The Blind Eye

Question 1

Which layer of the retina is next to the choroid?

What are the 4 layers of the retina?

Answer 1

The outer most - the retinal pigmented epithelium (non neural)
RPE, photoreceptors, cells of the inner retina, ganglion cells

Question 2

Which layer of the retina is next to the vitreous?

Answer 2

The inner most - the ganglion cells

Question 3

What is the percentage decussation at the optic chiasm in a) cats and b) dogs

Answer 3

a) cats = 66%

b) dogs = 75%

Question 4

Which photoreceptor cells are used more in low levels of light?

Answer 4

Rods

Question 5

Which photoreceptor cells are used more in high levels of light?

Answer 5

Cones

Question 6

How can long standing corneal pathology cause blindness? (vague processes)

Answer 6

Scarring, vascularization, pigment deposition

Question 7

Give examples of chronic corneal pathology which could cause blindness

Answer 7

KCS
LPI
EK 
Sequestra
Pigmentary keratitis

Question 8

Give examples of ulcerative causes which could lead to blindness

Answer 8

KCS-related

Traumatic

Question 9

What is symblepharon?

Answer 9

Adhesions of the conjunctiva onto itself and the cornea

Question 10

Can you think of any conditions which may cause symblepharon?

Answer 10

“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

Question 11

What potentially blinding problem do pugs with entropion often get?

Answer 11

Pigmentary keratitis

Question 12

What is a leukoma?

Answer 12

Persistant pupillary membranes spanning from iris to cornea

Question 13

What do you get with persistant pupillary membranes stretching from iris to lens?

Answer 13

a cataract

Question 14

Why do you get flare and KP with uveitis?

Answer 14

Uveitis leads to leakage of plasma or blood, we can then get flare/KPs/hypopion/hyphema/ clots in the AC and or vitreous

Question 15

Why do you sometimes get corneal oedema with uveitis?

Answer 15

Damage to the endothelium

Question 16

Where does the iris adhere to in uveitis?

Answer 16

Can adhere to the lens at the pupillary zone (posterior synechia)
or the cornea at the ciliary zone (peripheral synechia and closure of ICA)

Question 17

What does PIFMs stand for?

Answer 17

preiridial fibrovascular membranes

Question 18

How do you get secondary glaucoma with uveitis?

Answer 18

Through clogging/closure of the ICA by PIFMs, peripheral synechia etc

Question 19

How can cataracts lead to secondary uveitis?

Answer 19

Phacolytic uveitis due to leakage of lens proteins into aqueous humour. This protein is normally encapsulated so not tolerated by the immune system

Question 20

What is facoclastic uveitis?

What is facolytic uveitis?

Answer 20

Inflammtion of the uvea due to release of lens proteins after penetration by a foreign body
Leakage of lens proteins with cataract –> uveitis

Question 21

recurrant uveitis is caused by breakdown of the BOB true or falsE?

Answer 21

true. Can lead to cataracts, glaucoma

Question 22

What is the proper name for periodic opthalmia/moon blindness?

Answer 22

Equine recurrant uveitis

Question 23

What might put you off about using topical steroids after surgery for diabetic cataracts?

Answer 23

steroids mess with diabetic control

Question 24

Name 4 cat diseases that can lead to blindness

Answer 24

FIP
FIV
FeLV
Toxo

Question 25

Name an exotic dog disease that causes blindness through vasculopathy

Answer 25

leishmania

Question 26

What is the name of the condition that causes uveitis/blindness and alopecia/depig in dogs?

Answer 26

uveodermatological syndrome | vkh like syndrome

Question 27

What parts of the lens can cataracts be in?

Answer 27

Any - equator, nucleus or cortex

Question 28

PPMs can lead to..

Answer 28

cataract

Question 29

WHat are cataracts sometimes associated with in rabbits and cats?

Answer 29

E cuniculi

Question 30

What electrolyte abnormality can cause cataracts in dogs?

Answer 30

hypocalcaemia

Question 31

Persistent hyaloid vasculature can be normal in what species up to what age?

Answer 31

calves 16m

Question 32

What diagnostic technique can you use to rule out vitreous problems such as failure of regression of fetal vessels?

Answer 32

ultrasound

Question 33

What is the name for liquefaction of the vitreous?

Answer 33

Syneresis

Question 34

What is asteroid hyalosis?

Answer 34

Particulate matter in the vitreous, often calcium and cholesterol crystals May give a snow globe appearance

Question 35

what is collie eye anomoly?

Answer 35

choroidal hypoplasia. May be associated with a hole (coloboma) in the optic nerve head

Question 36

What does SARD stand for and how does it present?

Answer 36

``` Sudden Acute Retinal Degeneration fundus looks normal cushings like biochem & PUPD sudden onset blindness Flat ERG ```

Question 37

What is IMR?

Answer 37

immune mediated retinopathy | like SARD but no cushings like signs

Question 38

WHat might this be: Sudden onset blindness, ERG is normal, possible haemorrhage of the optic nerve head

Answer 38

meningitis of unknown origin

Question 39

What are the causes of bullous retinal detachment in dogs and cats?

Answer 39

cat - hypertension | dog - rare, steroid responsive retinal detachment

Question 40

What might cause toxic retinopathy?

Answer 40

Cats on enro

Question 41

Is GPRA painful?

Answer 41

no

Question 42

What does retinal atrophy look like?

Answer 42

hyperreflective tapetum, attenuation of retinal vessels, possibly cataracts in late stage