Use of an ocular wound chamber for the prevention of exposure keratopathy in a guinea pig model

Abstract

Current therapies available to treat and heal ocular surface injuries and periocular burns are frequently inadequate, costly, and labor intensive. To address these limitations, we have employed a flexible, semitransparent ocular wound chamber (OWC) to provide protection as well as a watertight seal to allow for the constant delivery of therapeutics to the ocular surface and surrounding periocular tissue. This study demonstrates the safety and utilization of the OWC on uninjured eyes and in our exposure keratopathy model. For initial safety studies (N = 3 per group), the eyelids remained intact and the eye uninjured. A blepharotomy (N = 6 per group) was performed to remove the upper and lower eyelids surrounding the left (OS) eye to create our exposure keratopathy model. Right (OD) eyes served as uninjured controls in all studies. Following OWC placement, 0.5 mL HPMC gel or balanced saline solution (BSS) was injected into the chamber. Animals were monitored daily and fully assessed via white light, fluorescein, and OCT imaging at least through 72 hours post OWC placement. In studies that included a blepharotomy, skin samples were analyzed by multiplex cytokine analysis. Results of safety experiments revealed no significant differences between treatment groups in corneal thickness, fluorescein staining, OCT imaging, or histological eye or skin sections when compared to control eyes. In our exposure keratopathy model, OWC treated eyes showed significantly less fluorescein uptake and also were found to have significantly lower levels of cytokines IL-13 and IL-5 in skin samples. These results demonstrate for the first time that treatment using the OWC device is not only safe, but significantly protects against blepharotomy-induced exposure keratopathy. As a whole, this study advances our overall efforts to develop a feasible solution to treat ocular surface injuries, infections, and periocular burns.