The aim of this grant is to examine 435 core and 97 pilot patients (a total of 953 eyes) ten years after surgery in the Prospective Evaluation of Radial Keratotomy (PERK) study. These patients received radial keratotomy and were followed for five years in the initial phase of the PERK study from 1983-1989. Because radial keratotomy is the most frequently performed refractive corneal surgical procedure -- 150,000 or more operations being done annually in the United States -- hundreds of thousands being done worldwide, it is important to document the efficacy, safety, stability and predictability of radial keratotomy over the long term. 1) What are the results for major outcome variables: 1) cycloplegic and manifest (fogging technique) refraction, corrected and uncorrected visual acuity (NEI charts), central keratometric power (Bausch & Lomb keratometer), intraocular pressure and corneal thickness (ultrasonic pachometry)? 2) How have the refraction and visual acuity changed from five to ten years and what is the stability of the approximately 25% of eyes that showed a continued increase in the effect of the surgery between six months and four years? 3) How many eyes have lost two or more Snellen lines of spectacle corrected visual acuity compared to baseline and what other complications have arisen? 4) Are endothelial changes detectable by small-field and large-field specular microscopy with morphometric analysis? 5) What is the topography of the cornea after radial keratotomy as determined by computer- assisted videokeratography, and how do the aspheric corneal optics affect visual acuity and refraction as measured by refraction through fixed aperatures? 6) How does contrast sensitivity after radial keratotomy compare to that in the contralateral unoperated eye of the same patient and to that in age and refraction matched controls? 7) Can clinically meaningful amounts of glare be detected as measured by sine-wave gratings or Pelli-Robson charts? 8) What is the level of subjective patient satisfaction as determined by formal psychometric testing? 9) What is the pattern of glasses and contact lens wearing? Because of the intense effort to maintain the PERK population between the five and ten-year examinations, a 90% follow-up rate is expected. Nine clinical centers under the direction of an ophthalmologist principal investigator, with a coordinator- technician, will perform the standardized examinations during 1993. Patients living outside the metropolitan area of a PERK center will be returned to a center for examination.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Cooperative Clinical Research--Cooperative Agreements (U10)
Project #
5U10EY003761-12
Application #
3559112
Study Section
Vision Research and Training Committee (VSN)
Project Start
1980-09-30
Project End
1996-02-29
Budget Start
1992-03-01
Budget End
1993-02-28
Support Year
12
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Emory University
Department
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
McDonnell, P J; Nizam, A; Lynn, M J et al. (1996) Morning-to-evening change in refraction, corneal curvature, and visual acuity 11 years after radial keratotomy in the prospective evaluation of radial keratotomy study. The PERK Study Group. Ophthalmology 103:233-9
Waring 3rd, G O; Lynn, M J; McDonnell, P J (1994) Results of the prospective evaluation of radial keratotomy (PERK) study 10 years after surgery. Arch Ophthalmol 112:1298-308
Waring 3rd, G O; Lynn, M J; Strahlman, E R et al. (1991) Stability of refraction during four years after radial keratotomy in the prospective evaluation of radial keratotomy study. Am J Ophthalmol 111:133-44
Holladay, J T; Lynn, M J; Waring 3rd, G O et al. (1991) The relationship of visual acuity, refractive error, and pupil size after radial keratotomy. Arch Ophthalmol 109:70-6
Waring 3rd, G O; Lynn, M J; Nizam, A et al. (1991) Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study five years after surgery. The Perk Study Group. Ophthalmology 98:1164-76
Waring 3rd, G O; Lynn, M J; Fielding, B et al. (1990) Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 4 years after surgery for myopia. Perk Study Group. JAMA 263:1083-91
Lynn, M J; Waring 3rd, G O; Carter, J T (1990) Combining refractive error and uncorrected visual acuity to assess the effectiveness of refractive corneal surgery. Refract Corneal Surg 6:103-9;discussion 109-12
Lynn, M J; Waring 3rd, G O; Nizam, A et al. (1989) Symmetry of refractive and visual acuity outcome in the Prospective Evaluation of Radial Keratotomy (PERK) study. Refract Corneal Surg 5:75-81
Waring 3rd, G O (1989) Making sense of keratospeak II: Proposed conventional terminology for corneal topography. Refract Corneal Surg 5:362-7
Santos, V R; Waring 3rd, G O; Lynn, M J et al. (1988) Morning-to-evening change in refraction, corneal curvature, and visual acuity 2 to 4 years after radial keratotomy in the PERK Study. Ophthalmology 95:1487-93

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