Conditions of the Posterior Segment of the Canine Eyeball Flashcards
What is the colour of the tapetum in young puppies and kittens?
Blue
List four methods of examining and testing the canine and feline retina?
Electroretinography
PLR and Dazzle reflexes
Menace response
How may ‘active’ chorioretinitis appear?
Hyporeflective tapetal lesions.
White/cream lesions in the non-tapetum.
How may ‘inactive’ chorioretinitis appear?
Hyperreflective tapetal lesions.
Pigmentation in tapetum.
Depigmentation in non-tapetal lesion.
What age of dogs does inherited progressive retinal atrophy usually affect?
Typically dogs >3 years.
How may inherited progressive retinal atrophy present?
Hyperreflectivity
Vascular attenuation
Nyctalopia
How would sudden acquired retinal degeneration appear on electroretinography?
Flat line (indicating no electrical activity)
List the main two types of optic nerve disease.
Optic coloboma - ‘missing tissue’
Collie eye anomaly
What are the main two pathologies of canine glaucoma?
Outflow obstruction,
Ocular hypertension
What are the three different types of tonometry and what is the equipment for each called?
Indentation tonometry - Schiotz
Applanation tonometry - Tonopen
Rebound tonometry - Tonovet
How can carbonic anhydrase inhibitors be used to treat glaucoma?
Bicarbonate entry into aqueous is followed by water, so they will reduce aqueous production.
How can carbonic anhydrase inhibitors be used to treat glaucoma?
Bicarbonate entry into aqueous is followed by water, so they will reduce aqueous production.
How do beta blockers reduce aqueous production to treat glaucoma?
They block beta receptors in ciliary epithelium, this reduces cAMP and therefore aqueous production.
List two systemic conditions in which beta blockers are contraindicated.
Asthma and cardiovascular disease.
How do prostaglandin analogues treat glaucoma and which species will they NOT work in?
Prostaglandins increase aqueous outflow and they do not work in cats.
