Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ophtho final > posterior segment > Flashcards

posterior segment Flashcards

1
Q

structures in posterior segment

A

vitreous humor

retina

optic nerve

choroid-tapetum

posterior sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

vitreous development

A

primary vitreous-hyaloid artery, nourishment during embryogenesis, regression start d45 gestation, complete by postnatal d14

secondary vitreous: adult vitreous body

tertiary vitreous: lens zonules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

vitreous composition

A

water (98%) hyaluronic acid, collagen

semi-solid gel

transparent and colorless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

functions of vitreous

A

globe structure and growth

metabolism

refraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

retinal development

A

two layers of neuroectoderm apposed during invagination of optic cup

outer layer–>retinal pigmented epithelium

inner layer–>neurosensory retina

potential space between RPE and NS retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

retinal pigmented epithelium

A

outermost retinal layer

contains melanin-except dorsal half, allow visualizationof tapetum, lesser amounts in color dilute animals

functions: metabolism, phototransduction

vascular supplied by choroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

retinal blood vessels

A

within inner aspect of NS retina

nourish inner retina only

short posterior ciliary arteries-arise around optic disc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

retinal vascular patterns

A

Holangiotic

paurangiotic

merangiotic

anangiotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

holangiotic

A

dog, cat, cow

vessels across most of retinal surface

most common pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

paurangiotic

A

horse

vessels extend only a short distance around optic disc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

merangiotic

A

rabbit

vessels extending medially and laterally only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

anangiotic

A

birds, reptiles

no retinal vessels

pecten, conus papillaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mueller cells

A

structural and metabolic roles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

nerve fiber layer

A

axons of ganglion cells

form optic nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

photoreceptors

A

absorb photons, convert to electrical impulses

rods, cones

cells bodies in outer nuclear layer

outer segments interdigitate with RPE cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

rods

A

scotopic vision

motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cones

A

photopic vision

color

high-resolution vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

area centralis

A

higher concentration of cones

photoreceptor

dorsolateral to optic disc

fovae in some species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

light transmission

A

light entering eye first absorbed by PR

transmitted though layers to NFL

from NFL to optic nerve

impulse along optic nerve to optic chiasm

optic tract to lateral geniculate nucleus, pretectal nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

optic nerve

A

axons from ganglion cell layer mature towards optic stack

converge at optic disc, axons bundle together to form optic nerve

continue posteriorly: optic chiasm and optic tracts

transmission of impulses from eye to CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

location of optic nerve: dogs and cats

A

near tapetal/nontapetal junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

location of optic nerve: horses

A

within nontapetal fundus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

choroid includes:

A

blood vessels

tapetum

melanocytes

connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

choroidal blood vessels

A

supply outer retina

larger vessels: parallel to retina, osmotic gradient pulling fluid out of RPE

choriocapillaris: perpendicular to retina, supplies outer retina, “Stars of Winslow”-end of capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

tapetum

A

inner choroid

superior half of globe

triangular

reflectivity and color depend on composition

increases available light

absent in diurnal, most primates, most birds and reptiles, pigs

26
Q

sclera

A

outer fibrous tunic: collagen, fibrocytes, melanocytes, cartilage and bone in some spp

insertion of EOM

lamina cribrosa-sieve like optic nerve exit

27
Q

subalbinotic: variation of normal

A

color dilute animals

decreased melanin in RPE

allows visualization of choroidal vessels

tapetum may be absent

28
Q

neuro-ophthalmic exam

A

testing intergrity of visual pathways

Menase response

dazzle

PLR

29
Q

menace response

A

CN II, VII, cortex, cerebellum

some vision

30
Q

dazzle

A

CN II, subcortical visual pathways

does not test vision

31
Q

pupillary light reflex

A

direct and consensual

CN II, III

does not test vision

32
Q

fundic examination

A

use indirect ophthalmoscope or direct fundoscopy, PanOptic

33
Q

ultrasound

A

when fundus is not visible

retinal detachment

masses

vitreous debris

34
Q

electroretinogram (ERG)

A

retinal function-PR

electrical potential generated when photons strike PR

indications: assessment of retinal function when fundus is not visble or is normal in appearance

35
Q

blurry images

A

entire image should be in focus at same time

if not, objects in different planes-depressed lesion, raised lesion, retinal detachments

36
Q

optic nerve changes

A

shape: coloboma, growths (neoplasia, excessive myelin)
color: red (bleeding), dark (atrophy)
borders: should be distinct, indistinct indicate optic neuritis
size: small (micropapilla, atrophy), large (optic neuritis)

