Topical insulin for refractory persistent corneal epithelial defects

To evaluate insulin eye drops for persistent epithelial defects (PEDs) that are refractory to usual treatment in clinical practice and to analyze how it may improve epithelization.

A prospective non-randomized hospital-based study was performed. Patients with PEDs that were refractory to conventional treatment were treated with insulin eye drops four times a day. Patients' demographics, PED etiology, concomitant treatments, and comorbidities were reviewed. The rate of PED closure and epithelial healing time were considered the primary outcome measures.

21 patients were treated with insulin drops (12 females and 9 males; mean age 72.2 years). Mean PED area before treatment was 17.6 ± 16.5 mm² (median 13.2; range 3.9-70.6). PED comorbidities included seven eyes with infectious keratitis (33%), five eyes with calcium keratopathy (24%), ocular surgery on three eyes (14%), three eyes with lagophthalmos (14%), two eyes with bullous keratopathy (10%), and one patient with herpetic eye disease (5%). The eyes of 17 patients (81%) with refractory PEDs had reepithelized and four patients (19%) had still presented an epithelial defect by the end of the study follow-up period, although it had decreased in size. In patients where PED closure was achieved, mean time until reepithelization was 34.8 ± 29.9 days (median 23; range 7-114). In the remaining patients, a mean area reduction of 91.5% was achieved for the PEDs.

Topical insulin can promote and accelerate corneal reepithelization of refractory PEDs. It also offers many other advantages, including excellent tolerance, availability, and cost-effectiveness.