Bitemporal Hemianopsia in Ethambutol-Induced Optic Neuropathy

ABSTRACT

PURPOSE: To report three cases with bitemporal hemianopsia after using ethambutol to treat tuberculosis. CASE SUMMARY: A 50-year-old male with chronic renal failure and tuberculous pleurisy, a 57-year-old male with diabetic retinopathy and pulmonary tuberculosis, and a 59-year-old male with diabetes and pulmonary tuberculosis were referred for evaluation due to decreased visual acuity for several months after taking ethambutol to treat tuberculosis. All 3 patients had abnormal color vision and visual evoked potential in both eyes. Visual field showed bitemporal hemianopsia with or without central scotoma. Brain imaging tests were normal. Although ethambutol was discontinued in all three patients, one patient with renal disease showed further decrease in visual acuity and visual field worsened to total field defect. CONCLUSIONS: Ethambutol-induced optic neuropathy is a wide spectrum disorder and based on our cases, can present as bitemporal hemianopsia mimicking compressive chiasmal lesions. A thorough history should be taken and immediate discontinuation of ethambutol is recommended in cases when bitemporal hemianopia occurs.