Exophthalmos

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"Proptosis" redirects here. For the condition of drooping of the eyelid, see Ptosis (eyelid).
This article is about proptosis. For the weevils, see Exophthalmus.
Exophthalmos
Classification and external resources
406907P-PA-OCULAR.jpg
Patient with left eye proptosis
ICD-10 H05.2
ICD-9 376.2-376.3
DiseasesDB 18612
MedlinePlus 003033
eMedicine oph/616
MeSH D005094

Exophthalmos (also called exophthalmus, exophthalmia, proptosis, or exorbitism) 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.

In the case of Graves' disease, the displacement of the eye is due to abnormal connective tissue deposition in the orbit and extraocular muscles which can be visualized by CT or MRI.[1]

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[edit]

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.[1]

The term exophthalmos is often used when describing proptosis associated with Graves' disease.[2]

Anatomy[edit]

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.[3] 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.[3]

Causes[edit]

Inflammatory/Infection:

Neoplastic:

Cystic:

Vascular:

Others:

  • 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[edit]

Exophthalmos in a Pug
Main article: Eye proptosis

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.

See also[edit]

References[edit]

  1. ^ a b Owen Epstein, David Perkin, John Cookson, David P de Bono (April 2003). Clinical examination (3rd ed.). St. Louis: Mosby. ISBN 0-7234-3229-5. 
  2. ^ Mercandetti, Michael. "Exophthalmos". WebMD, LLC. Medscape. Retrieved 6 December 2012. 
  3. ^ a b Mitchell, Richard N. "Eye". Pocket companion to Robbins and Cotran pathologic basis of disease (8th ed.). Philadelphia, PA: Elsevier Saunders. ISBN 978-1416054542. 
  4. ^ a b Goldman, Lee. Goldman's Cecil Medicine (24th ed. ed.). Philadelphia: Elsevier Saunders. p. 2430. ISBN 1437727883. 

External links[edit]