Early age-related macular degeneration impairs tolerance to stimulus degradation.
Early age-related macular degeneration impairs tolerance to stimulus degradation.
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DOI：
10.1097/opx.0b013e3181e3dc10
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发表时间：
2010-08
期刊：
影响因子：
--
通讯作者：
White J
中科院分区：
文献类型：
--
作者：
Liu L;White J
与早期年龄相关性黄斑变性（AMD）相关的视网膜光感受器的病理变化已经被很好地确定，但是该疾病通常在早期阶段是无症状的，并且传统的阈上临床测试常常不能揭示功能缺陷。本研究的目的是证明早期AMD眼阈上视功能的微妙变化。通过随机删除纹理检查，预仔细辨别纹理刺激的质量被系统地降低。受试者的任务是对两个同等退化的斑块是否包含相同或不同类型的纹理样本进行强制选择。在年轻和老年正常对照组和早期AMD患者中测量了对纹理刺激降解的耐受性。受试者接受训练，以执行纹理歧视的任务，直到他们在区分完整的纹理很少的错误。纹理歧视恶化，增加刺激退化在所有科目。年轻和老年正常对照组之间的性能没有显着差异。在一系列降解水平下，早期AMD眼睛对刺激降解的耐受性显著低于年龄相似的正常对照。在控制视力后，正常受试者的视力仍明显优于早期AMD眼，约22%的检查缺失。早期AMD患者较好眼与晚期AMD患者对侧眼之间差异无统计学意义。退化纹理任务的表现与视力无关。轻微的模糊的刺激退化纹理的歧视几乎没有影响。早期AMD可能不会直接影响阈上视觉功能时，刺激是完整的，并包含冗余的信息，但可能表现为减少耐受性的刺激退化的形式，局部信息丢失。当视觉刺激包含较少冗余信息时，早期AMD患者的表现可能会受到影响。
Pathologic changes of retinal photoreceptors associated with early age-related macular degeneration (AMD) have been well established, but the disease is usually asymptomatic at the early stage and traditional suprathreshold clinical tests often fail to reveal functional deficiencies. The aim of this study is to demonstrate subtle changes of one suprathreshold visual function in early AMD eyes. The quality of pre-attentively discriminable texture stimuli was systematically degraded through random deletion of texture checks. The subjects’ task was to make a forced-choice decision on whether two equally degraded patches contained samples of the same or different types of textures. Tolerance to texture stimulus degradation was measured in young and elderly normal controls and in patients with early AMD. Subjects were trained to perform the texture discrimination task until they made few errors in discriminating intact textures. Texture discrimination deteriorated with increasing stimulus degradation in all subjects. There was no significant difference between performance of young and elderly normal controls. Early AMD eyes showed significantly less tolerance to stimulus degradation than age-similar normal controls at a range of degradation levels. After controlling for visual acuity, normal subjects still performed significantly better than early AMD eyes around 22% check deletion. There was no significant difference between better eyes of early AMD patients and fellow eyes of late AMD eyes. Performance on the degraded texture task was not correlated with visual acuity. A mild blur of the stimulus had little effect on discrimination of degraded textures. Early AMD may not directly affect suprathreshold visual functions when the stimuli are intact and contain redundant information, but may manifest itself as a reduction of tolerance to stimulus degradation in the form of localized information loss. The performance of patients with early AMD may be compromised when the visual stimulus contains less redundant information.