Long-Term Follow-Up of Accelerated Transepithelial Corneal Crosslinking for Post-LASIK Ectasia: A Pilot Prospective Observational Study

Abstract

Background: Keratectasia after corneal refractive surgery is a rare but serious postoperative complication, and reports on accelerated transepithelial corneal crosslinking (ATE-CXL)-based treatment of patients with post-laser-assisted in situ keratomileusis (LASIK) ectasia are limited. Therefore, this study evaluated the long-term efficacy and safety of ATE-CXL for progressive post-LASIK ectasia.Methods: This prospective observational study was conducted at the Eye and ENT Hospital, Fudan University, Shanghai, China, and 25 eyes from 25 patients with post-LASIK ectasia undergoing ATE-CXL were examined. Clinical examinations were conducted preoperatively and postoperatively to assess parameters such as manifest refraction, corrected distance visual acuity (CDVA), endothelial cell density; keratometry, corneal thickness, posterior elevation and topometric indices were measured using Pentacam; sectoral pachymetry and epithelial thickness were evaluated using optical coherence tomography. A paired t-test, Wilcoxon rank-sum test, Kruskal-Wallis test, and repeated measures analysis of variance were used for statistical analysis.Results: Participants were examined for an average of 46 months. No severe complications occurred during or after ATE-CXL. CDVA improved from 0.25 ± 0.31 preoperatively to 0.15 ± 0.17 postoperatively (p = 0.011). Maximum keratometry decreased from 55.20 ± 8.33 D to 54.40 ± 7.98 D, with no statistical significance (p = 0.074), and the central corneal thickness increased from 414.92 ± 40.96 μm to 420.28 ± 44.78 μm (p = 0.047) at the final follow-up. Posterior elevation, pachymetry, and epithelial thickness remained stable (p > 0.05) throughout the follow-up. No significant differences were noted in topometric indices, except the central keratoconus index, which decreased significantly (p < 0.001) at the final follow-up.Conclusion: Improvements in CDVA and stabilization in corneal keratometry and posterior elevation after ATE-CXL were noted at the 46-months follow-up, demonstrating that ATE-CXL is a safe and effective treatment for progressive post-LASIK ectasia.

Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia

“…However, the incidence of post LASIK ectasia, although rare, remains a major concern for ophthalmic surgeons. 17 Although a constellation of preoperative and/or operative features are very frequently found in post LASIK ectasia cases, the absence of such features in some rare instances confounds our understanding of this devastating complication. 12 …”

“…However, the incidence of post LASIK ectasia, although rare, remains a major concern for ophthalmic surgeons. 17 Although a constellation of preoperative and/or operative features are very frequently found in post LASIK ectasia cases, the absence of such features in some rare instances confounds our understanding of this devastating complication. 12 In all the previous trials of CXL in cases with post LASIK ectasia, the effective CXL only involved the anterior corneal layer, so the major portion of the CXL effect is rather consumed in strengthening the corneal flap rather than the deeper corneal stroma, and this will lead to a lower overall CXL effect for the effective residual stromal bed that actively shares in maintaining the corneal integrity post LASIK.…”

“…[6][7][8]18 In a study by Kymionis et al 19 on a small cohort of patients having KC and post LASIK ectasia, corneal confocal microscopy showed full-thickness keratocytes repopulation in the anterior and mid-corneal stroma 6 months following the CXL treatment, with preservation of the corneal endothelium and no significant detectable morphological changes. Some studies showed the long-term stability and effectiveness of conventional CXL, 7,20 while others declared that better outcomes could be obtained using the transepithelial accelerated CXL protocols, 17,21,22 owing to the reduced corneal haze and lesser keratocyte apoptosis and induced inflammation compared to its conventional counterpart.…”

Comprehensive management of post‐LASIK ectasia: From prevention to treatment

“…For accelerated epi‐off CXL, 0.1% riboflavin was applied every 2 min for 10 min with continuous UV‐irradiation of 30 mW/cm 2 for 4 min and intermittent UV‐irradiation of 30 mW/cm 2 in a ratio of 1:1 for 8 min (Tong et al, 2017). Accelerated epi‐on CXL increased the riboflavin concentration to 0.25% by soaking in Paracel solution containing the osmotic enhancer EDTA for 4 min, followed by Vibex Xtra solution for 6 min, and interrupted UV‐irradiation of 45 mW/cm 2 in a ratio of 1:1 for 5 min 20 s (Tian et al, 2021). This acceleration strategy has now been found to be safe and effective in several studies (Jee et al, 2014; Tong et al, 2017; Zhang, Sun, et al, 2020; Zhang, Zhang, et al, 2020) of Table 2.…”

“…Since total thickness decreases further after epithelial removal, several studies have attempted epi‐on CXL (Tian et al, 2021; Zhang, Sun, et al, 2020; Zhang, Zhang, et al, 2020). However, the presence of epithelial barrier can reduce the penetration capacity of riboflavin (Caporossi et al, 2013; Cerman et al, 2015).…”