The medical term that describes the abnormal protrusion of the eye(s) is proptosis or exophthalmos. Unilateral describes protrusion of only one eye while bilateral means both eyes. Experts may also refer to this condition as just bulging or protruding eyes.
The most common cause of proptosis is Grave's disease. Grave's disease leads to hyperthyroidism, or when the body produces an excessive amount of the hormones that control metabolism. In turn, this can cause swelling of the tissue, fat and muscles in the eye socket, forcing the eye to bulge outwards. Other causes of proptosis include glaucoma, orbital cellulitis, hemangioma and histiocytosis. In addition, neuroblastoma and leukemia are also causes of proptosis.