Lens: hereditary primary cataract

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Sections available in full article Introduction, Presenting signs, Age predisposition, Breed predisposition, Cost considerations, Pathogenesis, Etiology, Predisposing factors, Pathophysiology, Timecourse (incubation, duration), Diagnosis, Presenting problems, Client history, Clinical signs, Diagnostic investigation, Confirmation of diagnosis, Differential diagnosis, Treatment, Initial symptomatic treatment, Monitoring, Prevention, Control, Sequelae, Prognosis, Expected response to treatment, Reasons for treatment failure, Sources, Publications, Vetstream contributor(s),
Contributors Dr Dennis E Brooks DVM PhD DipACVO
Dr David L Williams MA VetMB PhD CertVOphthal FRCVS

Introduction

  • Cataract is an opacity in the lens, primary cataract occurs in the absence of any other ocular disease has a bilateral potential and is hereditary. Secondary cataract occurs as a sequela to other trauma, ocular disease, eg progressive retinal atrophy.
  • Cause : usually autosomal recessive inheritance, possibly dominant with incomplete penetrance in some Retriever breeds.
  • Signs : lens opacity, may be focal or diffuse - appearance usually characteristic for the particular breed. May be progressive or stationary. May be congenital in some breeds, often associated with microphthalmos.
  • Diagnosis : lens opacity seen by distant direct ophthalmoscopy, direct ophthalmoscopy or slit-lamp biomicroscopy gives better resolution.
  • Treatment : lendectomy by phacoemulsification (before cataract matures or uveitis is present). Earlier extraction → prevents lens-induced uveitis.
  • Prognosis : reasonable if phacoemulsification and no other ocular abnormalities, many post-operative complications possible.

Diagnosis

Clinical signs

  • Opacity in lens → Cataract: primary hereditary non-congenital - Golden Retriever represented by interruption in fundus reflex with distant direct ophthalmoscopy.
  • If dense diffuse cataract, assess pupillary light reflex (PLR) Neuro exam: pupillary reflexes - if cataract is secondary to retinal disease, PLR likely to be poor.
  • Thorough ophthalmic and general examination to rule out other cause for cataract.

Diagnosis

Differential diagnosis

  • Other causes of leucocoria, eg retinal detachment.
  • 'False' cataracts - persistent hyaloid artery, persistent suture lines (common in puppies, may disappear with age), persistent pupillary membranes (membranes may insert on anterior lens capsule and be associated with cataract).
  • Other congenital conditions - PHPV/PHTVL (persistent hyperplastic primary vitreous/persistent hyperplastic tunica vasculosa lentis - seen in Dobermann and Staffordshire Bull Terrier as hereditary condition).
  • Secondary cataract Cataract - secondary to other ocular disease (glaucoma, uveitis, lens luxation, retinal dysplasia, generalized progressive retinal atrophy), traumatic, metabolic (diabetes mellitus), toxic/dietary, senile.
  • Senile nuclear sclerosis - lens appears cloudy in older dogs, but no interruption to fundus reflex on distant direct ophthalmoscopy.
  • Corneal opacity:
    • Edema.
    • Lipid.
    • Scar.
  • Hypopyon.

Sequelae

Prognosis

  • Congenital cataract usually stationary if only nucleus in involved.
  • Cataracts associated with equatorial vacuoles likely to progress to total.
  • Prognosis reasonable following cataract extraction, if routinely monitored and appropriately treated.

Expected response to treatment

  • Most animals have significantly improved vision after surgery.

Reasons for treatment failure

  • Post-operative complications - retinal detachment, chronic glaucoma.

Sources

Publications

Refereed papers

  • Recent references from 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 , 347-353.
  • Curtis R & Barnett K C (1989) A survey of Cataracts in Golden and Labrador Retrievers. JSAP 30 , 277.
  • Barnett K C (1988) Inherited eye disease in the dog and cat. JSAP 29 , 462.
  • Strande A, Nicolaissen B & Bjerkas I (1988) Persistent pupillary membrane and congenital cataract in a litter of English Cocker Spaniels. JSAP 29 , 257.
  • Barnett K C (1986) Hereditary caract in the German Shepherd Dog. JSAP 27 , 387.
  • Barnett K C (1985) The diagnosis and differental diagnosis of cataract in the dog. JSAP 26 , 305.
  • Barnett K C & Startup F G (1985) Hereditary cataract in the Standard Poodle. Vet Rec 117 , 15.
  • Curtis R (1984) Late-onset cataract in the Boston Terrier. Vet Rec 115 , 577.
  • Narfstrom K & Dubielzig R (1984) Posterior Ienticonus, cataracts and microphthalmia: congenital ocular defects in the Cavalier King Charles Spaniel. JSAP 25 , 669.
  • Narfstrom K (1981) Cataract in the West Highland White Terrier. JSAP 22 , 467.
  • Barnett KC (1980) Hereditary cataract in the Welsh Springer Spaniel. JSAP 21 , 621.
  • Gelatt K N et al(1979) Cataracts in Chesapeake Bay Retreivers. JAVMA 183 , 99.
  • Barrie K P, Peiffer R L, Gelatt K N & Williams L W (1979) Posterior Ienticonus, microphthalmia, congential cataracts and retinal folds in an Old english Sheepdog. JAVMA 15 , 715.
  • Barnett K C (1978) Hereditary cataract in the dog. JSAP 19 , 109.
  • Yakely W L (1978) A study of heritability of cataracts in the American Cocker Spaniel. JAVMA 172 , 814.
  • Olesen H P, Jensen O A & Norn M S (1974) Congenital hereditary cataract in Cocker Spaniels. JSAP 15 , 741.

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