Prospective topographic analysis in peripheral arcuate keratotomy for astigmatism

Delimited peripheral arcuate keratotomy was performed on five eyes of four patients with naturally-occurring astigmatism. Refraction, keratometry, and computer-assisted corneal topographic analysis were performed before and after the procedure. In some eyes, preoperative topographic analysis revealed steepening distributed symmetrically about the corneal apex; in three eyes the steepening was asymmetrically distributed about the corneal apex. In one eye, surgery in a single, steep hemi-meridian superior to the corneal apex flattened that steep hemi-meridian but did not appear to alter the topography of the inferior steep hemi-meridian. Refractive and keratometric astigmatism decreased in all eyes (mean reductions of 3.25 and 2.30 diopters, respectively), and all incisions healed without incident. Surgery extended beyond the zone of steepening in one eye, shifting the axis of astigmatism. A large, multicenter, randomized trial will be necessary to determine whether detailed preoperative topographic analysis can be used to improve the results of surgery for astigmatism.