The Safety and Tolerability of a Single Scleral Treatment With a Cooling Device in Rabbits.

Purpose: To evaluate the preclinical safety of a single treatment of a topical scleral cooling device.

Methods: Two Good Laboratory Practice prospective preclinical device safety studies were performed: study 1 in normal healthy rabbit eyes (n = 5) and study 2 in healthy rabbit eyes that underwent a surgically induced corneal epithelial defect (n = 3). Following sedation, eyes were treated for 10 minutes by applying the cooling device to the sclera. Key assessments for both studies included clinical observations, Schirmer's I and II tests, ophthalmic examinations, intraocular pressure (IOP) measurements, and histopathology. Study 1 assessments were performed on days -3, 7, 14, 21, 28, 42 (±2 days), and 56 (±2 days). In study 2, a 3-mm diameter corneal defect was created in both eyes of each animal 14 days after the cooling device application. Corneal fluorescein staining was monitored at 3, 6, 24, 30, 48, 54, and 72 hours after defect creation.

Results: Minimal changes in conjunctival redness, peripheral corneal haze, and fluorescein staining were observed, which completely self-resolved within 4 weeks after treatment. Schirmer's I and II and IOP results were within normal ranges in all animals. All epithelial defects in both groups had fully healed within 48 hours.

Conclusions: No adverse effects were observed within 8 weeks following a single scleral application of the topical cooling device in rabbit eyes.

Translational relevance: This article introduces a novel ocular cooling device for the treatment of chronic ocular surface pain, a condition with a considerable unmet need for more effective therapies.