Corneal Cross-Linking for Keratoconus and Post-LASIK Ectasia and Failure Rate: A 3 Years Follow-Up Study.

Wassef Chanbour,Elias Chelala,Lulwa El Zein,Mohamad Issa,Mohamad Ali Younes,Elias Jarade,Pramod Warhekar

doi:10.7759/cureus.19552

Abstract

PurposeTo report the response of keratoconus (KC) and post-LASIK ectasia (referred to as “ectasia”) to the corneal crosslinking (CXL) and to compare the rate of progression between KC and ectasia at three years.MethodsA retrospective cohort study of patients undergoing CXL for either KC or ectasia. Fifty-four eyes (31 patients) with ectasia and 111 eyes (67 patients) with KC were included in the study. Corrected distance visual acuities (CDVA), refraction, keratometry (K), and pachymetry were followed up for three years. Simultaneous photorefractive keratectomy (PRK) and CXL were performed on 20 KC and 20 ectasia eyes. Intrastromal Corneal Ring Segments (ICRS) were performed on 51 KC and six ectasia eyes.ResultsIn KC, CDVA, spherical equivalence, sphere, cylinder, and mean K improved at three years post-CXL (p-value<0.05), but these values improved without reaching a statistical significance in ectasia(p-values <0.05). 12 of 54 eyes with ectasia (22.2%) and 4 of 111 eyes (3.6%) with KC had progression post CXL(p-value:0.0001). Ectasia patients diagnosed with progression were older at presentation (36.1 years) than non-progressive ectasia patients (31 years) (p-value 0.02) and also older than KC patients.Sub-analysis excluding PRK and ICRS cases showed that there was an improvement in mean sphere (from -5.23±4.2D to-4.46±3.89D) (p-value 0.03) cylinder (from 2.54 ± 1.68D to 1.97 ± 1.51D) (p-value 0.03) mean keratometry (from 46.81 ± 3.78D to 46.01 ± 3.25D) (p-value 0.006) in KC patients 3 years post CXL (40 patients). Compared to baseline, all the mean refractive and topographic variables deteriorated at three years post CXL in ectasia (28 patients) (p-value>0.05). Also, 2 of 40 patients with KC (5%) vs. 7 of 28 patients with ectasia (25%) had progression three years post-CXL, and the difference between both groups remained statistically significant(p-value 0.027).ConclusionEyes with post-LASIK ectasia seem to be less responsive to CXL than KC.

Highlights

Keratectasias are progressive, non-inflammatory corneal diseases defined by thinning, bulging, and distortion of the cornea leading to irregular astigmatism and reduction in vision [1]
In KC, Corrected distance visual acuities (CDVA), spherical equivalence, sphere, cylinder, and mean K improved at three years post-CXL, but these values improved without reaching a statistical significance in ectasia(p-values
Sub-analysis excluding photorefractive keratectomy (PRK) and Intrastromal Corneal Ring Segments (ICRS) cases showed that there was an improvement in mean sphere (p-value 0.03) cylinder (p-value 0.03) mean keratometry (p-value 0.006) in KC patients 3 years post CXL (40 patients)

Summary

Introduction

Keratectasias are progressive, non-inflammatory corneal diseases defined by thinning, bulging, and distortion of the cornea leading to irregular astigmatism and reduction in vision [1]. Progressive disease is treated with corneal crosslinking (CXL) to stabilize the cornea, while end-stage cases are treated with penetrating or deep anterior lamellar keratoplasty. After introducing CXL with riboflavin in 2003, it became the primary treatment to reduce the keratoconus and post-LASIK ectasia progression [2]. How to cite this article Chanbour W, El Zein L, Younes M, et al (November 13, 2021) Corneal Cross-Linking for Keratoconus and Post-LASIK Ectasia and Failure Rate: A 3 Years Follow-Up Study.

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