Evaluation of fixation characteristics in amblyopia using microperimetry.

Abstract

To evaluate fixation characteristics in amblyopia using macular analyzer integrity assessment (MAIA) microperimetry and to investigate the factors affecting fixation stability. This prospective, cross-sectional study enrolled a total of 58 amblyopic patients who were between 8 and 55years old. Average threshold macular sensitivity (AT) and fixation characteristics were assessed using MAIA microperimetry. Two Bivariate contour ellipse area (BCEA) fixation indices (63% and 95% proportional values) and the percentage of fixation points within 1° and 2° from the fovea (P1 and P2) were used to assess fixation stability. Non-amblyopic fellow eyes were used as the control group for comparison. AT and fixation stability indices (P1, P2, BCEA 63%, BCEA 95%) were worse in the amblyopic eyes than in the fellow eyes (p < 0.05, for all indices). There was a moderate positive correlation between best corrected visual acuity (BCVA), and AT, and P2, and a moderate negative correlation between BCVA, and BCEA indices. 48% of the eyes were eccentrically fixating (the percentage was 25% in the anisometropic group, 52% in the strabismic group, and 69% in the combined group) and 32% in the non-amblyopic eye (p = 0.052). The preferred fixation eccentricity in amblyopic eyes was significantly greater than the non-amblyopic eyes (p = 0.004), and there was a negative correlation between preferred fixation eccentricity and BCVA (p = 0.012, r = -0.327). Our data showed a decrease in fixation stability, a positive correlation between fixation stability and BCVA, and a negative correlation between preferred fixation eccentricity and BCVA in amblyopic eyes.