The blind eye Flashcards
What is symblepharon?
Conjunctiva attaches to cornea Any part of the conjunctiva can attach
What infection is symblepharon commonly seen with?
Feline herpesvirus type 1
What causes pigmentary keratitis?
Entropion, distichiasis and euryblepharon
What is pigmentary keratitis?
Pigmented sclera and cornea
What do persistent pupillary membranes look like?
Strands originating from iris colourette and go to the cornea and lens Can cause corneal opacity or lens opacity
What are the clinical signs of uveitis?
Flare, hypopion, hyphema (diffuse or localised), synechia and decreased intraoclular pressure
How do you differentiate between PPMs and posterior synechia?
Look for where adhesion comes from as synechia appear from edge of iris not the middle
What are the complications of uveitis?
Corneal oedema, cataracts, synechiae, PIFMs, retinal detachment, lens luxation in cats and glaucoma
What are the causes of uveal problems?
Systemic hypertension Infectious agents (FeLV, FIV, Toxoplasma, Cryptococcus, bacteria) Immune mediated Neoplasia (lymphoma/metastatic adenocarcinoma)
What causes reflex uveitis?
Complicated ulcers
What is the treatment for uveitis?
Treat cause, systemic anti-inflammatories and topical anti-inflammatory treatment
What are cataracts?
Opacity of the lens impeding light transmission
What is the relationship between cataracts and uveitis?
Causes uveitis by phacolysisphacoclastic processes where protein leaks into aqueous humour and is seen as foreign leading to a massive inflammatory reaction Sequel to uveitis due to poor nourishment of the lens and altered chemistry of the aqueous humour
Describe the characteristics of inherited cataracts
Breed related and rarely congenital (juvenile or adult onset) Morphology and progression genetically determined Labs and Staffies get posterior bullae type
What are the characteristics of congenital cataracts?
Rarely inherited Always nuclear Can cause severe visual deficits
Describe traumatic cataracts
From foreign bodies/cat scratches Might need removal of the lens via phacoemulsification and suturing of corneal deficit induces phacoclastic uveitis
What is the pathophysiology of the metabolic cause of cataracts?
Diabetes mellitus increases blood glucose which increases level of glucose in aqueous humour so more glucose moves into the lens resulting in a high lens concentration of glucose which is converted into sorbitol which is highly osmotically active so water moves into the lens and it becomes swollen
Why are nutritional cataracts more uncommon now?
It is caused by puppies and kittens being fed inappropriate milk replacement which doesn’t happen now there are suitable commercial diets available
How does progressive retinal atrophy cause cataracts?
It releases toxins such as glutamate
What do senile cataracts look like?
In the cortex, wedge shaped lesions, severity dependent on size of defect
What vitreal diseases can cause blindness?
Persistent hyaloid artery and primary vitreous generally seen in young Pinschers and Schnauzers
What are the three main types of retinal dysplasia?
Retinal folds, geographic and retinal detachment
What breeds is retinal dysplasia inherited in?
CKCS and ESS
What is the progression of progressive retinal atrophy (PRA)?
Night blindness-> day blindness Starts in middle age and leads to cataracts
What are the clinical examination findings of PRA?
Hyperreflective tapetum, vascular attenuation and in late stages cataracts
What drug causes retinal toxicity?
Enrofloxacin
What is SARDS?
Sudden Acquired Retinal Degeneration Syndrome Acute/sub-acute vision loss and is diagnosed by electroretinography
What are the causes of retinal detachment?
Inflammatory = retina pushed by fluid, looks bullous Disinsertional = retina loses peripheral attachments, folds down and see ribbon like white structure
What causes optic neuritis?
Distemper, ehrilichia and cryptococcus
What does optic neuritis look like clinically?
Hyperaemia of the papilla, vascular congestion and peripapillary haemorrhages
What other optic nerve disease can caused blindness?
Optic nerve meningioma
What is Collie Eye Anomally?
Combination of choroidal hypoplasia and optic nerve head coloboma Can develop retinal detachment and hyphoma or vitreal haemorrhage
