Experimental correction of irregular corneal astigmatism using topography-based flying-spot-mode excimer laser photoablation

Am J Ophthalmol. 1998 Feb;125(2):252-6. doi: 10.1016/s0002-9394(99)80102-0.

Abstract

Purpose: To present a novel experimental approach for treating irregular corneal astigmatism.

Methods: After decomposition of topographic analysis data into orthogonal Zernike polynomials, a regular target surface was defined, and the ablation profile was calculated. In a polymethylmethacrylate with an irregular surface, computer-controlled ablation was performed using a 193-nm excimer laser in "flying-spot mode."

Results: The difference between flattest and steepest hemimeridians in the 3-mm zone, surface regularity index, and surface asymmetry index were reduced from 8.7 to 1.1 diopters, 1.19 to 0.39, and 1.84 to 0.14, respectively.

Conclusion: Tying corneal topography into laser software offers a straightforward concept for correction of irregular corneal astigmatism in an experimental model.

MeSH terms

  • Astigmatism / surgery*
  • Cornea / surgery*
  • Corneal Topography*
  • Humans
  • Lasers, Excimer
  • Models, Anatomic
  • Photorefractive Keratectomy / methods*
  • Polymethyl Methacrylate

Substances

  • Polymethyl Methacrylate