Optical modeling of radial keratotomy incision patterns

American Journal of Ophthalmology
J SchwiegerlingM L Palmer

Abstract

To determine the optical effects of higher-order corneal shape variations resulting from radial keratotomy. Videokeratoscopic height data were obtained postoperatively from several patients who had undergone radial keratotomy. For each of clear central zone sizes 3.00 mm, 4.00 mm, and 4.75 mm, two patients were chosen randomly from the larger study group. Data obtained 2 weeks postoperatively from these six patients were decomposed into the Zernike polynomials, and the low-order expansion terms were removed to disclose corneal height variations (the radial keratotomy artifact). The artifact was applied to a schematic eye model, and exact ray-tracing was used to evaluate visual performance, which was defined as a function of pupil diameter, optical zone (central clear zone) size, and radial keratotomy artifact centration. The radial keratotomy artifact degrades visual performance at midspatial frequencies more than it does at high spatial frequencies. This effect is most pronounced for smaller optical zones and for a pupil diameter of 4 mm. Visual performance remains nearly constant for small decentration (0.5 mm or less) of the radial keratotomy optical zone from the corneal apex. Residual refractive error, corneal asphericity,...Continue Reading

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Citations

Feb 23, 2000·Journal of Cataract and Refractive Surgery·J Schwiegerling, R W Snyder
Dec 11, 2002·Clinical & Experimental Optometry : Journal of the Australian Optometrical Association·D Robert IskanderLeo G Carney
Jun 10, 2004·Clinical & Experimental Optometry : Journal of the Australian Optometrical Association·David A Atchison
Jun 15, 2006·Optometry and Vision Science : Official Publication of the American Academy of Optometry·Rafael NavarroJos L Hernández-Matamoros
Sep 8, 1998·Journal of the Optical Society of America. A, Optics, Image Science, and Vision·J Schwiegerling, R W Snyder
Nov 17, 2004·Optometry and Vision Science : Official Publication of the American Academy of Optometry·Jason Turuwhenua, Jon Henderson
Jan 5, 2002·Ophthalmology·Debby K Holmes-HigginMerwyn R Greenlick
Dec 31, 2002·Survey of Ophthalmology·Nancy I Fan-PaulGeorge J Florakis

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