Customized LASIK treatment for myopia based on preoperative manifest refraction and higher order aberrometry: the Rochester nomogram.

Abstract

PURPOSE:

To develop and test the efficacy of myopic treatment, based on preoperative manifest refraction and higher order aberrations, in enhancing the postoperative refractive error following customized LASIK treatment and compare results with the manufacturer-recommended sphere offset Zyoptix treatment nomogram, which does not account for the preoperative higher order aberrations.

METHODS:

One hundred seventy-five myopic eyes (89 patients) were treated based on the Rochester nomogram, which specified the amount of myopia to be treated based on preoperative manifest refraction and higher order aberrations, including third order aberrations and spherical aberration. Postoperative refractive error was measured at 1 month and compared to that theoretically estimated with the Zyoptix nomogram.

RESULTS:

The mean preoperative sphere and cylinder were -4.52 +/- 2.05 diopters (D) and -0.81 +/- 0.70 D, respectively. The mean postoperative spheres were +0.04 +/- 0.33 D and +0.31 +/- 0.54 D, using the Rochester and Zyoptix nomograms, respectively. The mean postoperative spherical equivalent refractions were -0.11 +/- 0.34 D and +0.15 +/- 0.53 D using the Rochester and Zyoptix nomograms, respectively. The Rochester nomogram reduced the range of postoperative spherical equivalent to +/- 1.00 D, which was significantly better than that using the Zyoptix nomogram (t = 5.46, P < .0001), which would have resulted in 8% of eyes with a postoperative spherical equivalent refraction > +/- 1.00 D. Using the Rochester nomogram, 93.1% of eyes attained a postoperative UCVA > or = 20/20. The percentage of postoperative hyperopic overcorrection decreased to 2.8% in the Rochester nomogram group from 22.3% using the Zyoptix nomogram, which only adjusts spherical values based on preoperative sphere and does not account for preoperative aberrations.

CONCLUSIONS:

The Rochester nomogram compensates for the effect of preoperative higher order aberrations on sphere and provided reduced range of postoperative spherical equivalent refraction.

• Authors: Manoj V Subbaram, Scott M MacRae
• Journal: Journal of refractive surgery (Thorofare, N.J. : 1995) (J Refract Surg) Vol. 23 Issue 5 Pg. 435-41 (May 2007) ISSN: 1081-597X [Print] United States
• PMID: 17523502 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Corneal Topography
• Humans
• Keratomileusis, Laser In Situ (methods)
• Myopia (physiopathology, surgery)
• Nomograms
• Postoperative Period
• Preoperative Care
• Refraction, Ocular
• Regression Analysis
• Time Factors
• Treatment Outcome
• Visual Acuity