Contrast visual acuity after excimer laser photorefractive keratectomy

Photorefractive keratectomy (PRK) is rapidly becoming the most frequently performed method of surgical correction of myopia. Some patients, however, express dissatisfaction with their postoperative 'quality of vision' despite having uncorrected visual acuities of 20/20 or better. We evaluated retrospectively the preoperative and postoperative contrast visual acuities of 21 eyes of 18 patients (mean age 30.4±7.2 years, mean correction 5.50±2.28 D, mean preoperative refraction -5,56±2.27 D) who underwent PRK. Variable Contrast Visual Acuity Charts (VCVAC) were used to test contrast visual acuities. All subjects included in this study had postoperative uncorrected visual acuities of 20/20 or better at both 3 and 6 months. Overall, in the medium and low contrast charts, statistically significant decreases were observed at both 3 and 6 months. These subjects were then separated into two groups, based on whether slit-lamp examination showed haze. Significant decreases in medium and low contrast visual acuities were observed in the group with haze but not in the group with on haze. These results suggest that prevention of postoperative haze is important to the patients' 'quality of vision' after PRK.