Photorefractive keratectomy for myopia using a 4.5-millimeter ablation zone.
BACKGROUND
Argon fluoride (193 nm) excimer laser photorefractive keratectomy for myopia is under evaluation by the United States Food and Drug Administration.


METHODS
We report a consecutive prospective series of 100 patients (one eye per patient) treated as part of the Phase IIB FDA-approved protocol, with 80 patients followed for 1 year. Patients' ages ranged from 21 to 62 years (mean, 35 years). The Summit Technology, Inc ExciMed UV200LA with a 4.5-mm diameter ablation was used.


RESULTS
Baseline spherical equivalent refraction ranged from -2.00 to -6.90 diopters (D) (mean -4.60 D). Ninety-five percent of eyes reepithelialized by 72 hours. At 1 year, the difference between attempted and achieved correction was +/- 0.50 D for 42 eyes (53%) and +/- 1.00 D for 60 eyes (75%). During the first 6 months, there was a trend toward overcorrection and the majority of eyes showed some loss of initial refractive correction; 10 eyes (14%) changed by 1.00 D or more between 6 and 12 months. An uncorrected visual acuity of 20/25 or better was achieved by 50 eyes (63%) and 20/40 or better by 61 eyes (77%). Of the 10 eyes (12%) that lost two or more Snellen lines of spectacle-corrected or glare visual acuity, two had visual acuity of worse than 20/25. Central subepithelial corneal haze was absent to mild in 77 (96%) eyes at 12 months.


CONCLUSIONS
Excimer laser photorefractive keratectomy as performed in this study was generally effective and safe in reducing simple spherical myopia. Further studies of the effect of a larger diameter ablation zone, smoother transitional corneal contours, and the effect of postoperative topical corticosteroids may lead to further improvements in outcome.
Waring
G O
GO
Department of Ophthalmology, Emory University, Atlanta, Ga, USA.
O'Connell
M A
MA
Maloney
R K
RK
Hagen
K B
KB
Brint
S F
SF
Durrie
D S
DS
Gordon
M
M
Steinert
R F
RF
D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D003315:Cornea / Q000502:physiology / Q000601:surgery*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D010149:Postoperative Pain / Q000503:physiopathology; D017060:Patient Satisfaction; D018903:Photorefractive Keratectomy; D011183:Postoperative Complications; D011446:Prospective Studies; D014481:United States; D014486:United States Food and Drug Administration; D014792:Visual Acuity / Q000502:physiology; D014945:Wound Healing / Q000502:physiology