When introduced to the United States in 1978, radial keratotomy (RK) was performed by affixing razor blade fragments to a blade holder and hand adjusting the depth of the blades using a depth gauge block. The optical zones were as small as 2.5 mm, and as many as 24 to 32 incisions were directed from the limbus to the optical center.1-3 Typically, these techniques were able to correct up to 3 diopters (D) of myopia with poor predictability (Table). A substantial percentage of patients suffered postoperative glare and photophobia. In the next two years, variations in surgical techniques were performed, some with disastrous results.4,5 Through appropriate in vitro and in vivo laboratory studies, it was subsequently demonstrated that some of the techniques produced unpredictable and shallow incisions, that 24 and 32 incisions were not appreciably better than 16 incisions, and that the refractive change produced by eight and