The Abnormal Pupil Flashcards
anterior uveal cysts
not a problem unless numerous
what kinda of behaviour is caused by anterior uveal cysts
fly catching
simplest for of persistent pupillary membrane (PPM)
cumulus of central pupillary pigment dots
anterior uveal melanoma (AUM) in cats
benign melanosis leads to this
usually diffuse
is usually malignant but metastasises v.slowly
AUM - when does the change happen
Look for changes in surface architecture, not just color
pupillary changes at rest and with dilation
AUM - treatment
enucleation
order of the visual pathway
eye, optic nerve, optic chiasm, optic tract, lateral geniculate body, cerebral cortex
effect of a pre-chiasmal lesion on the menace response
no response on effected side
effect of a pre-chiasmal lesion on the PLR
no reflex in affected eye directly
normal reflex indirectly
Marcus Gunn sign
Prechiasmal, unilateral afferent lesion
Retina, Optic nerve head, Optic nerve
Not unilateral glaucoma
Marcus Gunn sign - why no unilateral glaucoma
Because with glaucoma, the affected eye has a mid-dilated, non-responsive pupil due to IOP damage to the Retina/Optic nerve head and the iris, so the iris will not move even in indirect PLR
sign of senile iris atrophy
ragged edges of the iris seen in tapetal reflex
What if post-chiasmal?
Central blindness
More difficult to pinpoint after cross-over of fibers
