Test 2: lecture 30 retina

Question 1

A biologic reflector system to enhance visual sensitivity in dim illumination

Answer 1

tapetum lucidum

Question 2

tapetum in carnivores is

Answer 2

cellular

Question 3

tapetum in herbivores is

Answer 3

fibrous

Question 4

what kind of retinal vasculature do carnivores, primates, even toes ungulates and most rodents have

Answer 4

holangiotic

Question 5

what kind of retinal vasculature do horses, odd-toed ungulates, guinea pigs have?

Answer 5

paurangiotic

Question 6

what kind of retinal vasculature do lagomophs have?

Answer 6

Merangiotic- extend horizontally

Question 7

what kind of retinal vasculature do birds, and monotremes have?

Answer 7

anangiotic- no vasculature in the retina, instead has a pecten in the vitrious that supplies nutrients

Question 8

fovea is surrounded by the

Answer 8

macula

humans and NHP

Question 9

fovea is an area of the eye with many —

Answer 9

cones- color seeing

humans and NHP

Question 10

other mammals have a — instead of a fovea

Answer 10

visual streak

Question 11

instead of a fovea dogs have

Answer 11

a visual streak with a small area centralis that has high number of Retinal Ganglion Cells and cones

Question 12

how to do fundus exam

Answer 12

optic nerve head(ONH): shape, degree of myelination, vascularization

retinal vascularization (pattern, tortuosity, attenuation/thinning)

tapetal fundus (hypo or hyperreflectivity)

non-tapetal fundus (normally pigmented but can be non-pigmented).

take picture or draw diagram

Question 13

— of the fundus changes with age

Answer 13

color

starts to form at 6 wks old and mature at 11 wks old

Question 14

Answer 14

normal

degeneration: hyperreflectivity and loss of vasculature

Question 15

what can cause this

Answer 15

hyporreflectivity- subretinal fluid, retinal detachment, retinal edema

Question 16

Answer 16

perivascular cuffing →retinitis

Question 17

where is the bleeding, what is the source?

Answer 17

subretinal- is from choroidal vessels

intraretinal and preretinal is from retinal vessels

Question 18

what can cause retinal hemorrhage

Answer 18

Trauma
Anemia, coagulopathy, hyperviscosity
Systemic hypertension
Infectious diseases (e.g ehrlichiosis)

Question 19

how to exam retina if there is a loss of transparency of cornea, aqueous humor or lens

Answer 19

ocular ultrasound

Useful to detect retinal detachment

Question 20

how does OCT work

Answer 20

sends infared waves into eye to map eye

Optical coherence tomography (OCT)
(= non-invasive imaging of the retinal layers)

needs to be sedated

Question 21

test to measure if rods and cones are working

Answer 21

ERG- Electroretinography

Question 22

when to use Electroretinography

Answer 22

to measure if retina(cones and rods) is working

prior to cataract
early diagnosis of retinal degeneration
blind dog but everything looks normal

Question 23

retinal dysplasia is caused by

Answer 23

genetic
maternal viral infections: herpes, panleuk
toxicities in utero

neuroretina does not attach to the RPE and folds onto itself forming rosettes

Question 24

3 forms of retinal dysplasia

Answer 24

focal/multifocal- vision usually normal

geographic- vision depends on how big lesion is

complete retinal dysplasia with detachment- blind, skeletal dysplasia- labs and samoyeds

retinal dysplasia: Congenital, developmental abnormality of the retina where retina does not bind to RPE and folds onto itself forming rosettes

more common in dogs then cats/cattle

Question 25

collie eye anomaly is caused by —

Answer 25

genetic (NHEJ1)

Question 26

collie eye anomaly will cause

Answer 26

choroidal hypoplasia +/- posterior coloboma (< 10% of cases)

Question 27

how to diagnosis collie eye anomaly

Answer 27

have to find it before RPE becomes pigmented (6-10 weeks old)

choroidal hypoplasia

Question 28

inherited retinopathies are normally

Answer 28

autosomal recessive > XL> autosomal dominant

most common rods affected but can attack cones, rods, RPE

Question 29

the most common cause of later onset progressive retinal atrophy is by a defect in — gene

Answer 29

PRCD
progressive rod cone degeneration

effects toy poodles, cocker, labs and many other breeds

Question 30

clinical signs of inherited retinopathies

Answer 30

vision loss: night and day vision loss
↓ PLRs
tapetal hyperreflectivity
retinal arterioles then venules get smaller
optic disc atrophy
+/- secondary cataract

Question 31

SARDS

Answer 31

Sudden Acquired Retinal Degeneration Syndrome

cause unknown, no treatment

dogs with acute blindness, dilated pupils, responsive to bring blue light, no response to bright red light

Question 32

how to diagnosis SARDS

Answer 32

ERG
PLR slow
no response to bright red
responsive to bright blue light

cause unknown- suddent blindness in dogs

Question 33

active retinitis/chorioretinitis will look

Answer 33

Borders poorly defined, hyporeflectivity, perivascular cuffing, exudative retinal detachments

Question 34

inactive Retinitis/ Chorioretinitis will look

Answer 34

Sharp borders, hyperreflectivity, depigmentation in non-tapetal fundus

Question 35

what are some causes of retinitis/chorioretinitis

Answer 35

Dogs: Distemper, fungi, ehrlichia, rickettsia, Prototheca

Cats: FIP, FeLV, FIV, Toxoplasmosis, fungi

Question 36

Separation of the neuroretina from the RPE

Answer 36

retinal detachment

Question 37

Rhegmatogenous

Answer 37

retinal tear allows vitreous to get under
neuroretina and separate it from RPE.