Documenta Ophthalmologica 100: 155–165, 2000.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.
Multifocal Pattern Electroretinogram does not
demonstrate localised field defects in glaucoma
ALEXANDER I. KLISTORNER, STUART L. GRAHAM and
ALESSANDRA MARTINS
Save Sight Institute, Department of Ophthalmology, Sydney University, Australia
Abstract. Purpose: To determine if a multifocal PERG could be recorded in normals, and to
examine changes in the multifocal PERG in glaucoma patients. To compare the ability of mul-
tifocal PERG and multifocal VEP responses in the same individuals to identify localised field
defects in glaucoma. Methods: Using the VERIS Scientific
TM
system multifocal PERGs were
recorded from 19 sites of the visual field according to pseudo-random binary m-sequence.
Twenty normals and 15 glaucoma subjects were tested. Multifocal pattern VEPs were also
recorded in the glaucoma cases using a cortically scaled stimulus. Results: The second order
kernel of the PERG shows a consistent signal. The overall PERG amplitude decreases with
age in normals. In glaucoma the PERG amplitude was reduced across the field, but reductions
did not correspond to the area of the scotoma. The VEP showed localised signal reductions
in all 15 cases of glaucoma. Conclusion: A multifocal PERG can be recorded in normals.
However it did not reflect localised ganglion cell losses, whereas the multifocal pattern VEP
recorded to a very similar stimulus in the same individual did show losses in the scotoma area.
Key words: glaucoma, multifocal ERG, multifocal VEP, pattern stimulation, visual field
Introduction
The objective assessment of the visual field using multi-focal visually evoked
cortical potentials (VEPs) has been reported recently [1–8]. Using pseudo-
random stimulus presentation (m-sequences), stimulation of multiple loc-
ations of the visual field can be performed simultaneously. VEPs can be
recorded from all areas of the field up to 26 degrees of eccentricity using
a cortically scaled checkerboard stimulus and bipolar electrodes straddling
the inion, termed bipolar occipital straddle (BOS) [2]. Since the conventional
pattern electroretinogram (PERG) is reported to be abnormal in glaucoma [9–
15] we sought to establish if a multifocal PERG could be reliably recorded
in normals, and if it could identify localised field defects in glaucoma. We
also wished to compare multifocal PERG and VEP responses in the same
individuals.
A previous report by Vaegan and Buckland had examined the spatial dis-
tribution of multifocal ERG losses across the posterior pole of glaucomatous