Purpose: The purpose of this study was to investigate the relationship between fixation stability deficits in anisometropic amblyopia and various visual functions, as well as the underlying retinal structure.
Methods: All 164 patients with anisometropic amblyopia were recruited in this cross-sectional study. The contrast sensitivity function (CSF) was measured using the qCSF method, whereas the MP-3 microperimeter was used to assess fixation stability and locate the preferred retinal locus. Bivariate contour ellipse area (BCEA) of both the amblyopic and the fellow eyes was used as the dependent variable. Based on previous research and clinical practice, the following variables were selected as independent variables for regression modeling to explore potential influencing factors: gender, age, area under the log CSF (AULCSF), absolute interocular difference (IOD) in spherical equivalent refraction (SER), AULCSF-IOD, the eccentricity of the preferred retinal locus, patching history, and the log BCEA of the contralateral eye.
Results: A total of 161 participants (87 men and 74 women, average age = 20.26 ± 8.79 years, ranging from 5 to 51 years old) completed all examinations. Three participants were excluded due to their inability to complete the required examinations. There were significant differences between the amblyopic and the fellow eyes in terms of SER, best-corrected visual acuity, AULCSF, log BCEA, and the eccentricity of the preferred retinal locus (all P < 0.001). Both the amblyopic and the fellow eyes exhibited fixation stability deficits and eccentric fixation. The regression model showed that fixation stability in the amblyopic eye (log BCEA) was significantly associated with age, AULCSF of the amblyopic eye, AULCSF-IOD, eccentricity of the amblyopic eye, and log BCEA of the fellow eye (all P < 0.05). Fixation stability in the fellow eye (log BCEA) was significantly associated with eccentricity of the fellow eye, and log BCEA of the amblyopic eye (all P < 0.05).
Conclusions: Eccentric fixation and fixation stability deficits were observed in both the amblyopic and the fellow eyes, with fixation stability in both eyes being correlated with the eccentricity of the preferred retinal locus. These findings suggest that in the clinical management of amblyopia, attention should be given to the fixation stability and fixation characteristics of both the amblyopic and fellow eyes.