A new study shows that patients who undergo photorefractive keratectomy (PRK) with extended mitomycin c (MMC) may be less likely to experience corneal breakthrough haze after surgery.
The single-center, retrospective study included 3,854 patients and looked at the post-operative incidence and risk factors for corneal breakthrough haze, which can worsen vision. Researchers grouped the eyes by intraoperative time, MMC application time, and pre-operative refraction. In addition, they measured onset time, incidence, and the severity of patients’ corneal haze.
The findings showed that patients with the lowest incidence of haze after surgery had an MMC application time of more than 40 seconds. Eyes were almost twice as likely to develop haze if they had high vs. low-to-moderate myopia and three-and-a-half times more likely with high vs. low astigmatism. Eyes treated for hyperopia vs. myopia were eight times more likely to develop haze.
The study also found that haze was more likely to occur when the epithelium was removed with alcohol as compared with those patients who had trans-epithelial PRK. On average, mild early haze reached peak levels at 69 days and late haze at 115 days.
While other studies have examined the risk factors for developing corneal haze after PRK, the research reinforces findings that patients with hyperopia, high myopia, or astigmatism are more likely to experience breakthrough haze in spite of MMC use. The study shows that longer MMC application could reduce the incidence of haze in these high-risk groups.
