To evaluate the efficacy of insulin eye drops for dry eye disease in reducing corneal staining and improving symptoms.

In this retrospective case series, patients with dry eye disease treated with off-label use of insulin eye drops were collected. The main inclusion criterion was diagnosis of dry eye disease with epithelial damage and acceptance of the off-label use of topical insulin. Age, sex, type of dry eye disease, time since diagnosis, previous ocular surgeries, concomitant treatment, best corrected visual acuity, symptoms, conjunctival hyperemia and corneal staining were recorded. Data from the 1 and 3-month visit were included.

16 patients (32 eyes) were treated with insulin (14 females and 2 males; mean age 61.3 ± 16.8 years). 12 patients (71%) were also on autologous serum and 10 patients (63%) on cyclosporine. Symptoms were 3.4 ± 1.3 (range 2–5) when scaled from 0 to 5. Mean hyperemia was 1.0 ± 0.9 (range 0–3) and corneal staining was 2.5 ± 1.3 (range 0–5). After 3 months, 5 patients (31%) referred to be much better, 6 (38%) better, 3 (19%) slightly better and 2 patients (13%) were subjectively similar, mean symptoms being 2.3 ± 1.0 (range 1–4; p = 0.001). Hyperemia was 0.3 ± 0.4 (range 0–1) and corneal staining was 1.1 ± 1.0 (range 0–3; both p < 0.001). Topical insulin was well tolerated with no adverse events.

The excellent results presented in these case series illustrate topical insulin as a promising treatment in dry eye disease with refractory epithelial damage.