Cataract

From Dog
Cataract formation and uveal cysts (black spheres) in a 9-year-old Boston Terrier[1]
Cataract and secondary lens subluxation in a 12-year-old dog[2]

Cataracts are a degenerative ophthalmic disease of dogs characterized by opacity of the ocular lens.

Formation of cataracts is a result of swelling and retention of lenticular cortical nuclei and nuclear debris within the lens that are not removed by the lymphoeticular system[3], leading to deposition of opaque light-reflective proteins.

Cataracts may be classified according to their location, such as nuclear, cortical and capsular.

Although cataracts develop as a primary age-related disease (senile nuclear sclerosis) in medium- to large-breed dogs[4], there are a number of secondary disease conditions which can precipitate their formation, including:

- autosomal-recessive cataracts in the Boston Terriers[5], American Cocker Spaniel, Miniature Schnauzer, Staffordshire Bull Terrier, Labrador Retriever, Miniature Poodle, Entlebucher Mountain Dog[6]
- autosomal-dominant cataracts in the Australian Shepherd[7]
- Oculoskeletal dysplasia[8]

Clinically affected dogs present with cloudiness of the central pupil, and a fixed iris unresponsive to bright light.

Lens-induced uveitis is a common complications and should be treated pre-operative with topical corticosteroids[12].

In Boston Terriers, cataracts begin as an equatorial spoke-like cataract, which slowly progresses undetected under the iris for many years prior to emerging at the pupil margin and being detected by the owner[1].

Immature and mature cataracts are most commonly treated by extracapsular phacoemulsification and intraocular lens implantation by veterinary ophthalmologists and the visual prognosis for each eye is usually excellent.

The aldose reductase inhibitor Kinostat™ can ameliorate the onset or progression of cataracts in dogs with naturally occurring diabetes mellitus[13].

References

  1. 1.0 1.1 Grahn BH et al (2012) Diagnostic ophthalmology. Can Vet J 53(3):321-322
  2. 2.0 2.1 Sandmeyer LS et al (2011) Diagnostic ophthalmology. Can Vet J 52(9):1023-1024
  3. Pendergrass W et al (2011) Age-related retention of fiber cell nuclei and nuclear fragments in the lens cortices of multiple species. Mol Vis 17:2672-2684
  4. Urfer SR et al (2011) The curious case of canine cataract: new insights into aging in dogs. J Vet Behav 6(1):99
  5. Gelatt KN & Mackay EO (2005) Prevalence of primary breed-related cataracts in the dog in North America. Vet Ophthalmol 8:101–111
  6. Kuster N et al (2011) Hereditary eye disease in the Entlebucher Mountaindog in Switzerland: a retrospective study from 1999 to 2009. Schweiz Arch Tierheilkd 153(6):269-275
  7. Mellersh CS et al (2009) Mutation in HSF4 is associated with hereditary cataract in the Australian Shepherd. Vet Ophthalmol 12(6):372-378
  8. Goldstein O et al (2010) COL9A2 and COL9A3 mutations in canine autosomal recessive oculoskeletal dysplasia. Mamm Genome 21(7-8):398-408
  9. Pumphrey SA et al (2012) Glaucoma associated with uveal cysts and goniodysgenesis in American Bulldogs: a case series. Vet Ophthalmol Oct 30
  10. Steele KA et al (2012) Outcome of retinal reattachment surgery in dogs: a retrospective study of 145 cases. Vet Ophthalmol 15(2):35-40
  11. Lane LV et al (2012) Disseminated protothecosis diagnosed by evaluation of CSF in a dog. Vet Clin Pathol 41(1):147-152
  12. Braus BK et al (2012) Cataracts are not associated with retinal detachment in the Bichon Frise in the UK--a retrospective study of preoperative findings and outcomes in 40 eyes. Vet Ophthalmol 15(2):98-101
  13. Kador PF et al (2010) Topical KINOSTAT™ ameliorates the clinical development and progression of cataracts in dogs with diabetes mellitus. Vet Ophthalmol 13(6):363-368