dont worry about a thing if ur color blind then still its fine.i personally know friends who have got in inspite of having to wear glasses and like i said i had a cavity myself and i have just recieved a pay hike from tcs so rest assured the medical test is the last thing u should be worried about. if anything find out where u will be posted (ur base branch) and what kind of projects are present in that location.
peice of advise - dont stay on bench for more than 45 days.thats something to worry about