OPTICAL AND RETINAL LIMITS TO VISUAL PERFORMANCE

光学和视网膜对视觉表现的限制

• 批准号: 2159288
• 负责人: LARRY N THIBOS
• 金额: $ 12.74万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-01-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2159288
• 关键词: color visions; form /pattern perception; fovea centralis retinae; human subject; neural information processing; neuroanatomy; psychophysics; pupil; retinal ganglion; vision; vision tests; visual fields; visual perception; visual stimulus

DESCRIPTION (Investigator's abstract): The long term goal of this research program is to determine how optical and retinal factors affect vision. Specific aims for the next project period fall into three categories: acuity, aliasing and optics. Acuity is the most important measure of visual function in clinical practice and it plays a key role in current debates about the limits to performance imposed by the neural architecture f the visual system. Previous experiments have shown that in peripheral vision, resolution acuity is limited by the ambiguity of aliasing due to neural undersampling of the retinal image, probably by the relatively sparse array of retinal ganglion cells. The investigators propose to test this ganglion cell hypothesis by mapping the resolution acuity of the human observer over the entire visual field using the aliasing criterion, a psychophysical task which is known to be sampling-limited, and then comparing the results with recent anatomical estimates of ganglion cell density. In this way the investigators aim to establish the functional significance of ganglion cell density for normal peripheral acuity, and thus the consequences of nerve fiber loss in the diseased eye. Aliasing is the false perception of a pattern too fine to be resolved. Such illusory percepts occur naturally in peripheral vision and are due to neural undersamplng. Evidence of the functional utility of aliased images will be south by comparing visual performance before and after anti-alias filtering of visual stimuli. Resolution and detection of harmonically-rich patterns will be measured for peripheral vision and the results compared with that obtained for sinusoidal grating to determine how the higher frequency, non-resolvable components affect performance. This approach will be adapted for clinical testing of peripheral vision by employing a striped-letter optotype which is visible due to aliasing independently of the size of the letter. With such targets the investigators expect to demonstrate aliasing in a clinical context and thus exploit an essential difference between foveal and peripheral vision which may have diagnostic value for glaucoma and other ocular diseases characterized by the death of retinal ganglion cells. Optical filtering of the retinal image by the eye represents a potential limiting factor for any visual task. Recently the investigators have developed a simple schematic eye which accounts well for the effects of chromatic aberration and diffraction on vision. The only free parameters of the model involve the position of the pupil relative to the eye's nodal point and visual axis. The investigators now propose to survey the distribution of pupil locations in a large number of individual eyes using a previously developed, two-color vernier-alignment technique. The investigators also propose to examine the importance of axial pupil location on the modulation transfer function of the model eye and to extend these theoretical calculations to include color contrast.

描述（研究者摘要）：本研究的长期目标 该计划旨在确定光学和视网膜因素如何影响视力。 下一个项目期间的具体目标分为三类： 敏锐度、混叠和光学特性。 视力是临床上最重要的视功能指标 实践，它在当前关于限制的辩论中发挥着关键作用， 由视觉系统的神经结构强加的性能。 先前的实验表明，在周边视觉中，分辨率 由于神经采样不足，混淆的模糊性限制了敏锐度 的视网膜图像，可能是由相对稀疏的视网膜阵列， 神经节细胞 研究人员建议测试这种神经节细胞 通过将人类观察者的分辨率敏锐度映射到 使用混叠标准的整个视野，这是一项心理物理任务 这是已知的抽样限制，然后比较结果与 神经节细胞密度的最新解剖学估计。 以这种方式 研究者的目标是确定神经节细胞的功能意义， 密度为正常的周边敏锐度，因此神经的后果 患病眼睛中的纤维损失。 混淆是对一个太精细而无法分辨的模式的错误感知。 这种错觉在周边视觉中自然发生，是由于 神经欠采样 别名图像的功能效用的证据 将正南通过对比反锯齿前后的视觉表现 过滤视觉刺激。 谐波丰富的分辨率和检测 模式将被测量周边视觉和结果进行比较 与获得的正弦光栅，以确定如何更高 频率、不可分辨的分量影响性能。 这种方法 将适用于周边视觉的临床测试， 条纹字母视标，由于独立于 信的大小。 有了这样的目标，调查人员预计， 在临床环境中演示混叠，从而利用基本的 中心凹视觉和周边视觉之间的差异可能具有诊断性 青光眼和其他以死亡为特征的眼部疾病的价值 视网膜神经节细胞 眼睛对视网膜图像的光学滤波代表了一种潜在的 任何视觉任务的限制因素。 最近，调查人员 开发了一个简单的示意眼，它很好地解释了 色差和衍射。 唯一的自由参数 涉及瞳孔相对于眼睛节点的位置 点和视轴。 调查人员现在建议调查 在大量个体眼睛中的瞳孔位置的分布， 一种先前开发的双色游标对准技术。 的 研究人员还建议检查轴向瞳孔的重要性， 位置上的调制传递函数的模型眼睛，并扩展 这些理论计算包括颜色对比度。