Yang Qing, Le Thanh-Thuan, Kapoula Zoi
IRIS Physiopathologie de la vision et de la motricité binoculaire, Service d'Ophtalmologie-ORL-Stomatologie, Hôpital Européen Georges Pompidou, Paris, France.
Invest Ophthalmol Vis Sci. 2009 Mar;50(3):1145-51. doi: 10.1167/iovs.08-2474. Epub 2008 Oct 24.
To examine gain, speed, and temporal characteristics of initial and closed-loop components of vergence eye movements in young and elderly subjects.
Vergence eye movements in 13 elderly and 10 young adults were examined. A table with light-emitting diodes was used to elicit vergence starting from near (convergence, 40-20 cm; divergence, 20-40 cm) or from far (convergence, 150-40 cm; divergence, 40-150 cm). Vergence eye movements were recorded with a video eye tracker or an infrared eye movement device.
There were no aging effects on the gain or peak velocity of vergence. Vergence duration was longer in elderly than in young adults, but only for the second, closed-loop components, driven by visual feedback. Elderly and young adults showed higher peak velocity and gain for convergence than for divergence.
This observation is discussed in the context of physiological evidence of a robust convergence, rather than a divergence, generator at the brain stem level. Such a specific effect of aging on the duration of the closed-loop component is attributed to the reduced capacity of cortical processing of visual binocular disparity; slowing of vergence would allow good final accuracy.
研究年轻和老年受试者的聚散性眼球运动的初始和闭环成分的增益、速度及时间特征。
对13名老年人和10名年轻人的聚散性眼球运动进行了检查。使用带有发光二极管的桌子，从近处（集合，40 - 20厘米；散开，20 - 40厘米）或远处（集合，150 - 40厘米；散开，40 - 150厘米）引发聚散。使用视频眼动追踪仪或红外眼动设备记录聚散性眼球运动。
年龄对聚散的增益或峰值速度没有影响。老年人的聚散持续时间比年轻人长，但仅针对由视觉反馈驱动的第二个闭环成分。老年人和年轻人在集合时的峰值速度和增益高于散开时。
这一观察结果在脑干水平存在强大的集合而非散开发生器的生理学证据背景下进行了讨论。衰老对闭环成分持续时间的这种特定影响归因于皮质对双眼视差处理能力的下降；聚散速度减慢将使最终准确性良好。
