Coordination of Eye and Head Movements in Central Field Loss

摘要 老年性黄斑变性是中央视野视力丧失的最常见原因，使 中心场损失(CFL)是当今世界的一个主要问题.三分之二的CFL患者抱怨说 前庭问题，如头晕和不稳定，导致潜在致命事故的高发生率 然后摔倒。患者群体的高龄加剧了这个问题，因为有记录的 衰老时前庭功能下降。CFL患者的前庭功能障碍可能是由于校准错误所致 或非最佳的稳定眼球运动-许多基本的眼球运动行为高度依赖于视网膜 输入。前庭反应受损的个体在视野稳定性、导航、 以及自我和外部的运动感知。这些限制对CFL患者尤其适用，他们的视力 视力已经受损，前庭系统成了他们的主要运动来源 信息。此外，前庭缺陷可能会影响患者使用头部运动来补偿 由于视觉偏心和视野斑块，导致眼球运动受限。尽管在日常生活中， 视觉和前庭的相互作用，这些行为在CFL中还没有得到全面的研究。 这项提议旨在解决这一差距。第一个目标是考察头部运动对流畅的贡献 在CFL患者中的追求。这一目标将先前量化CFL中平滑追逐缺陷的工作扩展到更多 自然的头部自由状态，以确定头部运动在CFL中是有益的还是有害的。 了解头部运动的作用可以指导未来的康复策略和临床 在这群人中进行测试。第二个目的是检查CFL对角前庭-眼反射的影响。 (VOR)。这种反射对中心凹的依赖性很小，因此在CFL中很可能不受影响。然而，小凹 众所周知，视觉有助于校准这种反射并抑制其当头部 运动跟随目标运动。角度VOR的任何方面的缺陷都会对视力造成影响 受影响个体的不稳定和前庭不适。了解这些问题将有助于 在这一人群中进行必要的治疗。最终目的是考察CFL对翻译VOR的影响，a 完全依赖中心凹的行为，当身体有运动时，这是必不可少的。确定 其损害程度和CFL的确切影响是了解因此而导致的前庭功能障碍的关键 视力缺陷。VOR反应将在被动和意志的主动运动中进行研究。以前的研究 表明这两种类型的行为在处理过程中存在根本差异，这表明它们 可能会受到中央视力丧失的不同影响。如果存在，这种二分法可能会对如何 建议和训练患者与周围环境互动，同时保持积极和富有成效的 生活方式。主动行为(包括无头平稳追逐)将在 这个项目，而被动的前庭研究构成了独立研究的主体。

ABSTRACT Age-related macular degeneration is the most common cause of vision loss in the central visual field, making central field loss (CFL) a major problem in the world today. Two-thirds of patients with CFL complain of vestibular problems, such as dizziness and instability, leading to a high incidence of potentially fatal accidents and falls. The problem is exacerbated by the patient population's advanced age, due to the documented decline in vestibular function in senescence. Vestibular deficits in CFL patients are likely due to miscalibrated or non-optimal stabilizing eye movements - many essential oculomotor behaviors are highly reliant on retinal input. Individuals with compromised vestibular responses have difficulties with visual field stability, navigation, and self- and external motion perception. These limitations are particularly true for CFL patients, whose visual acuity is already compromised and for whom the vestibular system becomes the predominant source of motion information. Furthermore, vestibular deficits likely affect patients' use of head movements to compensate for oculomotor limitations due to eccentric viewing and a patchy visual field. Despite the day-to-day importance of visual and vestibular interaction, these behaviors have not been comprehensively studied in CFL. This proposal seeks to address this gap. The first aim examines the contribution of head movements to smooth pursuit in CFL patients. This aim extends previous work quantifying smooth pursuit deficits in CFL to a more natural, head-unrestrained condition to determine if head movements are helpful or detrimental in CFL. Understanding the contribution of head movements can guide future rehabilitation strategies and clinical testing in this population. The second aim examines the effect of CFL on the angular vestibuloocular reflex (VOR). The reflex has little foveal dependence and is thus likely to be unaffected in CFL. However, foveal vision is known to contribute to both the calibration of this reflex and to its suppression when the head movement follows target motion. A deficit in any aspect of angular VOR will have consequences on the visual instability and vestibular discomfort of the affected individuals. Understanding these problems would inform necessary treatments in this population. The final aim examines the effects of CFL on translational VOR, a behavior that is completely fovea-dependent and is essential when body movement is present. Determining the degree of its impairment and exact influences of CFL is key to understanding vestibular dysfunction due to this visual deficit. VOR responses will be studied during passive and volitional, active motion. Previous research suggests fundamental differences in the processing of these two types of behavior, which indicates that they might be affected differently by central vision loss. If present, this dichotomy could have implications on how patients are advised and trained to interact with their environment while maintaining an active and productive lifestyle. Active behaviors (including head-free smooth pursuit) will be examined during the mentored portion of this project, while passive vestibular studies make up the bulk of the independent research.