Jacobson S G, Marmor M F, Kemp C M, Knighton R W
Department of Ophthalmology, University of Miami School of Medicine, Bascom Palmer Eye Institute, Florida 33101.
Invest Ophthalmol Vis Sci. 1990 May;31(5):827-38.
Photoreceptor-mediated mechanisms were studied in patients with a recently identified retinopathy typified by night blindness, cystoid maculopathy, and similar scotopic and photopic electroretinograms (ERGs). Dark-adapted spectral sensitivity functions were only partly explained as composites of rod and cone curves shifted to lower sensitivities; there was unusually high sensitivity from 400-460 nm. A rod mechanism, reduced in sensitivity by at least 3 log units, was detectable with dark adaptometry. No measurable rhodopsin was found with fundus reflectometry. Light-adapted spectral sensitivities were subnormal for wavelengths greater than 500 nm but supernormal from 420-460 nm. On a yellow adapting field, the supernormal spectrum approximated that of the short-wavelength-sensitive (SWS) cone system. With spectral ERGs, two mechanisms were demonstrated. Dark- and light-adapted ERGs to green, orange-yellow, and red stimuli had similar waveforms and coincident intensity-response functions on a photopic intensity axis. ERGs to blue and blue-green stimuli were similar, and intensity-response functions coincided on a SWS cone intensity axis. Patients varied in the degree to which rod and midspectral cone function were decreased and SWS cone function was increased.
对患有最近发现的视网膜病变的患者进行了光感受器介导机制的研究，该视网膜病变的典型特征为夜盲、黄斑囊样病变以及类似的暗视和明视视网膜电图（ERG）。暗适应光谱敏感性函数仅部分可解释为杆体和锥体曲线向较低敏感性偏移后的组合；在400 - 460纳米处存在异常高的敏感性。通过暗适应测量法可检测到一种敏感性至少降低3个对数单位的杆体机制。眼底反射测量法未发现可测量的视紫红质。对于波长大于500纳米的光适应光谱敏感性低于正常水平，但在420 - 460纳米处高于正常水平。在黄色适应背景下，超常光谱近似于短波敏感（SWS）锥体系统的光谱。通过光谱ERG，证实了两种机制。对绿色、橙黄色和红色刺激的暗适应和光适应ERG具有相似的波形，并且在明视强度轴上具有一致的强度 - 反应函数。对蓝色和蓝绿色刺激的ERG相似，并且强度 - 反应函数在SWS锥体强度轴上一致。患者在杆体和中光谱锥体功能降低以及SWS锥体功能增加的程度上存在差异。
