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Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 Years After Surgery

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 Years After Surgery 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. References 1. Curtin BJ. The Myopias: Basic Science and Clinical Management . New York, NY: Harper & Row Publishers Inc; 1985. 2. Sperduto RD, Seigel D, Roberts J, Rowland M. Prevalence of myopia in the United States . Arch Ophthalmol . 1983;101:405-407.Crossref 3. Leibowitz HM, Krueger DE, Maunder LR, et al. The Framingham Eye Study monograph: an ophthalmological and epidemiological study of cataract, glaucoma, diabetic retinopathy, macular degeneration, and visual acuity in a general population of 2631 adults, 1973-1975 . Surv Ophthalmol . 1980;24( (suppl) ):476. 4. Waring GO. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992. 5. Leaming DV. Practice styles and preferences of ASCRS members: 1993 survey . J Cataract Refract Surg . 1994;20:459-467.Crossref 6. Schimmelpfennig BH, Waring GO. Development of refractive keratotomy in the nineteenth century . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:171-178. 7. Akiyama K, Shibata H, Kanai A, et al. Development of radial keratotomy in Japan, 1939-1960 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:179-220. 8. Waring GO. Development of refractive keratotomy in the Soviet Union, 1960-1990 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:221-236. 9. Waring GO. Development of refractive keratotomy in the United States, 1978-1990 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:237-258. 10. Waring G, Lynn M, Nizam A, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study five years after surgery . Ophthalmology . 1991;98:1164-1176.Crossref 11. Waring GO, Lindstrom KL. Results of refractive keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby Year Book Inc; 1992:781-848. 12. Spigelman A, William P, Lindstrom R. Further studies of four incision radial keratotomy . Refract Corneal Surg . 1989;5:292-295. 13. Salz JJ, Salz JM, Salz M, Jones D. Ten years experience with a conservative approach to radial keratotomy . Refract Corneal Surg . 1991;7:12-22. 14. Deitz M, Sanders D, Raanan M. A consecutive series (1982-1985) of radial keratotomies performed with the diamond blade . Am J Ophthalmol . 1987;103:417-422. 15. Werblin TP, Stafford GM. The Casebeer system for predictable keratorefractive surgery: one year evaluation of 205 consecutive eyes . Ophthalmology . 1993;100:1095-1102.Crossref 16. Deitz MR, Sanders DR, Raanan MG, DeLuca M. Long-term (5- to 12-year) follow-up of metal-blade radial keratotomy procedures . Arch Ophthalmol . 1994;112:614-620.Crossref 17. Spigelman AV, Williams PA, Nichols BD, Lindstrom RL. Four-incision radial keratotomy . J Cataract Refract Surg . 1988;14:125-128.Crossref 18. Waring G, Moffitt S, Gelender H, et al. Rationale for and design of the National Eye Institute Prospective Evaluation of Radial Keratotomy (PERK) Study . Ophthalmology . 1983;90:40-58.Crossref 19. Waring G, Lynn M, Culbertson W, et al. Three-year results of the Prospective Evaluation of Radial Keratotomy (PERK) Study . Ophthalmology . 1987;94:1339-1354.Crossref 20. Waring G, Lynn MJ, Fielding B, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 4 years after surgery for myopia . JAMA . 1990;263:1083-1091.Crossref 21. Waring GO, Lynn M, Gelender H, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study one year after surgery . Ophthalmology . 1985;92:177-198.Crossref 22. Waring G, Lynn M, Strahlman E, et al. Stability of refraction during four years after radial keratotomy in the Prospective Evaluation of Radial Keratotomy Study . Am J Ophthalmol . 1991;111:133-144. 23. Sawelson H, Marks R. Five-year results of radial keratotomy . Refract Corneal Surg . 1989;5:8-20. 24. Arrowsmith P, Marks R. Visual, refractive and keratometric results of radial keratotomy: a five-year follow-up . Arch Ophthalmol . 1989;107:506-511.Crossref 25. Neumann AC, Osher RH, Fenzl RE. Radial keratotomy: a comprehensive evaluation . Doc Ophthalmol . 1984;56:275-301.Crossref 26. Lynn M, Waring G, Nizam A, et al. Symmetry of refractive and visual outcome in the Prospective Evaluation of Radial Keratotomy (PERK) Study . Refract Corneal Surg . 1989;5:75-81. 27. Cowden J, Lynn M, Waring GO, PERK Study Group. Repeated radial keratotomy in the Prospective Evaluation of Radial Keratotomy (PERK) Study . Am J Ophthalmol . 1987;103:423-431. 28. Zadnick K, Mutti D, Adams A. The repeatability of measurement of the ocular components . Invest Ophthalmol Vis Sci . 1992;33:2325-2333. 29. SAS Institute Inc. SAS/STAT Software: Changes and Enhancements, Release 6.07 . Cary, NC: SAS Institute Inc; 1992:287-368. 30. Mandelbaum S, Waring G, Forster R, Culbertson W, Rowsey J, Espinal M. Late development of ulcerative keratitis in radial keratotomy scars . Arch Ophthalmol . 1986;104:1156-1160.Crossref 31. Busin M, Suarez H, Bieber S, McDonald MB. Overcorrected visual acuity improved by antiglaucoma medication after radial keratotomy . Am J Ophthalmol . 1986;101:374-375. 32. Deitz MR, Sanders DR, Raanan MG. Progressive hyperopia in radial keratotomy: longterm follow-up of diamond-knife and metal-blade series . Ophthalmology . 1986;93:1284-1289.Crossref 33. Lynn M, Waring G, Sperduto R, PERK Study Group. Factors affecting outcome and predictability of radial keratotomy in the PERK Study . Arch Ophthalmol . 1987;105:42-51.Crossref 34. Sanders D, Deitz M, Gallagher D. Factors affecting predictability of radial keratotomy . Ophthalmology . 1985;92:1237-1243.Crossref 35. Smith RS, Cutro J. Computer analysis of radial keratotomy . CLAO J . 1984;10:241-248. 36. Holladay JT, Waring GO. Optics and topography of radial keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:101-107. 37. Hanna KD, Jouve FE. Preliminary computer simulation of radial keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:1031-1055. 38. Binder PS, Nayak SK, Deg JK, Zavala EY, Sugar J. An ultrastructural and histochemical study of long-term wound healing after radial keratotomy . Am J Ophthalmol . 1987;103:432-440. 39. Binder PS. What we have learned about corneal wound healing from refractive surgery . J Refract Corneal Surg . 1989;5:98-120. 40. Nelson JD, Williams P, Lindstrom RL, Doughman DJ. Map-dot-fingerprint changes in the corneal epithelial basement membrane following radial keratotomy . Ophthalmology . 1985;92:199-205.Crossref 41. Nizam A, Waring GO, Lynn MJ, et al. Stability of refraction and visual acuity during 5 years in eyes with simple myopia . Refract Corneal Surg . 1992;8:439-447. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 Years After Surgery

