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Invest Ophthalmol Vis Sci. 2009 Mar;50(3):1145-51. doi: 10.1167/iovs.08-2474. Epub 2008 Oct 24.

Aging effects on the visually driven part of vergence movements.

Author information

1
IRIS Physiopathologie de la vision et de la motricité binoculaire, Service d'Ophtalmologie-ORL-Stomatologie, Hôpital Européen Georges Pompidou, Paris, France. yangqing165@hotmail.fr

Abstract

PURPOSE:

To examine gain, speed, and temporal characteristics of initial and closed-loop components of vergence eye movements in young and elderly subjects.

METHODS:

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.

RESULTS:

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.

CONCLUSIONS:

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.

PMID:
18952920
DOI:
10.1167/iovs.08-2474
[Indexed for MEDLINE]

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