Felis ISSN 2398-2950

Orbit / globe: proptosis / prolapse

Contributor(s): Dennis E Brooks, Paul Evans, Newman Lorna, Philip K Nicholls, David Williams

Introduction

  • Cause: trauma.
  • Signs:
    • Proptosis = anterior displacement of the globe.
    • Prolapse = dislocation of globe beyond eyelid margin, often due to trauma.
  • Diagnosis: signs.
  • Treatment: immediate replacement of globe (often lateral canthotomy required) vital to save vision; if severe ocular damage with no hope of restoring vision enucleation should be considered.
  • Prognosis: guarded due to associated ocular trauma. Amount of trauma required to prolapse cat eye is relatively greater than for many dogs, especially brachycephalics, therefore other ocular trauma may occur concurrently and prognosis often worse.

Pathogenesis

Etiology

  • Trauma, eg road traffic accident, attack by dog, scruffing - mainly in already naturally exophthalmic cats, ie Persians Persian longhair.

Predisposing factors

General

  • Exophthalmos Eye: exophthalmos - DSH 9 years .

Pathophysiology

  • Risk of blindness high, especially if signs of intraocular damage are seen concurrently.
  • Risk of corneal exposure and secondary ocular (particularly optic nerve) damage, particularly if there is delay in replacing the globe.
  • Trauma   →   prolapse of an already exophthalmic globe   →   tension on optic nerve +/- trigeminal nerve, optic blood vessels, rectus muscles   →   lid spasm and tissue swelling compromises drainage exacerbating proptosis; blindness or permanent strabismus in affected eye.

Timecourse

  • Immediate.
  • Spasm of eyelids and swelling of retrobulbar tissue occurs very quickly   →   increased difficulty replacing globe.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gilger B C, Hamilton H L, Wilkie D A et al (1995) Traumatic ocular proptoses in dogs and cats - 84 cases (1980-1993). JAVMA 206 (8), 1186-1190 PubMed.

Other sources of information

  • Petersen-Jones S & Crispin S (2002) BSAVA Manual of Small Animal Ophthalmology. 2nd edn. British Small Animal Veterinary Association. ISBN 0 905214 54 4


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