Contrast visual testing in neurovisual diagnosis.

Contrast visual testing (CVT) is a psychophysical visual test of undetermined diagnostic capability in many neurovisual disorders. CVT of 32 controls and 39 patients was compared with the pattern visual evoked response (PVER) from each group. CVT was more sensitive than PVER in detecting visual dysfunction in pseudotumor cerebri and subclinical optic neuritis and showed potential in distinguishing papilledema from pseudopapilledema. PVER was more sensitive than CVT in detecting subclinical visual dysfunction in MS and optic nerve compression. Neither was abnormal in asymptomatic Leber's optic neuropathy. In nonorganic visual loss, CVT data were variable and inconsistent, supporting this diagnosis; PVER was consistently normal. Although in certain disease conditions, each detected subclinical visual dysfunction, neither CVT nor PVER provided specific information leading to an etiologic diagnosis.