Original Article
Corneal collagen cross-linking using riboflavin and ultraviolet A for the treatment of mild to moderate keratoconus: 2-year follow-up

https://doi.org/10.1016/j.jcjo.2012.11.007Get rights and content

Abstract

Objective

To evaluate the safety and efficacy of corneal ultraviolet A/riboflavin collagen cross-linking (CXL) in patients with mild-to-moderate keratoconus.

Participants

Thirty-nine eyes from 30 patients who underwent CXL for progressive mild and moderate keratoconus were included.

Methods

Clinical charts for keratoconus patients who had undergone CXL alone from November 2008 to February 2011 were reviewed for preoperative and postoperative uncorrected and best corrected distance visual acuity (UDVA and BDVA, respectively), manifest refraction, topographical and Scheimpflug imaging, as well as ultrasound pachymetry and haze. Mean and steepest keratometry, central corneal thickness, and root mean-square from corneal aberrations were extracted from the topography. Central and thinnest corneal thicknesses were extracted from the Scheimpflug imaging

Results

A significant improvement in UDVA was seen at 3, 6 and 24 months with an average change in logMAR of 0.39 (p = 0.003) at 24 months compared with baseline. Change in BDVA failed to reach significance, but subgroup analysis showed that a baseline BDVA worse than 0.1 logMAR was associated with better improvement. Stability of refraction, keratometry, and aberrations was demonstrated. Presence of haze was statistically significant up to 12 months (p≤0.001), being maximal at 3 months, then insignificant by 24 months. No complications were observed during the follow-up period.

Conclusions

CXL is a safe and effective stabilizing strategy for progressive mild-to-moderate keratoconus with significant improvement of the UDVA. There was a trend toward improvement of BDVA in patients with lower preoperative BDVA value.

Résumé

Objet

Évaluation de la sécurité et de l'efficacité de la réticulation du collagène cornéen (RCC) à la riboflavine et aux rayons ultraviolet A chez les patients qui ont un kératocône doux à modéré.

Nature

Étude rétrospective de cohorte.

Participants

Trente-neuf yeux de 30 patients ayant reçu une RCC pour kératocône progressif doux à modéré.

Méthodes

Les dossiers cliniques de patients qui, atteints de kératocône, avaient subi une RCC seule entre les mois de novembre 2008 et février 2011 ont été passés en revue. L'on en a extrait les données concernant l'acuité visuelle à distance, préopératoire et postopératoire, non corrigée et corrigée au mieux (AVDNC et AVDCM), la réfraction manifeste, l'imagerie topographique et de Scheimpflug ainsi que la pachymétrie à l'ultrason et le voile (haze). La kératométrie (K) moyenne ainsi que la plus prononcée, l'épaisseur du centre de la cornée (ÉCC) et la valeur quadratique moyenne (VQM) des aberrations cornéennes ont été extraites de la topographie. L'ÉCC et la plus faible épaisseur cornéenne (FÉC) ont été extraites de l'imagerie de Scheimpflug.

Résultats

L'on a noté une importante amélioration de l'AVDNC après 3, 6 et 24 mois avec une moyenne de changement de 0,39 (p = 0,003) à l'échelle logMar après 24 mois, comparativement aux données de base. Le changement de l'AVDCM n'a pas été significatif, mais l'analyse du sous-groupe a démontré qu'une AVDCM de base inférieure à 0,1 logMar était associée à une meilleure amélioration. La stabilité de la réfraction, la kératométrie et les aberrations étaient démontrées. La présence du voile était statistiquement significative jusqu'à 12 mois (P ≤.001); elle était maximale à 3 mois et insignifiante à 24 mois. Aucune complication n'est apparue pendant la période de suivi.

Conclusions

La RCC est une stratégie sure et efficace de stabilisation, de progression douce à modérée du kératocône avec une amélioration significative de l'AVDNC. Il y avait une tendance vers l'amélioration de l'AVDCM chez les patients qui avaient une plus faible valeur préopératoire d'AVDCM.

Section snippets

Study design

This study reviewed the charts of all consecutive patients undergoing CXL surgery alone performed between November 2008 and February 2011 at the Yonge-Eglinton Laser Center. The patients included in the study had mild-to-moderate keratoconus defined as grade I and II of the Amsler–Krumeich classification with Snellen best corrected distance visual acuity (BDVA) of 20/80 (logMAR 0.6) or better. The inclusion criteria for progressive keratoconus were defined as a newly developed contact lens

Results

Thirty-nine keratoconic eyes from 30 patients who underwent CXL were included in this study. Patients with both eyes treated with CXL had each eye considered independent. The group consisted of 22 males (73%) and 8 females (27%) with a mean age of 26.8±10.3 years (SD), ranging from 15 to 56 years. Only 5 patients (16.7%) were older than 35 years. The average follow-up was 15.8 months, with 17 eyes (43.6%) having completed 24 months. The preoperative data are summarized in Table 1.

Discussion

In this study, we assessed safety and efficacy of CXL for progressing mild-to-moderate keratoconus. No complications were seen during the entire follow-up period.19, 20 Despite previous results in the literature suggesting to restrict CXL to patients younger than 35 years,19 we included older patients provided that their decrease in vision was attributable to progression of the ectasia. This small subgroup of older patients did not evolve differently than the younger ones.

Although a recent

Disclosure

The authors have no proprietary or commercial interest in any materials discussed in this article.

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