There are 100s of medical conditions that will bar you from joining the military.
My Dad had a childhood friend who lost an eye in an accident. Like Dad, this friend was drafted to fight in World War II. He tried to get out of serving, telling the sergeant about his lost eye. The sergeant pointed to the friend’s real eye and artificial eye and said, “I see 2 eyes. Son, you’re in.”
During World War II, I suppose the military wasn’t all that picky.