Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 Years After Surgery
- 1 October 1994
- journal article
- clinical trial
- Published by American Medical Association (AMA) in American Journal of Ophthalmology
- Vol. 112 (10), 1298-1308
- https://doi.org/10.1001/archopht.1994.01090220048022
Abstract
Objective: To determine the long-term effects and stability of refraction following a standardized technique of radial keratotomy for myopia in the nine-center Prospective Evaluation of Radial Keratotomy (PERK) Study 10 years after surgery. Methods: Radial keratotomy using eight centripetal incisions was performed to reduce myopia of -2.00 to -8.75 diopters in 1982 and 1983. A mean of 10 years later, patients underwent a standardized ophthalmic examination similar to previous study examinations. Results: Of 427 patients (793 eyes that underwent radial keratotomy), 374 patients (88%) (693 eyes) returned for the 10-year examination. Of 675 eyes with refractive data, 38% had a refractive error within 0.50 D and 60% within 1.00 D. For 310 first-operated eyes, the mean refractive error was -0.36 D at 6 months and changed in a hyperopic direction to +0.51 D at 10 years. The average rate of change was +0.21 D/y between 6 months and 2 years and +0.06 D/y between 2 and 10 years. Between 6 months and 10 years, the refractive error of 43% of eyes changed in the hyperopic direction by 1.00 D or more. The hyperopic shift was statistically associated with the diameter of the clear zone. Uncorrected visual acuity was 20/20 or better in 53% of 681 eyes and 20/40 or better in 85%. Loss of spectaclecorrected visual acuity of 2 lines or more on a Snellen chart occurred in 3% of all 793 eyes that underwent surgery. Among 310 patients with bilateral radial keratotomy, 70% reported not wearing spectacles or contact lenses for distance vision at 10 years. Conclusion: The PERK technique of radial keratotomy eliminated distance optical correction in 70% of patients, with a reasonable level of safety. A shift of the refractive error in the hyperopic direction continued during the entire 10 years after surgery.Keywords
This publication has 13 references indexed in Scilit:
- Three year results of refractive keratotomy using the Casebeer SystemJournal of Cataract & Refractive Surgery, 1996
- Practice styles and preferences of ASCRS members—1993 surveyJournal of Cataract & Refractive Surgery, 1994
- Long-term (5- to 12-Year) Follow-up of Metal-Blade Radial Keratotomy ProceduresAmerican Journal of Ophthalmology, 1994
- Four incision radial keratotomyJournal of Cataract & Refractive Surgery, 1988
- A Consecutive Series (1982-1985) of Radial Keratotomies Performed with the Diamond BladeAmerican Journal of Ophthalmology, 1987
- Factors Affecting Outcome and Predictability of Radial Keratotomy in the PERK StudyAmerican Journal of Ophthalmology, 1987
- Late Development of Ulcerative Keratitis in Radial Keratotomy ScarsAmerican Journal of Ophthalmology, 1986
- Overcorrected Visual Acuity Improved by Antiglaucoma Medication After Radial KeratotomyAmerican Journal of Ophthalmology, 1986
- Radial keratotomy: A comprehensive evaluationDocumenta Ophthalmologica, 1984
- Prevalence of Myopia in the United StatesAmerican Journal of Ophthalmology, 1983