Association between Anisometropia as Well as Visual Acuity, Aniseikonia, and Stereopsis in the Absence of Strabismus

Objective: The current study aimed to assess the association between the type of anisometropia and its effects on monocular and binocular best-corrected vision acuity (BCVA), aniseikonia, and stereopsis in the absence of strabismus. Methods: In total, 162 individuals with anisometropia and healthy eyes and without a previous history of amblyopia therapy and eye surgery were included in the analysis. According to spherical and cylindrical components and spherical equivalent, they were divided into the spherical hyperopic anisometropia (SHA, n = 31), spherical myopic anisometropia (SMA, n = 45), astigmatic or cylindrical hyperopic anisometropia (CHA, n = 22), and astigmatic or cylindrical myopic anisometropia (CMA, n = 64) groups. Patients without anisometropia (NA, n = 188) were classified under the control group. The effects of anisometropia on monocular and binocular BCVA, aniseikonia, and stereoacuity were examined. Results: The NA group had a significantly lower LogMAR of BCVA of the right eye (RE), left eye (LE), worse eye than the SHA, SMA, CMA, and CHA groups. Moreover, the SMA group had significantly lower LogMAR of BCVA than the CHA group (p < 0.05). However, there was no significant difference between the groups in terms of the descriptive values of aniseikonia (p = 0.052). The NA group had significantly lower stereoacuity values in log10 arc seconds than the CHA (p < 0.05), CMA (p < 0.05), and SMA (p < 0.05) groups. The SMA groups had significantly lower stereoacuity values in log10 arc seconds than the CMA (p < 0.05) and SHA (p < 0.05) groups. There was a significantly positive correlation in the anisometropia group between aniseikonia and stereoacuity values in log10 arc seconds (r = 0.160; p = 0.041). Conclusion: Worse visual levels of the RE, LE, worse eye, BCVA difference, and lower stereopsis were evidenced in each type of anisometropia defined in this study. Cylindrical hyperopic anisometropia (CHA) resulted in a statically significant worsening VA level and stereopsis than cylindrical myopic (CMA) or spherical myopic anisometropia.