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Abstract
Application of the synchronous detection technique is described for the measurement of the visual evoked response (VER). Direct numerical measurements are obtained of average amplitude and phase at varying frequencies of stimulation, and an average time delay is derived from the phase information. Some characteristics of the phase-frequency curves are noted in subjects with normal vision and in patients with definite macular pathology. Precise retinal focusing is not necessary, so the method can be applied to patients with opaque media. In order to test the possible application of this method for estimating macular function, patients with dense cataracts were examined before operation, and an estimation was made of their potential postoperative vision based upon certain specific criteria. The actual vision obtained was then compared with the predicted results.