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.

Leber's optic neuropathy and Charcot-Marie-Tooth disease. Report of a case.

The case of a patient with Charcot-Marie-Tooth disease who developed the acute fundus findings of Leber's optic neuropathy is described. Previous reports have proposed a genetic interrelationship between the two diseases. This relationship has been speculative, however, because the acute fundus findings of Leber's have never been observed in a case of Charcot-Marie-Tooth disease. This case adds support for a suggested genetic relationship between the two diseases. It is also possible that the optic atrophy previously described in Charcot-Marie-Tooth may represent the late findings of Leber's optic neuropathy.

The effect of pilocarpine on the visual field in normals.

Despite generalized consensus that pilocarpine-induced miosis results in some degree of visual field constriction, studies describing the predictability of this occurrence, as well as the nature of the field defects that may be seen, have not been undertaken. We studied 20 normal subjects, ranging in age from 24 to 57 years. Baseline refraction, pupillary measurements, and visual fields were performed in both eyes on a standardized Goldmann perimeter with the I-2e, I-3e, and I-4e test objects. Pilocarpine 2% was then instilled into the study eye and the field repeated at 30 and 120 minutes. An IBM PC computer program, designed by the authors, was used to calculate the area contained within each isopter. The probability of visual field constriction at 30 and 120 minutes after instillation of pilocarpine was found to be significant, especially with pupillary diameters of 2 mm or less. The I-2e isopter was most sensitive to miosis. Visual field constriction persisted with correction of ciliary spasm induced myopia, suggesting that miosis, especially when marked, can independently alter the visual field. The clinician, then, should make every effort to control visual field testing conditions in glaucoma patients on miotics to allow reliable serial comparisons.