We performed one-step procedures of photorefractive keratectomy (PRK) with the use of the excimer laser (193 nm) on 1519 myopic eyes during 1 year. From this group, we prospectively evaluated visual and refractive results of 202 (13%) consecutive myopic eyes that were followed for more than 1 year. Myopic eyes were divided into two groups according to the amount of myopia: group I, 135 eyes, 87 patients, less than -7.00 D, and group II, 67 eyes, 48 patients (-7.25 D to -13.50 D). The excimer laser system used was the ExciMed 200UV (Summit Technology, Inc, Waltham, Mass), the one-step computer program was fixed at a maximum ablation up to -6.00 D correction. Uncorrected visual acuity of 20/25 or better was achieved in 89.6% of eyes in group I and 47.8% in group II at 1 year. Best spectacle corrected visual acuity was equal to, or better than, the preoperative level in 93.8% of eyes. The difference between attempted and achieved refractive correction was within +/- 1.00 D in 91.4% in group I, and 51.7% in group II. The mean reduction of manifest (spherical equivalent) refraction in group II was 6.84 D at 1 year. Keratometric readings and central corneal thickness showed gradual changes until 6 months after surgery. Corneal haze disappeared in most of eyes at 1 year. The most common subjective complaint was glare and/or decreased vision at night or under dim light.(ABSTRACT TRUNCATED AT 250 WORDS)