Will they re-test my color vision at basic?

If you have been disqualified for a certain job in the military due to your defective color vision, you can usually request a retest. I am not sure how it works in the Coast Guard, but I was in the Navy. I tested and was given the same prognosis. In basic, they had a day in which you could change your contract if you wanted. I requested a rating in which I needed to have normal color vision, and they offered me another chance at a vision test. I declined because I knew I was color blind. So they probably do the same in the Coast Guard, but be aware, if you had trouble with the test you might be color blind. Almost all individuals with normal color vision can see the numbers instantly, and do not need more than a second or two.