stereoacuity after photorefractive keratectomy in anisometropia

purpose: to determine changes in streoacuity in anisometropic myopic eyes after photorefractive keratectomy (prk). methods: this quasi-experimental clinical trial was performed in myopic patients with at least 1 d of in anisometropia spherical, astigmatic or spherical equivalent who underwent photorefractive keratectomy (prk) using the technolas 217 z excimer laser machine. changes in streoacuity were evaluated. tno and butterfly stereoacuity tests before prk and at 2 weeks, 1 month and 3 months after prk. results: overall, 98 eyes of 49 patients (71.4% male and 28.6% female subjects) with mean age of 28±5.5 years and mean myopia of -3.32±1.74d and mean astigmatism of 1.3±1.3 d were enrolled in study. preoperative mean stereoacuity values were 102±103.44 sec/arc and 56.8±41 sec/arc by tno and butterfly stereoacuity tests which changed to 90±110.52 sec/arc (p=0.009)، and 56.5±41.3 sec/arc (p=0.80) respectively 3 months after prk. total proportion of improvement in stereoacuity values was 10.2% and 6.12% by tno and butterfly stereoacuity tests respectively. conclusion: stereoacuity improves after photorefractive keratectomy in anisometropic myopic patients. this  improvement is more significant with tno test than the butterfly stereoacuity test.