My friend, you worry too much. Denying you a visa based on color blindness would be as ridiculous as denying you entry because you are blind or deaf. These are disabilities you have no control over and they are not contagious. Besides, color blind people can function more or less like anybody else. Being unable to perceive a few colors is no reason to deny a visa. Like I said, relax. Other people are worrying about passing the IELTS, obtaining settlement funds and passing the interview with the visa officer. Those are issues of concern. You are maximizing on the minimum. Again. Relax.