Canis ISSN: 2398-2942

Proptosis / prolapse orbit / globe

Contributor(s): Dennis E Brooks, David L Williams

Introduction

  • Proptosis = anterior displacement of the globe Exophthalmos  proptosis , common in exophthalmic breeds, eg Pekingese Pekingese.
  • Prolapse = dislocation of globe beyond eyelid margin, often due to trauma.
    This condition is an emergency: traction on optic and trigeminal nerves and neighboring structures + rapid edema and inflammation.
  • Cause: trauma or increased pressure behind globe.
  • Treatment: immediate replacement of globe is vital to save vision, enucleation if majority of globe attachments are severed.
  • Prognosis: guarded.

Pathogenesis

Etiology

  • Trauma:
    • Road traffic accident.
    • Attack by larger dog.
    • Scruffing.
  • Hemorrhage behind orbit.

Predisposing factors

General
  • Exophthalmia Exophthalmos  proptosis Exophthalmos 01 Exophthalmos 02.

Specific

  • In brachycephalic breeds, eg Pug Pug , Lhasa Apso Lhasa Apso and Shih Tzu Shih Tzu , can occur with minimal trauma.

Pathophysiology

  • Trauma (often quite mild) → prolapse of an already exophthalmic globe → stretching of optic nerve +/- trigeminal nerve, optic blood vessels, rectus muscles → blindness or permanent strabismus in affected eye.
  • Exposed tissue rapidly dries out.
  • Eyelids close behind the globe → vascular occlusion → ischemia of globe.
  • Hemorrhage behind globe and conjunctival edema → difficulty in replacing.

Timecourse

  • Immediate.
  • Spasm of eyelids 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.
  • Fritsche J, Rühl M, Spiess M & Blliger J (1996) Prolapse of the eyeball in small animals - a retrospective study of 36 cases. Tierarztl Prax 24 (1), 55-61 PubMed.
  • Gilger B C, Hamilton H C, Wilkie D A, van der Woerdt A, McLoughlin S A & Whitley R D (1995) Traumatic ocular proptoses in dogs and cats - 84 cases (1980-1993). JAVMA 206 (8), 1186-1190 PubMed.
  • Mughannan A J & Reinke J D (1994) Two cosmetic techniques for enucleation using a periorbital flap. JAAHA 30 (4), 308-312 VetMedResource.
  • Hamor R E, Roberts S M & Severin G A (1993) Use of orbital implants after enucleation in dogs, horses and cats -161 cases (1980-1990). JAVMA 203 (5), 701-706 PubMed.


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