Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Visual Performance After Photorefractive Keratectomy: A Prospective Study

Visual Performance After Photorefractive Keratectomy: A Prospective Study Abstract Objective: To prospectively examine the effect of excimer laser photorefractive keratectomy (PRK) on best-corrected visual performance using psychophysical tests that were likely to be more sensitive to image degradation than high-contrast Snellen visual acuity. Design: Prospective cases series. Patients: A cohort of 18 subjects with an average of -5.08 diopters (D) of myopia (SD=±1.63 D) was tested before PRK and at 3, 6, and 12 months after PRK. Intervention: Photorefractive keratectomy was performed using a laser (Excimed UV200, Summit Technology, Waltham, Mass) and a polymethylmethacrylate mask; a 5-mm ablation zone was used. Main Outcome Measures: Best-corrected highcontrast visual acuity, best-corrected low-contrast visual acuity (18% Weber contrast), and best-corrected letter-contrast sensitivity. Measurements were repeated with dilated pupils and in the presence of a glare source. Results: One year after PRK, the mean best-corrected high-contrast visual acuity was reduced by half a line (P=.01), and the mean best-corrected low-contrast visual acuity was reduced by 11/2 lines (P=.002). The losses were somewhat greater when the subject's pupils were dilated and a glare source was used. The reduction in dilated low-contrast visual acuity was positively correlated with the decentration of the ablation zone (r=0.47), providing evidence of an association between corneal topography and the functional outcome of PRK. Conclusion: Low-contrast visual acuity losses after PRK are notably greater than high-contrast visual acuity losses for best-corrected vision. Low-contrast visual acuity is a sensitive measure for gauging the outcome success and safety of refractive surgery. References 1. Trokel SL, Srinivasan R, Braren B. Excimer laser surgery of the cornea . Am J Ophthalmol . 1983;96:710-715. 2. Seiler T, Wollensak J. Myopic photorefractive keratectomy with the excimer laser: one-year follow-up . Ophthalmology . 1991;98:1156-1163.Crossref 3. Gartry DS, Kerr Muir MG, Marshall J. Excimer laser photorefractive keratectomy: 18-month follow-up . Ophthalmology . 1992;99:1209-1219.Crossref 4. Maguen E, Salz JJ, Nesburn AB, et al. Results of excimer laser photorefractive keratectomy for the correction of myopia . Ophthalmology . 1994;101:1548-1556.Crossref 5. Epstein D, Fagerholm P, Hamberg-Nystrom H, Tengroth B. Twenty-four-month follow-up of excimer laser photorefractive keratectomy for myopia: refractive and visual acuity results . Ophthalmology . 1994;101:1558-1563.Crossref 6. Talley AR, Hardten DR, Sher NA, et al. Results one year after using the 193-nm excimer laser for photorefractive keratectomy in mild to moderate myopia . Am J Ophthalmol . 1994;118:304-311. 7. Dutt S, Steinert RF, Raizman MB, Puliafito CA. One-year results of excimer laser photorefractive keratectomy for low to moderate myopia . Arch Ophthalmol . 1994;112:1427-1436.Crossref 8. O'Brart DP, Lohmann CP, Fitzke FW, et al. Disturbances in night vision after excimer laser photorefractive keratectomy . Eye . 1994;8:46-51.Crossref 9. O'Brart DP, Lohmann CP, Fitzke FW, Smith SE, Kerr-Muir MG, Marshall J. Night vision after excimer laser photorefractive keratectomy: haze and halos . Eur J Ophthalmol . 1994;4:43-51. 10. Ficker LA. Bates AK, Steele AD, et al. Excimer laser photorefractive keratectomy for myopia: 12 month follow-up . Eye . 1993;7:617-624.Crossref 11. Ambrosio G, Cennamo G, De Marco R, Loffredo L, Rosa N, Sebastiani A. Visual function before and after photorefractive keratectomy for myopia . Refract Corneal Surg . 1994;10:129-136. 12. Butuner Z, Elliott DB, Gimbel HV, Slimmon S. Visual function one year after excimer laser photorefractive keratectomy . Refract Corneal Surg . 1994;10:625-630. 13. Lohmann CP, Gartry DS, Muir MK, Timberlake GT, Fitzke FW, Marshall J. Corneal haze after excimer laser refractive surgery: objective measurements and functional implications . Eur J Ophthalmol . 1991;1:173-180. 14. Mannis MJ. Results of excimer laser photorefractive keratectomy for the correction of myopia: discussion . Ophthalmology . 