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Patient with left eye proptosis
Exophthalmos, also called 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). Complete or partial dislocation from the orbit is also possible from trauma or swelling of surrounding tissue resulting from trauma.
If left untreated, exophthalmos can cause the eyelids to fail to close during sleep leading to corneal dryness and damage. Another possible complication would be a form of redness or irritation called "Superior limbic keratoconjunctivitis", where the area above the cornea becomes inflamed as a result of increased friction when blinking. The process that is causing the displacement of the eye may also compress the optic nerve or ophthalmic artery, leading to blindness.
Measurement of the degree of exophthalmos is performed using an exophthalmometer.
Most sources define exophthalmos/proptosis as a protrusion of the globe greater than 18 mm.
Proptosis is the anterior displacement of the eye from the orbit. Since the orbit is closed off posteriorly, medially and laterally, any enlargement of structures located within will cause the anterior displacement of the eye. Swelling or enlargement of the lacrimal gland causes inferior medial and anterior dislocation of the eye. This is because the lacrimal glands are located superiorly and laterally in the orbit.
- Graves' ophthalmopathy due to Graves' disease, usually causes bilateral proptosis.
- Orbital cellulitis - often with unilateral proptosis, severe redness, and moderate to severe pain, sinusitis and an elevated white blood cell count.
- Orbital pseudotumor - presents with acute, usually unilateral proptosis with severe pain.
- High altitude cerebral edema
- Wegener's granulomatosis
- Meningioma, (of sphenoid wing)
- Nasopharyngeal angiofibroma
- Hand–Schüller–Christian disease
- Hemangioma, cavernous
- Carotid-cavernous fistula
- Aortic insufficiency: manifests as a pulsatile pseudo proptosis, described by British cardiothoracic surgeon, Hutan Ashrafian in 2006.
- Orbital fracture: apex, floor, medial wall, zygomatic
- Retrobulbar hemorrhage: trauma to the orbit can lead to bleeding behind the eye. The hemorrhage has nowhere to escape and the increased pressure pushes the eye out of the socket, leading to proptosis and can also cause blindness if not treated promptly.
- Cushing's syndrome (due to fat in the orbital cave)
- Pfeiffer Syndrome
Exophthalmos in dogs
Exophthalmos is commonly found in dogs. It is seen in brachycephalic (short nosed) dog breeds because of the shallow orbit. However, it can lead to keratitis secondary to exposure of the cornea. Exophthalmos is commonly seen in the Pug, Boston Terrier, Pekingese, and Shih Tzu.
- Owen Epstein, David Perkin, John Cookson, David P de Bono (April 2003). Clinical examination (3rd ed.). St. Louis: Mosby. ISBN 0-7234-3229-5.
- Mercandetti, Michael. "Exophthalmos". WebMD, LLC. Medscape. Retrieved 6 December 2012.
- Mitchell, Richard N. "Eye". Pocket companion to Robbins and Cotran pathologic basis of disease (8th ed.). Philadelphia, PA: Elsevier Saunders. ISBN 978-1416054542.
- Goldman, Lee. Goldman's Cecil Medicine (24th ed. ed.). Philadelphia: Elsevier Saunders. p. 2430. ISBN 1437727883.