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23 spring: med surg > Test 2: lecture 27+28 cornea > Flashcards

Test 2: lecture 27+28 cornea Flashcards

1
Q
A

descemet’s membrane
above the endothelial cell layer of cornea

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2
Q

layers of the cornea

A

epithelial layer 6-15 layers
stroma- collagen avascular
descemet’s membrane
single endothelial cell layer

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3
Q

how does cornea get nutrition

A

front from: aqueous layer of tears

edothelial cell layer from: anterior chamber- aqueous humor

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4
Q

function of the cornea

A

refraction of light

main barrier to penetration by mirco-organisms

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5
Q
A

conjunctiva hyperemia

episcleral congestion

conjunctiva clear membrane over sclera, then episcleral membrane, then sclera

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6
Q

why is cornea clear

A

avascular
regularly arranged collagen
relatively dehydrated: Na/K pumps in the internal endothelial layer, that pumps H20 out

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7
Q
A

corneal edema

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8
Q

what causes this

A

corneal edema

corneal epithelium or endothelium becomes damaged and there is a build up of fluid inside the cornea

bluish- cobblestoned

endothelial disease: diffuse
epithelial- focal/corneal ulcer

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9
Q

diffuse blue eyes means

A

endothelial disease leading to edema in the cornea

distemper

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10
Q

damage to what layer of the cornea will lead to focal/corneal ulcers

A

epithelial (outer layer)

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11
Q

3 causes of endothelial disease of the cornea

A

breed related endothelial dystrophy
* spontaneous, progressive
* Boston

age-related endothelial degeneration
* common

secondary/intraocular disease
* uveitis
* glaucoma

disruption of Na/K pump- makes blue eyes- edema of cornea

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12
Q

bullous keratopathy

A

progressive cornea edema that leads to bulla/blister formation and corneal ulcer

can treat with Na/Cl solution

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13
Q

how to treat bullous kertopathy

A

Na/Cl soultion

thermokeratoplasy- burn cornea to form scar that prevents fluid from coming into cornea

progressive edema- blisters that lead to corneal ulcers

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14
Q

acute bullous keratopathy in cats

A

can happen suddenly/over night

emergency- can lead to corneal rupture

systemic cyclosporine appears to be a risk factor- may be from descemet’s membrane damage

treat by forcing eye closed for a few weeks

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15
Q

corneal ulcers is caused by loss of —

A

epithelium +/- stroma

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16
Q
A

descemetocele

damage of cornea down to descemet’s membrane, then pressure of eye pushes membrane up forming bubble- needs surgery ASAP

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17
Q

superficial ulcers heal by

A

rapid epithelialization
5-7 days

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18
Q

what causes melting?

A

collagenases

deep ulcers require vascularization and collagen deposition

collagenases are used during wound healing to reform collagen layers- bacteria can cause over activaity of collagenases that then “melt/eat” the eye

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19
Q

can you use pred on corneal ulcer?

A

no!

it will cause increased collagenase activity → melting of cornea

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20
Q

what are the “little trees”

A

blood vessels form to try to heal corneal ulcer

take 3-5 days to form, grow 1mm/day

never go away but blood leaves once healing is done

21
Q

initial treatment of superficial corneal ulcer

A

remove underlying cause: eyelash, thorn ect

give ecollar to prevent rubbing

antibiotics- 3-4 x a day

there are no pain meds for eye!
* can use atropine to stop spasms but will dilate pupil for long periods

Can’t use steroids- will cause worse problems

22
Q

1st step to treat infected ulcer

A

take cytology
culture

use Q 2 hr fluoroquinolones

23
Q

what can help with corneal melting?

