Photorefractive Keratectomy Followed by Cross-linking Versus Cross-linking Alone for Management of Progressive Keratoconus: Two-Year Follow-up

doi:10.1016/j.ajo.2012.07.004

American Journal of Ophthalmology

Volume 155, Issue 1, January 2013, Pages 54-65.e1

https://doi.org/10.1016/j.ajo.2012.07.004 Get rights and content

Purpose

To compare visual, refractive, topographic, and corneal higher-order aberration outcome at the 2-year follow-up after customized photorefractive keratectomy (PRK) followed by cross-linking (CXL) as a single procedure versus CXL alone in eyes with progressive keratoconus.

Design

Prospective, interventional, nonrandomized clinical trial.

Methods

Seventeen patients (34 eyes) with progressive keratoconus were assigned to 2 groups: the worse eye (17 eyes) was assigned to the PRK plus CXL group and the better eye (17 fellow eyes) was assigned to the CXL group.

Results

In the PRK plus CXL group, uncorrected distance acuity improved significantly, from a mean ± standard deviation of 0.63 ± 0.36 logarithm of the minimal angle of resolution (logMAR) units to 0.19 ± 0.17 logMAR units (P < .05) and best distance acuity from 0.06 ± 0.08 logMAR to 0.03 ± 0.06 logMAR (P < .05). Manifest refraction spherical equivalent and spherical and cylindrical power improved significantly (P < .05). Simulated keratometry, flattest, steepest, average, cylindrical, apex keratometry, and inferior–superior value decreased significantly (P < .05). Total and coma-like aberrations significantly decreased for all pupil diameters (P < .05). In the CXL group, uncorrected distance acuity improved, but not significantly, from 0.59 ± 0.29 logMAR units to 0.52 ± 0.29 logMAR units, and best distance acuity improved from 0.06 ± 0.11 logMAR units to 0.04 ± 0.07 logMAR units (P > .05). Manifest refraction spherical equivalent and cylindrical power improvement was not significant (P > .05), unlike spherical power (P < .05). Steepest simulated keratometry, average simulated keratometry, and inferior–superior value significantly decreased (P < .05), unlike flattest simulated keratometry, cylindrical simulated keratometry, and apex keratometry (P > .05). Total and coma-like aberrations were not decreased significantly for all pupil diameters (P > .05). No significant endothelial changes were observed in either group.

Conclusions

The PRK plus CXL procedure may be a good option to reduce corneal aberrations and stabilize corneas with progressive keratoconus.

Section snippets

Methods

Seventeen patients (4 women and 13 men) with progressive keratoconus in both eyes were enrolled in this study. Mean age was 31.17 ± 8.12 years (range, 21 to 46 years). Inclusion criteria were a documented progression of keratoconus in the previous 12 months, a corneal thickness of at least 450 μm at the thinnest point in the worse eye, hard contact lens and full spectacle correction intolerance because of blurred or distorted vision or subjective perception of comet-like asymmetric starbursts,

Visual Acuity and Refractive Outcome

Table 1 summarizes preoperative and postoperative visual and refractive data for both groups: PRK plus CXL and CXL alone. UDA and BDA changes over time are shown in Figures 1 and 2. In the PRK plus CXL group, the eyes with UDA of 20/40 or better increased from 3 (17.6%) before surgery to 14 (82.3%) at the last follow-up examination; in the CXL only group, the eyes with UDA of 20/40 or better were 3 (17.6%) before surgery, and these remained unchanged at the last postoperative visit.

The

Discussion

This prospective study investigated the visual acuity, refractive, topographic, and HOA outcomes of the PRK plus CXL procedure performed using the iVIS suite platform compared with the CXL only procedure in eyes diagnosed with progressive keratoconus over a follow-up of 24 months. Although the goal of the PRK plus CXL procedure was not emmetropia, the results showed that at the last postoperative examination, the PRK plus CXL procedure provided better UDA, lower manifest refraction spherical

Giovanni Alessio, MD, is an Associate Professor of Ophthalmology in the Department of Ophthalmology and Otorhinolaryngology at University of Bari, Italy. His research focuses on refractive surgery, external eye diseases. His clinical and surgical practice include cataract surgery and corneal transplantations.

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Cited by (68)

