Study: Mitomycin reduces haze, regression after PRK

Applying diluted mitomycin to the corneal stroma may reduce haze and myopic regression resulting from photorefractive keratectomy, a retrospective study indicates. The technique involves therapeutic scraping of the cornea followed by application of a 0.02% mitomycin C solution.

Luca Vigo, MD, and colleagues at the Carones Ophthalmology Center in Milan, Italy, evaluated the technique in a noncomparative, nonrandomized study of 35 eyes that underwent PRK for myopia and developed haze and regression postoperatively.

With regression after PRK for myopia, these patients had refractive errors ranging from –0.75 D to –5.5 D and haze of grade 3 to 4. The haze and myopic regression resulted in a visual acuity loss of between one and six Snellen lines, the study authors said.

All eyes were treated for the haze at 6 to 12 months after PRK. In all cases, a 20% alcohol solution was used to loosen the epithelium. The stromal surface was then scraped to remove as much scar tissue as possible. This was followed by a 2-minute application of mitomycin solution using a sponge. Although no additional laser ablation was performed, all eyes received the same postop therapy as described for PRK.

All eyes showed a significant improvement in corneal transparency, with most eyes having corneal haze lower than grade 1. Four eyes had haze between grades 1 and 2. Two of those eyes underwent an additional treatment using the same technique.

Complete re-epithelialization was seen within 5 days postop. Patients did not have more pain or discomfort than that experienced following the original PRK procedure, the authors reported.

No toxic effects were observed during re-epithelialization or the follow-up period. All eyes were within 1.5 D of original intended correction at 1 year after treatment.

The study was published in the July/August issue of Journal of Refractive Surgery.