Data from: Monocular blur alters the tuning characteristics of stereopsis for spatial frequency and size

Our sense of depth perception is mediated by spatial filters at different scales in the visual brain - low spatial frequency channels provide the basis for coarse stereopsis, whereas high spatial frequency channels provide for fine stereopsis. It is well established that monocular blurring of vision results in decreased stereoacuity. However, previous studies have used tests that are broadband in their spatial frequency content. It is not yet entirely clear how the processing of stereopsis in different spatial frequency channels is altered in response to binocular input imbalance. Here, we applied a new stereoacuity test based on narrow-band Gabor stimuli. By manipulating the carrier spatial frequency, we were able to reveal the tuning dynamics of stereopsis to spatial frequency, spanning from coarse to fine stereopsis, under blurred conditions. Our findings show that increasing monocular blur elevates stereoacuity thresholds ‘selectively’ at high spatial frequencies, gradually shifting the optimum frequency to lower spatial frequencies. Surprisingly, stereopsis for low frequency targets was only mildly affected even with an acuity difference of eight lines on a standard letter chart. Furthermore, we examined the effect of monocular blur on the size tuning function of stereopsis. The clinical implications of these findings are discussed.

我们的深度知觉由视觉脑内不同尺度的空间滤波器介导——低空间频率通道构成粗略立体视的基础，高空间频率通道则支撑精细立体视。已有充分研究证实，单眼视力模糊会导致立体视锐度（stereoacuity）下降。然而，既往研究所使用的测试，其空间频率成分均为宽带范围。目前尚不完全明确，不同空间频率通道的立体视加工过程，会如何响应双眼输入失衡而发生改变。本研究采用一种基于窄带Gabor刺激（Gabor）的新型立体视锐度测试。通过调控载波空间频率，我们得以在视力模糊条件下，揭示立体视对空间频率的调谐动态，涵盖从粗略到精细的立体视范围。研究结果显示，增加单眼模糊程度会选择性地升高高空间频率下的立体视锐度阈值，逐步将最优频率向更低的空间频率偏移。令人意外的是，即便标准字母视力表上的视力差异达到8行，低频目标对应的立体视仅受到轻微影响。此外，我们还考察了单眼模糊对立体视大小调谐函数的影响。最后讨论了本研究发现的临床意义。