Diseases of the Retina and Optic Nerve

Question 1

What is a “fundus”?

Answer 1

The portion of an organ opposite from its opening

Question 2

What 2 structures make up the fundus of the eye?

Answer 2

1. Retina

2. Optic disc

Question 3

Which of the photoreceptors is responsible for day vision?

Answer 3

Cones

Question 4

Which of the photoreceptors is responsible for night blindness?

Answer 4

Cones

Question 5

Which of the photoreceptors is responsible for night vision?

Answer 5

Rods

Question 6

What are 4 methods of examining the fundus?

Answer 6

1. Behavioral/functional tests (e.g. maze test)
2. Ophthalmoscopy
3. Ultrasonography
4. Electroretinography

Question 7

Which form of ophthalmoscopy is inverted and revered?

Answer 7

Indirect ophthalmoscope

Question 8

Which form of ophthalmoscopy allows for the largest magnification of the retina?

Answer 8

Direct ophthalmoscope

Question 9

Which animals are atapetal?

Answer 9

1. Pigs
2. Primates
3. Squirrels
4. Birds

Question 10

The animals that are atapetal are usually (1) diurnal or (2) nocturnal?

Answer 10

Diurnal

Question 11

What color is an atapetal retina? Why?

Answer 11

Red to orange due to the reflection of the choroidal vasculature

Question 12

In tapetal animals, where does the tapetum lie?

Answer 12

Behind the retinal pigment epithelium

Question 13

Which species have holangiotic retinas?

Answer 13

1. Cat
2. Dog
3. Cow

Question 14

Which species have a paurangiotic retina?

Answer 14

1. Horse
2. Elephant
3. Rhinoceros
4. Marsupials

Question 15

What does paurangiotic mean?

Answer 15

Blood vessels within the retina only occur near the optic disc

Question 16

What type of retina do rabbits have?

Answer 16

Merangiotic

Question 17

Describe a merangiotic retina.

Answer 17

Blood vessels and myelinated nerve fibers transverse the retina in a horizontal plain

Question 18

Which species have an anangiotic retina?

Answer 18

1. Birds
2. Reptiles
3. Bats

Question 19

Describe an anangiotic retina.

Answer 19

Absence of any vasculature within the retina

Question 20

There are many variations to the fundus in the dog. These changes are dependent on what 3 factors?

Answer 20

1. Age
2. Breed
3. Coat color

Question 21

A dog’s fundus will appear blue up until what age?

Answer 21

6 - 10 weeks of age

Question 22

Which structure is always seen on the lateral side during a fundic exam in a dog?

Answer 22

Area centralis

Question 23

Progressive retinal atrophy in the dog is developmental, inherited, or acquired?

Answer 23

Inherited

Question 24

Progressive retinal atrophy in the dog is progressive loss of what type of vision FIRST?

Answer 24

Night vision (followed by day vision)

Question 25

Progressive retinal atrophy affects which first, cones or rods?

Answer 25

Rods

Question 26

Which 2 dog breeds are most affected by progressive retinal atrophy?

Answer 26

1. Poodles | 2. Cocker spaniel

Question 27

Describe progressive retinal atrophy in the dog clinically.

Answer 27

1. Night blindness 2. Absent PLR 3. Tapetal hyper-reflectivity 4. Optic nerve atrophy 5. +/- cataracts

Question 28

True or False: You can use blood to check for the genetic mutation associated with PRA in the dog.

Answer 28

TRUE

Question 29

What is the treatment for PRA in the dog?

Answer 29

There is no treatment at present

Question 30

How would you prevent PRA in the dog?

Answer 30

Screen blood and do NOT breed

Question 31

True or False: Progressive retinal atrophy is not a condition recognized in cats/

Answer 31

FALSE: But PRA is RARE in cats.

Question 32

What are the 2 forms of PRA recognized in cats?

Answer 32

1. Rod/cone dysplasia (in kittens) | 2. Rod/cone degeneration (older cats)

Question 33

Is optic neuritis generally unilateral or bilateral?

Answer 33

Bilateral

Question 34

Describe the optic nerve head in optic neuritis.

