Fixation stability improvement after occlusion treatment for severe amblyopia.

Abstract

To investigate the improvement of fixation stability of severe amblyopia with traditional patching treatment by the MP-1 microperimeter. Eighteen patients with severe unilateral amblyopia were enrolled and received prescribed 6h per day of patching of the fellow eye with optical correction if needed. Fixation test was performed on eighteen severe unilateral amblyopia patients by the MP-1 microperimeter in baseline, 3-month and 6-month after treatment. The bivariate contour ellipse area (BCEA, deg2) was used to quantify fixation stability. The RMANOVA showed that significant differences were found in best-corrected visual acuity (BCVA) between amblyopia eyes/fellow eyes (AE/FE) group (F = 113.52, p < 0.001) and among follow-up time (F = 74.684, p < 0.001). Moreover, a significant interaction could be found between AE/FE group and follow-up time (baseline/3-month/6-month, F = 60.189,p < 0.001). Post hoc analysis by Bonferroni showed significant improvement of BCVA in AE at 3-month (p < 0.001) and 6-month (p < 0.001), compared to baseline, and also significant between 3-month and 6-month (p = 0.002). The RMANOVA showed that significant differences were found in BCEA between AE/FE group (F = 8.432, p = 0.006) and among follow-up time (F = 10.431, p = 0.003). Moreover, a significant interaction could be found between AE/FE group and follow-up time (F = 9.099, p = 0.005). The mean BCEA of AE changed from 13.14 ± 17.97 deg2 at baseline to 6.03 ± 7.27 deg2 at 3-month (p = 0.084) and 3.38 ± 6.40 deg2 at 6-month (p = 0.018). No significant difference of BCEA in fellow eyes was found during the follow-up period (between baseline and 3-month: p = 0.230; between baseline and 6-month: p = 0.692. 0.89 ± 1.02, 0.58 ± 0.40, and 0.03 ± 0.04deg2 for baseline, 3-month and 6-month, respectively). No significant correlation could be found between BCEA and BCVA of AE, both in enrollment and follow-up (p > 0.05). The fixation stability in theamblyopic eyes is significantly worse than that of thefellow eyes in patients withunilateral severeamblyopia. The fixation stability became better after 6-month occlusion treatment, but the change offixation stabilitywasnot correlated with visual acuity improvement. These quantitative results highlight the importance of fixation in the mechanism of amblyopia.