Holopigian K, Greenstein V C, Seiple W, Hood D C, Carr R E
Department of Ophthalmology, New York University Medical Center, New York 10016, USA.
Invest Ophthalmol Vis Sci. 1997 Oct;38(11):2355-65.
To determine whether the rod and cone photoreceptors are affected in patients with diabetic retinopathy.
Twelve patients with diabetes and varying levels of retinopathy and nine age-similar control observers participated in this study. Two-color (500 versus 650 nm) dark-adapted thresholds were measured as a function of retinal eccentricity. Full-field flash electroretinograms were obtained using brief, high-intensity flashes. Dark-adapted rod-isolated (Wratten 47B filter) and light-adapted cone-isolated (Wratten 26 filter) electroretinographic responses were measured as a function of flash intensity. The a-wave data were fitted with a model based on photopigment transduction to obtain values for the parameters of Rmax (the maximal response) and log S (sensitivity). Standard clinical 30-Hz flicker electroretinographic responses were also measured.
Psychophysically measured dark-adapted thresholds were elevated primarily at eccentricities of 5 degrees and 10 degrees from the fovea. Analysis of rod and cone a-wave data showed that Rmax was normal in most of the patients, but log S was reduced. Analysis of b-wave and oscillatory potential parameters showed rod and cone postreceptoral abnormalities, including changes in the rod-isolated semisaturation constant (log k), cone-mediated 30-Hz flicker, and cone-isolated oscillatory potentials. The electrophysiological results were not significantly correlated with blood glucose or glycosylated hemoglobin level.
The results provide evidence for rod and cone receptoral and postreceptoral deficits in patients with diabetic retinopathy. The photoreceptor changes are primarily in the log S (sensitivity) parameter and are attributed to transduction abnormalities.
确定糖尿病视网膜病变患者的视杆和视锥光感受器是否受到影响。
12名患有不同程度视网膜病变的糖尿病患者和9名年龄相仿的对照观察者参与了本研究。测量双色（500对650纳米）暗适应阈值作为视网膜离心度的函数。使用短暂的高强度闪光获得全视野闪光视网膜电图。测量暗适应视杆隔离（Wratten 47B滤光片）和明适应视锥隔离（Wratten 26滤光片）视网膜电图反应作为闪光强度的函数。对a波数据进行基于光色素转导的模型拟合，以获得Rmax（最大反应）和log S（敏感度）参数的值。还测量了标准临床30赫兹闪烁视网膜电图反应。
心理物理学测量的暗适应阈值主要在距中央凹5度和10度的离心度处升高。对视杆和视锥a波数据的分析表明，大多数患者的Rmax正常，但log S降低。对b波和振荡电位参数的分析显示视杆和视锥感受器后异常，包括视杆隔离半饱和常数（log k）的变化、视锥介导的30赫兹闪烁和视锥隔离振荡电位。电生理结果与血糖或糖化血红蛋白水平无显著相关性。
结果为糖尿病视网膜病变患者视杆和视锥感受器及感受器后缺陷提供了证据。光感受器变化主要在log S（敏感度）参数，归因于转导异常。
