Five-year outcomes of epithelium-off Corneal Crosslinking for keratoconus

PurposeTo assess the influence of epithelium-off (epi-off) crosslinking (CXL) on overall flattening of the cone & pachymetry and in different cone locations (central, paracentral, and peripheral) at 5-year and to analyse preoperative factors influencing cone flattening at 5-year in keratoconus.MethodsAll patients with at least 5-year follow-up were included. Data was collected on age, sex, and cone location. Cone location (Central (3 mm centrally), paracentral (3-5 mm) and peripheral (beyond 5 mm)) were classified based on maximum keratometry (Kmax). Data was collected for preoperative, 1-, and 5-year visits. Anterior Kmax and thinnest pachymetry changes were also analysed for various cone locations. Stepwise backward multiple regression analysis was performed to look at the preoperative factors (sex, age, cone location, preoperative Kmax, and thinnest pachymetry) influencing cone flattening at 5-year.Results53 eyes (53 patients) (M:F = 36:17) were included. There was a significant change between preoperative Vs. 5-year Kmax (P < 0.01) and they were significantly correlated (r = 0.86, p < 0.01). Peripheral and paracentral cones flattened more at 5-year. Whereas there was a significant thinning between preoperative and at 1-year only (P = 0.01) and they were significantly correlated too (r = 0.83, p < 0.01). Central cones thinned more over 5-year. Only preoperative Kmax was significantly correlated to postoperative cone flattening at 5-year.ConclusionThere is a significant flattening at 5-year and peripheral and paracentral cones flattened more. Whereas significant thinning of the cones were only observed until 1-year and central cones thinned more. Flattening of cone at 5-year was only related to preoperative Kmax.