Patients with senile dementia of the Alzheimer type frequently have difficulty performing visual tasks. These difficulties may be due, at least partially, to degenerative changes in both the primary visual pathway and the visual association areas. To determine whether retinal ganglion cell dysfunction contributes to visual loss in senile dementia of the Alzheimer type, we tested a group of patients with this disease (n = 13) using the pattern-reversal electroretinogram to both low (4.0 reversals per second) and high (16.0 reversals per second) temporal frequency checkerboard patterns (1.0 degree checks). Significant amplitude reductions were noted for the patients relative to age-matched control subjects (n = 30). In addition, the observed amplitude reductions were most pronounced for the high temporal frequency condition. Therefore, the results are consistent with retinal ganglion cell dysfunction and support the notion that optic nerve damage induced by senile dementia of the Alzheimer type preferentially affects the larger, faster-conducting retinal ganglion cells along with their retinocortical projections.

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Five women were examined with dark adaptometry and a signal detection procedure for seven consecutive days in the middle of their menstrual cycles. Their discriminability indices show significant (p < 0.05) increases in visual sensitivity on the basal body temperature rise day, while five control observers show no changes across four consecutive days.

1. Spatial sensitivity of human foveal vision was examined using sinusoidally modulated gratings. Our primary concern was the influence of interocular light adaptation upon monocular visibility. 2. Interocular adapting influences depend upon spatial frequency and adapting luminance. Interocular adaptation has a negligible influence upon the sensitivity to 1 cycle/deg gratings. Any visible interocular adapting field improves the sensitivity to intermediate spatial frequencies (2‐5 cycles/deg). 3. Brighter interocular backgrounds (greater than 0.1 cd/m2) improve sensitivity to higher spatial frequencies (10‐20 cycles/deg). 4. The interocular adapting influences summarized in (2) and (3) above cannot be duplicated by monocular or binocular adaptation. Similarly, monocular or binocular adaptation have negligible influences upon binocular visibility. 5. The interocular adapting effect summarized in (3) above can be duplicated by pressure blinding the contralateral eye. We conclude that monocular spatial sensitivity is subject to a tonic interocular suppression (TIS) from the dark‐adapted eye. 6. The spatial sensitivity resulting from binocular viewing is nearly identical to that observed by combining monocular viewing with interocular light adaptation. We suggest that the improvement in sensitivity resulting from two‐eyed viewing may be attributable to the removal of TIS instead of to binocular physiological summation.

Fifty-four patients with a unilateral pigmented choroidal lesion were studied with electrooculography (EOG). Eighteen of 21 patients with histologically proven (13) or presumed (8) malignant tumors of the choroid had light peak-dark trough ratios (L/D) less than or equal to 150. Seventeen of 21 patients in the malignant group had an interocular L/D difference (L/Dd) greater than or equal to 23%, whereas only one of 33 patients with nevi or a condition simulating a nevus had a percent difference of such magnitude. Combining the L/D and L/Dd criteria resulted in a 98% accurate double-blind prediction of the final clinical/pathological results. The EOG is an objective, noninvasive test useful in the diagnosis of choroidal malignant melanomas.