1994;101:1556-1557. 15. Doane JF, Cavanaugh TB, Durrie DS, Hassanein KM. Relation of visual symptoms to topographic ablation zone decentration after excimer laser photorefractive keratectomy . Ophthalmology . 1995;102:42-47.Crossref 16. O'Brart DP, Corbett MC, Lohmann CP, Kerr Muir MG, Marshall J. The effects of ablation diameter on the outcome of excimer laser photorefractive keratectomy: a prospective, randomized, double-blind study . Arch Ophthalmol . 1995;113:438-443.Crossref 17. O'Brart DP, Lohmann CP, Klonos G, et al. The effects of topical corticosteroids and plasmin inhibitors on refractive outcome, haze, and visual performance after photorefractive keratectomy: a prospective, randomized, observer-masked study . Ophthalmology . 1994;101:1565-1574.Crossref 18. Maguire LJ. Keratorefractive surgery, success, and the public health . Am J Ophthalmol . 1994;117:394-398. 19. Bailey IL, Lovie JE. New design principles for visual acuity letter charts . Am J Optom Physiol Optom . 1976;53:740-745.Crossref 20. Bailey IL, Bullimore MA, Raasch TW, Taylor HR. Clinical grading and the effects of scaling . Invest Ophthalmol Vis Sci . 1991;32:422-432. 21. Pelli DG, Robson JG, Wilkins AJ. The design of a new letter chart for measuring contrast sensitivity . Clin Vis Sci . 1988;2:187-199. 22. Elliott DB, Bullimore MA, Bailey IL. Improving the reliability of the Pelli-Robson contrast sensitivity test . Clin Vis Sci . 1991;6:471-475. 23. Elliott DB, Bullimore MA. Assessing the reliability, discriminative ability, and validity of disability glare tests . Invest Ophthalmol Vis Sci . 1993;34:108-119. 24. Terrell J, Bechara SJ, Nesburn A, Waring GO, Macy J, Maloney RK. The effect of globe fixation on ablation zone centration in photorefractive keratectomy . Am J Ophthalmol . 1995;119:612-619. 25. Applegate RA, Howland HC. Magnification and visual acuity in refractive surgery . Arch Ophthalmol . 1993;111:1335-1342.Crossref 26. Applegate RA, Chundru U. Experimental verification of computational methods to calculate magnification in refractive surgery . Arch Ophthalmol . 1995;113:571-577.Crossref 27. Balakrishnan V, Lim AS, Tseng PS, Hong LC. Decentered ablation zones resulting from photorefractive keratectomy with an erodible mask . Int Ophthalmol . 1993;17:179-184.Crossref 28. O'Brart DP, Lohmann CP, Fitzke FW, et al. Discrimination between the origins and functional implications of haze and halo at night after photorefractive keratectomy . Refract Corneal Surg . 1994;10( (suppl) ):S281. 29. Lohmann CP, Timberlake GT, Fitzke FW, Gartry DS, Muir MK, Marshall J. Corneal light scattering after excimer laser photorefractive keratectomy: the objective measurements of haze . Refract Corneal Surg . 1992;8:114-121. 30. Maloney RK, Friedman M, Harmon T, et al. A prototype erodible mask delivery system for the excimer laser . Ophthalmology . 1993;100:542-549.Crossref 31. Hersh PS, Patel R. Correction of myopia and astigmatism using an ablatable mask . Refract Corneal Surg . 1994;10( (suppl) ):S250-S254. 32. Amano S, Tanaka S, Shimizu K. Topographical evaluation of centration of excimer laser myopic photorefractive keratectomy . J Cataract Refract Surg . 1994;20:616-619.Crossref 33. Lin DT. Corneal topographic analysis after excimer photorefractive keratectomy . Ophthalmology . 1994;101:1432-1439.Crossref 34. Schwartz-Goldstein BH, Hersh PS. Corneal topography of phase III excimer laser photorefractive keratectomy: optical zone centration analysis . Ophthalmology . 1995;102:951-962.Crossref 35. Seiler T, Reckmann W, Maloney RK. Effective spherical aberration of the cornea as a quantitative descriptor in corneal topography . J Cataract Refract Surg . 1993;19( (suppl) ):155-165.Crossref 36. Casson EJ, Jackson WB, Mintsioulis G. High and low contrast acuity following excimer photorefractive keratectomy . In: Vision Science and Its Applications . Washington, DC: Optical Society of America Technical Digest Series; 1995;1:45-48. 37. Salz JJ, Maguen E, Nesburn AB, et al. A two-year experience with excimer laser photorefractive keratectomy for myopia . Ophthalmology . 1993;100:873-882.Crossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

