Retina-Choroid

Question 1

What are we looking at during a fundic exam anterior to posterior?

Answer 1

Vitreous
Retina
Choroid
Sclera

Question 2

Syneresis

Answer 2

Liquefaction of the vitreous humor

Question 3

What is it called when there are calcium phospholipids and degenerative change to the vitreous in older animals?

Answer 3

Asteroid hyalosis

Question 4

If there is hemorrhage in the vitreous humor what would the source be?

Answer 4

Ciliary body

Retina

Question 5

Where is the retina’s anterior attachment?

Answer 5

Right behind the Ciliary body

Question 6

What contains the tapetum?

Answer 6

Choroid

Question 7

What layers of the retina are neurosensory? What layer are rods and cones in?

Answer 7

Layers 1-9

Layer 9 = Rods and cones (photoreceptors)

Question 8

What do rods do?

Answer 8

Predominant photoreceptor by #

• dim light vision
• black and white

Question 9

What do cones do?

Answer 9

bright light

color vision

Question 10

What is the tapetum’s function?

Answer 10

Reflective layer in choroid, dorsal fundus that captures light that bypasses the retina

Question 11

What species do NOT have a tapetum?

Answer 11

Camelid
Pig
Bird
Rabbit
Rats
Mice

Question 12

What word describes the retinal vasculature in most species? What does this mean?

Answer 12

Holangiotic

Vessels extend from optic disc out to periphery of fundus

Question 13

Paurangiotic? Species? Where does most retina get nutrients?

Answer 13

Retina vessels extend only a short distance from optic disc

Horse

choroid

Question 14

Merangiotic? Species?

Answer 14

Retina vessels extend medially and laterally from optic disc

Rabbit

Question 15

Anangiotic? Species?

Answer 15

Retina is supplied by choroid vasculature

Guinea pig
Bird
Reptiles

Question 16

What species have a myelinated optic disc?

Answer 16

Dog
Horse
\+/- cow
Goat
Sheep
Pig

Question 17

What species have a non-myelinated optic disc?

Answer 17

Cat
Camelid
Mice
Rat

Question 18

If you look into a dog or cat eye and don’t see a tapetum what may be the reason?

Answer 18

Dilute coat color (White, merle) and blue iris

Usually associated with lack of pigment. This is a normal variation

Question 19

What part of the retina does the choroid supply nutrients?

Answer 19

Supplies outer half of retina in holangiotic species.

Supplies entire retina in anangiotic species

Question 20

What is unique about the avian fundus?

Answer 20

Pecten

darkly pigmented vasculature structure that sits on top of optic disc - disc is not visible
Has a secretory, nutritive function

Question 21

What does the fundus look like in dilute coat color and blue iris animals?

Answer 21

Clear tapetum
Choroidal vessels
Retinal vessels
Sclera is visible

Question 22

T/F

Birds don’t have an optic disc

Answer 22

False

You just can’t see it

Question 23

What is Collie eye anomaly (CEA)?

Answer 23

Bilateral congenital, genetic condition of the choroid, retina, and sclera in dogs

Question 24

What are 3 abnormalities associated with Collie eye anomaly

Answer 24

• Choroidal hypoplasia
• Optic nerve coloboma
• Retinal detachment

Question 25

What is an electroretinography (ERG)?

Answer 25

- Quantitates retinal function - Retina stimulated by light - Electrical activity carried to cornea - Contact lens perceives electrical activity - Waveform generated: amplitude measured

Question 26

What does SARD stand for?

Answer 26

Sudden acquired retinal degeneration

Question 27

What happens in SARD?

Answer 27

Acute death of photoreceptors

Question 28

What are the two types of retinal detachment?

Answer 28

Rhegmatogenous - tear within the retina Serous - fluid, cells under retina

Question 29

What is it called when the retina is torn 360 degrees but remains intact around the optic disc?

Answer 29

Disinsertion (type of rhegmatogenous detachment)

Question 30

What may cause serous retinal detachment?

Answer 30

Hypertension | Inflammatory

Question 31

What may cause rhegmatogenous retinal detachment?

Answer 31

Cataract Lens luxation Vetreoretinal dysplasia (Shih Tzu)

Question 32

What blood pressure would you consider hypertensive retinopathy?

Answer 32

systolic > 160

Question 33

What do you call inflammation of choroid that extends into retina?

Answer 33

Chorioretinitis

Question 34

What are three things that can go wrong with the optic nerve?

Answer 34

1. Coloboma 2. Cupping 3. Optic neuritis

Question 35

What is optic nerve cupping?

Answer 35

depressed optic disc associated with chronic glaucoma

Question 36

What is the pathogenesis for optic neuropathy due to vitamin A deficiency?

Answer 36

Defective osteoclast activity in optic canal --> osteoblasts lay down bone --> compresses optic nerve

Question 37

What are two ophthalmoscopic signs of retinal degeneration?

Answer 37

Thinning of retinal vessels | Tapetal hyperreflectivity

Question 38

What is the risk of giving Baytril to a cat?

Answer 38

Retinal degeneration | Acute blindness