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Publisher
American Medical Association
Copyright
Copyright © 1994 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.1994.01090220048022
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Abstract

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. References 1. Curtin BJ. The Myopias: Basic Science and Clinical Management . New York, NY: Harper & Row Publishers Inc; 1985. 2. Sperduto RD, Seigel D, Roberts J, Rowland M. Prevalence of myopia in the United States . Arch Ophthalmol . 1983;101:405-407.Crossref 3. Leibowitz HM, Krueger DE, Maunder LR, et al. The Framingham Eye Study monograph: an ophthalmological and epidemiological study of cataract, glaucoma, diabetic retinopathy, macular degeneration, and visual acuity in a general population of 2631 adults, 1973-1975 . Surv Ophthalmol . 1980;24( (suppl) ):476. 4. Waring GO. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992. 5. Leaming DV. Practice styles and preferences of ASCRS members: 1993 survey . J Cataract Refract Surg . 1994;20:459-467.Crossref 6. Schimmelpfennig BH, Waring GO. Development of refractive keratotomy in the nineteenth century . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:171-178. 7. Akiyama K, Shibata H, Kanai A, et al. Development of radial keratotomy in Japan, 1939-1960 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:179-220. 8. Waring GO. Development of refractive keratotomy in the Soviet Union, 1960-1990 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:221-236. 9. Waring GO. Development of refractive keratotomy in the United States, 1978-1990 . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:237-258. 10. Waring G, Lynn M, Nizam A, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study five years after surgery . Ophthalmology . 1991;98:1164-1176.Crossref 11. Waring GO, Lindstrom KL. Results of refractive keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby Year Book Inc; 1992:781-848. 12. Spigelman A, William P, Lindstrom R. Further studies of four incision radial keratotomy . Refract Corneal Surg . 1989;5:292-295. 13. Salz JJ, Salz JM, Salz M, Jones D. Ten years experience with a conservative approach to radial keratotomy . Refract Corneal Surg . 1991;7:12-22. 14. Deitz M, Sanders D, Raanan M. A consecutive series (1982-1985) of radial keratotomies performed with the diamond blade . Am J Ophthalmol . 1987;103:417-422. 15. Werblin TP, Stafford GM. The Casebeer system for predictable keratorefractive surgery: one year evaluation of 205 consecutive eyes . Ophthalmology . 1993;100:1095-1102.Crossref 16. Deitz MR, Sanders DR, Raanan MG, DeLuca M. Long-term (5- to 12-year) follow-up of metal-blade radial keratotomy procedures . Arch Ophthalmol . 1994;112:614-620.Crossref 17. Spigelman AV, Williams PA, Nichols BD, Lindstrom RL. Four-incision radial keratotomy . J Cataract Refract Surg . 1988;14:125-128.Crossref 18. Waring G, Moffitt S, Gelender H, et al. Rationale for and design of the National Eye Institute Prospective Evaluation of Radial Keratotomy (PERK) Study . Ophthalmology . 1983;90:40-58.Crossref 19. Waring G, Lynn M, Culbertson W, et al. Three-year results of the Prospective Evaluation of Radial Keratotomy (PERK) Study . Ophthalmology . 1987;94:1339-1354.Crossref 20. Waring G, Lynn MJ, Fielding B, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 4 years after surgery for myopia . JAMA . 