Canis ISSN: 2398-2942

Cataract: acquired

Contributor(s): Paul Gerding, David L Williams

Introduction

  • See also cataract Cataract for details of diagnosis and management.
  • Cause: multiple etiologies all resulting in similar clinical picture.
  • Signs: of underlying disease and lens opacity.
  • Diagnosis: recognition of cataract and identification of underlying cause.
  • Treatment: manage cause, cataract surgery may be indicated.
  • Prognosis: depends on cause.

Pathogenesis

Etiology



Trauma
  • If injury penetrates lens capsule → cataract Cataract traumatic - Jack Russell Terrier 2 years.
  • Cataract may be focal (at point of capsular penetration) or may over days/weeks radiate (from point of capsular penetration) to involve whole lens.
  • Also occur following radiation damage, eg radiotherapy for nasal neoplasia.
Progressive retinal atrophy Uveitis
  • May be associated with posterior synechiae.
  • Uveitis Uveitis may occur secondary to lens damage (in this case may be aqueous flare in acute phase and possible posterior synechiae as a later change).
Glaucoma Lens luxation
  • All luxated lens Lens: luxation eventually → cataracts.
  • May → glaucoma → cataract.
  • Cataract Cataract secondary to retinal dysplasia - English Springer Spaniel may be associated with retinal detachment or other concurrent ocular anomalies that result in uveitis.
Drug toxicity
  • May be transient Cataract toxic 01 - Beagle young adult.
  • Increased levels of free radicals in lens, eg substituted hydrocarbons → transient hyperglycemia → cataract.
Neoplasia
  • Uncommon cause of cataract occasionally due to intra-ocular tumor abutting lens.
  • Neoplasia may also cause glaucoma/lens subluxation/uveitis → cataract.
Metabolic
  • Hyperglycemia, ie diabetes mellitus results in altered osmotic gradient and water is drawn into the lens Diabetic cataract Crossbred 12 years.
  • Hypocalcemia is very rare cause.
Dietary deficiencies
  • Occurs in puppies fed milk replacements.
  • Cause may be amino acid imbalance.
  • Often do not progress to total vision loss.

Timecourse

  • May be acute (diabetes mellitus) Diabetes mellitus (over days) or develop over months.

Treatment

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Denis H M, Brooks D E, Alleman A R, Andrew S E & Plummer C (2003) Detection of anti-lens crystallin antibody in dogs with and without cataracts. Vet Ophthalmol (4), 321-327 PubMed.
  • Williams D L, Boydell I P & Long R D (1996) Current concepts in the management of canine cataract - a survey of techniques used by surgeons in Britain, Europe and the USA and a review of recent literature. Vet Rec 138 (15), 347-353 PubMed.
  • Davidson M, Nasisse M, Jamieson V et al (1991) Traumatic anterior lens disruption. JAAHA 27 (4), 410-414 VetMedResource.


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