Multicenter study of photorefractive keratectomy for myopia of 6.00 to 8.00 diopters. VISX Moderate Myopia Study Group.
OBJECTIVE
To summarize the initial results of excimer laser photorefractive keratectomy (PRK) on 89 eyes of 80 patients with moderate myopia (myopia of -6.00 to -8.00 diopters [D]; mean -6.98 +/- 0.90 D) at nine investigational sites.


METHODS
All treatments used an argon fluoride excimer laser (VISX, Inc, Santa Clara, Calif) using standard settings. Sixty eyes received single-zone 6.0-millimeter ablations and 29 eyes received two-zone ablations. Follow up ranged from 1 month (n = 89) to 6 months (n = 46).


RESULTS
At 3 months, uncorrected visual acuity measured 20/40 or better in 75% and 20/20 or better in 18%; 78% were within +/- 1.00 D of intended correction, 38% were within +/- 0.50 D, and 9% lost two or more lines of spectacle-corrected visual acuity. At 6 months, uncorrected visual acuity measured 20/40 or better in 74% and 20/20 or better in 17%; 67% were within 1.00 D of intended correction, 38% within 0.50 D, and 2% (1/46) lost two lines of spectacle-corrected visual acuity.


CONCLUSIONS
PRK for moderate myopia with large diameter ablation zones appears safe and more predictable than that done using smaller ablation zone diameters. Longer follow up is needed to better define stability, the effects of postoperative corticosteroids, and the use of single-versus double-zone ablations.
D000328:Adult; D001251:Astigmatism / Q000209:etiology; D003315:Cornea / Q000601:surgery*; D003318:Corneal Opacity / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007429:Intraocular Pressure; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D009883:Ophthalmic Solutions; D018903:Photorefractive Keratectomy; D011182:Postoperative Care; D011183:Postoperative Complications; D012029:Refraction, Ocular; D014792:Visual Acuity
D005938:Glucocorticoids; D009883:Ophthalmic Solutions