Visual Function of Tuberculosis Patients Receiving Ethambutol in Kassala, Sudan: A Cross-Sectional Study

Background: Ethambutol is a first‑line antituberculosis drug whose dose‑dependent optic neuropathy may lead to irreversible vision loss if undetected. However, real-world data on its ocular impact from Sudan remain scarce, despite a high tuberculosis burden and prevalent malnutrition. To describe the visual function findings (visual acuity, color vision, pupillary reactions, intraocular pressure, and fundoscopic appearance) in tuberculosis patients receiving ethambutol-containing regimens. Methods: A hospital‑based cross-sectional study was conducted from July to December 2024. Seventy‑three adult TB patients receiving ethambutol without pre-existing vision problems were interviewed, and ocular assessments, including visual acuity, Ishihara color vision, pupil reactions, intraocular pressure, and direct fundoscopy, were performed by ophthalmologists. Data were analyzed descriptively. Results: Most participants were 25–34 years old (42.5 %) and male (53.4 %). After commencing ethambutol, 13.7 % reported subjective vision changes, and symptoms suggestive of ocular toxicity (e.g., blurred central vision, difficulty reading) were present in 15.1 %. Despite this, 94.5 % of right eyes and 95.9 % of left eyes maintained 6/6 visual acuity, and abnormal color vision was documented in only 1.4 % of eyes. Fundoscopy revealed optic‑nerve or retinal abnormalities in 1.7 % of patients. Notably, no participant reported any chronic comorbidity, and 82.2% consumed vitamin-rich or diverse diets. Conclusion: Clinically significant ethambutol‑induced ocular toxicity was infrequent in this Sudanese cohort, possibly due to the absence of comorbidities and favorable nutritional status.