Einfluss des Astigmatismus auf die Stereopsis

Purpose: Astigmatism is one of the most common forms of refractive error and can affect visual acuity as well as stereopsis. The aim of this study was to examine the influence of uncorrected symmetrical mixed astigmatism on binocular visual acuity and stereo threshold in different axis orientations. Material and Methods: In a non-randomized cross-sectional study, 40 participants were examined in two age groups (18 - 30 years and over 50 years). Using trial lenses, symmetrical mixed astigmatism was simulated in three axis orientations (90°, 0°, 45°) and two magnitudes (0.5 D and 1.0 D). Binocular visual acuity was determined as an interpolated logMAR value, while the stereo threshold was measured using the Stereo Acuity Test D10. Data were analyzed using repeated-­measures ANOVA and non-parametric tests. Results: Binocular visual acuity significantly decreased with an increasing magnitude of simulated astigmatism (p < 0.001). Visual acuity was significantly worse at 1.0 D compared to 0.5 D. The stereo threshold also significantly increased with higher astigmatism (p < 0.01), indicating a decrease in stereopsis. The axis orientation of astigmatism had a significant effect on stereopsis: Against-the-rule and oblique astigmatism caused greater impairments than with-the-rule astigmatism. The effect of age was significant only for with-the-rule astigmatism at 1.0 D (p = 0.019), with older participants showing greater deterioration in stereopsis than younger ones. Conclusion: Uncorrected mixed astigmatism leads to a significant decrease in binocular visual acuity and stereopsis, with the impact varying depending on axis orientation and astigmatism magnitude. The results suggest that even low levels of astigmatism should be corrected, particularly in individuals with limited accommodative ability.