Abstract
Abstract: :
Purpose:To evaluate visual function in eyes that underwent LASIK to correct high or low myopia and to objectively simulate the vision of those eyes. Methods:The modulation transfer function (MTF) was obtained under cycloplegia in LASIK patients pre- and postoperatively using a new point spread function analysis system (PSFAS). The pattern in MTF was checked with the corrected refractive power after LASIK and the size of the artificial pupil (2, 4, or 6 mm). The retinal images of various sized Landolt's rings were simulated by convolution with single-pass PSF obtained by PSFAS. The effect of the corrected refractive power and the size of the artificial pupil on the contrast of those images was studied. Results:The postoperative MTF decreased compared with the preoperative MTF in all patients, and more so in high myopia than in low myopia. The MTF increased as the size of the artificial pupil decreased, within the sizes studied. The visual simulation of Landolt's rings objectively showed the difference in vision in those eyes. The contrast of the simulated retinal images decreased not only as the corrected refractive power increased but also as the size of the artificial pupil increased. Conclusion:Visual function in LASIK patients was affected both by the corrected power and the pupil size. The visual simulation using this system is clinically useful to objectively evaluate the visual function of these eyes.
Keywords: 500 optical properties • 519 physiological optics • 550 refractive surgery: optical quality