The Effect of Photorefractive Keratectomy with Technolas 217z and Lasersight LSX Excimer Laser Systems on the Refractive Errors Correction

Document Type : Original Article (s)

Authors

1 Professor, Department of Ophtalmology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

2 Resident, Department of Ophtalmology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

3 Associate Professor, Department of Ophtalmology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

4 Assistant Professor, Department of Ophtalmology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

Abstract

Background: To evaluate refractive, visual, topographic, and wavefront outcome of photorefractive keratectomy (PRK) for treatment of myopia and myopic astigmatism with two different excimer laser systems: Technolas 217z and Lasersight LSX excimer lasers.Methods: 183 eyes of 95 patients enrolled in this clinical trial. Patients underwent PRK in a Sadra refractive surgery center with Technolas or Lasersight system by a single surgeon between 2007 and 2011. For PRK we used Technolas 217z in one group and Lasersight LSX excimer laser in another group. Subjects examined before and 24 months after surgery evaluating vision, refraction, Orbscan topography, and Wavefront analysis. Data collected, analyzed with SPSS 16. We used Student t-test for statistical data analysis.Finding: 83 eyes were in the Lasersight group and 100 eyes in the Technolas group. Pre-op spherical equivalent refraction was not different in two groops. After surgery it was -0.93 ± 0.73 in Technolas and -0.19 ± 0.40 in Lasersight group, the difference was statistically significant (P < 0.001). Post-op difference vector of astigmatic correction was 0.44 ± 0.58 in Technolas and 0.41 ± 0.26 diopters in Lasersight group (P = 0.04). Post-op LogMAR Acuity was 0.015 ± 0.027 in Technolas and 0.0005 ± 0.005 in Lasersight group (P < 0.001). Post-op Q value of asphericity was 0.24 ± 0.33 in Technolas and 0.46 ± 0.37 in Lasersight group (P < 0.001).  Conclusion: Post-op spherical equivalent refractive outcome, best corrected distance visual acuity and satisfaction were better in Lasersight group. We did not find any difference regarding post-op wavefront analysis between groups.

Keywords

References

  1. Verdon W, Bullimore M, Maloney RK. Visual performance after photorefractive keratectomy. A prospective study. Arch Ophthalmol 1996; 114(12): 1465-72.
  2. Ditzen K, Anschutz T, Schroder E. Photorefractive keratectomy to treat low, medium, and high myopia: a multicenter study. J Cataract Refract Surg 1994; 20(Suppl): 234-8.
  3. Artal P, Benito A, Tabernero J. The human eye is an example of robust optical design. J Vis 2006; 6(1): 1-7.
  4. Manns F, Ho A, Parel JM, Culbertson W. Ablation profiles for wavefront-guided correction of myopia and primary spherical aberration. J Cataract Refract Surg 2002; 28(5): 766-74.
  5. Cano D, Barbero S, Marcos S. Comparison of real and computer-simulated outcomes of LASIK refractive surgery. J Opt Soc Am A Opt Image Sci Vis 2004; 21(6): 926-36.
  6. Porter J, Yoon G, Lozano D, Wolfing J, Tumbar R, Macrae S, et al. Aberrations induced in wavefront-guided laser refractive surgery due to shifts between natural and dilated pupil center locations. J Cataract Refract Surg 2006; 32(1): 21-32.
  7. Chalita MR, Chavala S, Xu M, Krueger RR. Wavefront analysis in post-LASIK eyes and its correlation with visual symptoms, refraction, and topography. Ophthalmology 2004; 111(3): 447-53.
  8. Jankov MR, Panagopoulou SI, Tsiklis NS, Hajitanasis GC, Aslanides M, Pallikaris G. Topography-guided treatment of irregular astigmatism with the wavelight excimer laser. J Refract Surg 2006; 22(4): 335-44.
  9. Kapadia MS, Krishna R, Shah S, Wilson SE. Surgically induced astigmatism after photorefractive keratectomy with the excimer laser. Cornea 2000; 19(2): 174-9.
  10. McCormick GJ, Porter J, Cox IG, Macrae S. Higher-order aberrations in eyes with irregular corneas after laser refractive surgery. Ophthalmology 2005; 112(10): 1699-709.
  11. Koller T, Seiler T. Four corneal presbyopia corrections: simulations of optical consequences on retinal image quality. J Cataract Refract Surg 2006; 32(12): 2118-23.
  12. Seiler T, Kaemmerer M, Mierdel P, Krinke HE. Ocular optical aberrations after photorefractive keratectomy for myopia and myopic astigmatism. Arch Ophthalmol 2000; 118(1): 17-21.
  13. Mrochen M, Eldine MS, Kaemmerer M, Seiler T, Hutz W. Improvement in photorefractive corneal laser surgery results using an active eye-tracking system. J Cataract Refract Surg 2001; 27(7): 1000-6.
  14. Mihashi T. Higher-order wavefront aberrations induced by small ablation area and sub-clinical decentration in simulated corneal refractive surgery using a perturbed schematic eye model. Semin Ophthalmol 2003; 18(1): 41-7.
  15. Mrochen M, Kaemmerer M, Mierdel P, Seiler T. Increased higher-order optical aberrations after laser refractive surgery: a problem of subclinical decentration. J Cataract Refract Surg 2001; 27(3): 362-9.
  16. Thibos LN, Applegate RA, Schwiegerling JT, Webb R. Standards for reporting the optical aberrations of eyes. J Refract Surg 2002; 18(5): S652-S660.
  17. Buhren J, Kohnen T. Factors affecting the change in lower-order and higher-order aberrations after wavefront-guided laser in situ keratomileusis for myopia with the Zyoptix 3.1 system. J Cataract Refract Surg 2006; 32(7): 1166-74.
  18. Webber SK, McGhee CN, Bryce IG. Decentration of photorefractive keratectomy ablation zones after excimer laser surgery for myopia. J Cataract Refract Surg 1996; 22(3): 299-303.
  19. Davies N, Diaz-Santana L, Lara-Saucedo D. Repeatability of ocular wavefront measurement. Optom Vis Sci 2003; 80(2): 142-50.
  20. Stojanovic A, Nitter TA. 200 Hz flying-spot technology of the LaserSight LSX excimer laser in the treatment of myopic astigmatism: six and 12 month outcomes of laser in situ keratomileusis and photorefractive keratectomy. J Cataract Refract Surg 2001; 27(8): 1263-77.
  21. Hashemi H, Nazari R, Amoozadeh J, Beheshtnejad AH, Jabbarvand M, Mohammadpour M, et al. Comparison of postoperative higher-order aberrations and contrast sensitivity: tissue-saving versus conventional photorefractive keratectomy for low to moderate myopia. J Cataract Refract Surg 2010; 36(10): 1732-40.
  22. Serrao S, Lombardo G, Ducoli P, Lombardo M. Optical performance of the cornea six years following photorefractive keratectomy for myopia. Invest Ophthalmol Vis Sci 2011; 52(2): 846-57.
  23. Guirao A, Williams DR, MacRae SM. Effect of beam size on the expected benefit of customized laser refractive surgery. J Refract Surg 2003; 19(1): 15-23.
  24. Huang D, Arif M. Spot size and quality of scanning laser correction of higher order wavefront aberrations. J Refract Surg 2001; 17(5): S588-S591.
Journal of Isfahan Medical School
Volume 29, Issue 136 - Serial Number 136
March and April 2011
Pages 467-474

Files

History

  • Receive Date: 23 May 2011
  • Revise Date:
  • Accept Date: 06 April 2022

Share

How to cite

Statistics