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

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

doi:10.7759/cureus.19552

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

Cureus. 2021 Nov 13;13(11):e19552. doi: 10.7759/cureus.19552. eCollection 2021 Nov.

Authors

Wassef Chanbour¹, Lulwa El Zein², Mohamad Ali Younes³, Mohamad Issa⁴, Pramod Warhekar⁵, Elias Chelala⁶, Elias Jarade⁷

Affiliations

¹ Ophthalmology, Beth Israel Deaconess Medical Center (BIDMC), Boston, USA.
² Pediatric Ophthalmology, Bascom Palmer Eye Institute, Miami, USA.
³ Internal Medicine, Faculty of Medical Sciences - Lebanese University, Hadath, LBN.
⁴ Ophthalmology, Hospital Foundation Adolphe De Rothschild, Paris, FRA.
⁵ Ophthalmology, Mediclinic City Hospital, Dubai, ARE.
⁶ Ophthalmology, Saint Joseph University, Beirut, LBN.
⁷ Ophthalmology, Beirut Eye & ENT Specialist Hospital, Beirut, LBN.

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.

Keywords: collagen cross-linking; keratoconus; post-lasik ectasia; prk; topography.