Reduced contrast sensitivity in compressive lesions of the anterior visual pathway

A clinical procedure for determining contrast sensitivity was performed on patients with suspected sella area masses. The test consisted of a series of six plates, each containing a bar pattern of fixed sinusoidal spatial frequency in which contrast varies along the length of the bar. Patients with compressive lesions of the chiasm or optic nerve showed loss of contrast sensitivity over the whole range of spatial frequencies. The general loss in contrast was evident even in patients with 20/20 Snellen acuity. After surgery, contrast sensitivity improved, as did other measures of vision, but significant contrast deficits remained. Contrast sensitivity is a sensitive indicator for the diagnosis and evaluation of compressive lesions of the chiasm.