5: cornea - giuliano Flashcards Preview

IP 11 Ophthalmology > 5: cornea - giuliano > Flashcards

Flashcards in 5: cornea - giuliano Deck (58):
1

what are the 4 layer to the cornea? [exterior to interior]

epithelium
stroma
descemet's membrane
endothelium

2

which layers of the cornea are hydrophillic?
clin significanc?

stroma

the fluorescein stain is hydrophillic so adheres to the stroma if there is a perforation to the epithelium [corneal ulcer]

3

what is a corneal ulcer?

exposed stroma - perforated corneal epithelium

4

what are the functions of the cornea?

- component of fibrous tunic
- main ocular surface barrier - entry of pathogens, penetration of therapeutic agents

5

t/f

any dec in clarity in the cornea is indicative of pathology

true

6

why is the cornea clear?

- absence of blood vessels
- deturgescence
- regular arrangement of collagen
- absence of pigment
- relatively acellular

7

what is deturgescence and how does the cornea achieve and maintain it?

relative dehydration of the cornea

stroma is sandwiched btwn 2 layers that keep the water out - surface layer of epithelium and endothelium

endothelium has active Na/K ATPase pumps that pump water out

8

what is the order of MDB tests:

STT, fluorescein staining, IOP measurement

9

what are the 7 deadly corneal colors?

red
bule
white
yellow
greasy tan
brown
black

10

what do blood vessels tell you about the state of the eye / dz of the eye?

that the dz is due to chronic irritation

11

how do vessels tell you where the dz is?

superficial: corneal epi dz, fine/branching (tree)

deep: stromal or intraocular dz, NON branching (hedge)

12

describe conjunctival vessels?
what do they tell you about dz?

superficial, tortorous, branching, move w conj, blance w eip

superficial dz

13

describe scleral vessels?
what do they tell you about dz?

deeper, straighter, less branching, immobile, blanch slowly w epi,

deep, intra ocular dz

14

in general, what does hyperemia tell you?

vasodilation is occurring in the eye

15

what 2 ocular dzz are vision robbing in a matter of 24 hours?

glaucoma
uveitis

16

what are 2 categories of dz that superficial vessels suggest?

insufficient corneal protection
excessive corneal irritation

17

what might cause insufficient corneal protection?

lagophthalmos
macropalpebral fissure
CrN 5 or 7 paralysis
ectropion
KCS

18

what might cause excessive corneal irritation?

entropion
distichiasis
ectopic cilia
trichiasis
FB
lid tumor
blepharitis

19

what types of dzz might be occurring when deep vessels are visible?

deep keratitis
scleritis
uveitis
glaucoma

20

what does blue cornea indicate?

edema

21

ddx?
diffuse blue color to cornea
fluorescein negative
marked
non painful
not inflammed
normal IOP
flare absent

endothelial degeneration
endothelial dystrophy


monitor for corneal bullae & 2* ulceration

22

ddx?
diffuse blue color to cornea
fluorescein negative
marked
painful
inflamed
abnormal IOP
flare present

*****

glaucoma
uveitis
anterior lens luxation

*****

23

ddx?
focal blue color to cornea
fluorescein positive
mild/focal
painful
inflammed

corneal ulceration

24

what species MC gets infectious keratomalacia?

horses

25

when dealing with chemicals around eyes, always make sure you use ____ and NEVER ____

solution and NEVER scrub

26

what does whispy white/grey in the cornea indicate?

scar tissue - disorganization of stromal collagen

27

when scar tissue is present, what will fluorescein test results be?

negative

28

t/f

scar tissue is painful for the patient

false

29

Tx of scar tissue in the cornea?

none!

will remodel very slowly on its own

30

what does a sparkly white color in the cornea look like?

lipid [cholesterol] or mineral [Ca] deposits

31

typical presentation of primary dystrophy of the cornea?

bilateral [not necessarily symmetrical]

young dogs [inherited]

32

what is degenaration vs dystrophy?

degeneration - started normal and deteriorates [often 2* to a problem]

dystrophy - inherited [not necessarily congenital b/c not always present at birth]

33

what are ddx of a sparkly white cornea?

corneal lipid degeneration
corneal lipid dystrophy
corneal limbal lipid infilatrates

34

what is corneal lipid degeneration?

often dev 2* to what condition?

lipid and mineral corneal stromal infiltrates that are accompanied by vascularization, scarring and pigmentation

2* to chronic corneal ulceration or non ulcerative keratitis

35

what is corneal lipid dystrophy?

1* symmetric, bilateral, non inflammatory, inherited corneal opacity that is assoc w lipid infiltrate in the corneal stroma

may affect epi [recurrent erosions], stroma or endo [chronic corneal edema]

characteristic race track appearance of white tissue in cornea

36

what is corneal limbal lipid infiltrates?

bilateral, limbal associated stromal infiltrates 2* to lipid-laden serum in the limbus

may extend around entire limbus [arcus]

sys hyperlipidosis - look for systemic metabolic abnormalities]

37

how dies pigment get into the cornea?

carried there by vessels - insoluble, intracellular pigment; grows from limubs

impregnated - ruptured eye [iris shows through], FB

cornea sequestrum - cats, brachycephalics - necrotic cells

38

pigment laid down in cornea by vessels might be due to what?

insufficient corneal protection [lagophthalmos, macropalpebral fissure, CrN 5 or 7 paralysis, ectropion, KCS]

excessive corneal irritation [entropion, distichiasis, trichiasis, ectopic cilia, FB, lid tumor, blepharitis]

immume mediated [chronic superficial keratitis (pannus)]

39

what is common loc for pigment deposition in brachycephalics, such as pugs?

why?

nasal deposition

b/c medial lower eyelid entropion is common

40

what do greasy / tan precipitates in the eye called and what dz do they indicate?

keratic precipitates (KPs)

uveitis (prior or chronic)
"classic" cats w FIP

41

where do keratic precipitates deposit?

deposit as endothelial plaques

42

what does yellow/green cornea indicate?

cellular infilatrates => stromal inflammatory cells

43

what are important r/o for a green/yellow cornea?

bacT keratitis
fungal keratitis
corneal FB
contusion

44

what diagnostic test is ESSENTIAL for a yellow/green cornea?

culture and sensitivity
cytology

45

what condition almost always co exists with yellow/green cornea?

uveitis

46

what causes keratitis AND conjunctivitis?

feline corneal sequestrum
feline eosinophilic keratitis
feline herpes virus
nodular granulomatous episclerokeratoconjunctivitis (NGE)

47

what is pannus?

chronic superficial keratitis

48

what is the etiology of pannus?

immune mediated dz of obscure cause

49

what is common initial presentation of pannus?

begins as reddened plaque at ventrolateral cornea

usually bilateral but NOT always symmetrical

50

t/f

pannus can progress to involve the entire cornea, eventually resulting in blindness

true

51

what ocular structure does "atypical" pannus involve?

the 3rd eyelid

52

risk factors to the development of pannus?

german shepherds and greyhounds

high altitude
solar radiation

53

tx of pannus?

topical steroids
topical cyclosporine
b-radiation if difficult cases

54

t/f

pannus is a curable condition

false

it is NOT curable - it is controllable

55

what is a choristoma?

normal tissue in an abnormal location

consider it a benign tumor

56

what is a dermoid?

a choriostoma on the eye

57

what does dermoid cause?

chronic irritation
dec tear production

58

tx of dermoid?

keratectomy
+/- conjunctival graft