Here's my story with color blindness. When I did my DoDMERB exam, the optometrist told me I might be partially colorblind because I failed the PIP test (the one with the dots where you have to identify the numbers. So they put down color deficiency and I had to have a follow up at a military medical facility in order to take the FALANT (red/green/white lights).
After I passed the FALANT, my status for USNA was medically qualified. When I reported I took and failed the PIP again, so they had me take the FALANT. Again, all was fine.
In September we had optometry exams for our precommissioning physicals and the same thing happened again. As of this past week I'm medically qualified for any service selection.
So long story short, if you can see red/green fine and pass the FALANT, you won't have any issues. If you can't see red/green you can ONLY go restricted line or Marine Corps Ground so you'll have to get a waiver which, as mentioned before, is not very easy.