Exophthalmos

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Proptosis
)
Exophthalmos
Bilateral exophthalmos in a 17-year old girl with facial symptoms of Pfeiffer syndrome
SpecialtyOphthalmology Edit this on Wikidata

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 results from abnormal connective tissue deposition in the orbit and

MRI.[1]

If left untreated, exophthalmos can cause the eyelids to fail to close during sleep, leading to

blindness
.

Causes

According to the

NCBI, the following conditions feature exophthalmos:[2]

  • 4p partial monosomy syndrome
Exophthalmos in Acrocephalosyndactyly type 1
Exophthalmos in cloverleaf skull
Exophthalmos in Crouzon syndrome
Exophthalmos in microcephaly (with turricephaly)

Anatomy

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]

Diagnosis

Measurement

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.[4]

Animals

Exophthalmos in a Pug

Exophthalmos is commonly found in

head trauma and pressure exerted on the front of the neck too hard in dogs. In cats, eye proptosis is uncommon and is often accompanied by facial fractures.[5]

About 40% of proptosed eyes retain vision after being replaced in the

keratoconjunctivitis sicca and keratitis and often require lifelong treatment. If the damage is severe, the eye is removed in a relatively simple surgery known as enucleation of the eye
.

The

rectus muscles. The rectus muscles normally help hold the eye in place and direct eye movement. Rupture of more than two rectus muscles usually requires the eye to be removed, because significant blood vessel and nerve damage also usually occurs.[7] Compared to brachycephalic breeds, dochilocephalic (long-nosed) breeds usually have more trauma to the eye and its surrounding structures, so the prognosis is worse.[8]

See also

References

  1. ^ .
  2. ^ "Proptosis (Concept Id: C0015300)". www.ncbi.nlm.nih.gov. Retrieved 2024-03-24.
  3. ^ .
  4. ^ Exophthalmos (Proptosis) at eMedicine
  5. ^ "Prolapse of the Eye". The Merck Veterinary Manual. 2006. Retrieved 2007-03-23.
  6. ^ Gelatt, Kirk (2002). Treatment of Orbital Diseases in Small Animals. Proceedings of the 27th World Congress of the World Small Animal Veterinary Association. Retrieved 2007-03-23.
  7. ^ ]
  8. ^ Bjerk, Ellen (2004). Ocular Injuries in General Practice. Proceedings of the 29th World Congress of the World Small Animal Veterinary Association. Retrieved 2007-03-23.

External links