Can Insulin Drops Accelerate Corneal Healing After Corneal Cross-Linking? A Preliminary Case Series

Background and Objectives: Corneal cross-linking (CXL) is the standard treatment for progressive keratoconus, but delayed epithelial healing remains a concern, increasing infection risk and patient discomfort. Studies suggest that insulin may promote corneal epithelial cell migration and proliferation, potentially accelerating wound healing. Its benefit has been observed in neurotrophic keratitis and diabetic epithelial defects, and it may offer similar effects post-CXL. Our objective is to evaluate the effect of topical insulin on epithelial healing after CXL in a small case series. Materials and Methods: Eight patients undergoing CXL for keratoconus were divided into two groups (n = 4 each). The insulin group received topical insulin eye drops (1 IU/mL in Systane^®) five times daily, in addition to standard postoperative care. The control group received Systane^® alone with the same regimen. Daily follow-up included slit-lamp exam, anterior segment OCT, and photodocumentation until epithelial defect closure. Results: Baseline parameters (central corneal thickness, keratoconus stage, Schirmer test, tear break up test) were comparable. While not statistically significant, the insulin group showed numerically smaller epithelial defects on day 2, suggesting a possible trend toward faster healing. By day 3, re-epithelialization was complete in all patients. Pain decreased over time in both groups without significant differences. No adverse effects were noted. Conclusions: Topical insulin may modestly accelerate epithelial healing after CXL, as suggested by smaller defects on day 2 in the insulin group. Although results were not statistically significant, the trend warrants further investigation in larger studies.