Using two preferred retinal loci for different lighting conditions in patients with central scotomas.
Using two preferred retinal loci for different lighting conditions in patients with central scotomas.
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DOI：
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发表时间：
1997-08
影响因子：
4.4
通讯作者：
Hong Lei;Ronald A. Schuchard
中科院分区：
文献类型：
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作者：
Hong Lei;Ronald A. Schuchard
目的利用激光扫描检眼镜，发现部分相对中心暗点患者在不同的刺激照度下，可靠地使用两个不同的首选视网膜位点（PRL）。本文介绍了适应病人的PRL固定时，调暗的刺激增加了相对暗点的大小。方法应用激光扫描检眼镜对28例黄斑病变患者的黄斑暗点边缘进行定位。高照度PRL（PRLhi）和低照度PRL（PRLlo）分别定义为患者用于固定高或低照度刺激的PRL。评估PRL在相应照度下完成视觉任务的能力及其特征。结果随着刺激照度的改变，PRL在PRLhi和PRLlo之间一致地移动。在亮度允许的情况下，视觉系统更喜欢使用PRLhi，其在视觉功能（例如注视稳定性）方面通常具有更好的性能。有没有显着差异之间的PRLhi和PRLlo的追求和扫视能力，主观评级评估时。引起移动的照度范围从106到3437 troland。PRLhi总是位于相对暗点区域内，通常在中心凹或仅在密集暗点之外。PRLlo位于相对健康的视网膜区域，在视野中通常位于PRLhi的下方或左侧。结论：在视觉系统中，当视觉功能适应黄斑病变时，可以产生两种定义明确的PRL，每种PRL的使用取决于视觉任务中使用的物体的亮度。康复和治疗策略应考虑多种PRL的存在。
PURPOSE Using a scanning laser ophthalmoscope, it was found that some patients with relative central scotomas reliably used two different preferred retinal loci (PRLs) at different stimulus illuminances. This article describes adaptations in a patient's PRL for fixation when dimming the stimulus increased the relative scotoma size. METHODS Twenty-eight patients with macular diseases had their dense and relative macular scotoma borders mapped with the scanning laser ophthalmoscope. The high-illuminance PRL (PRLhi) and low-illuminance PRL (PRLlo) were operationally defined as the PRLs that patients used to fixate a high or low illuminance stimulus, respectively. The PRLs' abilities to do visual tasks and their characteristics at the corresponding illuminances were assessed. RESULTS The PRL consistently shifted between the PRLhi and the PRLlo as the stimulus illuminance was changed. Brightness permitting, the visual system prefers to use the PRLhi with generally better performance in visual function such as fixation stability. There were no significant differences between the PRLhi and the PRLlo in pursuit and saccadic abilities, when assessed by subjective ratings. The illuminances that induced shifting ranged from 106 to 3437 trolands. The PRLhi was always located within an area of relative scotoma, usually at the fovea or just outside a dense scotoma. The PRLlo was located in relatively healthy retinal area, and usually below or to the left of the PRLhi in the visual field. CONCLUSIONS In the visual system, two well-defined PRLs can develop when visual function is adapting to maculopathy, with the use of each depending on the brightness of objects used in visual tasks. Rehabilitation and treatment strategies should consider the existence of multiple PRLs.