Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil.
Invest Ophthalmol Vis Sci. 2021 Apr 1;62(4):29. doi: 10.1167/iovs.62.4.29.
The purpose of this study was to characterize changes in the full-field flash electroretinogram (ERG) in association with psychophysical dark-adapted visual thresholds in patients with genetically characterized Duchenne muscular dystrophy (DMD) either lacking Dp427 (Up 30) or at least Dp260 in addition to Dp427 (Down 30).
Twenty-one patients with DMD and 27 age-similar controls participated in this study. Dark-adapted (0.01, 3.0, and 10 cd.s/m² flashes) and light-adapted (3.0 cd.s/m² flash) ERGs were recorded following International Society for Clinical Electrophysiology of Vision (ISCEV) standard protocols. Visual detection thresholds to 625-nm (cone function) and 527-nm (rod function) light-emitting diode (LED) flashes (2 degree diameter) were measured during a dark adaptation period after a 1-minute exposure to a bleaching light (3000 cd/m²). Initially, 8 minutes of interleaved 625-nm and 527-nm thresholds were measured. After an additional 5 minutes of dark-adaptation, a second set of threshold measurements to 527-nm stimuli was performed during the subsequent 6 minutes.
Dark-adapted b-wave amplitude was significantly reduced to all strengths of flash and a-wave in response to the strong flash stimulus was delayed (15.6 vs. 14.7 ms, P < 0.05) in patients with Down 30 compared with controls. Dark-adapted cone thresholds did not differ among the groups (-2.0, -1.8, and -1.7 log cd/m² for Down 30, Up 30, and controls, respectively, P = 0.21). In contrast, dark-adapted rod thresholds were elevated (F(2,36) = 8.537, P = 0.001) in patients with Down 30 (mean = -3.2 ± 1.1 log cd/m²) relative to controls (mean = -4.2 ± 0.3 log cd/m²). Dark-adapted b-wave amplitudes were correlated with dark-adapted rod sensitivity in patients with DMD (Spearman Rho = 0.943, P = 0.005). The changes were much smaller or absent in patients with intact Dp260.
Dp260 is particularly required for normal rod-system function in dark adaptation.
本研究旨在描述在具有遗传特征的杜兴氏肌营养不良症（DMD）患者中，全视野闪光视网膜电图（ERG）与心理物理暗适应视觉阈值的变化，这些患者要么缺乏 Dp427（Up 30），要么除了 Dp427 之外至少还缺乏 Dp260（Down 30）。
本研究纳入了 21 名 DMD 患者和 27 名年龄匹配的对照者。按照国际临床电生理学视觉协会（ISCEV）的标准方案，记录暗适应（0.01、3.0 和 10 cd·s/m² 闪烁）和明适应（3.0 cd·s/m² 闪烁）ERG。在 3000 cd/m² 的漂白光照射 1 分钟后，进行暗适应期，测量 625nm（锥体细胞功能）和 527nm（视杆细胞功能）发光二极管（LED）闪烁（2 度直径）的视觉检测阈值。最初，测量 8 分钟的 625nm 和 527nm 阈值。在暗适应 5 分钟后，在随后的 6 分钟内，对 527nm 刺激进行第二组阈值测量。
与对照组相比，Down 30 患者的所有强度闪光的暗适应 b 波振幅均显著降低，对强闪光刺激的 a 波反应延迟（15.6 对 14.7 ms，P<0.05）。各组暗适应锥体细胞阈值无差异（Down 30、Up 30 和对照组分别为-2.0、-1.8 和-1.7 log cd/m²，P=0.21）。相比之下，Down 30 患者的暗适应视杆细胞阈值升高（F（2，36）=8.537，P=0.001）（均值=-3.2±1.1 log cd/m²），而对照组（均值=-4.2±0.3 log cd/m²）。DMD 患者的暗适应 b 波振幅与暗适应视杆细胞敏感性相关（Spearman Rho=0.943，P=0.005）。在保留 Dp260 的患者中，这些变化较小或不存在。
Dp260 特别需要正常的视杆系统功能在暗适应。