Answer 34

Hyperemic

Question 35

Which of the following is false: (a) Optic neuritis is associated with cataracts, (b) optic neuritis is associated with dilated pupils, (3) optic neuritis is associated with blindness and a fixed stare.

Answer 35

(1) Optic neuritis is NOT associated with catarcts

Question 36

What are 5 causes of optic neuritis?

Answer 36

1. Inflammation 2. Infectious disease 3. Neoplasia 4. Trauma 5. Idiopathic (~50%)

Question 37

How might you diagnose optic neuritis?

Answer 37

1. Clinical signs 2. MRI 3. ERG

Question 38

What is the prognosis for optic neuritis?

Answer 38

Guarded to poor

Question 39

Optic nerve atrophy is often secondary to what conditions?

Answer 39

1. Glaucoma 2. PRA 3. Other orbital diseases: GME, optic neuritis

Question 40

What does SARDS stand for?

Answer 40

Sudden acquired retinal degeneration syndrome

Question 41

Describe SARDS clinically.

Answer 41

1. Sudden loss of vision (vision may come and go) 2. Variable degree of PLR 3. Lack of lesions initially

Question 42

Which dogs are more predisposed to SARDS (signalment)?

Answer 42

1. Females 2. Middle-aged 3. Mildly obese

Question 43

Which breeds of dogs are more predisposed to SARDS?

Answer 43

1. Miniature schnauzers 2. Dachshunds 3. Poodles 4. Mixed breeds

Question 44

SARDS has an unknown etiology. Currently it is suspected to be what?

Answer 44

Immune-mediated

Question 45

Which conditions is chorioretinitis associated with in the dog?

Answer 45

1. Distemper 2. Fungi 3. Autoimmune

Question 46

Which conditions is chorioretinitis associated with in the cat?

Answer 46

1. FIP 2. FeLV 3. Toxoplasma 4. Fungi

Question 47

What conditions is chorioretinitis associated with in the horse?

Answer 47

Uveitis

Question 48

Describe active chorioretinitis.

Answer 48

Out of focus borders

Question 49

Describe inactive chorioretinitis.

Answer 49

Sharp borders

Question 50

What are 3 causes of retinal detachment?

Answer 50

1. Traumatic 2. Inflammation 3. Neoplasia

Question 51

What are the 2 types of retinal detatchment and how do they differ?

Answer 51

1. Non-rhegmatogenous: no retinal tear | 2. Rhegmatogenous: retinal tear/hole

Question 52

What can cause HEMORRHAGIC retinopathy?

Answer 52

1. Coagulopathy 2. Systemic infection 3. Systemic hypertension

Question 53

HYPERTENSIVE retinopathy can develop secondary to what conditions/diseases?

Answer 53

1. Hyperthyroidism 2. Renal failure 3. High-salt diet 4. Hypertrophic cardiomyopathy 5. Arthrosclerosis

Question 54

What are the clinical effects of hypertensive retinopathy?

Answer 54

1. Acute blindness 2. Dilated pupils 3. Retinal detachment

Question 55

Is hypertensive retinopathy seen more in cats or dogs?

Answer 55

Cats

Question 56

What is the treatment for hypertensive retinopathy?

Answer 56

1. Calcium channel blockers (amlodipine) | 2. Systemic and topical steroids

Question 57

As enrofloxacin toxicity is of concern in cats, what dose should not be exceed per day?

Answer 57

5 mg/kg

Question 58

What is enrofloxacin toxicity associated with in cats?

Answer 58

Retinal degeneration

Question 59

What drug can be used in place of enrofloxacin in the cat?

Answer 59

Pradofloxacin

Question 60

What type of drug is pradogloxacin?

Answer 60

3rd generation FQ

Question 61

Pradofloxacin has no adverse retinal effects in the cat up to _____ times the labeled dose for 23 days.

Answer 61

6.7

Question 62

A maximally opened mouth, as with the use of a mouth-gag, may lead to retinal ischemia in cats due to impairment of blood flow through which artery?

Answer 62

Maxillary artery

Question 63

Chronic taurine deficiency in the cat can lead to severe ____ and ____.

Answer 63

1. Retinal degeneration | 2. Irreversible blindness