Randomized Controlled Trial of Topical Insulin for Healing Corneal Epithelial Defects Induced During Vitreoretinal Surgery in Diabetics.

PURPOSE: To determine the effect of topical insulin of 3 concentrations [0.5, 1, and 2 units per drop 4 times per day (QID)] on postoperative corneal epithelial wound healing in diabetic patients.

DESIGN: A double blind randomized controlled hospital-based study involving diabetic patients with postoperative corneal epithelial defect after vitreoretinal surgery.

METHODS: Diabetic patients were randomized to 3 different concentrations of topical insulin (DTI 0.5, DTI 1, and DTI 2) or placebo in the control group (DNS). Primary outcome measure was the rate of corneal epithelial wound healing (mm² per hour) over pre-set interval and time from baseline to minimum size of epithelial defect on fluorescein stained anterior segment digital camera photography. Secondary outcome measure was any adverse effect of topical insulin. Follow-up was 1 month.

RESULTS: Thirty-two eyes of 32 patients undergoing intraoperative corneal debridement with resultant epithelial defect (8 eyes per group) were analyzed. DTI 0.5 was superior to other concentrations achieving 100% healing rate within 72 hours of treatment compared with 62.5% in DNS, 75% in DTI 1, and 62.5% in DTI 2. Statistically, DTI 0.5 achieved significant results (P = 0.036) compared with the diabetic control group (DNS) in terms of mean rate of corneal epithelial wound healing from maximum to minimum defect size. No adverse effect of topical insulin was reported.

CONCLUSIONS: Topical insulin 0.5 units QID is most effective for healing corneal epithelial defect in diabetic patients after vitrectomy surgery compared with placebo and higher concentrations. Topical insulin is safe for human ocular usage.