Week 2- Conditions of the Uvea Flashcards
What are the three main parts of the uvea
Iris ciliary body and choroid
What is the collarette in the iris
The transition zone between the central pupillary and peripheral ciliary zones
What are persistent pupillary membranes PPMs
Incomplete regression of embryonal tissue spanning across the pupil
What can iris to lens PPMs cause
Capsular cataracts
What can iris to cornea PPMs cause
Adherent leukoma
What is subalbinism in dogs
Absence of melanin from anterior stroma resulting in blue irises
What is merle ocular dysgenesis
Genetic disorder in merle breeds causing multiple ocular abnormalities
Name two findings in merle ocular dysgenesis
Microphthalmos retinal detachment
What is polycoria
Presence of more than one pupil
What is a coloboma
Congenital defect resulting in missing tissue in the iris or choroid
What is a common location for iris hypoplasia
Dorsal iris especially in heterochromic eyes
Are single iris to iris PPM bands clinically significant
No
What is benign iris hyperpigmentation called
Freckles or nevi
What features suggest malignant iris pigment lesions
Raised lesion vascular distortion flare secondary glaucoma
What is ocular melanosis
Accumulation of pigment in uveal tissue potentially leading to glaucoma
Which breed is commonly affected by ocular melanosis
Cairn Terrier
How can ocular melanosis affect vision
Pigment blocks aqueous drainage leading to glaucoma
What is the most common primary intraocular neoplasm in dogs
Melanocytoma or melanoma
Where do most uveal tumours arise from
Iris or ciliary body
What is a key feature of intraocular melanoma in cats
High metastatic rate
What is a common presentation of feline intraocular melanoma
Diffuse pigmented thickening of the iris in older cats
What is the metastatic rate of feline diffuse iris melanoma
Around 63 percent
Are melanomas in dogs usually benign or malignant
Usually benign but locally invasive
What is the second most common intraocular tumour in dogs
Iridociliary adenoma or adenocarcinoma
What colour are adenocarcinomas typically
Pink
What can large uveal tumours result in
Secondary glaucoma uveitis vitreal haemorrhage
What are common secondary intraocular tumours
Lymphoma haemangiosarcoma metastatic carcinomas
How is intraocular neoplasia diagnosed
Ophthalmic and systemic examination including ultrasound cytology or biopsy
What is the preferred treatment for large or invasive intraocular tumours
Enucleation
What should always be done after enucleation
Submit the globe for histopathology
What are uveal cysts
Clear or pigmented fluid-filled remnants of optic vesicle
How can uveal cysts be differentiated from tumours
Ultrasound and transillumination
What breed is predisposed to uveal cysts associated with glaucoma
Golden Retriever
What is hyphaema
Presence of blood in the anterior chamber
Name three causes of hyphaema
Trauma clotting disorders systemic hypertension
What are three complications of hyphaema
Glaucoma synechiae phthisis bulbi
How is hyphaema treated
Cage rest corticosteroids mydriatics monitor IOP
What is anterior uveitis
Inflammation of the iris and ciliary body
What is panuveitis
Inflammation of all parts of the uvea
What are common infectious causes of uveitis in cats
FIV FeLV FIP Toxoplasma
What is phacolytic uveitis
Low grade uveitis due to slow leakage of lens proteins
What is phacoclastic uveitis
Severe uveitis due to traumatic rupture of lens capsule
What is aqueous flare
Protein leakage into aqueous humour seen as Tyndall effect
What is hypopyon
Pus accumulation in the anterior chamber
What are keratitic precipitates
Inflammatory cell deposits on the corneal endothelium
What is miosis in uveitis caused by
Prostaglandins and ciliary muscle spasm
What is a common cause of hypotony in uveitis
Reduced aqueous production due to ciliary body inflammation
What drug is contraindicated in glaucoma but used for uveitis pain
Atropine
Which topical corticosteroid is used frequently in uveitis
Dexamethasone
Which systemic NSAID is commonly used in chronic uveitis
Aspirin
