Radial keratotomy: an analysis of the American experience.

A total of 223 patients with bilateral nonprogressive myopia ranging from - to - 11 D underwent partial-thickness radial keratotomy (400 eyes). Topical anesthesia was used for all surgery and all patients had 16 radial incisions from a preset central optical zone, determined by table and/or formula. Neither corneal diameter or scleral rigidity was taken into account in these groups. Substantial reduction of myopia resulted immediately in all cases, with Group 1 showing a 44% regression of the myopia with stabilization occurring at three months. Group 2 showed a 14% regression of effect. In Group 1, 28% attained an unaided visual acuity (postoperatively) of 20/40 or better for most of the day, while 61% of Group 2 attained the same result. Night glare was present in both groups, usually subsiding in three months. Fluctuation was reported in both groups. Side effects were mild. The comparison of the two groups shows that incisions carried almost to Descemet's membrane and deepened in the periphery resulted in much greater reduction of the myopia and a more permanent and stable effect following surgery. New methods of measuring corneal curvature are necessary and a more satisfactory blade needs to be developed for surgery. Corneal thickness measurements have been made more accurate by the development of the ultrasonic pachymeter.