VISUAL-VESTIBULAR INTERACTION WITH LOW-VISION AIDS

意义 许多低视力患者具有受损的中央敏锐度， 尽管理论上 受益于放大。 这可能是因为视觉康复 使用望远镜眼镜的限制是放大镜的不稳定性， 视网膜图像在不自主的头部运动，并在协调 视觉搜索所需的眼头运动。 视网膜图像 稳定性通常由视觉-前庭-眼反射提供 （VVOR），由前庭眼反射与 视觉和预测机制（视觉前庭相互作用，VVI）。 必须定量评估使用望远镜的VVOR性能 适当放大，以避免动态的实质性损害 头部运动时的视力。 尽管如此，知识 缺乏关于衰老和病理因素对人体的影响的研究 垂直VVI 目的和方法。 总体目标是定量评估 垂直面VVI机制，作为有用视力的决定因素 在生理性头部运动期间使用望远镜。 眼睛和 将使用磁探测线圈测量头部运动。 效果 在垂直VVOR上的望远镜眼镜的数量将被定量地 以主动和被动头部的生理范围为特征 速度和频率，在正常视力和低视力的成年人。 结果将与视觉引导的单独测量结果相关联。 跟踪. 对VVI和不可预测运动跟踪的影响， 亮度和对比度降低、衰老、病理性眼球震颤和视觉 将研究现场缺陷。 瞬间之间的关系 垂直视网膜图像滑动速度和动态视力，将 研究与使用望远镜的观看策略有关 眼镜 通过研究眼睛和头部的水平和垂直运动 在无限制的视觉搜索中，实验将识别 最优视觉搜索策略的特征 眼镜 最小化视网膜图像的搜索策略的改进 还将评估不稳定性和搜索时间。 这些数据将 加强对人类垂直眼球运动的基本了解，并提供 临床洞察临床低视力的重要问题。

Significance. Many low vision patients have impaired central acuity but cannot successfully use telescopic spectacles despite the theoretical benefit from magnification. this may be because visual rehabilitation with telescopic spectacles is limited by instability of the magnified retinal image during involuntary head movements, and during coordinated eye-head movements necessitated by visual search. Retinal image stability is ordinarily provided by the visual-vestibulo-ocular reflex (VVOR), produced by interaction of the vestibulo-ocular reflex with visual and predictive mechanisms (visual-vestibular interaction, VVI). VVOR performance with telescopic spectacles must be quantitatively appropriate to magnification to avoid substantial impairment of dynamic visual acuity during head movements. Despite this importance, knowledge is lacking regarding the effects of aging and pathologic factors on human vertical VVI. Aims and Methods. The overall aim is to quantitatively evaluate mechanisms of VVI in the vertical plane, as determinants of useful vision with telescopic spectacles during physiologic head movements. Eye and head movements will be measured using magnetic search coils. The effect of telescopic spectacles on vertical VVOR will be quantitatively characterized in the physiologic range of active and passive head velocities and frequencies, in normally sighted and low vision adults. Findings will be correlated with separate measurements of visually guided tracking. The effects on VVI and tracking of unpredictable motion, reduced luminance and contrast, aging, pathologic nystagmus, and visual field defects will be studied. The relationship between instantaneous vertical retinal image slip velocity, and dynamic visual acuity, will be studied in relation to viewing strategies employed with telescopic spectacles. By studying horizontal and vertical eye and head movements during unrestrained visual search, experiments will identify characteristics of optimal visual search strategies with telescopic spectacles. Modification of search strategy to minimize retinal image instability and search time will also be evaluated. This data will enhance basic understanding of human vertical eye movements, and provide clinical insight into an important problem in clinical low vision.