Visual Performance After Photorefractive Keratectomy: A Prospective Study

Loading next page...
 
/lp/american-medical-association/visual-performance-after-photorefractive-keratectomy-a-prospective-6us8kZeCD9
Publisher
American Medical Association
Copyright
Copyright © 1996 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.1996.01100140663003
Publisher site
See Article on Publisher Site

Abstract

Abstract Objective: To prospectively examine the effect of excimer laser photorefractive keratectomy (PRK) on best-corrected visual performance using psychophysical tests that were likely to be more sensitive to image degradation than high-contrast Snellen visual acuity. Design: Prospective cases series. Patients: A cohort of 18 subjects with an average of -5.08 diopters (D) of myopia (SD=±1.63 D) was tested before PRK and at 3, 6, and 12 months after PRK. Intervention: Photorefractive keratectomy was performed using a laser (Excimed UV200, Summit Technology, Waltham, Mass) and a polymethylmethacrylate mask; a 5-mm ablation zone was used. Main Outcome Measures: Best-corrected highcontrast visual acuity, best-corrected low-contrast visual acuity (18% Weber contrast), and best-corrected letter-contrast sensitivity. Measurements were repeated with dilated pupils and in the presence of a glare source. Results: One year after PRK, the mean best-corrected high-contrast visual acuity was reduced by half a line (P=.01), and the mean best-corrected low-contrast visual acuity was reduced by 11/2 lines (P=.002). The losses were somewhat greater when the subject's pupils were dilated and a glare source was used. The reduction in dilated low-contrast visual acuity was positively correlated with the decentration of the ablation zone (r=0.47), providing evidence of an association between corneal topography and the functional outcome of PRK. Conclusion: Low-contrast visual acuity losses after PRK are notably greater than high-contrast visual acuity losses for best-corrected vision. Low-contrast visual acuity is a sensitive measure for gauging the outcome success and safety of refractive surgery. References 1. Trokel SL, Srinivasan R, Braren B. Excimer laser surgery of the cornea . Am J Ophthalmol . 1983;96:710-715. 2. Seiler T, Wollensak J. Myopic photorefractive keratectomy with the excimer laser: one-year follow-up . Ophthalmology . 1991;98:1156-1163.Crossref 3. Gartry DS, Kerr Muir MG, Marshall J. Excimer laser photorefractive keratectomy: 18-month follow-up . Ophthalmology . 1992;99:1209-1219.Crossref 4. Maguen E, Salz JJ, Nesburn AB, et al. Results of excimer laser photorefractive keratectomy for the correction of myopia . Ophthalmology . 1994;101:1548-1556.Crossref 5. Epstein D, Fagerholm P, Hamberg-Nystrom H, Tengroth B. Twenty-four-month follow-up of excimer laser photorefractive keratectomy for myopia: refractive and visual acuity results . Ophthalmology . 1994;101:1558-1563.Crossref 6. Talley AR, Hardten DR, Sher NA, et al. Results one year after using the 193-nm excimer laser for photorefractive keratectomy in mild to moderate myopia . Am J Ophthalmol . 1994;118:304-311. 7. Dutt S, Steinert RF, Raizman MB, Puliafito CA. One-year results of excimer laser photorefractive keratectomy for low to moderate myopia . Arch Ophthalmol . 1994;112:1427-1436.Crossref 8. O'Brart DP, Lohmann CP, Fitzke FW, et al. Disturbances in night vision after excimer laser photorefractive keratectomy . Eye . 1994;8:46-51.Crossref 9. O'Brart DP, Lohmann CP, Fitzke FW, Smith SE, Kerr-Muir MG, Marshall J. Night vision after excimer laser photorefractive keratectomy: haze and halos . Eur J Ophthalmol . 1994;4:43-51. 10. Ficker LA. Bates AK, Steele AD, et al. Excimer laser photorefractive keratectomy for myopia: 12 month follow-up . Eye . 1993;7:617-624.Crossref 11. Ambrosio G, Cennamo G, De Marco R, Loffredo L, Rosa N, Sebastiani A. Visual function before and after photorefractive keratectomy for myopia . Refract Corneal Surg . 1994;10:129-136. 12. Butuner Z, Elliott DB, Gimbel HV, Slimmon S. Visual function one year after excimer laser photorefractive keratectomy . Refract Corneal Surg . 1994;10:625-630. 13. Lohmann CP, Gartry DS, Muir MK, Timberlake GT, Fitzke FW, Marshall J. Corneal haze after excimer laser refractive surgery: objective measurements and functional implications . Eur J Ophthalmol . 1991;1:173-180. 