Gouras P, MacKay C J
Department of Ophthalmology, Columbia University, New York, New York 10032.
Invest Ophthalmol Vis Sci. 1992 Mar;33(3):508-15.
In 12 successive cases of unilateral central retinal vein occlusion (CRVO), the strongly light-adapted cone electroretinogram (both a- and b-wave) was always slower and larger (supernormal) to long-wave stimuli compared with that of the unaffected eye. This supernormality became less as the level of light adaptation decreased; in the dark-adapted state, long-wave stimuli produced subnormal responses from the affected eye in all but two subjects. This supernormality was not caused by ineffectiveness of the adapting light related to a reduced cone quantal catch because it occurred in the dark. At any one state of adaptation, the supernormality increased with the wavelength of stimulation, paralleling the relative absorption ratio of long-middle wavelength-sensitive cones. This suggests that cones, especially long wavelength-sensitive cones, are less able to reduce their responsiveness to light with increasing levels of light adaptation in a retina affected by CRVO.
在连续12例单侧视网膜中央静脉阻塞（CRVO）患者中，与未受影响的眼睛相比，强光适应状态下的视锥细胞视网膜电图（a波和b波）对长波刺激的反应总是更慢且更大（超常）。随着光适应水平降低，这种超常现象减弱；在暗适应状态下，除两名受试者外，长波刺激在患眼中均产生低于正常的反应。这种超常现象并非由于与视锥细胞量子捕获减少相关的适应光无效所致，因为它在黑暗中也会出现。在任何一种适应状态下，超常现象都随着刺激波长的增加而增强，这与长-中波长敏感视锥细胞的相对吸收比率平行。这表明，在受CRVO影响的视网膜中，视锥细胞，尤其是长波长敏感视锥细胞，随着光适应水平的提高，降低其对光反应性的能力较弱。
