Visual field loss in senile dementia of the Alzheimer's type.

Abstract

Visual performance is impaired in patients with senile dementia of the Alzheimer's type (SDAT). We investigated the visual field topography of these deficits. Humphrey automated perimetry (Program 30-2) was used to measure differential luminance sensitivity within the central 60 degrees of the visual field in SDAT patients (n = 61) and in visually and cognitively normal volunteer subjects of similar age (n = 61). Twenty-three SDAT patients were retested 18 months after the original examination. Reliable visual fields (by manufacturer's criteria) were obtained in 72.1% (44/61) of the control subjects and 55.7% (34/61) of the SDAT group. In the SDAT group, differential luminance sensitivity was significantly reduced relative to the control group. Visual sensitivity was reduced throughout the visual field, but deficits were most pronounced in the inferior visual field, where they presented most commonly as arcuate defects. Patients with more severe dementia exhibited greater reductions in visual sensitivity. On follow-up, 14 of 23 SDAT patients exhibited progression of visual field loss, whereas only two of 23 patients exhibited a regression of the visual field loss. 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.