An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.

An ophthalmologist has the training to do much more than just prescribe glasses. They are physicians specially trained to diagnose and treat disorders of the eyes and vision. These doctors are experts on the complicated anatomy of the eye and are trained to treat eye diseases through both medical and surgical methods.Some common conditions that ophthalmologists treat are cataracts, glaucoma, strabismus, diabetic retinopathy, macular degeneration and amblyopia. In addition, ophthalmologists can provide prescriptions for eye glasses and contact lenses and perform LASIK surgery and other corrective surgeries for refractive errors like myopia (near-sightedness), hyperopia (far-sightedness), astigmatism and presbyopia.