Cornea

Question 1

What happens when there is increased fluid in corneal stroma?

Answer 1

reduced transparency of cornea

Question 2

What occurs with injury to the corneal endothelium (posterior side)

Answer 2

Absorbs fluid from aqueous humour

Can be caused by glaucoma or immune-mediated inflammation

Question 3

What occurs when there is injury to the corneal epithelium?

Answer 3

Absorbs fluid from tear film

Can be caused by corneal inflammation (keratitis)

Question 4

What does keratitis inflamm of the cornea indicate?

Answer 4

Persistent injury
results in the loss of corneal transparency and adaptive cutaneous metaplasia (epithelial hyperplasia, Keratinisation, Pigmentation, stromal fibrosis and vascularisation)

Question 5

What occurs with keratoconjunctivitis sicca?

Answer 5

Lack lacrimal secretions
Mostly due to immune-mediated disorders
common in dogs
Adaptive corneal cutaneous metaplasia

Question 6

Chronic Superficial keratitis: Pannus

Answer 6

Suspected immune mediated disorder of greyhounds
Exacerbated by UV light
Both eyes can be affected but not always
Superficial fleshy vascularised stromal infiltrate

Question 7

Describe the different type of corneal ulcers?

Answer 7

Corneal necrosis:
- occur too rapidly for cutaneous metaplasia to occur
- rapid desiccation from traumatic injuries (FHV, Moraxella bovis)
Keratomalacia
- melting ulcer causes stromal necrosis, contaminated ulcer and neutrophils
Descemetocoele
- deep loss of stroma down to descements membrane
- bulges anteriorly into defect
- will not take up a stain
Perforating ulcer
- decements membrane is ruptured
- aqueous humour is lost

Question 8

Corneal sequestrum

Answer 8

Occurs after chronic ulceration
Causes necrosis of the corneal stroma
Characterised by dark-brown corneal leathery pigment