Repeat corneal crosslinking (CXL) is a safe and effective treatment for progressive keratoconus, even in cases when the primary CXL failed, suggest results from a retrospective study published in the British Journal of Ophthalmology. Failure of primary CXL was associated with younger age and reduced K2 flattening.
Currently, data is limited about the optimal management for keratoconus progression after an initial successful primary CXL, and no consensus exists in the literature. This study sought to identify risk factors associated with failure of primary CXL, evaluate the safety and efficacy of repeat CXL, and compare the safety and efficacy of primary vs repeat CXL.
The researchers evaluated data from 1535 eyes that underwent primary CXL and were followed for a 10-year period. Repeat CXL for progressive keratoconus was required for 21 eyes (1.37%) of 20 patients. Patients of South Asian descent were overrepresented in the cohort (48%), which aligns with epidemiology data indicating a higher incidence of keratoconus in this population.
The mean interval between primary and repeat corneal crosslinking was 47.1 months. Patients who were significantly younger at the primary CXL were more likely to need repeat CXL (21.3 years vs 26.7 years; P =.0008). Reduced flattening of the K2 tomography parameter after the primary CXL was also correlated with failure (–0.4 D vs –1.3 D; P =.03).
After repeat CXL, 95% eyes remained clinically stable compared with 96% of eyes after primary CXL. There were no immediate postoperative complications after primary or repeat CXL. There was no clinically significant corneal haze reported for any patients after repeat CXL. One patient (5%) lost more than 2 Snellen lines of best-correct visual acuity (BCVA) after repeat CXL compared with no BCVA reduction in any patients after primary CXL.
The researchers note that repeat CXL is associated with greater postoperative reduction in corneal thickness compared with primary CXL. As such, the study authors advise, “perhaps repeat CXL should be approached with caution in patients with thin corneas. Our practice is to perform CXL or repeat CXL only for patients with corneas >400 μm immediately prior to UV-A light exposure.”
Although the results were limited by access to retrospective data for a small sample, this study evaluated the largest cohort to date of patients undergoing repeat corneal crosslinking.