37
Q

vascular changes

A

tortuosity

engorgement

hemorrhage

vessel attenuation

lack of vessels across nerve head (dogs)

38
Q

tapetal changes

A

hyperreflectivity

hyporeflectivity

39
Q

nontapetal changes

A

depigmentation

infiltrates

hemorrhage

40
Q

Persistent hyaloid artery

A

failure of regression of hyaloid artery

complete or partial

patent or nonpatent

may be associated with cataract

rarely requires tx

41
Q

vitreous degeneration

A

breakdown of gel structure

vitreous liquefies

may prolaspe anteriorly-could plug drainage channel

may predispose to retinal detachment

normal aging change

post-inflammatory

no tx needed

42
Q

asteroid hyalosis

A

calcium and phospholipid precipitates in vitreous “floaters”

normal aging change

no treatment needed

43
Q

vitritis

A

inflammation of the vitreous

extension of chorioretinitis

RBC, WBC, proteinaceous debris

very slow turnover

44
Q

micropapilla & optic nerve hypoplasia

A

congenitally small optic nerve

uni or bi lateral

+/- blindness

no tx

hypoplasia-A, normal-B

45
Q

retinal dysplasia

A

abnormal differentiation of retinal layers

nonprogressive

may now be predisposed to retinal detachments, visual deficits and blindness

acquire: Feline panleukopenia, k9 Herpesvirs, BVD

46
Q

retinal dysplasia types

A

folds-liniear, hyporeflective or white, raised

geographic-horseshoe shape, dorsal renital venule

complete: retinal detachment, blind

47
Q

retinal dysplasia tx

A

none-few folds, no behavioral signs of vision loss

periodic monitoring-more extensive retinal area affects, looking for retinal detachment

48
Q

Collie eye anomaly (CEA)

A

abnormal mesodermal differentiation

bilateral

polygenic

lesions: Choroidal hypoplasia-temporal to optic disc, posterior polar coloboma, retinal detachment, hyphema

49
Q

What does “go normal” mean in regards to Collie eye anomaly?

A

as dogs age, their RPE melanin increases which can mask underlying hypoplasia

screening for CEA should be performed by 8 weeks of age

50
Q

tx for collie eye anomaly

A

usually none-possible sx for retinal detachment

breeding programs to minimize DEA within population

51
Q

taurine deficiency

A

feline central retinal degeneration

normally-high taurine concentrations in photoreceptors and heart muscle

PR degeneration-tapetal hyperreflectivity, begins in area centralis (superior and temporal to optic disc), enlarges into a ellipse extending nasally, eventually diffuse

concurrent dilated cardiomyopathy

52
Q

taurine deficiency dx and tx

A

confirm with blood taurine levels

taurine supplementation-will stop progression but not reverse changes, will reverse cardiomyopathy

53
Q

progressive retinal atrophy (PRA)

A

inherited photoreceptor degeneration

bilateral, symmetrical

progressive vision loss over months

early onset or later onset

54
Q

typical hx of patient with PRA

A

purebred dog/cat, young adult

visual deficits first noted at night or dim light

slowly day viison also compromised

abnormalities occur and worsen over months

55
Q

PE findings for PRA

A

resting mydriasis

slow to absent PLR

meance may be absent

retinal vascular attenuation

tapetal hyperreflectivity

dark optic disc

severeity of examination findings correlates stage of disease

56
Q

Tx for PRA

A

none

due to inherited nature, avoid breeding affected or carrier animals

57
Q

sequela of PRA

A

cataracts

almost all dogs

may occur years after PRA dx

progressive

lens-induced uveitis must be managed to avoid painful complications-glaucoma, lens luxation

58
Q

Sudden acquired retinal degeneration syndrome (SARDS)

A

dogs

bilateraly symmetrical, idiopathic, acute retinal degeneration

predisposed: middle age, FS, overweight, more common in winter

59
Q

Typical hx for SARDS

A

sudden blindness (within 1 day)

cushing’s-like signs

PU,PD, PP, blood work ofte shows increased ALP, lymphopenia, increased chol

60
Q

SARDS examination findings

A

resting mydriasis

normal or slow PLR

menace absent

normal funduscopic exam

confirm blindness with electroretinogram-no waveform

61
Q

tx for SARDS

A

no proven effective therapy

ophtho final (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions