Remaining peripheral corneal segments may relax following PRK

Cornea. 2011;30(2):130-135.

After corneal lamellae are centrally severed during myopic PRK, the remaining peripheral segments may relax, a study suggested.

The nonrandomized, prospective study included 84 myopic eyes without systemic or ocular disease. Central corneal thickness and corneal volume were measured using Pentacam Scheimpflug densitometry (Oculus) before surgery and at 1 month, 3 months and 6 months postop.

Mean preop refraction was –4.93 D. One month after PRK, the central corneal thickness mean difference was 73.2 µm and the corneal volume mean difference was 2.2 mm³. At 3 and 6 months postop, central corneal thickness mean difference was 66.6 µm and 65.3 µm, respectively. At these two follow-ups, corneal volume mean difference was 1.4 mm³.

The amount of treatment was correlated with central corneal thickness changes at all follow-up points but not with corneal volume changes.

The lack of correlation for corneal volume is due to a reduction of tension in the lamellae after PRK, according to the study authors.

This was the first investigation of corneal volume changes in eyes that underwent PRK, the authors said.