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IP 11 Ophthalmology > 6: cornea, sclera - giuliano > Flashcards

6: cornea, sclera - giuliano Flashcards

1
Q

t/f

an appropriate Tx for ulcers are topical steroids

A

false

NEVER put steroids on a corneal ulcer

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2
Q

what are 5 conditions that considered an ophthalmic emergency?

A 
keratitis [corneal ulcers]
uveitis [hyphema]
glaucoma [acute 1*, 2* to lens luxation]
orbital dz [proptosis]
adnexae [eyelid lacerations]
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3
Q

what does a rose bengal stain evaluate for?

A

FHV-1

KCS

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4
Q

what CrNn does palpebral reflex require?

A

CrN 5 and 7

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5
Q

important things to consider while describing corneal ulcers:

A 
size
depth
position relative to limbus
health of surrounding cornea
chrnoicity / cause
# of ulcers
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6
Q

what is the significance of the position of the ulcer relative to the limbus?

A

if ulcer is deep, it needs neovascularization which comes from the limbus

so if near limbus, that is good

if positioned too centrally and far from the limbus, may recommend Sx instead

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7
Q

underlying causes of corneal ulcers:

A 
trauma (save for last)
FB
eyelid abnormalities 
infectious etiologies
neurologic defect
KCS***
congenital abnormalities
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8
Q

underlying infectious causes of corneal ulcer in cats:

A

FHV-1

1* infection common

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9
Q

underlying infectious causes of corneal ulcer in dogs:

A

1* infectious keratitis does not ‘typically’ occur

r/o all other causes 1st in dogs (KCS)

2* infection may result in progressive ulceration, stromal malacia, perforation

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10
Q

what neurologic deficits will be present w CrN 5 issue?

A

sensory deficit, neurotrophic keratitis

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11
Q

what neurologic deficits will be present w CrN 7 issue?

A

lagophthalmos

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12
Q

superficial corneal onset typical presentation?

A

acute

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13
Q

what tissue layers are lost in superficial corneal ulcer?

what does this look like on fluoroscein stain?

A

epithelial tissue loss only
stroma intact

sharp distinct borders to stain
minimal corneal inflammatory response b/c acute

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14
Q

what is reflux uveitis?

A

axonal reflex mediated by CrN 5 w release of inflammatory mediators (PG)

cornea richly innervated so if nerve ending abrasion, signal sent back to uveal tract [PG mediated response] -> ciliary spasm and uveal tract spasm to close the eye

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15
Q

simple corneal ulcer Tx:

A
  • find and remove underlying cause
  • px 2* infection - broad spectrum topical abx
  • tx refulx uveitis (atropine, oral NSAIDs)
  • px self trauma (e-collar)
  • NO topical corticosteroids
  • recheck 7 d
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16
Q

what is SCCED?

A

spontaneous chronic corneal epithelial defect

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17
Q

what is an indolent ulcer?

A

SCCED - a superficial ulcer that should heal but does not heal

chronic or likely to become chronic

minimal corneal inflammatory effect - epithelium tries to cover the defect but cannot adhere

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18
Q

what tissue is lost in an indolent ulcer?

what does the STT look like?

A

epithelial loss only - stroma intact

non-adherent epithelial “lip” - creates indistinct borders with stain - “halo” like effect

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19
Q

tx of indolent ulcers?

A 
px 2* infection
promote healing - topical anesthetic, debride, perform grid keratotomy or diamond burr keratectomy
tx reflex uveitis
px self trauma
recheck 7-10 d
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20
Q

for indolent ulcers, what is believed to be the problem that is preventing healing?

A

corneal anterior stromal problem

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21
Q

with just a dry q tip debridement, what % of indolent ulcers will heal?

A

50%

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22
Q

how do you do a grid keratotomy?

what species is it appropriate for?

what % will heal?

A

make hash marks in superficial cornea - get through anterior stroma so epithelial cells have more healthy stroma to adhere

use 27 gauge needle***

85% heal

dogs

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23
Q

why is grid keratotomy NOT appropriate for cats and horses typically?

A

the MC cause for feline and equine is infectious - you will inoculate the deeper tissue w the bacT => BAD

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24
Q

what abx for indolent ulcers?

A

oxytet
terramyciin

atropine - to effect - to dilate pupil

oral NsAID
oral analgesic (tramadol)
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25
Q

if the grid keratectomy does not repair the indolent ulcer, what should be done?

A

refer

may need superficial keratectomy

or 2nd grid keratotomy or corneal thermal cautery

26
Q

what is a descemetocele?

A

a deep ulcer = complex ulcer = melting ulcer = deep stromal ulcer

27
Q

what are the characteristics of a stromal ulcer?

