Efficacy of vitamin supplementation in preventing color vision abnormalities among patients undergoing DOTS for Tuberculosis

ABSTRACT

Objective@#To determine if vitamin supplementation can prevent the development of color vision abnormalities in patients taking ethambutol as part of DOTS for tuberculosis (TB).@*Methods@#A randomized, placebo-controlled, single-blind clinical trial was conducted among newly diagnosed category-1 TB patients enrolled in DOTS health centers in the third district of Manila from June 2011 to August 2012. Before starting therapy, the participants underwent a complete eye evaluation including baseline color vision tests using the Ishihara Color Vision Plates (Ishihara), Farnsworth Panel D-15 (FD 15), and Lanthony Desaturated D-15. Only subjects who passed the three color vision tests were included in the study. They were divided into 2 groups Group A received vitamin supplementation and Group B received a placebo. Follow-up color vision testing was done monthly for 3 months.@*Results@#There were 105 patients included in the study, 77 males and 28 females, age ranging from 16 to 68 years with a mean of 37 years. Forty three (43) patients received vitamin supplementation (group A) and 62 received placebo (group B). After one month of DOTS, 5 of 43 patients (11. 6%) in group A and 10 of 62 patients (16.1%) in group B developed color vision abnormalities, detected only with the Lanthony Desaturated test. The absolute risk reduction (ARR) of color vision abnormalities by vitamin supplementation was 4.5%, with the number needed to treat (NNT) of 23. After the second month of therapy, ARR was 7.4% and NNT was 14. ARR was highest in the third month at 8.3%, with a corresponding decreased NNT of 12. Among patients who developed color vision abnormalities, reversal of the abnormalities was observed in 80% of 5 subjects in group A, and 40% of 10 patients in group B. By the third month of treatment, all in group A already had normal color vision, while 40% in group B still showed abnormal color vision. @*Conclusion@#This study showed that vitamin supplementation was effective in reducing the risk of, and in reversing cases of, color vision abnormalities among patients undergoing DOTS therapy for tuberculosis.