Exophthalmos (also called exophthalmia or proptosis) is a bulging of the eye anteriorly out of the orbit. Exophthalmos can be either bilateral (as is often seen in Graves' disease) or unilateral (as is often seen in an orbital tumor). Measurement of the degree of exophthalmos is performed using an exophthalmometer. Complete or partial dislocation from the orbit is also possible from trauma or swelling of surrounding tissue resulting from trauma. Trauma to the orbit can lead to bleeding behind the eye, a condition called retrobulbar hemorrhage. The hemorrhage has nowhere to escape and the increased pressure pushes the eye out of the socket, leading to exopthalmos or proptosis and can also cause blindness if not treated promptly...