A
  • acute or chronic
  • epithelial AND stromal tissue loss
  • fluorescein stains walls and floor of ulcer
  • stroma frequently unhealthy: edema, inflammatory cells, “melting” or keratomalacia
28
Q

what is appearance of deep corneal ulcer?

A
  • severe corneal edema {blue}
  • variable depth of stromal loss
  • soft, melting corneal stroma
  • yellow-cream stromal infiltrates
  • corneal neovascularization
  • anterior uveitis {hypotony, miosis, equeous flare, hypopyon or fibrin in AC}
29
Q

what are causes of deep ulcer?

A
  • endogenous proteinases [WBCs, corneal epithelial cells, stromal fibroblasts]
  • 2* bacT infections [collagenase prod, B-hemolytic strep]
  • topical corticosteroids [local immune suppression, potentiation of collagenase activity]
30
Q

what does the Seidel test evaluate for?

A

if concerned that patient might still be actively leaking

put fluorescein stain on eye and do not dilute it, wait, then if positive, you will see the leak

31
Q

dx of deep corneal ulcer:

A

corneal cytology and swab [under anesthesia]

be careful and DO NOT touch eyelids

swab margin of ulcer bed

32
Q

deep ulcer Tx?

A
  • find and remove underlying cause
  • Px / Tx 2* infection - assume already infected
  • Tx reflex uveitis
  • px corneal melting: serum
  • bandage
  • Sx?
  • e collar
  • recheck w/in 7 d
33
Q

what does serum do to help ulcer heal?

A

anti collagenase activity

34
Q

surgical options for deep ulcer tx:

A

conjunctival graft
corneo-conjunctival transposition
REFER

35
Q

when should Sx be considered for deep ulcer?

A

greater than 1/2 stromal depth loss
rapidly progressive or melting
no neovascular response
perforated and actively leaking

36
Q

medical mgmt of deep ulcer?

A
  • abx based on cytology and culture
    g + = cefazolin
    g - = fluoroquinolone
  • use solutions - NOT ointments
37
Q

what is the function of proteinase inhibitors in deep ulcer Tx?

A

inhibit endogenous and BacT collagenases

px melting or Tx ongoing stromal melting

38
Q

when should atropine be used?

A

initially - to maintain pupillary dilation => Px synechia [iris adhering to other tissue]
cycloplegia for ciliary M spasm assoc w reflex uveitis
stabilize blood-eye barrier via dec vasc permeability

39
Q

when is systemic therapy appropriate to Tx deep ulcers?

A

appropriate for deep ulcers

analgesic
systemic anti inflammatory
systemic abx - if perforation possible and to px ascending infection

40
Q

Sx Tx of deep ulcer?

A

conjunctival graft [pedicle]
corneal graft
ophthalmic tissue glue

41
Q

t/f

a conjunctival graft will restore vision completely in a patient with a deep ulcer

A

false

will restore functional vision but not complete vision

42
Q

what is a corneal facet?

A

chronic ulcer hx: deep ulcer that healed

intact epithelium, healthy tissue but still thin and is a defect - an area of weakness

43
Q

how long does debridement take?

A

hours

44
Q

how long does epithelial flattening and migration take?

A

hours

45
Q

how long does epithelial mitosis take?

A

days

46
Q

how long does basement mem deposition take?

A

days to weeks

47
Q

how long does stromal collagen deposition take?

A

days to weeks

48
Q

how long does stromal collagen remodeling take?

A

months

49
Q

what are 3 reasons an ulcer will NOT heal in 7-10 days?

A
  • original cause still present
  • it has become infected
  • it is an indolent ulcer
50
Q

what is the sclera?

A

white of the eye

part of the outer fibrous tunic

51
Q

what are the specialized areas of the sclera?

A

limbus
intrascleral venous plexus
equatorial extra ocular muscle insertions
lamina cribrosa

52
Q

what is the lamina cribrosa?

A

exit of optic nerve - it is the axons of ganglia cells

53
Q

MC scleral dzz?

A

coloboma
neoplasia
immune med disorders
trauma

54
Q

what is a sclera coloboma?

A

a hole in the scleral tissue

55
Q

ddx for brown pigment in the sclera?

A

melanoma

benign melanocytoma

56
Q

what can you visualize with gonioscopy?

A

the irido corneal angle

57
Q

what is NGE?

etiology?

A

episcleritis and episclerokeratoconjunctivitis => nodular granulomatous

immune mediated

58
Q

NGE MC seen in what species and breed?

A

collies and collie crosses

59
Q

Tx of NGE?

A

top and sys steroids
top cyclosporine
sys tetracycline
sys azathiopirne

60
Q

what is predominate cell type present in NGE?

A

macrophages

IP 11 Ophthalmology (13 decks)

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