A

anti-collagenase

serum: has antiprotease/anticollagenases in it

give every 2-4 hours

24
Q

prognosis of complicated corneal ulcer

A

can take 3 weeks to heal

initial 48 hours checks, if ulcer is improving/not getting any deeper can wait and let eye heal

if not improving, may need surgery

25
Q

when to consider surgery on corneal ulcer

A

greater then 80% deep
descemetocele
corneal perforation
not getting better with medial treatment

26
Q

surgery to fix deep ulcers

A

conjunctival graft

tectonic support- promotes healing and fibroblasts

27
Q

indolent corneal ulcer are

A

superficial uninfected corneal ulcer that does not heal in appropriate time

epithelilal cells are damaged for some reason

boxers- SCCED, feline herpes

28
Q

how to treat indolent corneal ulcer

A

debride/ scratch off epithelial layer and let eye try to make new layer better

promotes epithelialization, vascularization

can use qtip of diamond butt debridement

29
Q

why do contacts help with healing

A

protect new epithelial layer from being rubbed away when blinking

30
Q

pannus

A

chronic superficial keratitis cause by UV damage

usually starts ventralateraly and moves progressively inwars

common in german shepherd

31
Q

— starts ventrolaterally and is a progressive chronic superficial keratitis caused by —

A

pannus

UV light/ immune mediated?

common in german shepherd

32
Q

how to treat pannus

A

steroids, tacrolimus

often managed not cured- can lead to blindness

33
Q

— is similar to pannus in cats

A

eosinophilic keratitis

proliferation with eosinophil and mast cells

can be caused by feline herpes

34
Q

what kind of cells in pannus vs eosinophilic keratitis

A

pannus: dogs: plasma cells

eosinophilic keratitis: cats: eosinophils and mast cells

35
Q

how to treat eosinophilic keratitis

A

steroids and antivirals

steroids can risk making underlying feline herpes virus worse

managed, rarely cured

cat/horse eye- pink/white raised plaques in ventral/lateral eye

36
Q
A

corneal pigmentation- melanin deposition

non- specific response to inflammation dogs

pugs and pekingese

37
Q

how to treat corneal pigmentation

A

melanin deposition is in response to inflammation

try to remove cause of inflammation

increase lubrication

can suture eyelid mostly closed in pugs to allow eyelids to blink- increase protection of cornea

38
Q

what can cause corneal sequestrum

A

cats

breed specific: himalyains
feline herpes
corneal ulcer
entropion
corneal debridement

change in color from corneal necrosis. NOT the same as corneal pigmentation in dogs which in mealnin deposition

39
Q
A

corneal sequestrum-

change in color from corneal necrosis. NOT the same as corneal pigmentation in dogs which in mealnin deposition

can be caused in certain breeds or from herpes, chronic corneal ulcer, entropion, or corneal debridement

treat: keratectomy +/- graft

40
Q

how to treat corneal sequestrum

A

happens in cats

cut out necrosis- keratectomy +/- graft

41
Q

white crystalline is caused by —

A

corneal mineralization
lipid or calcium

from systemic disease (high fat) or topical corticosteroids

treat: underlying cause, stop steroids

42
Q
A

corneal dystrophy

bilateral slow progression

heritable- husky 4-6 years old

usually lipid, not painful, no treatment

43
Q

how to treat corneal dystrophy

A

no treatment

not painful

bilateral slow progression, heritable (husky)- round white lipid accumultion in the eye

44
Q

— is deposition of calicum into cornea after chronic corneal disease

A

corneal degeneration

common in old dogs

+/- vascularization

can be painful, recurrent corneal ulcers

treat: lubricant, keratectomy

45
Q

how to treat corneal degeneration

A

topical lubricant
keratectomy

calcium deposition from chronic corneal disease → painful

46
Q
A

episcleritis

nodular
+/- pain
immune mediated: cocker spaniels

treat: steroid and doxy

47
Q

episcleritis occurs in

A

cocker spaniels

immune mediated?
nodular +/- painful

treat: steroid and doxy

48
Q

how to treat episcleritis

A

topical immunosuppression

oral doxycycline; corticocsteroids

nodular +/- painful, immune mediated- cocker spaniels

49
Q

five-year old DSH
24-hour history of a painful, wet left eye
STT: 15 OU
fluroscein positive OS
PLR present OU
anisocoria OS< OD (left pupil smaller then right)

list two possible causes for the fluorescein uptake in the left eye

what is your initial treatment plan? what is the prognosis?

A

corneal ulcer or herpes

treat with lubricant and antibiotic, e-collar
anti viral

wait- depending on how deep, check in 48 hours if stable let heal for 7-10 days

good if superifical, poor if deep and doesnt heal well
herpes life long disease

23 spring: med surg (60 decks)

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