Ophthalmologists perform diagnosis and treatment of disorders of the eye, as well as routine vision care. Surgery is performed to repair ailments such as cataracts and retinal detachments, nearsightedness and astigmatism. Diagnosis and treatment of glaucoma is also included in Ophthalmology. Detection of disease in other parts of the body may be made through eye examination, such as diabetes, thyroid disease, brain tumors and hypertension. Comprehensive eye examinations and prescriptions for eyeglasses and contact lens are given.