Check out the FAR link below.
http://www.cami.jccbi.gov/AAM-300/part67.html
Look at parts 67.103 (1st class), 67.203 (2nd class) and 67.303 (3rd class) for eye requirements for medical certificates. I have to admit however that the language on color perception is not as clear as you'd think it should be.
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Safe flying to you...