ISSN 2398-2969      

Eye: iris atrophy

icanis
Contributor(s):

David Gould

Rhea Morgan

Synonym(s): Senile iris atrophy, degeneration


Introduction

  • Iris atrophy is relatively common in dogs.
  • Primary iris atrophy is usually age-related (senile iris atrophy), but iris thinning may also develop secondary to chronic uveitis Uveitis , chronic glaucoma Glaucoma or a traumatic injury.

Pathogenesis

Etiology

  • Senile iris atrophy: age-related degeneration of iris sphincter (constrictor) muscle.
  • Secondary iris atrophy: thinning of the iris usually following development of synechiae associated with chronic uveitis or glaucoma that involves the iris sphincter muscle.

Predisposing factors

General
  • Age.
  • Breed.

Specific

  • Chronic intra-ocular disease such as chronic uveitis or glaucoma (uncommon).

Pathophysiology

  • Senile iris atrophy: age-related degeneration of iris sphincter muscle leads to reduced ability to constrict the pupil, which is manifested by decreased pupillary light reflexes despite normal vision. The iris stroma may also be affected, causing dyscoria, thinning of the iris stroma, occasional color changes within iris (often iris darkening as underlying pigment is exposed) areas of iris translucency or the development of actual holes in the iris.
  • Secondary iris atrophy: chronic uveitis or glaucoma may lead to thinning of the iris and degeneration of iris sphincter muscle, especially in association with synechiae. Unlike primary iris atrophy, vision may be affected in these cases, from the underlying disorder. The remaining discussion below, pertains only to senile iris atrophy.

Timecourse

  • Months to years.

Epidemiology

  • Increased frequency in aged populations.

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.
  • Grahn B H, Cullen C L (2004) Diagnostic ophthalmology. Iris atrophy. Can Vet J 45 (1), 77-78 PubMed.
  • Belkin P V (1975) Iris atrophy in a dog. Mod Vet Pract 56 (4), 259 PubMed.

Other sources of information

  • Marlar A J (2008)Neuroophthalmology.In: Morgan R VHandbook of Small Animal Practice.5th ed. Elsevier, Saunders, St. Louis, 2008, pp 1030-1041.
  • Hendrix D V H (2007)diseases and Surgery of the Canine Anterior Segment.In:Veterinary Ophthalmology. 4th edn. Ed KN Gelatt, Blackwell Publishing, Iowa, USA, pp 812-858.
  • Crispin S M (2002)The uveal tract.In:BSAVA Manual of Small Animal Ophthalmology.2nd edition. Eds S Petersen-Jones and S Crispin, BSAVA Publications UK, pp162-184.

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