Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Krembil Research Institute, Donald K Johnson Eye Institute, University Health Network, Toronto, Ontario, Canada.
Ophthalmic Physiol Opt. 2022 Mar;42(2):258-271. doi: 10.1111/opo.12925. Epub 2021 Dec 4.
For normally sighted observers, the centre of the macula-the fovea-provides the sharpest vision and serves as the reference point for the oculomotor system. Typically, healthy observers have precise oculomotor control and binocular visual performance that is superior to monocular performance. These functions are disturbed in patients with macular disease who lose foveal vision. An adaptation to central vision loss is the development of a preferred retinal locus (PRL) in the functional eccentric retina, which is determined with a fixation task during monocular viewing. Macular disease often affects the two eyes unequally, but its impact on binocular function and fixational control is poorly understood. Given that patients' natural viewing condition is binocular, the aim of this article was to review current research on binocular visual function and fixational oculomotor control in macular disease. Our findings reveal that there is no overall binocular gain across a range of visual functions, although clear evidence exists for subgroups of patients who exhibit binocular summation or binocular inhibition, depending on the clinical characteristics of their two eyes. The monocular PRL of the better eye has different characteristics from that of the worse eye, but during binocular viewing the PRL of the better eye drives fixational control and may serve as the new reference position for the oculomotor system. We conclude that evaluating binocular function in patients with macular disease reveals important clinical aspects that otherwise cannot be determined solely from examining monocular functions, and can lead to better disease management and interventions.
对于正常视力的观察者来说,黄斑中心——中央凹——提供最清晰的视觉,并作为眼动系统的参考点。通常,健康的观察者具有精确的眼动控制和优于单眼的双眼视觉性能。黄斑疾病患者的这些功能受到干扰,因为他们失去了中央凹视力。对中心视力丧失的一种适应是在功能偏心视网膜中发展出一个首选视网膜位置(PRL),这可以通过单眼观察时的注视任务来确定。黄斑疾病通常会使双眼受到不同程度的影响,但对双眼功能和固视眼动控制的影响知之甚少。鉴于患者的自然观察条件是双眼,本文的目的是综述黄斑疾病中双眼视觉功能和固视眼动控制的当前研究。我们的研究结果表明,尽管在某些患者中存在双眼总和或双眼抑制的证据,但在一系列视觉功能中,没有整体的双眼增益,这取决于他们双眼的临床特征。好眼的单眼 PRL 与坏眼的 PRL 具有不同的特征,但在双眼观察时,好眼的 PRL 驱动固视控制,并可能成为眼动系统的新参考位置。我们得出结论,评估黄斑疾病患者的双眼功能可以揭示出重要的临床方面,而这些方面仅通过检查单眼功能是无法确定的,并且可以导致更好的疾病管理和干预。