Topical insulin as interim therapy in neurotrophic keratitis
An 84-year-old female with a history of cataracts and glaucoma was referred for evaluation and culturing of a corneal ulcer in the left eye extending into the visual axis. She was using multiple topical medications, artificial tears, and an oral antibiotic. At presentation, the ulcer appeared improved compared to the referring provider’s prior examination. She was started on fortified vancomycin and tobramycin every 1–2 hours while awake, frequent preservative-free artificial tears, and continued Neoplydex 3 times daily.
On follow-up, the epithelial defect enlarged with marked inflammation, significant keratic precipitates, and decreased corneal sensation in all quadrants. While awaiting approval for cenegermin, the patient was started on insulin eye drops 4 times daily and oral valacyclovir. The epithelial defect subsequently improved, though severe inflammation persisted. Loteprednol 0.25% was initiated and later increased due to ongoing inflammation.
Early corneal neovascularization later developed. Insulin and loteprednol were tapered, and the patient began an 8-week course of cenegermin.
This case highlights the role of topical insulin as an interim therapy while awaiting initiation of cenegermin. Compounded insulin drops are an emerging, off-label treatment option for persistent epithelial defects and neurotrophic keratitis, particularly when access to nerve growth factor therapy is delayed. Potential advantages include lower cost, faster accessibility, and less frequent dosing. However, because insulin does not promote corneal nerve regeneration, there may be an increased risk of recurrence compared to therapies specifically targeting corneal innervation. Adjunctive measures such as oral vitamin C (1–3 g daily) may also be considered to support corneal collagen synthesis and help stabilize an at-risk cornea.
Reference
Lock P. The Non-Healing Ulcer: Recognizing Neurotrophoc Keratoconjunctivitis. . Poster presented at: SECO2026; February 25–March 1, 2026; Atlanta, GA.
