Brainscape's Knowledge GenomeTM

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


See full index

Opthalmology2 > Cornea > Flashcards

Cornea Flashcards

1
Q

corneal anatomy

A

1) outermost epithelium
2) stroma (mostly collagen-90% of thickness)
3) descement’s membrane (thickens with age)
4) innermost endothelium (monolayer, the pump)

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

cornea functions

A
  • anterior structure for globe
  • protection
  • clear medium for vision
  • REFRACTION
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

3 reasons why the cornea is clear

A

1) avascular
2) anhydrous
3) regular collagen arrangement

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

what can cause corneal opacification

A
  • cellular infiltrate (infection)
  • fibrosis (irregular collagen after injury)
  • pigment (2nd to chronic irritation)
  • neovascularization (source of edema; superficial = tree, deep = forest)
  • edema
  • mineralization/ lipid deposition (mostly underneath epithelium)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the most common presenting ophthalmic condition

A

corneal ulcers

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

what are the 3 things that treatment of corneal ulcers depend on

A

1) depth (superficial, stromal, descemetocele, full thickness/ iris prolapse)
2) etiology (trauma, infection, immune mediated)
3) response to therapy (simple, complicated)

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

_____ is the only structure lost in superficial corneal ulcers

A

epithelium

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

how does the corneal epithelium respond to injury

A
  • mitosis stops
  • cells at wound edge enlarge, lose attachment and migrate to injury (0.6mm/day if not infected)
  • initial monolayer of cells cover injury, eventually will grow
  • mitosis resumes after wound closure
  • takes 6 weeks for BM to attach to stroma
  • epithelium increases form 8 to 15 cell layers after injury
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how does the stroma respond to injury

A
  • re synthesis and cross linking of collagen
  • balance of resorptive remodeling and restorative repair by fibroblasts
  • PMNs get rid of necrotic tissue
  • vessels aid healing, when done they collapse but “ghost vessels” remain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  • corneal blood vessels move at ___mm/day
  • WBC move in the cornea at ____mm/day
  • epithelial cells move ___mm/day
A
  • 1mm/day
  • 8.6mm/day
  • 1mm/day
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

dermoids

A
  • normal tissue in abnormal location

- congenital

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

2 rules for ulcers

A
  • treat aggressively

- recheck often

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

clinical signs for corneal ulcers

A
  • blepharospasm
  • epiphora
  • serous to mucopurulent discharge
  • miosis
  • edema
  • corneal vascularization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

diagnostics of corneal ulcer

A
  • culture if suggestive of infection
  • STT
  • fluorescein stain EVERY eye that shows pain
  • cytology (horses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

descemetocele ulcer

A
  • epithelium and stroma are 100% lost and DM is the only thing left
  • DM will bulge due to pressure from AqH
  • when staining, the only thing that will stain is the stroma so it will stick to the sides of the ulcer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

iris prolapse ulcer

A
  • DM has ruptured leaving a hole in the cornea open to the outside
  • vision is lost
  • iris passively follows AqH and plugs hole
17
Q

melting ulcer

A
  • proteases are active
  • need to distinguish from corneal edema
  • action of proteases is potentiated by topical steroids !!!!!!!!!
18
Q

what is contained in tear film that is produced by inflammatory cells, epithelial cells, and fibroblasts that can prolong corneal healing in mild cases of imbalance ?

A

MMPs

Serine Proteases

19
Q

3 bacteria + 3 fungi + 1 virus that commonly cause infectious ulcers

A

bacteria: pseudomonas, strep, staph
fungi: aspergillus, candida, fusarium
virus: herpes

20
Q

goals of therapy for corneal ulcers

A
  • sterilize wound bed
  • control 2nd uveitis
  • slow collagen breakdown
  • provide structural support (cone of shame)
21
Q

_____ is found in serum and can aid in reducing tear protease activity

A

alpha 2 macroglobulin with anticollagenase activity

-serum is: good for 8days; also contains nutrients that promote healing

22
Q 
reflex uveitis
(not even really sure what this its... what does the "reflex" mean?)
A

all ulcers are associated with some iridocyclitis

-give atropine and systemic NSAIDs

23
Q

True / false

topical corticosteroids are contraindicated in the face of corneal ulceration

A

TRUE !!!!!

-but can use topical NSAIDs if uveitis is the main problem… but be safe and stick to systemic NSAIDs

24
Q

true / false

antibiotics are not toxic to epithelial cells

A

false ! they are !

25
Q

therapy for superficial ulcers

A
  • cone of shame
  • triple antibiotic
  • 1% atropine
  • maybe serum
  • recheck 2-3d
  • should be looking better within 24-48hrs
26
Q

therapy for stroma/ complicated ulcers

A
  • antibiotics based on cytology
  • antifungals if needed
  • serum or EDTA or acetylcysteine
  • atropine
  • systemic NSAIDs
  • maybe surgery if needed
  • healing will be 360 starting at limbus
27
Q

therapy for melting ulcer

A
  • same as stroma/ complicated but more aggressive PLUS analgesics
  • should increase stroma rigidity within 24hrs
28
Q

iris prolapse therapy

A

emergency !

  • antibiotics and sx repair (reposition or amputate iris and suture cornea)
  • topical antibiotics and atropine (NO ointments)
29
Q

how to treat corneal lacerations

A

as if they were serious corneal ulcers

usually need sx

30
Q

refractory ulcer

A
  • aka indolent or boxer ulcer
  • superficial with epithelial flaps
  • need to remove abnormal epithelium with dry q-tip and topical anesthesia
  • can do grid or multiple punctate keratotomy (NOT IN CATS OR HORSES )
31
Q

corenal sequestration in cats

A

black spots, corneal nigrum, focal corneal degeneration, or corneal mummification
-all breeds but Persian, Humalayan, Burmese pridisposed

32
Q

pannus

A

chronic superficial keratitis

  • immune mediated
  • UV radiation
  • causes corneal vascularization and pigmentation
  • no cure, topical steroids and cyclosporine, keratectomy, beta irradiation
33
Q

corneal dystrophy in dogs

A
  • both eyes, does not have to be symmetrical
  • may be inherited
  • deposition of cholesterol and triglycerides in stroma but serum cholesterol is normal
34
Q

how does the endothelium respond to injury

A
  • limited mitosis
  • remaining cells enlarge and migrate
  • give topical hyperosmotics, think conjunctival grafts, thermal keratotomy
35
Q

what is the hallmark of corneal endothelial disease

A

dense corneal edema

Opthalmology2 (10 decks)

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