Systemic diseases can present with ocular manifestations to the emergency physician. Although most ocular findings serve to alert the physician to a possible ocular complication, many are different enough to aid the physician in making an obscure diagnosis. Knowledge of the characteristic ophthalmologic manifestations of systemic disease can aid the physician in diagnosing a particular disorder, limit the progression of more common diseases, and prevent further visual loss or blindness in patients with serious ophthalmologic complications.