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IP 11 Ophthalmology > 5: cornea - giuliano > Flashcards

5: cornea - giuliano Flashcards

1
Q

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

A

epithelium
stroma
descemet’s membrane
endothelium

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2
Q

which layers of the cornea are hydrophillic?

clin significanc?

A

stroma

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

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3
Q

what is a corneal ulcer?

A

exposed stroma - perforated corneal epithelium

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4
Q

what are the functions of the cornea?

A
  • component of fibrous tunic

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

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5
Q

t/f

any dec in clarity in the cornea is indicative of pathology

A

true

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6
Q

why is the cornea clear?

A
  • absence of blood vessels
  • deturgescence
  • regular arrangement of collagen
  • absence of pigment
  • relatively acellular
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7
Q

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

A

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

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8
Q

what is the order of MDB tests:

A

STT, fluorescein staining, IOP measurement

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9
Q

what are the 7 deadly corneal colors?

A 
red
bule
white
yellow
greasy tan
brown
black
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10
Q

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

A

that the dz is due to chronic irritation

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11
Q

how do vessels tell you where the dz is?

A

superficial: corneal epi dz, fine/branching (tree)
deep: stromal or intraocular dz, NON branching (hedge)

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12
Q

describe conjunctival vessels?

what do they tell you about dz?

A

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

superficial dz

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13
Q

describe scleral vessels?

what do they tell you about dz?

A

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

deep, intra ocular dz

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14
Q

in general, what does hyperemia tell you?

A

vasodilation is occurring in the eye

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15
Q

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

A

glaucoma

uveitis

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16
Q

what are 2 categories of dz that superficial vessels suggest?

A

insufficient corneal protection

excessive corneal irritation

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17
Q

what might cause insufficient corneal protection?

A 
lagophthalmos
macropalpebral fissure
CrN 5 or 7 paralysis
ectropion
KCS
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18
Q

what might cause excessive corneal irritation?

A 
entropion
distichiasis
ectopic cilia
trichiasis
FB
lid tumor
blepharitis
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19
Q

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

A

deep keratitis
scleritis
uveitis
glaucoma

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20
Q

what does blue cornea indicate?

A

edema

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21
Q 
ddx?
diffuse blue color to cornea
fluorescein negative 
marked
non painful
not inflammed
normal IOP 
flare absent
A

endothelial degeneration
endothelial dystrophy

monitor for corneal bullae & 2* ulceration

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22
Q 
ddx?
diffuse blue color to cornea
fluorescein negative 
marked
painful
inflamed 
abnormal IOP
flare present
A

glaucoma
uveitis
anterior lens luxation

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23
Q 
ddx?
focal blue color to cornea
fluorescein positive
mild/focal
painful
inflammed
A

corneal ulceration

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24
Q

what species MC gets infectious keratomalacia?

A

horses

25
Q

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

A

solution and NEVER scrub

26
Q

what does whispy white/grey in the cornea indicate?

A

scar tissue - disorganization of stromal collagen

27
Q

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

A

negative

28
Q

t/f

scar tissue is painful for the patient

A

false

29
Q

Tx of scar tissue in the cornea?

A

none!

will remodel very slowly on its own

30
Q

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

A

lipid [cholesterol] or mineral [Ca] deposits

31
Q

typical presentation of primary dystrophy of the cornea?

A

bilateral [not necessarily symmetrical]

young dogs [inherited]

32
Q

what is degenaration vs dystrophy?

A

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

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

33
Q

what are ddx of a sparkly white cornea?

A

corneal lipid degeneration
corneal lipid dystrophy
corneal limbal lipid infilatrates

34
Q

what is corneal lipid degeneration?

often dev 2* to what condition?

A

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

2* to chronic corneal ulceration or non ulcerative keratitis

35
Q

what is corneal lipid dystrophy?

A

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
Q

what is corneal limbal lipid infiltrates?

A

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
Q

how dies pigment get into the cornea?

A

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

impregnated - ruptured eye [iris shows through], FB

cornea sequestrum - cats, brachycephalics - necrotic cells

38
Q

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

A

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
Q

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

why?

A

nasal deposition

b/c medial lower eyelid entropion is common

40
Q

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

A

keratic precipitates (KPs)

uveitis (prior or chronic)
“classic” cats w FIP

41
Q

where do keratic precipitates deposit?

A

deposit as endothelial plaques

42
Q

what does yellow/green cornea indicate?

A

cellular infilatrates => stromal inflammatory cells

43
Q

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

A

bacT keratitis
fungal keratitis
corneal FB
contusion

44
Q

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

A

culture and sensitivity

cytology

45
Q

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

A

uveitis

46
Q

what causes keratitis AND conjunctivitis?

A

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

47
Q

what is pannus?

A

chronic superficial keratitis

48
Q

what is the etiology of pannus?

A

immune mediated dz of obscure cause

49
Q

what is common initial presentation of pannus?

A

begins as reddened plaque at ventrolateral cornea

usually bilateral but NOT always symmetrical

50
Q

t/f

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

A

true

51
Q

what ocular structure does “atypical” pannus involve?

A

the 3rd eyelid

52
Q

risk factors to the development of pannus?

A

german shepherds and greyhounds

high altitude
solar radiation

53
Q

tx of pannus?

A

topical steroids
topical cyclosporine
b-radiation if difficult cases

54
Q

t/f

pannus is a curable condition

A

false

it is NOT curable - it is controllable

55
Q

what is a choristoma?

A

normal tissue in an abnormal location

consider it a benign tumor

56
Q

what is a dermoid?

A

a choriostoma on the eye

57
Q

what does dermoid cause?

A

chronic irritation

dec tear production

58
Q

tx of dermoid?

A

keratectomy

+/- conjunctival graft

IP 11 Ophthalmology (13 decks)

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