Fulton A B, Hansen R M
Department of Ophthalmology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
Invest Ophthalmol Vis Sci. 2000 May;41(6):1588-96.
PURPOSE. Test the hypothesis that the developmental increases in rod photoreceptor sensitivity and rod-mediated visual sensitivity at 10 degrees, 20 degrees , and 30 degrees eccentric are concurrent. It is known that maturation of the parafoveal (10 degrees eccentric) rod outer segments and visual sensitivity is delayed compared to that at 30 degrees eccentric.
Rod isolated electroretinographic (ERG) responses to full-field stimuli were obtained from dark-adapted subjects (n = 71), ranging in age from early infancy through middle age. Rod photoreceptor sensitivity was calculated by fitting a model of the activation of phototransduction to the a-wave response. Rod driven b-wave sensitivity was calculated from stimulus-response functions. A logistic growth model was used to summarize the developmental increases in sensitivity of the rod photoreceptors and the b-wave. Previously reported dark-adapted, rod-mediated visual sensitivities at 10 degrees , 20 degrees, and 30 degrees eccentric, obtained using preferential looking procedures, were reanalyzed using the logistic growth model.
The logistic growth model accounted for 57% to 85% of the variance of each sensitivity parameter with age in normal subjects. The shape of the growth curve and the age at which sensitivity reaches 50% of the adult value is similar (10.0-13.5 weeks) for the rods, the b-wave, and peripheral visual sensitivity, but is significantly older, 19.5 weeks, for rod-mediated parafoveal visual sensitivity.
Rod photoreceptor sensitivity and peripheral, rod-mediated visual sensitivity develop concurrently. A parsimonious explanation is that rod photoreceptor sensitivity determines dark-adapted, rod-mediated visual sensitivity during development.
目的。验证以下假设：在10度、20度和30度偏心度时，视杆光感受器敏感性和视杆介导的视觉敏感性的发育性增加是同时发生的。已知与30度偏心度相比，旁中央凹（10度偏心度）视杆外段和视觉敏感性的成熟延迟。
从年龄范围从婴儿早期到中年的71名暗适应受试者中获得对全视野刺激的视杆分离视网膜电图（ERG）反应。视杆光感受器敏感性通过将光转导激活模型拟合到a波反应来计算。视杆驱动的b波敏感性从刺激-反应函数计算得出。使用逻辑增长模型总结视杆光感受器和b波敏感性的发育性增加。使用逻辑增长模型重新分析先前报道的使用优先注视程序获得的在10度、20度和30度偏心度时的暗适应视杆介导的视觉敏感性。
在正常受试者中，逻辑增长模型解释了每个敏感性参数随年龄变化的57%至85%的方差。视杆、b波和周边视觉敏感性的增长曲线形状以及敏感性达到成人值50%时的年龄相似（10.0 - 13.5周），但视杆介导的旁中央凹视觉敏感性明显更晚，为19.5周。
视杆光感受器敏感性和周边视杆介导的视觉敏感性同时发育。一个简洁的解释是，视杆光感受器敏感性在发育过程中决定了暗适应视杆介导的视觉敏感性。
