Is it possible to be blind in one eye and still be an ophthalmologist?

Are You Kidding? Yes: An ophthalmologist is a doctor of vision. If the person who is blind in one eye is capable of finishing medical school & then becoming an ophthalmologist- then the answer is yes.

Would be tough: I suppose anything is possible but it would be difficult to perform a proper dilated exam since proper depth perception and "stereopsis" is necessary for this and is impossible with one eye. Surgery would also be very challenging. Still, sometimes with time people are able to adjust to the use of one eye and can do remarkable things.

Caution!: Ophthalmology requires incredible stereopsis for many tasks. The chairman of the department of ophthalmology at the time of my training did not have stereo vision. He could no longer do modern cataract surgery, in fact they were disastrous! yes there are sub-specialties within ophthalmology such as pathology, neurology, pediatrics where stereo vision is not as essential.