Visual evoked potentials in chiasmal gliomas in four adults [Case Report]
Kupersmith MJ; Siegel IM; Carr RE; Ransohoff J; Flamm E; Shakin E
Visual evoked potentials (VEPs) were recorded from four patients with surgically verified chiasmal gliomas. Despite good visual acuity, 6/12(20/40) or better in each eye, these patients showed substantially reduced VEP amplitudes to a diffuse flash stimulus and hardly detectable responses to a highly textured checkerboard-pattern stimulus. The dissociation between evoked electrical activity and visual acuity is noteworthy; this differs from previously reported findings in patients with extrinsic compressing lesions of the chiasm or with lesions of demyelinating disease, which usually reduce VEP amplitude and increase conduction time in rough proportion to a loss of visual acuity
PMID: 7236065
ISSN: 0003-9942
CID: 65720
Reduced contrast sensitivity in compressive lesions of the anterior visual pathway
Kupersmith MJ; Siegel IM; Carr RE
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 of 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
PMID: 7194970
ISSN: 0028-3878
CID: 65721