Efficacy comparison of combining cross-linking and refractive laser ablation in progressive keratoconus: systematic review and meta-analysis
2024, Canadian Journal of Ophthalmology
This study assessed the effect of combining corneal collagen cross-linking (CXL) with refractive laser ablation techniques for the treatment of keratoconus, a progressive corneal disorder.
We performed a systematic review and meta-analysis to assess the effect of combined CXL and refractive techniques. We included all published clinical trials or observational studies published by September 1, 2023. We calculated and compared the standardized mean difference (SMD) between CXL alone and CXL plus laser ablation for uncorrected distance visual acuity, best-corrected distance visual acuity, spherical equivalent manifest refraction, sphere and cylinder, flat keratometry (K₁), steep keratometry (K₂), and central corneal thickness.
We identified 13 studies that fulfilled our inclusion and exclusion criteria. The average follow-up was 21.3 ± 11.8 months. The CXL plus laser ablation group showed improvement in uncorrected distance visual acuity logMAR (SMD, –0.35; 95% CI, –0.67 to –0.04; p = 0.029), best-corrected distance visual acuity logMAR (SMD, –0.17; 95% CI, –0.30 to –0.03; p = 0.014), spherical equivalent manifest refraction (SMD, –0.28; 95% CI, 0.06–0.50; p = 0.013), and change in maximal corneal curvature (K_max; SMD, –0.41; 95% CI, –0.69 to –0.13; p = 0.004) compared with CXL alone. However, central corneal thickness decreased further among patients who underwent CXL plus laser ablation (SMD, –0.37; 95% CI, –0.66 to –0.07; p = 0.016). No effect was observed in terms of sphere (p = 0.878), cylinder (p = 0.859), K₁ (p = 0.907), or K₂ (p = 0.169). Ectasia was not observed as an adverse effect resulting from the additional corneal ablation performed during the CXL treatments.
This study showed that combining refractive laser ablation techniques with standard or accelerated CXL treatment improved visual and refractive outcomes and anterior corneal curvature values.
Excimer laser in keratoconus management
2021, Journal Francais d'Ophtalmologie
La réhabilitation visuelle du kératocône est un défi, notamment en raison de l’important astigmatisme irrégulier et des aberrations optiques qu’il induit. De nombreuses techniques chirurgicales ont été développées en complément ou en cas d’échec des verres correcteurs et lentilles rigides perméables au gaz : anneaux intracornéens, implants intraoculaires, laser excimer et en dernier recours, greffe de cornée. Le laser excimer est un outil de photoablation, permettant de remodeler la surface cornéenne. Il existe différents modes de traitements (photoablation asphérique, aberroguidée et topoguidée) permettant de réaliser un traitement personnalisé si besoin. Son utilisation dans le kératocône a été décrite depuis les années 2000, seul ou en association avec d’autres procédures. Ainsi, l’association de la photoablation au « cross linking », technique permettant de rigidifier la cornée et donc de ralentir, voire de stopper l’évolution du kératocône, a montré son efficacité et sa sécurité dans de nombreuses études et plusieurs protocoles ont été décrits. Une triple procédure, associant anneaux intracornéens, laser excimer et « cross linking » a également donné des résultats très prometteurs dans les kératocônes évolutifs, permettant une amélioration significative de l’acuité visuelle et des données topographiques. L’association du laser excimer aux implants intraoculaires reste une piste encore peu explorée, qui permettra peut-être d’obtenir des résultats satisfaisants. L’objectif de cette revue est de synthétiser les données récentes de la littérature sur l’utilisation du laser excimer dans la prise en charge du kératocône.
Visual rehabilitation in keratoconus is a challenge, notably because of the significant irregular astigmatism and optical aberrations that it induces. Many surgical techniques have been developed in addition to, or in the case of failure of, spectacles and rigid gas permeable contact lenses: intracorneal ring segments, intraocular lenses, excimer laser and, as a last resort, keratoplasty. Excimer laser photoablates the cornea, allowing remodeling of its surface. There are various treatment modes (wavefront-optimized, wavefront-guided and topography-guided), allowing performance of a customized treatment if needed. Its use in keratoconus has been described since the 2000s, alone or in combination with other procedures. For example, the combination of photoablation and corneal cross linking, a technique that increases corneal rigidity and in so doing can slow or even stop the progression of keratoconus, proved its efficacy and safety in many studies, and various protocols have been described. A triple procedure, including intracorneal ring segments, excimer laser and cross linking, has also given some very promising results in progressive keratoconus, providing a significative improvement in visual acuity and topographic data. The combination of excimer laser and intraocular lenses remains a poorly explored lead that might provide some satisfactory results. The objective of this review is to summarize the recent data on excimer laser in keratoconus management.
Topography-guided excimer laser ablation in refractive surgery
2024, Frontiers in Ophthalmology
Keratoconus: A historical and prospective review
2023, Oman Journal of Ophthalmology
Outcomes of topography.guided PRK/CXL in keratoconus using the NIDEK CXIII system. hBharat Protocol h (Pilot study)
2023, Indian Journal of Ophthalmology
Three-years outcomes of simultaneous photorefractive surgery and customized corneal cross-linking for keratoconus
2023, International Ophthalmology

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Original articlePhotorefractive Keratectomy Followed by Cross-linking Versus Cross-linking Alone for Management of Progressive Keratoconus: Two-Year Follow-up

Purpose

Design

Methods

Results

Conclusions

Section snippets

Methods

Visual Acuity and Refractive Outcome

Discussion

J Cataract Refract Surg

Surv Ophthalmol

Ophthalmology

Ophthalmology

Am J Ophthalmol

J Cataract Refract Surg

Ophthalmology

Am J Ophthalmol

Am J Ophthalmol

J Cataract Refract Surg

J Cataract Refract Surg

Corneal collagen cross-linking for ectasia after excimer laser refractive surgery: 1-year results

J Refract Surg

Ultraviolet A/riboflavin corneal cross-linking for infectious keratitis associated with corneal melts

Cornea

UV-A collagen cross-linking treatment of bullous keratopathy combined with corneal ulcer

Cornea

Original article
Photorefractive Keratectomy Followed by Cross-linking Versus Cross-linking Alone for Management of Progressive Keratoconus: Two-Year Follow-up