The Abnormal Pupil

Question 1

What are the two main causes of an abnormal pupil?

Answer 1

Iridial disease or PLR pathway dysfunction

Question 2

Give examples of iridial diseases

Answer 2

Posterior synechiae
Glaucoma
PRA
PPM
Anterior uveal cysts
Melanocytic neoplasia

Question 3

What are anterior uveal cysts?

Answer 3

Bits of epithelial that pinches off and floats around in the anterior chamber. If many can block the ICA and cause glaucoma.

Question 4

What canine breeds are anterior uveal cysts seen in?

Answer 4

Great danes and retrievers

Question 5

What is the treatment for anterior uveal cysts?

Answer 5

Laser removal

Question 6

What clinical sign is seen in anterior uveal cysts?

Answer 6

Fly catching behaviour

Question 7

What is the difference between dogs and cats in terms of melanocytic neoplasia?

Answer 7

Cats are diffuse and malignant where as dogs are localised and benign

Question 8

What can cause PLR pathway dysfunction?

Answer 8

Retinal detachement
PRA
Synechiae
Unilateral extraocular lesions
Post-chiasmal lesions

Question 9

How would you differientiate between extraocular and post-chiasmal lesions?

Answer 9

Unilateral pre-chiasmal lesions:
Dx: Marcus Gunn signs (No menace and thus no vision, no direct or indirect PLR to other eye but indirect PLR fine).
Post-chiasmal lesions:
Central blindness, contralateral vision loss i.e. lesion in the left optic tract -> loss of sight in the right.