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Visual function deficits in glaucoma. Electroretinogram pattern and luminance nonlinearities.
J V Odom1, J G Feghali, J C Jin
1Department of Ophthalmology, West Virginia University School of Medicine, Morgantown 26506.
Archives of Ophthalmology (Chicago, Ill. : 1960)
|February 1, 1990
Summary
Glaucoma patients show abnormal pattern electroretinogram (PERG) and flicker electroretinogram (fERG) responses. Both conditions exhibited reduced electroretinogram amplitudes, confirming visual pathway dysfunction in glaucoma.
Area of Science:
- Ophthalmology
- Neuroscience
- Visual Electrophysiology
Background:
- The pattern electroretinogram (PERG) is known to be abnormal in glaucoma.
- Nonlinear luminance responses may contribute to PERG findings in glaucoma.
Purpose of the Study:
- To investigate glaucoma's effect on PERG component waves.
- To determine if nonlinear components of the flicker electroretinogram (fERG) are abnormal in glaucoma.
Main Methods:
- Tested 35 subjects under four conditions: 10- and 20-Hz flicker, and 4- and 10-Hz pattern reversal.
- Recorded only even harmonics for electroretinogram analysis.
- Compared electroretinogram amplitudes between glaucoma patients, those suspected of glaucoma, and normal subjects.
Main Results:
- Glaucoma patients exhibited reduced electroretinogram amplitudes across all tested measures compared to normal subjects.
- Individuals suspected of having glaucoma showed intermediate electroretinogram amplitudes.
- The most significant amplitude reductions were observed in the 10-Hz fERG and 4-Hz PERG.
Conclusions:
- Confirms existing evidence of PERG abnormalities in glaucoma.
- Reveals novel evidence of fERG abnormalities in glaucoma.
- Suggests both PERG and fERG are sensitive indicators of visual pathway dysfunction in glaucoma.