A Randomized Double-Masked Study Evaluating Safety and Efficacy of a Novel Topical Cooling Device for Chronic Ocular Surface Pain

INTRODUCTION: No therapy is currently FDA approved to treat ocular pain. This study evaluated the safety and efficacy of a novel topical ocular cooling device for chronic ocular surface pain (COSP). METHODS: This was a prospective, randomized, double-masked, multicenter clinical feasibility study in adults aged 22-90 years with COSP. The intervention was a handheld device that applied cold temperatures to the conjunctival surface above the long ciliary nerves via two metallic contact surfaces at the 3 and 9 o'clock positions. Subjects were randomized 2:1 to a one-time, 4-min treatment with the active (frozen) or sham (refrigerated) device and followed for 8 weeks. Subjective pain was assessed via the visual analog scale (VAS), ocular pain assessment survey (OPAS), and chronic ocular pain questionnaire (COP-Q). Corneal sensitivity was evaluated with Cochet-Bonnet esthesiometry. Main outcomes were change from baseline in VAS, OPAS, and COP-Q scores. Post hoc analyses were conducted in eyes with peripheral-dominant pain based on proparacaine challenge. Adverse events (AEs) were recorded. RESULTS: Unilateral treatments were administered to 31 subjects (20 active, 11 sham). All three patient-reported outcomes (PROs) showed greater reductions in eye pain at week 8 in the active versus sham arm. In eyes with peripheral-dominant pain, COP-Q eye pain severity improved significantly versus sham at week 8 (nominal p = 0.042), and OPAS overall eye pain trended towards statistical significance (nominal p = 0.088). All three PROs exceeded thresholds for clinically meaningful improvement. Baseline corneal sensitivity was below normal in both groups and improved significantly only in the active group (nominal p = 0.041). No serious AEs occurred; the most common AE was transient conjunctival hyperemia. CONCLUSION: A novel ocular surface cooling device is well tolerated and appears to provide durable relief of COSP in peripheral-dominant pain types for at least 8 weeks. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06479382.