Related Experiment Videos
Visual evoked responses in ethambutol induced optic neuritis
A K Srivastava1, U C Goel, S Bajaj
1PG Department of Medicine, SRN Hospital, Allahabad, 211001.
The Journal of the Association of Physicians of India
|March 7, 2001
Summary
Ethambutol, a tuberculosis drug, can cause subclinical optic nerve damage, detected by visual evoked response (VER). Higher doses and longer treatment increase toxicity risk, but damage may be reversible.
Area of Science:
- Ophthalmology
- Neurology
- Pharmacology
Background:
- Ethambutol is a first-line antituberculosis drug.
- Optic neuropathy is a known adverse effect of ethambutol.
- Early detection of ethambutol-induced optic neuropathy is crucial.
Purpose of the Study:
- To evaluate the incidence of subclinical optic nerve damage in tuberculosis patients treated with ethambutol using visual evoked response (VER).
- To identify risk factors associated with ethambutol-induced optic nerve toxicity.
Main Methods:
- Pattern evoked responses were recorded in 46 tuberculosis patients on ethambutol and 16 healthy controls.
- Visual acuity and P100 latency/amplitude were assessed.
- Correlation between VER findings and ethambutol dosage/duration was analyzed.
Main Results:
- Deterioration in visual acuity occurred in 4.3% of patients.
- P100 latency was delayed in 34.8% and both latency and amplitude were affected in 26.1%.
- Subclinical toxicity was higher in older patients, those on higher ethambutol doses (≥20 mg/kg/day), and with longer treatment durations.
Conclusions:
- Visual evoked response (VER) is a valuable objective tool for detecting subclinical optic nerve damage caused by ethambutol.
- Risk factors include older age, higher ethambutol dosage, and prolonged treatment.
- Ocular toxicity may be reversible upon ethambutol cessation.