Although automated perimetry requires considerable patient cooperation, many patients with SDAT can produce reliable visual field results. These patients exhibit significant reductions in global sensitivity. Visual field loss in SDAT is most pronounced in the inferonasal and inferotemporal arcuate regions of the visual field but also involves the central field.

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Physiologically healthy elderly individuals often exhibit visual deficits which result from age-related changes in both the transmission characteristics of the ocular media and the functional properties of the neural elements in the visual pathway. Many of the age-related changes in the optical quality of the ocular media have been identified, but the age-dependent variations in visual neurophysiology have not been clearly delineated. This investigation examined age-related alterations in pattern-specific biopotentials generated in the human retina and visual cortex. Counterphasing (2.0 and 7.5 rps) patterns (7.5', 15', 30' and 60' checks) were used to simultaneously monitor pattern-reversal visual evoked potentials (PRVEPs). Young visual normals (20-30 years of age) and healthy elderly observers (70-80 years of age) with visual acuity of 20/30 or better were studied. All data were corrected for the effects of senile miosis on retinal illumination. Significant variations in the waveform characteristics of both biopotentials were noted for the elderly individuals. PRRP amplitude was uniformly reduced for all stimulus conditions. PRVEP amplitude reductions were also noted but were more stimulus specific than the PRRP amplitude reductions. No significant PRVEP or PRRP latency changes were observed. These results suggest that alterations in the physiological properties of neural elements in both the retina and visual cortex are associated with normal aging.

Age-related visual deficits that occur in the absence of recognized visual disease are frequently observed. Many of the optical factors contributing to these deficits have been delineated, but the contributing neurophysiological alterations have not been clearly defined. This investigation examined age-related variations in the retinal and cortical processing of visual information. Pattern-specific retinal potentials (pattern electroretinogram or PERG in this series) and cortical potentials (VECPs) were recorded from nine young visual normals (20-30 years) and nine healthy elderly individuals (70-80 years). All subjects had best corrected visual acuity of 20/30 or better. Checkerboard patterns (7.5-60 min. checks) were modulated in a counterphase mode (2.0 and 7.5 rps). PERGs and VECPs were simultaneously recorded. Significant age-related alterations in waveform amplitude and latency were observed for both biopotentials. The VECP alterations were largely the result of the reduction in retinal illumination associated with senile miosis, but this factor could not account for most of the observed PERG alterations. These results suggest that neurophysiological changes in the retina may underlie some of the visual deficits observed in healthy elderly adults.

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