PHYSIOLOGY OF POTASSIUM CHANNELS IN RETINAL GLIAL CELLS

年龄相关性黄斑变性（ARMD）是65岁及以上人群视力损害的主要原因。ARMD经常导致影响中央凹的暗斑（盲点），从而导致中央视野丧失（CFL）。CFL对视力是毁灭性的，部分原因是它迫使使用外围视网膜来完成以前由中央凹完成的任务（例如阅读）。与使用外周视网膜的视力正常的人相比，CFL患者的敏锐度通常较低，阅读速度也较慢。这项研究的目的是了解何时以及为什么会出现这种情况。我们的基本假设是，CFL改变了周围视网膜处理视觉信息的能力。我们将测量由ARMD引起的中央视野丧失患者和具有模拟暗斑的正常视力受试者的灵敏度和阅读速度。我们将使用模拟暗点来确定暗点对中央视野丧失的视力的影响，并使用模拟暗点和图像稳定来评估视网膜位置和眼动控制对视力和阅读速度的影响。我们还将研究字母敏锐度、单词敏锐度和阅读眼动之间的关系。在这些模拟暗点的任务中的表现将与CFL患者在相同测试条件下的表现进行比较。这些研究产生的数据将帮助我们更好地了解外周视网膜视觉处理的局限性，以及在什么情况下，由于疾病导致的CFL患者相对于正常外周视网膜的视觉功能下降。这一新知识将为视力康复专家提供衡量成功与否的现实指导，并为他们开发康复方案和技术提供新的信息。例如，如果我们发现存在一个最佳的阅读视网膜经络，并且当文字稳定在读者的视网膜上时，阅读速度会更快，这可能会导致设计基于计算机的低视力阅读辅助设备，结合眼动追踪设备，提供这样的显示。这里提出的研究也将扩大我们对成人视觉系统可塑性的理解。有证据表明，视网膜暗斑发生后，皮层发生快速变化。我们将首次研究与视网膜暗斑相关的功能变化，包括短期适应（模拟暗斑）和长期适应（ARMD）。

Age-related macular degeneration (ARMD) is the leading cause of visual impairment in persons 65 years of age and older. ARMD often leads to scotomas (blindspots) affecting the fovea, which result in central field loss (CFL). CFL is devastating to vision, in part because it forces the use of peripheral retina to do tasks (e.g. reading) formerly done with the fovea. Patients with CFL often have reduced acuity and read more slowly than do normally-sighted observers using peripheral retina. The goals of this research are to understand when and why this is so. Our underlying assumption is that CFL changes the ability of peripheral retina to process visual information. We will measure acuity and reading speed in patients with central field loss due to ARMD and in normally-sighted subjects with simulated scotomas. We will use simulated scotomas to determine the impact of a scotoma on acuity with central field loss, and simulated scotomas and image stabilization to assess the impact of retinal location and eye movement control on acuity and reading speed. We will also investigate the relationship between letter acuity, word acuity, and reading eye movements. Performance on each of these tasks with simulated scotomas will be compared to the performance of patients with CFL under the same test conditions. The data generated by these studies will help us to better understand the limitations on visual processing in peripheral retina, as well as under what conditions patients with CFL due to disease have reduced visual function relative to normal peripheral retina. This new knowledge will provide vision rehabilitation specialists with realistic guidelines from which to gauge success, as well as provide them with new information for developing rehabilitation protocols and technologies. For example, should we find that there is an optimal retinal meridian for reading and that reading is faster when the words are stabilized on the reader's retina, this could lead to the design of computer-based low vision reading aids, combined with eye tracking devices, that would provide such a display. The research proposed here will also expand our understanding of the plasticity of the adult visual system. Evidence suggests that fast cortical changes occur in response to retinal scotomas. We will, for the first time, investigate the functional changes associated with retinal scotomas, both with short-term adaptation (simulated scotomas) and long-term adaptation (ARMD).