Outcomes of Collagen Crosslinking in Patients with Keratoconus and Co-Existent Limbal Stem Cell Deficiency

Abstract

Purpose: To analyse the outcomes of collagen crosslinking (CXL) in eyes with progressive keratoconus (KC) and secondary limbal stem cell deficiency (LSCD) caused by vernal keratoconjunctivitis (VKC). Methods: Patients with progressive KC and VKC having co-existent LSCD who underwent CXL from May 2016 to October 2023 were included. Demographic details, clinical and corneal topography data were collected preoperatively, at 1-months, 3-months, 6-months and 1-year. Details of the CXL procedure and early postoperative complications were noted. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA) and topographic indices including flattest keratometry (K1), steepest keratometry (K2), mean keratometry (Km), maximum keratometry (Kmax) and thinnest corneal thickness (TCT) were noted at 1-year and compared with the preoperative data. Results: Fifteen eyes of 11 patients were included in the study. Partial LSCD was present in 14 eyes and underwent epithelium-off CXL and 1 eye with total LSCD underwent transepithelial CXL. The mean logarithm of the minimum angle of resolution (logMAR) UCVA pre-CXL was 0.67±0.38 which improved to 0.54±0.32 at 6-months (p=0.05) and 0.65±0.35 logMAR at 1-year post-CXL (p = 0.005). Pre-CXL Km was 53.5±4.77 (median-51.95D) which decreased to post-cxl value of 51.72±3.65 at 6-months (p=0.014) and 52.34±3.83 (median-51.3D) at 1-year (p=0.09). Kmax reduced from 63.41±7.11 (median-63.7D) pre-CXL to 60.65±5.31 (median-59.6) (p=0.05) at 6-months and 61.4±6.01 (median-61.9D) at 1-year post-CXL (p=0.115). Of the 14 eyes that underwent epi-off CXL, 2 eyes (14.28%) had persistent epithelial defects (PEDs), one of which needed amniotic membrane graft (AMG). Conclusion: In our series, most eyes with keratoconus having co-existent LSCD had uncomplicated ocular surface healing post-CXL and remained stable at 1-year with significant improvement in visual acuity. Our study shows that CXL can be successfully performed in cases of Keratoconus with co-existing LSCD without any serious complications.