of ab interno trabeculotomy using the Trabectome in patients with pigmentary glaucoma compared to primary open angle glaucoma. Clin Exp Ophthalmol. 2016; 44(7): 563–569. PubMed Abstract | Publisher Full Text

[53] 53. Dang Y, Kaplowitz K, Parikh HA, et al.: Steroid-induced glaucoma treated with trabecular ablation in a matched comparison with primary open-angle glaucoma. Clin Exp Ophthalmol. 2016; 44(9): 783–788. PubMed Abstract | Publisher Full Text

[54] 54. Dang Y, Roy P, Bussel II, et al.: Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity [version 2; referees: 3 approved]. F1000Res. 2016; 5: 762. PubMed Abstract | Publisher Full Text | Free Full Text

[55] 55. Wang C, Dang Y, Waxman S, et al.: Angle stability and outflow in excisional ab interno trabeculectomy with active versus passive chamber management. Peer J Preprints. 2017; 5: e2762v2. Publisher Full Text

[56] 56. Esfandiari H, Pakravan M, Loewen N, et al.: Dataset 1 in: Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy. F1000Research. 2017. Data Source

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Abstract

Keywords

Revised Amendments from Version 1

Introduction

Methods

Study design

Surgical technique and postoperative management

Statistical analysis

Results

Table 1. Baseline characteristics of participants (mean±SD, median (range)).

Table 2. Intraocular pressure at each pre- and postoperative visit.

Table 3. List of postoperative interventions and complications.

Table 4. Bleb morphologic characteristics at each postoperative visit.

Discussion

Data availability

Competing interests

Grant information

Supplementary material

References

Comments on this article Comments (0)

Open Peer Review

Comments on this article Comments (0)

Open Peer Review

Reviewer Status

Reviewer Reports

Comments on this article

Browse by related subjects

The problem

How to fix it

Competing Interests Policy

Stay Updated