title: Photorefractive keratectomy for myopia of 6 to 12 diopters.
abstract: To conduct a prospective, nonrandomized clinical trial to assess the efficacy, stability and safety of the use of excimer laser photorefractive keratectomy (PRK) to correct myopia of greater than -6.00 diopters (D) in Singapore. Two hundred thirty-three eyes of 176 patients with a mean preoperative spherical equivalent refraction of -8.70 +/- 2.3 D (range, -5.75 D to -18.13 D) underwent PRK with a 193nm ArF excimer laser (ExciMed, Summit) for myopic corrections of between -6.20 D and -11.90 D. The first 66 of 233 eyes that reached at least 1 year of postoperative follow up are reported. One year postoperatively, the mean manifest spherical equivalent refraction was -1.50 D +/- 1.90 D (range -6.25 D to +3.25 D); 34% of eyes were within +/- 1.00 D of attempted correction; uncorrected visual acuity was 20/40 or better in 75% of eyes. No eyes lost two or more Snellen lines of spectacle corrected visual acuity. Central corneal haze was mild in 20% of eyes and moderate in 3% of eyes. Five eyes developed ocular hypertension that subsequently resolved with treatment. Excimer laser PRK is reasonably effective and safe in the treatment of -6.00 D to -12.00 D of myopia. However, it is less accurate than PRK in eyes with low to moderate myopia and is more likely to result in significant corneal haze.
authors.affiliation: Singapore National Eye Center.
authors.forename: W K
authors.initials: WK
authors.lastname: Chan
authors.forename: W J
authors.initials: WJ
authors.lastname: Heng
authors.forename: P
authors.initials: P
authors.lastname: Tseng
authors.forename: V
authors.initials: V
authors.lastname: Balakrishnan
authors.forename: T K
authors.initials: TK
authors.lastname: Chan
authors.forename: C H
authors.initials: CH
authors.lastname: Low
mesh_terms: D000328:Adult; D003315:Cornea / Q000502:physiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D012029:Refraction, Ocular; D014792:Visual Acuity / Q000502:physiology