Exophthalmos - Causes and Symptoms

Definition

Exophthalmos (outward eyes) is the pathological protrusion of one or both eye globes towards the outside of their orbits. The term is often used interchangeably with proptose; however, being rigorous, exophthalmos should indicate protruding eyes in endocrine-related conditions . In fact, the most frequent cause of exophthalmos is Graves' disease (hyperthyroidism), which causes lymphoid edema and infiltration of the orbital tissues.

Proptosis, on the other hand, can be caused by all local or systemic alterations that create an increase in volume within the fixed bone boundaries of the orbital cavity; these include tumor proliferation, vascular anomalies (eg fistula between carotid and cavernous sinus, arteriovenous aneurysm and cavernous sinus thrombosis) and inflammation due to physical, infectious or traumatic causes.

A sudden unilateral onset is generally associated with an intraorbital or retrobulbar hemorrhage (after surgery, retrobulbar injection or trauma), an orbital and facial fracture or an inflammation of the orbit or paranasal sinuses.

Other causes of proptosis include: congenital glaucoma, orbital cellulitis, dacryocystitis, mucormycosis, Wegener's granulomatosis and neuroblastoma.

If exophthalmos is progressive, the protrusion of the eye from the orbit can cause dryness (due to the difficulty of completely closing the eyelids), diplopia, exposure keratitis and corneal ulceration, with possible impairment of visual function.