Canis ISSN: 2398-2942

Cornea: lipidosis

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

Introduction

  • Cause: two main categories: crystalline stromal dystrophy, hereditary and lipid keratopathy (increased circulating lipids or after surgery).
  • Signs: opacification of cornea.
  • Diagnosis: signs, laboratory investigation.
  • Treatment: manage underlying cause, keratectomy may be required.

Pathogenesis

Etiology

Lipid keratopathy
  • Previous corneal trauma.
  • New blood vessels leak lipid into cornea.
  • Elevated blood lipid levels (in some cases).
Secondary lipid infiltration
  • Limbal melanoma.
  • Episcleritis.
  • Pannus.
  • Leak from new blood vessels to deposit in cornea.
  • Stromal dystrophy.
  • Hereditary.

Predisposing factors

General
  • Susceptible breeds.

Specific

  • Corneal injury.
  • Systemic blood lipid elevation, ie hypothyroidism.

Pathophysiology

  • Crystalline stromal dystrophy: non-painful, non-vascularized lesions with characteristic granular or ground glass appearance affecting central/paracentral cornea as circular or oval lesion (inherited + bilateral without systemic changes).
  • Lipid keratopathies: painful, vascularized lesions - usually secondary and may be associated with increased circulating lipids Lipid keratopathy Rough Collie male 3 years.
  • Secondary lipid infiltration: non-painful, non-vascularized. Secondary to limbal melanoma, episcleritis, pannus, leak from new blood vessels to deposit in cornea.
Crystalline corneal dystrophy
  • Lipid deposited in anterior stroma of central or paracentral cornea due to innate abnormality or localized error in corneal lipid metabolism.
  • Lesions may be deeper and more extensive in Siberian Husky Siberian Husky.
Lipid keratopathies
  • Crystalline lipid deposits penetrate corneal epithelium → irritation, vascularization and possibly ulceration Keratitis.
  • May be associated with abnormal levels of circulating lipids.
  • Usually occurs in conjunction with corneal degeneration.
  • Calcium is also involved in this pathological process.

Timecourse

  • Lifelong disease with slow progression in the dystrophies.
  • Keratopathy can occur following acute injury.

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.
  • Crispin S M (1993) Ocular manifestations of hyperlipoproteinaemia. JSAP 34 (10), 500-506 VetMedResource.
  • Cooley P L & Dice P F (1990) Corneal dystrophy in the dog and cat. Vet Clin North Am (SAP) 20 (3), 681-692 VetMedResource.
  • Crispin S M (1982) Corneal dystrophies in small animals. Vet Ann 22, 298-310 VetMedResource.

Other sources of information

  • Gelatt K N (1999)Veterinary Ophthalmology.3rd Edn. Williams & Wilkins.


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