The Blind Eye Flashcards
Which layer of the retina is next to the choroid?
What are the 4 layers of the retina?
The outer most - the retinal pigmented epithelium (non neural)
RPE, photoreceptors, cells of the inner retina, ganglion cells
Which layer of the retina is next to the vitreous?
The inner most - the ganglion cells
What is the percentage decussation at the optic chiasm in a) cats and b) dogs
a) cats = 66%
b) dogs = 75%
Which photoreceptor cells are used more in low levels of light?
Rods
Which photoreceptor cells are used more in high levels of light?
Cones
How can long standing corneal pathology cause blindness? (vague processes)
Scarring, vascularization, pigment deposition
Give examples of chronic corneal pathology which could cause blindness
KCS LPI EK Sequestra Pigmentary keratitis
Give examples of ulcerative causes which could lead to blindness
KCS-related
Traumatic
What is symblepharon?
Adhesions of the conjunctiva onto itself and the cornea
Can you think of any conditions which may cause symblepharon?
“cat flu”
mainly the FHV-1 component
Leads to corneal epithelial cell depletion, advancement of the conjunctiva over the cornea and permenant focal or diffuse scar
What potentially blinding problem do pugs with entropion often get?
Pigmentary keratitis
What is a leukoma?
Persistant pupillary membranes spanning from iris to cornea
What do you get with persistant pupillary membranes stretching from iris to lens?
a cataract
Why do you get flare and KP with uveitis?
Uveitis leads to leakage of plasma or blood, we can then get flare/KPs/hypopion/hyphema/ clots in the AC and or vitreous
Why do you sometimes get corneal oedema with uveitis?
Damage to the endothelium
Where does the iris adhere to in uveitis?
Can adhere to the lens at the pupillary zone (posterior synechia)
or the cornea at the ciliary zone (peripheral synechia and closure of ICA)
What does PIFMs stand for?
preiridial fibrovascular membranes
How do you get secondary glaucoma with uveitis?
Through clogging/closure of the ICA by PIFMs, peripheral synechia etc
How can cataracts lead to secondary uveitis?
Phacolytic uveitis due to leakage of lens proteins into aqueous humour. This protein is normally encapsulated so not tolerated by the immune system
What is facoclastic uveitis?
What is facolytic uveitis?
Inflammtion of the uvea due to release of lens proteins after penetration by a foreign body
Leakage of lens proteins with cataract –> uveitis
recurrant uveitis is caused by breakdown of the BOB true or falsE?
true. Can lead to cataracts, glaucoma
What is the proper name for periodic opthalmia/moon blindness?
Equine recurrant uveitis
What might put you off about using topical steroids after surgery for diabetic cataracts?
steroids mess with diabetic control
Name 4 cat diseases that can lead to blindness
FIP
FIV
FeLV
Toxo
Name an exotic dog disease that causes blindness through vasculopathy
leishmania
What is the name of the condition that causes uveitis/blindness and alopecia/depig in dogs?
uveodermatological syndrome
vkh like syndrome
What parts of the lens can cataracts be in?
Any - equator, nucleus or cortex
PPMs can lead to..
cataract
WHat are cataracts sometimes associated with in rabbits and cats?
E cuniculi
What electrolyte abnormality can cause cataracts in dogs?
hypocalcaemia
Persistent hyaloid vasculature can be normal in what species up to what age?
calves 16m
What diagnostic technique can you use to rule out vitreous problems such as failure of regression of fetal vessels?
ultrasound
What is the name for liquefaction of the vitreous?
Syneresis
What is asteroid hyalosis?
Particulate matter in the vitreous, often calcium and cholesterol crystals
May give a snow globe appearance
what is collie eye anomoly?
choroidal hypoplasia. May be associated with a hole (coloboma) in the optic nerve head
What does SARD stand for and how does it present?
Sudden Acute Retinal Degeneration fundus looks normal cushings like biochem & PUPD sudden onset blindness Flat ERG
What is IMR?
immune mediated retinopathy
like SARD but no cushings like signs
WHat might this be: Sudden onset blindness, ERG is normal, possible haemorrhage of the optic nerve head
meningitis of unknown origin
What are the causes of bullous retinal detachment in dogs and cats?
cat - hypertension
dog - rare, steroid responsive retinal detachment
What might cause toxic retinopathy?
Cats on enro
Is GPRA painful?
no
What does retinal atrophy look like?
hyperreflective tapetum, attenuation of retinal vessels, possibly cataracts in late stage
