The Blind Eye Flashcards
What are the eight main causes of blindness?
- Symblepharon
- Keratitis
- PPMs
- Uvea problems
- Cataracts
- Glaucoma
- Posterior segment
- Optic nerve disease
What is symblepharon?
Adhesions between conjunctiva/eyelid/cornea/TE
What disease is associated with symblepharon?
Feline herpesvirus type I
What is keratitis?
Inflammation of the cornea
Give examples of a common keratitis…
Pigmentary keratopathy which is common in brachycephalics. This is secondary to entropion, distichiasis and euryblepharon
What are PPMs?
Persistent pupillary membranes. They are an embryologic memebranes that should regress originating from the iris collaretes. If they persist they can cause corneal and lens opacity.
What are the clinical signs of uveal problems?
Tyndall effect Hypopyon Hyphema Synechia Decreased IOP If chronic, increased IOP
What are the complications of uveitis?
Corneal oedema Cataracts Synechia PFIMs Retinal detachment Lens luxation Glaucoma
What are the causes of corneal oedema?
Epithelial: Ulcer
Endothelial: Uveitis, glaucoma, lens luxation
Vascular: Vessels in the cornea
What are the causes of uveal problems?
Systemic hypertension Viral: FeLV, FIV Parasitic: Toxo, leishmania Fungal: Cryptococcus Bacterial: Pyometra Immune: Uveodermatological syndrome Neoplasticism: Lymphoma, metastatic adenocarinoma Complicated ulcers: Reflex uveitis
How would you treat uveal problems?
Treat the cause:
Hypertension - ACEI
Systemic anti-inflammatory - carpofen, meloxicam, prednisone
Topical anti-inflammatories - Steroid eyepdrops QID. (Prenisolone acetate or dexamethatsone phosphate)
Cycloplegics: Tropicamide BID
What are the other findings of systemic hypertension?
Hyphema, retinal haemorrhage, bullous retinal detachment
What are the 7 causes of cataracts?
- Inherited
- Congenital
- Traumatic
- Metabolic
- Nutritional
- PRA
- Senile
What is a nuclear cataract?
The most common type bringing with a gradual hardening of the central zone of the lens
What traumatic reasons cause a cataract?
Foreign bodies
Cat scratches
What should you do with traumatic causes of cataracts?
Always refer!
What is the reasons for metabolic cataracts?
Seen in patients with diabetes. Sorbitol builds up in the lens which then draws water in.
What are the nutritional causes of cataracts?
Puppies and kittens fed on inappropriate milk replacers but this is now uncommon
What is PRA?
Progressive retinal atrophy
Why does PRA cause cataracts?
Secondary to retinal degeneration. Retina when degenerated released the toxin glutamate that leads to cataracts.
How does glaucoma cause blindness?
High intraocular pressure progressed with neurodegenerative disease.
What are the reasons for blindness originating front he posterior segment?
1) Persistent hyaloid artery and primary vitreous
2) Retina dysplasia
3) PRA
4) Retinal toxicity
5) Acute retinal disease
a. SARDS (Sudden acquired retinal degeneration syndrome)
B. IMR (immunemediated retinopathy)
What are the three types of retinal dysplasia?
- Retinal folds (mild)
- Geographic
- Retinal detachment (severe)
How does PRA progress?
Initially as night blindness which progresses to day blindness. Often starting at middle age and can lead to cataracts.
How do you diagnose PRA?
Hyper reflective tatepum and vascular attenuation due to a thin retina and retinal vessels respectively
What is the cause of retinal toxicity?
High doses of enrofloxacin in cats, also marbofloxacin
How do you diagnose SARDS>
ERG (electoretinography)
What are the two types of retinal detachment?
1) Bullous - inflammatory. Retina is pushed by fluid
2) Rhematogenous - Disinsertional. Retina loses perishable attachments
What optic nerve disease can cause blindness?
Meningoencepahlitis of Unknown Origin MUO
Infectious - Distemper, Ehrlichia, Cryptococcus
Optic nerve neoplasia: Meningioma
Collie Eye Anomaly (CEA)
What is Collie Eye Anomaly?
A combination of 2 diseases - chorodial hypoplasia and optic nerve head coloboma. This can develop retinal detachment and hyphema
