Ophthalmology is the study of medical conditions relating to the eye. Ophthalmologists are doctors who specialize in the medical and surgical treatment of this organ. A general practice doctor may refer someone to an ophthalmologist if they show symptoms of cataracts, eye infections, optic nerve problems, or other eye conditions. Subspecialist ophthalmologists have usually completed training that allows them to work on eye conditions that are complex, involve a specific part of the eye, or affect certain groups of people. They also train more extensively than regular ophthalmologists to perform extremely intricate surgeries on delicate parts of the eye.