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

Abstract

Purpose To 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. Methods A 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. Results In 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). Conclusion Eyes with post-LASIK ectasia seem to be less responsive to CXL than KC.

Corneal Collagen Crosslinking for Ectasia After Refractive Surgery: A Systematic Review and Meta-Analysis

“…Finally, 15 studies were included in this review, including four RCTs [29][30][31][32] and eleven non-randomized cohorts. [33][34][35][36][37][38][39][40][41][42][43] We analyzed 421 patients, including 512 eyes diagnosed with post-laser corneal ectasia. The sample sizes of these trials ranged from 11 to 91.…”

“…43,46 However, contrasting results emerged from a different study, where the progression rate post-CXL was notably higher in patients with ectasia compared to those with keratoconus over three years. 39 Additionally, in another investigation, CDVA and Kmax were inferior in patients with ectasia compared to keratoconus patients after CXL. 65 This discrepancy may be attributed to heightened variability in the timeline of changes in ectasia patients compared to those with keratoconus.…”

Potential applications of artificial intelligence in image analysis in cornea diseases: a review

“…Early detection could allow surgeons to monitor disease progression and if necessary, to intervene appropriately to halt progression through corneal cross-linking [ 6 ]. KC also presents as the leading cause of ectasia post-laser vision correction and hence ideally should be detected pre-treatment [ 7 , 8 ]. Therefore, identification of subclinical keratoconus (SKC) is important in screening for suitable candidates for refractive surgery.…”

Indications for keratoplasty in management of corneal ectasia

“…The clinical benefits of CXL vary among patients. The rate of progression is reportedly higher in post-keratorefractive surgery ectasia patients, but few comparative studies have been published [16 ▪ ]. The majority of patients undergoing CXL still require contact lens correction following treatment [9 ▪▪ ].…”