Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 4 years after surgery for myopia. Perk Study Group.
The Prospective Evaluation of Radial Keratotomy Study is a nine-center clinical trial of a surgical technique to reduce simple myopia by making incisions in the cornea. There were 435 patients (one eye per patient is reported) enrolled in the study with a 91% follow-up rate at 4 years after surgery. After surgery, uncorrected visual acuity was 20/40 or better in 76% of eyes. Fifty-five percent of the eyes had a refractive error within +/- 1.00 diopter; 28% were undercorrected, and 17% were overcorrected by more than 1.00 D. The width of the prediction 90% interval for the refractive change was 4.42 D, indicating a lack of predictability. The refractive error was not stable in some eyes; between 6 months and 4 years after surgery, 23% of eyes had a continued effect of the surgery of more than 1.00 D. For 323 patients with both eyes operated on, 64% stated they wore no optical correction. There were few serious complications. Eleven eyes (3%) lost two or three lines of best corrected visual acuity. Two eyes developed delayed bacterial keratitis without significant loss in best corrected visual acuity.
Waring
G O
GO
Department of Ophthalmology, Emory Eye Center, Atlanta, GA 30322.
Lynn
M J
MJ
Fielding
B
B
Asbell
P A
PA
Balyeat
H D
HD
Cohen
E A
EA
Culbertson
W
W
Doughman
D J
DJ
Fecko
P
P
McDonald
M B
MB
D000328:Adult; D001251:Astigmatism; D002986:Clinical Trials as Topic; D005069:Evaluation Studies as Topic; D006801:Humans; D007646:Keratotomy, Radial / Q000706:statistics & numerical data; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D010043:Outcome and Process Assessment, Health Care / Q000706:statistics & numerical data*; D011183:Postoperative Complications; D011446:Prospective Studies; D012029:Refraction, Ocular; D014792:Visual Acuity