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.
Department of Ophthalmology, Emory Eye Center, Atlanta, GA 30322.
G O
GO
Waring
M J
MJ
Lynn
B
B
Fielding
P A
PA
Asbell
H D
HD
Balyeat
E A
EA
Cohen
W
W
Culbertson
D J
DJ
Doughman
P
P
Fecko
M B
MB
McDonald
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