Risk Factors For Progression Following Corneal Collagen Crosslinking In Keratoconus

To assess risk factors for progression following corneal collagen crosslinking (CXL) in eyes with keratoconus. Charts of patients who developed progression following conventional CXL treatment (Dresden protocol) were retrospectively evaluated in two centers (Center 1 and Center 2). 871 eyes of a total of 676 patients were analyzed. Progression was defined as > 1 diopter (D) increase in maximum keratometry (Kmax) readings compared to baseline. Progression was noted in 20 eyes of 20 patients (progression rate 3%). The mean age of the patients was 17.65 ± 5.76 (11–34)-years-old, and the mean follow-up following CXL was 36.70 ± 25.72 (12–84)-months-old. The gender distribution was 13 (65%) females and seven (35%) males. Four eyes (20%) had mild, 13 eyes (65%) had moderate, and three eyes (15%) had severe keratoconus at baseline. Fifteen eyes (75%) had allergic conjunctivitis, and 20 eyes (100%) reported eye-rubbing. Cone location was central in 17 (85%) eyes, and peripheral in 3 (15%) eyes. A mean of 2.21 ± 1.30 D (1.00–5.30 D) steepening was determined at Kmax 6 to 82 months following CXL treatment. Progression rate was found to be higher in the patients under the age of 17 years, female gender, allergic conjunctivitis, high preoperative Kmax (> 57 D), thin corneas (< 430 µm). The majority of progressive patients were central cone and moderate keratoconus.