Combined late haze, regression correlated to size of PRK correction

When late haze and regression occur after PRK, the amount of haze seems to correlate with the amount of attempted correction, a study suggests. No correlation was found between the amount of haze and the magnitude of the regression, the study authors said.

Irene C. Kuo, MD, and colleagues at the University of California, San Francisco, reviewed the charts of 542 patients who had undergone PRK with at least 6 months of follow-up. Two types of excimer laser, Visx and Nidek, were used. Average patient age was 40.5 years.

They found 10 eyes of eight patients that developed a progressive haze of greater than 1+ and myopic regression of more than –1 D at 3 or more months after undergoing PRK. Three of the patients were female. The incidence of combined haze and regression was 1.8%.

The mean attempted spherical equivalent refractive correction in these eyes was –6.69 D, with a range of –4 D to –12.25 D. The mean regression was –2.01 D. Regression leveled off at 9.8 months on average. Haze ranging up to 4+ peaked at a mean of 7.4 months.

Topical steroid treatment and epithelial scraping were performed in three eyes but were ineffective, the researchers said.

“These observations suggest a need for improved understanding of corneal wound healing following PRK and of biologic factors that may contribute to variability in outcomes,” the researchers said in the abstract of their study.

The study is published in the May issue of Cornea.