Wang Xi, Baldwin Alex S, Hess Robert F
Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
Invest Ophthalmol Vis Sci. 2021 Sep 2;62(12):10. doi: 10.1167/iovs.62.12.10.
Our visual system compares the inputs received from the two eyes to estimate the relative depths of features in the retinal image. We investigated how an imbalance in the strength of the input received from the two eyes affects stereopsis. We also explored the level of agreement between different measurements of sensory eye imbalance.
We measured the sensory eye imbalance and stereoacuity of 30 normally sighted participants. We made our measurements using a modified amblyoscope. The sensory eye imbalance was assessed through three methods: the difference between monocular contrast thresholds, the difference in dichoptic masking weight, and the contribution of each eye to a fused binocular percept. We referred them as the "threshold imbalance," "masking imbalance," and "fusion imbalance," respectively. The stereoacuity threshold was measured by having subjects discriminate which of four circles were displaced in depth. All of our tests were performed using stimuli of the same spatial frequency (2.5 cycles/degree).
We found a relationship between stereoacuity and sensory eye imbalance. However, this was only the case for fusion imbalance measurement (ρ = 0.52; P = 0.003). Neither the threshold imbalance nor the masking imbalance was significantly correlated with stereoacuity. We also found the threshold imbalance was correlated with both the fusion and masking imbalances (r = 0.46, P = 0.011 and r = 0.49, P = 0.005, respectively). However, a nonsignificant correlation was found between the fusion and masking imbalances.
Our findings suggest that there exist multiple types of sensory eye dominance that can be assessed by different tasks. We find only imbalances in dominance that result in biases to fused percepts are correlated with stereoacuity.
我们的视觉系统会比较从双眼接收到的输入信息，以估计视网膜图像中特征的相对深度。我们研究了双眼接收到的输入强度不平衡如何影响立体视觉。我们还探讨了不同感觉性眼不平衡测量方法之间的一致性水平。
我们测量了30名视力正常参与者的感觉性眼不平衡和立体视敏度。我们使用改良的弱视镜进行测量。通过三种方法评估感觉性眼不平衡：单眼对比阈值之间的差异、双眼分视掩蔽权重的差异以及每只眼睛对融合双眼感知的贡献。我们分别将它们称为“阈值不平衡”、“掩蔽不平衡”和“融合不平衡”。通过让受试者辨别四个圆圈中哪个在深度上发生了位移来测量立体视敏度阈值。我们所有的测试均使用相同空间频率（2.5周/度）的刺激进行。
我们发现立体视敏度与感觉性眼不平衡之间存在关系。然而，仅融合不平衡测量的情况如此（ρ = 0.52；P = 0.003）。阈值不平衡和掩蔽不平衡均与立体视敏度无显著相关性。我们还发现阈值不平衡与融合不平衡和掩蔽不平衡均相关（分别为r = 0.46，P = 0.011和r = 0.49，P = 0.005）。然而，融合不平衡与掩蔽不平衡之间的相关性不显著。
我们的研究结果表明，存在多种类型的感觉性眼优势，可以通过不同任务进行评估。我们发现只有导致融合感知偏差的优势不平衡与立体视敏度相关。
