Efficacy And Safety Of Topical Insulin In Patients With Dry Eye Disease: A Randomized Controlled Clinical Trial

To evaluate the effectiveness and safety of insulin eye drops in controlling dry eye disease (DED) compared with topical cyclosporine and placebo (artificial tears) in a randomized controlled clinical trial.

Hospital Clinico San Carlos, Madrid, Spain

Adults with a diagnosis of DED, persistent symptoms despite treatment with artificial tears, and corneal staining ≥ Oxford grade II were included. Key exclusion criteria included severe DED, recent ocular surgery, concomitant ocular surface pathology, contact lens use, pregnancy or lactation, and significant systemic disease interfering with study assessments. Treatment groups were: insulin 1 IU/mL four times daily, cyclosporine 0.05% twice daily and artificial tears four times daily. The primary efficacy outcome was change in corneal staining. Secondary outcomes included changes from baseline in Ocular Surface Disease Index (OSDI) score, corneal esthesiometry, non-invasive tear breakup time (NITBUT), and conjunctival hyperemia.

116 patients were randomized to receive insulin (n = 40), cyclosporine (n = 39), or artificial tears (n = 37). Of these, 33, 33, and 26 completed the 6-month follow-up. Four patients in the artificial tears group discontinued due to adverse events. No statistically significant differences were observed among groups at baseline (all p > 0.05). At 6 months, a difference among groups was observed in corneal staining scores (p = 0.024). The mean change from baseline in corneal staining was −1.05 ± 1.18 in the insulin group, −1.15 ± 1.27 in the cyclosporine group, and −0.31 ± 1.17 in the artificial tears group, indicating greater improvement with insulin and cyclosporine compared with artificial tears. No other differences were found.

Topical insulin 1 IU/mL administered four times daily was associated with a significant improvement in corneal staining compared with artificial tears after 6 months of treatment, demonstrating efficacy comparable to cyclosporine 0.05%. The treatment was generally well tolerated, with no safety concerns identified beyond those observed with standard therapy. These findings suggest that topical insulin may represent a safe and effective therapeutic alternative for patients with dry eye disease inadequately controlled with artificial tears.