Optical analysis of presbyLASIK treatment by a light propagation algorithm

J Refract Surg. 2007 Jan;23(1):39-44.


Purpose: To evaluate the changes in the optical quality of corneas of hyperopic patients operated using central multifocal presbyLASIK treatment through the study of light patterns around the retinal plane.

Methods: This study included eight hyperopic eyes that underwent central presbyLASIK surgery with Presby-one software using an H. Eye Tech Technovision excimer laser platform. Mean patient age was 57 years. Mean preoperative spherical equivalent refraction was 1.28 +/- 0.87 diopters (D). Mean distance decimal visual acuity with correction was 1.02 +/- 0.13 and without correction was 0.37 +/- 0.15. The optical quality was characterized by the Strehl ratio, the spot size on the retina, and objective decimal visual acuity calculated based on measured corneal topography using Fresnel propagation algorithm based on a realistic eye model.

Results: The postoperative spherical equivalent refraction was -0.55 +/- 0.48 D. The distance decimal visual acuity with correction was 0.94 and without correction was 0.70. The pseudoaccommodation range was 1.60 +/- 0.40 D. A good Pearson correlation coefficient was obtained (r2 = 0.86) for the linear fit between the real and calculated decimal visual acuity for the eight eyes. The Strehl ratio value on the retinal plane increased after the surgery by a mean factor of 4.7.

Conclusions: With a complete characterization of the eye and a complete propagation algorithm (that takes into account all refractive surfaces in the eye at the same time), it is possible to evaluate the optical quality in eyes of patients who have undergone central presbyLASlK treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Algorithms*
  • Cornea / pathology*
  • Corneal Topography
  • Humans
  • Keratomileusis, Laser In Situ / methods*
  • Middle Aged
  • Presbyopia / pathology
  • Presbyopia / surgery*
  • Refraction, Ocular
  • Treatment Outcome
  • Visual Acuity