14. Mannis MJ. Results of excimer laser photorefractive keratectomy for the correction of myopia: discussion . Ophthalmology . 1994;101:1556-1557. 15. Doane JF, Cavanaugh TB, Durrie DS, Hassanein KM. Relation of visual symptoms to topographic ablation zone decentration after excimer laser photorefractive keratectomy . Ophthalmology . 1995;102:42-47.Crossref 16. O'Brart DP, Corbett MC, Lohmann CP, Kerr Muir MG, Marshall J. The effects of ablation diameter on the outcome of excimer laser photorefractive keratectomy: a prospective, randomized, double-blind study . Arch Ophthalmol . 1995;113:438-443.Crossref 17. O'Brart DP, Lohmann CP, Klonos G, et al. The effects of topical corticosteroids and plasmin inhibitors on refractive outcome, haze, and visual performance after photorefractive keratectomy: a prospective, randomized, observer-masked study . Ophthalmology . 1994;101:1565-1574.Crossref 18. Maguire LJ. Keratorefractive surgery, success, and the public health . Am J Ophthalmol . 1994;117:394-398. 19. Bailey IL, Lovie JE. New design principles for visual acuity letter charts . Am J Optom Physiol Optom . 1976;53:740-745.Crossref 20. Bailey IL, Bullimore MA, Raasch TW, Taylor HR. Clinical grading and the effects of scaling . Invest Ophthalmol Vis Sci . 1991;32:422-432. 21. Pelli DG, Robson JG, Wilkins AJ. The design of a new letter chart for measuring contrast sensitivity . Clin Vis Sci . 1988;2:187-199. 22. Elliott DB, Bullimore MA, Bailey IL. Improving the reliability of the Pelli-Robson contrast sensitivity test . Clin Vis Sci . 1991;6:471-475. 23. Elliott DB, Bullimore MA. Assessing the reliability, discriminative ability, and validity of disability glare tests . Invest Ophthalmol Vis Sci . 1993;34:108-119. 24. Terrell J, Bechara SJ, Nesburn A, Waring GO, Macy J, Maloney RK. The effect of globe fixation on ablation zone centration in photorefractive keratectomy . Am J Ophthalmol . 1995;119:612-619. 25. Applegate RA, Howland HC. Magnification and visual acuity in refractive surgery . Arch Ophthalmol . 1993;111:1335-1342.Crossref 26. Applegate RA, Chundru U. Experimental verification of computational methods to calculate magnification in refractive surgery . Arch Ophthalmol . 1995;113:571-577.Crossref 27. Balakrishnan V, Lim AS, Tseng PS, Hong LC. Decentered ablation zones resulting from photorefractive keratectomy with an erodible mask . Int Ophthalmol . 1993;17:179-184.Crossref 28. O'Brart DP, Lohmann CP, Fitzke FW, et al. Discrimination between the origins and functional implications of haze and halo at night after photorefractive keratectomy . Refract Corneal Surg . 1994;10( (suppl) ):S281. 29. Lohmann CP, Timberlake GT, Fitzke FW, Gartry DS, Muir MK, Marshall J. Corneal light scattering after excimer laser photorefractive keratectomy: the objective measurements of haze . Refract Corneal Surg . 1992;8:114-121. 30. Maloney RK, Friedman M, Harmon T, et al. A prototype erodible mask delivery system for the excimer laser . Ophthalmology . 1993;100:542-549.Crossref 31. Hersh PS, Patel R. Correction of myopia and astigmatism using an ablatable mask . Refract Corneal Surg . 1994;10( (suppl) ):S250-S254. 32. Amano S, Tanaka S, Shimizu K. Topographical evaluation of centration of excimer laser myopic photorefractive keratectomy . J Cataract Refract Surg . 1994;20:616-619.Crossref 33. Lin DT. Corneal topographic analysis after excimer photorefractive keratectomy . Ophthalmology . 1994;101:1432-1439.Crossref 34. Schwartz-Goldstein BH, Hersh PS. Corneal topography of phase III excimer laser photorefractive keratectomy: optical zone centration analysis . Ophthalmology . 1995;102:951-962.Crossref 35. Seiler T, Reckmann W, Maloney RK. Effective spherical aberration of the cornea as a quantitative descriptor in corneal topography . J Cataract Refract Surg . 1993;19( (suppl) ):155-165.Crossref 36. Casson EJ, Jackson WB, Mintsioulis G. High and low contrast acuity following excimer photorefractive keratectomy . In: Vision Science and Its Applications . Washington, DC: Optical Society of America Technical Digest Series; 1995;1:45-48. 37. Salz JJ, Maguen E, Nesburn AB, et al. A two-year experience with excimer laser photorefractive keratectomy for myopia . Ophthalmology . 1993;100:873-882.Crossref

Journal

Archives of OphthalmologyAmerican Medical Association

Published: Dec 1, 1996

References