Multifocal ERG in ethambutol associated visual loss.
OBJECTIVE
To determine the anatomical site and extent of electrophysiological dysfunction in patients with ethambutol associated visual loss.


METHODS
A comparative case series. Four patients with ethambutol associated visual loss underwent multifocal electroretinography (mERG). Two patients had advanced visual loss while two had early signs of toxicity. The N1-P1, N1, P1 amplitudes, N1, and P1 latencies were compared to 10 age and sex matched controls.


RESULTS
mERG abnormalities were detected in the ethambutol treated patients. The N1 amplitude was significantly lower in the ethambutol treated patients than in the control group.


CONCLUSIONS
Ethambutol is possibly toxic to the retina, and not only the optic nerve. The multifocal ERG may be of value to diagnose and monitor patients taking ethambutol.
Behbehani
R S
RS
Neuro-ophthalmology Service, Wills Eye Hospital, 840 Walnut Street, Philadelphia, PA 19107, USA. r_behbehani@hotmail.com
Affel
E L
EL
Sergott
R C
RC
Savino
P J
PJ
D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000009:adverse effects*; D004596:Electroretinography; D004977:Ethambutol / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000503:physiopathology; D014786:Vision Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000473:pathology
D000995:Antitubercular Agents; D004977:Ethambutol