[Comparison of visual function in myopia over -6.0 dpt after photorefractive keratectomy and laser in situ...

1. 41 myopes undergoing PRK and 31 patients undergoing LASIK for correction of spherical refractive error were examined before and 1, 3, 6 a 12 months after surgery on Schwind Multiscan with ablation zone between 5 and 7 mm. Mean preoperative spherical equivalent of refraction was -8.0 +/- 1.7 D in PRK group and -9.2 +/- 2.1 D in LASIK one. 2. Contrast sensitivity (CS) was tested on a computerized system of the Contrast sensitivity 8010 type in 6 spatial frequencies (0.74; 1.97; 3.69; 7.39; 14.77; 29.55 c/deg) and the best corrected visual acuity (BCVA) was measured on the normalized charts with Landolt rings. 3. At 12 months postoperatively, mean spherical equivalent of refraction was -0.6 +/- 1.0 D (PRK) and -1.0 +/- 0.8 D (LASIK). A refractive error within +/- 0.5 D had 31.5% (PRK) and 57.5% (LASIK) patients. Increasing of BCVA was measured in 51.5% (PRK) and 41.9% (LASIK) patients about 1 optotype to 2.5 lines. Mean CS in 6 frequencies reached 99.4; 102; 105; 109; 115 and 140% of preoperative values in PRK group and only 96; 95.8; 96.3; 95.8; 97.8 and 94.6% in LASIK one. 4. At 12 months after surgery, mean spherical equivalent, CS was better and number of patients with increased BCVA was significantly higher after PRK, than those attained with LASIK. On the other hand, a number of patients with a refractive error within +/- 0.5 D was higher and percentage of reoperations was lower in LASIK group.