Visual function deficits in glaucoma. Electroretinogram pattern and luminance nonlinearities
J. V. Odom, J. G. Feghali, J. C. Jin and G. W. Weinstein
Department of Ophthalmology, West Virginia University School of Medicine, Morgantown 26506.
The pattern electroretinogram is abnormal in glaucoma. Part of the pattern
electroretinogram may be attributed to the summation of responses to
luminance increases and decreases (nonlinear luminance responses). We
conducted a study to investigate the effect of glaucoma on the pattern
electroretinogram component waves and to determine if the flicker
electroretinogram nonlinear components are abnormal in glaucoma. We tested
35 subjects in two replications of four conditions: 10- and 20-Hz flicker,
and 4- and 10-Hz pattern reversal. Only the even harmonics were recorded.
The patients with glaucoma had reduced electroretinogram amplitudes for all
measures relative to the normal subjects. Electroretinogram amplitudes of
those suspected of having glaucoma were intermediate. The greatest
amplitude reductions were for the 10-Hz flicker electroretinogram and the
4-Hz pattern electroretinogram. These results confirm pattern
electroretinogram abnormalities and reveal flicker electroretinogram
abnormalities in glaucoma.
