Krembil Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada.
Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
PLoS One. 2020 Feb 25;15(2):e0229168. doi: 10.1371/journal.pone.0229168. eCollection 2020.
Glaucoma is considered a progressive optic neuropathy because of the damage and death of the retinal ganglion cells. It is also a neurodegenerative disease because it affects neural structures in the visual system and beyond, including the corpus callosum-the largest white matter structure involved in inter-hemispheric transfer of information. In this study we probed the dysfunction of the inter-hemispheric processing in patients with mild glaucoma using the phenomenon of binocular rivalry. Patients with mild glaucoma and no measurable visual field defects and age-matched controls underwent a thorough visual assessment. Then they participated in a series of psychophysical tests designed to examine the binocular rivalry derived from intra- and inter-hemispheric processing. Static horizontal and vertical sinewave gratings were presented dichoptically using a double-mirror stereoscope in 3 locations: centrally, to probe inter-hemispheric processing, and peripherally to the left or to the right, to probe intra-hemispheric processing. Although the two groups were matched in functional measures, rivalry rate of the glaucoma group was significantly lower than that of the control group for the central location, but not for the peripheral location. These results were driven mainly by the patients with normal tension glaucoma whose average rivalry rate for the central location (from which information reaches the two hemispheres) was almost half (46% lower) that of the controls. These results indicate a dysfunction in inter-hemispheric transfer in mild glaucoma that can be detected behaviourally before any changes in standard functional measures.
青光眼被认为是一种进行性视神经病变，因为视网膜神经节细胞的损伤和死亡。它也是一种神经退行性疾病，因为它影响视觉系统内外的神经结构，包括胼胝体——参与信息半球间传递的最大白质结构。在这项研究中，我们使用双眼竞争现象来探测轻度青光眼患者半球间处理的功能障碍。轻度青光眼患者和无可测量的视野缺陷且年龄匹配的对照组接受了全面的视觉评估。然后，他们参加了一系列旨在检查来自半球间和半球内处理的双眼竞争的心理物理测试。使用双镜立体镜在 3 个位置呈现静态水平和垂直正弦光栅：中央位置，探测半球间处理，以及左侧或右侧的外围位置，探测半球内处理。尽管两组在功能测量上匹配，但青光眼组的竞争率在中央位置（信息到达两个半球的位置）明显低于对照组，但在外围位置则不然。这些结果主要是由正常眼压性青光眼患者驱动的，他们在中央位置（信息到达两个半球的位置）的平均竞争率几乎是对照组的一半（低 46%）。这些结果表明，轻度青光眼存在半球间传递功能障碍，在标准功能测量出现任何变化之前，可以通过行为检测到。
