There are a lot of different kinds of doctors. There are family physicians who see patient in an office for sickness, general tests, physicals etc. There are onocologists who are cancer doctors. They treat patients with cancer. Opthamologists take care of the eyes. They do cataract surgery, basic eye exams and treat patients who have had trauma to the eye and other various problems. Pediatricians specialize in the treatment of children. Orthopedic doctors specialize in the treatments of bones and joints and injuries.