good morning sir, my father is 68 years retired from iit kanpur had gone through lung TB treatment and had taken eutembutol for almost 9 months ,and he is totally fit now,treatment is also closed. he is facing blurred vision problem in both the eyes by last 45 days, due to that he is rest less and anxiety .he is taking Vitamin A tablets and restile tablets. please tell me how much time side effect of ETB will remain, and any other suggestion , presently his eye power is 6/10. please advice