1990;263:1083-1091.Crossref 21. Waring GO, Lynn M, Gelender H, et al. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study one year after surgery . Ophthalmology . 1985;92:177-198.Crossref 22. Waring G, Lynn M, Strahlman E, et al. Stability of refraction during four years after radial keratotomy in the Prospective Evaluation of Radial Keratotomy Study . Am J Ophthalmol . 1991;111:133-144. 23. Sawelson H, Marks R. Five-year results of radial keratotomy . Refract Corneal Surg . 1989;5:8-20. 24. Arrowsmith P, Marks R. Visual, refractive and keratometric results of radial keratotomy: a five-year follow-up . Arch Ophthalmol . 1989;107:506-511.Crossref 25. Neumann AC, Osher RH, Fenzl RE. Radial keratotomy: a comprehensive evaluation . Doc Ophthalmol . 1984;56:275-301.Crossref 26. Lynn M, Waring G, Nizam A, et al. Symmetry of refractive and visual outcome in the Prospective Evaluation of Radial Keratotomy (PERK) Study . Refract Corneal Surg . 1989;5:75-81. 27. Cowden J, Lynn M, Waring GO, PERK Study Group. Repeated radial keratotomy in the Prospective Evaluation of Radial Keratotomy (PERK) Study . Am J Ophthalmol . 1987;103:423-431. 28. Zadnick K, Mutti D, Adams A. The repeatability of measurement of the ocular components . Invest Ophthalmol Vis Sci . 1992;33:2325-2333. 29. SAS Institute Inc. SAS/STAT Software: Changes and Enhancements, Release 6.07 . Cary, NC: SAS Institute Inc; 1992:287-368. 30. Mandelbaum S, Waring G, Forster R, Culbertson W, Rowsey J, Espinal M. Late development of ulcerative keratitis in radial keratotomy scars . Arch Ophthalmol . 1986;104:1156-1160.Crossref 31. Busin M, Suarez H, Bieber S, McDonald MB. Overcorrected visual acuity improved by antiglaucoma medication after radial keratotomy . Am J Ophthalmol . 1986;101:374-375. 32. Deitz MR, Sanders DR, Raanan MG. Progressive hyperopia in radial keratotomy: longterm follow-up of diamond-knife and metal-blade series . Ophthalmology . 1986;93:1284-1289.Crossref 33. Lynn M, Waring G, Sperduto R, PERK Study Group. Factors affecting outcome and predictability of radial keratotomy in the PERK Study . Arch Ophthalmol . 1987;105:42-51.Crossref 34. Sanders D, Deitz M, Gallagher D. Factors affecting predictability of radial keratotomy . Ophthalmology . 1985;92:1237-1243.Crossref 35. Smith RS, Cutro J. Computer analysis of radial keratotomy . CLAO J . 1984;10:241-248. 36. Holladay JT, Waring GO. Optics and topography of radial keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:101-107. 37. Hanna KD, Jouve FE. Preliminary computer simulation of radial keratotomy . In: Waring GO, ed. Refractive Keratotomy for Myopia and Astigmatism . St Louis, Mo: Mosby-Year Book Inc; 1992:1031-1055. 38. Binder PS, Nayak SK, Deg JK, Zavala EY, Sugar J. An ultrastructural and histochemical study of long-term wound healing after radial keratotomy . Am J Ophthalmol . 1987;103:432-440. 39. Binder PS. What we have learned about corneal wound healing from refractive surgery . J Refract Corneal Surg . 1989;5:98-120. 40. Nelson JD, Williams P, Lindstrom RL, Doughman DJ. Map-dot-fingerprint changes in the corneal epithelial basement membrane following radial keratotomy . Ophthalmology . 1985;92:199-205.Crossref 41. Nizam A, Waring GO, Lynn MJ, et al. Stability of refraction and visual acuity during 5 years in eyes with simple myopia . Refract Corneal Surg . 1992;8:439-447.

Journal

Archives of OphthalmologyAmerican Medical Association

Published: Oct 1, 1994

References