Comparison between the effect of two different widths of circular lamellar keratectomy on refraction and corneal curvature in rabbits' eyes.

Twenty rabbits' eyes were subjected to circular lamellar keratectomy. Two trephines were used to mark rings at a depth of 0.3 mm, and the lamellar cornea in between was removed. A 1-mm-wide ring was removed from the right eyes, and a 0.5-mm-wide ring from the left ones. We found that removing a 1-mm ring more effectively corrected hypermetropia (3.09 +/- 1.72 diopters) than removing a 0.5-mm ring (1.81 +/- 0.95 D).