Dexamethasone-eluting contact lens for the prevention of post-photorefractive keratectomy scar in a New Zealand White rabbit model.

Abstract

Purpose : Corneal haze is a post-operative complication of photo refractive keratectomy (PRK) that can limit post-operative vision. Some ophthalmologists are wary of performing PRK due to the risk of haze, especially in poorly complaint patients. Steroid eye drops with or without intraoperative Mitomycin C is the most common treatment, but compliance with drops is often poor. This study compared the efficacy of an experimental dexamethasone-eluting contact lens (Dex-Lens) against dexamethasone drops in decreasing post-PRK corneal haze in a New Zealand White (NZW) rabbit model.

Methods : The right eye of 32 NZW rabbits underwent PRK that was performed by epithelium removal and 10D treatment with a VISX Star S4 IR laser followed by tarsorrhaphy. The rabbits were randomized to one of 4 study arms (n=8): tarsorrhaphy only (without steroids or contact lens), bandage contact lens (BCL) for 1 week plus topical 0.1% dexamethasone for 4 weeks, BCL replaced weekly for 4 weeks plus topical dexamethasone for 4 weeks, and Dex-Lens changed weekly for 4 weeks. The left eye of each rabbit underwent PRK but served as an untreated control. Each week, for 4 total weeks post-operatively, the tarsorrhaphies on the right eyes were opened, underwent evaluation and testing, and tarsorrhaphies were replaced. Contact lenses (CL) were cultured upon removal. Central cornea haze was quantified using the Pentacam densitometry readings each week prior to sacrifice, and was also measured by anterior segment OCT on the last week. After 4 weeks, all eyes were enucleated for histopathology.

Results : Most CL cultures had no growth. The central haze as measured by OCT was lower for Dex-Lenses compared to the control group (p=0.03; Tukey test). The densitometry as measured by Pentacam was not significantly different between Dex-Lenses and BCLs plus topical dexamethasone.

Conclusions : In the post-PRK rabbit model, the Dex-Lenses were safe, effective, and weekly placement was comparable to 4x/day dosing of 0.1% dexamethasone drops in decreasing corneal haze.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.