Introduction
- A cataract is an opacification of the lens.
- May be primary (breed-related) or secondary due to disease (uveitis, diabetes, PRA).
- Developmentally staged as incipient, immature (tapetal reflex present), mature (no tapetal reflex/blindness) and hypermature (wrinkled lens capsule).
- Either congenital, eg Miniature Schnauzer, Boston Terrier, Welsh Springer Spaniel, at early age, eg Afghan Hound, German Shepherd dog or at later stage, eg Standard Poodle.
- Usually inherited (autosomal recessive).
- Inherited as incomplete dominant in Labrador Retriever, Golden Retriever (posterior subcapsular opacity).
- Good prognosis if phacoemulsification performed and if no other ocular structures involved.
- Early developing cataract: remove at an early stage either by irrigation, aspiration, extracapsular extraction or phacoemulsification → prevents lens-induced uveitis.
Diagnosis
Clinical signs
- Lens opacification.
- May be uveitis in some cases, eg aqueous flare, miosis.
- Slit lamp exam to localize opacity.
- Ophthalmoscopy - unable to see fundus in mature cataracts.
Sequelae
Prognosis
- Cataracts that progress to maturity can produce uveitis, secondary glaucoma and retinal detachment.
Expected response to treatment
- Vision is present.
Reasons for treatment failure
- Post-operative glaucoma.
- Post-operative retinal detachment.
- Post-operative ophthalmitis.
- Poor compliance with medical therapy after surgery.
Sources
Publications
Refereed papers
- Gelatt K N (1998) Veterinary Ophthalmology. 3rd edn. Williams & Wilkins.
- 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), 347-53.
