Abstract
Purpose::
To investigate the clinical manifestations and incidence of ethambutol-induced optic neuropathy (EON) in Korea and to identify factors that contribute to the development of the disease
Methods::
This study is a retrospective chart review of the 857 patients who have had ethambutol medication for tuberculosis (TB) infection between January 2003 and December 2005 at Seoul National University Hospital, Korea. Eighty nine patients, who complained about decreased vision and referred to the ophthalmologic clinic were included in this study. Charts from these patients were reviewed for the following data like age, gender, comorbid conditions, the clinical manifestation of TB, the duration and dose of ethambutol, and for the ophthalmologic examinations like visual acuity, color vision, presence of a relative afferent papillary defect, the presence of disc abnormality, visual field, and electroretinography (ERG).
Results::
Fourteen patients were diagnosed as EON, 9 were men, and 5 were women. The age was ranged between 31 and 86 years (mean, 57.29 ± 16.41 years). The average dose of ethambutol was 800 mg/day. The most frequently involved organ of TB was lung. Abnormal ophthalmologic findings included decreased visual acuity (64.3%), abnormal color vision (71.4%), abnormal visual field (50.0%), pupillary abnormality (35.7%), optic disc abnormality (35.7%), and abnormal ERG finding (75.0%). The duration and daily dose of ethambutol medication and the presence of renal dysfunction were shown to be positively related with EON development.
Conclusions::
The clinical ophthalmologic findings of EON were not all that different from the previous studies. In this study, the incidence of EON in Korea revealed as 1.6%. Renal dysfunction and the duration and daily dose of ethambutol treatment were shown to be related with EON development.