Ageing and the spatiotemporal discrimination performance of the visual system

Visual ageing is generally associated with a decline in spatial vision for stationary stimuli, especially those which are of high spatial frequency. Some, but probably not all of this loss can be attributed to apparently normal age-related changes in the ocular media that attenuate and scatter incident light. The loss in the temporal resolving capacity of the senescent visual system is even more prominent and appears to be due almost completely to neural mechanisms, including alterations in the functioning of both the 'transient' and 'sustained' types of visual channel. The losses with age in both spatial and temporal vision are highly consistent with the type and degree of visual problems elderly persons report that they experience in carrying out daily tasks. Further research will be needed to determine the mechanisms which underlie these changes as well as to determine the degree to which they can be remedied.