Stereoacuity after Wavefront‑guided Photorefractive Keratectomy in Anisometropia

Purpose: To determine changes in stereoacuity in anisometropic myopic eyes after photorefractive keratectomy (PRK). Methods: Myopic patients with at least 1 diopter (D) of anisometropia in sphere, astigmatism, or spherical equivalent who were referred to our hospital for excimer refractive surgery were enrolled as a prospective sequential interventional case series. All patients underwent wavefront‑guided photorefractive keratectomy (WFG‑PRK) using the Technolas Perfect Vision (217z) Excimer laser machine. Changes in binocular stereoacuity were evaluated using the TNO and Butterfly stereoacuity tests before and at 2 weeks, 1 month, and 3 months after the operation. Results: Between January and November 2015, a total of 98 eyes of 49 patients (71.4% men) with a mean age of 28 ± 5.5 years, mean myopia of −3.32 ± 1.74 D, and mean astigmatism of 1.3 ± 1.3 D were enrolled in this study. Preoperative mean stereoacuity values were 102 ± 103.44 and 56.8 ± 41 seconds of arc (s/arc)as measured by the TNO and Butterfly stereoacuity tests. Mean stereoacuity improved to 90 ± 110.52 s/arc (P = 0.009) and 56.5 ± 41.3 s/arc (P = 0.80), respectively, 6 months after WFG‑PRK. Overall improvement in stereoacuity was 10.2% and 6.12% according to the TNO and Butterfly stereoacuity tests, respectively. Conclusion: Stereoacuity improves after WFG‑PRK for treatment of anisometropic myopia. This improvement is more accurately detectable by the TNO than the Butterfly stereoacuity test.