07 - diseases of the cornea Flashcards
1
Q
layers of the cornea
what are the 6 layers of the cornea (first one is tear film…)
A
- tear film
- epithelium
- basement membrane
- stroma
- Descemet membrane (doesn’t take up fluorescein stain)
- endothelium
2
Q
1-3. what are three corneal responses to insult?
A
- edema
- vascularization (normal cornea doesn’t have blood vessels)
- pigmentation (chronic irritation)
3
Q
what is keratitis?
A
inflammation of the cornea
4
Q
(keratoconjuctivitis sicca)
- what is this?
A
- inflammation of the cornea and conjuctiva as a result of low aqueous component of tear film
5
Q
(keratoconjuctivitis sicca)
1-7. causes?
A
- immune mediated destruction of tear glands
- congenital (gland aplasia)
- iatrogenic (excision of nictitans gland)
- drug induced
- trauma (proptosis)
- neurogenic
- infection (distemper in dogs, herpesvirus)
6
Q
(keratoconjuctivitis sicca)
1-4. Cx?
A
- ocular irritation/pain
- conjunctivitis…
- keratitis…
- ocular discharge
7
Q
(KCS)
- what test is helpful to dx?
A
- schirmer tear test
8
Q
(KCS)
1-3. 3 treatment options?
A
- cyclosporine -> reduce immune destruction of tear producing glands
- pilocarpine -> stimulate tear production
- parotid duct transposition
9
Q
(ulcerative keratitis)
- use what to demonstrate ulcer?
A
- fluorsecien stain (descemet’s membrane doesn’t stain!)
- swab for culture
10
Q
(superficial corneal ulcers)
- treat initially with broad spec abx -> will typically heal in 3-5 days -> if it doesn’t what does this mean?
A
- cause for ulcer still present, ulcer is infected, indolent ulcer present
11
Q
- what is an indolent ulcer?
- cause in dogs?
- in cats?
A
- slow-healing ulcer
- failure of epi to adhere to basement membrane (in dogs)
- FHV-1
12
Q
(indolent ulcer)
- treatment for dogs?
- for cats?
A
- debride and grid keratotomy
- don’t do grid keratotomy -> can lead to corneal sequestrum
13
Q
(midstromal corneal ulcer)
- potentially more serious
A
14
Q
(deep corneal ulcer)
- why should it be treated as emergency?
- tx?
A
- perforation can occur
- surgical repair (conjuctival pedicle flap)
15
Q
(herpesvirus keratitis)
- common in what species?
- conjuctivitis with or without corneal ulcer
- tx?
A
- cat
- topical antiviral medication