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Objective perimetry in glaucoma: recent advances with multifocal stimuli.
S L Graham1, A Klistorner, J R Grigg
1Save Sight Institute, Department of Ophthalmology, Sydney University, NSW, Australia.
Survey of Ophthalmology
|July 23, 1999
Summary
Multifocal pattern visual evoked potential (PVEP) effectively detects glaucoma-related visual field loss. This electrophysiologic technique shows strong correlation with standard perimetry, offering objective assessment of vision changes.
Area of Science:
- Ophthalmology
- Neuroscience
- Medical Imaging
Background:
- Electrophysiologic techniques, specifically multifocal stimulus recording, have advanced visual field examination.
- The multifocal pattern visual evoked potential (PVEP) is an adaptation for detecting visual field loss.
Purpose of the Study:
- To evaluate the correlation between PVEP amplitudes and perimetric thresholds in glaucoma patients.
- To assess the utility of multifocal PVEP for objective detection of visual field defects in glaucoma.
Main Methods:
- Multifocal pseudorandomly alternated pattern stimuli, cortically scaled, were presented using the VERIS-Scientific system.
- Bipolar occipital straddle electrodes were employed to investigate the visual field up to 25 degrees.
- Forty-three glaucoma patients with reproducible visual field defects were tested.
Main Results:
- Bipolar PVEP showed good correspondence with Humphrey visual field defects, identifying signal loss in scotoma areas.
- A strong correlation (r = 0.49, P < 0.0001) was found between Humphrey quadrant threshold totals and PVEP quadrant amplitudes.
- The multifocal PVEP demonstrated good agreement with the visual field's topography.
Conclusions:
- Multifocal PVEP is a practical and objective method for detecting visual field defects in glaucoma.
- This technique provides a reliable electrophysiologic correlate to standard visual field testing.
- The study highlights the potential of multifocal PVEP in glaucoma diagnostics and monitoring.