Vision Loss Flashcards
Why would an eye with a retinal or optic nerve lesion not be entirely mydriatic?
(Consensual PLR reflex)
Why do you expect the PLRs and dazzle reflexes to be normal in a patient with an occipital cortex lesion?
(Because the pathway responsible for those responses splits off of the optic pathway prior to where it ends in the occipital lobe so an occipital lesions will not affect those reflexes (unless the lesion were to become big enough to then affect the subcortical area responsible for PLR and dazzle))
If you have a right occipital lobe lesion, which field of vision is lost, left or right?
(Left)
Is parasympathetic or sympathetic innervation responsible for constriction of the pupil?
(Parasympathetic → you don’t need floods of light when you’re chilling in your bed)
A lesion in the right oculomotor nerve will cause miosis/mydriasis (choose) of the left eye.
(Tricky me, it won’t cause either to the left eye; will cause MYDRIASIS of the RIGHT eye)
What disease is caused by injury/insult to the sympathetic innervation to the eye?
(Horners)
Is mild or dramatic anisocoria associated with insults to the efferent pathways of the eye?
(Dramatic, if an insult to the afferent pathway, will be mild)
What should you consider when trying to decide which pupil is abnormal in an anisocoric cat?
(Lighting conditions and animal stress)
What are some non-neurological causes of mydriasis?
(Iris atrophy, glaucoma, and drugs such as atropine)
What are some non-neurological causes of miosis?
(Uveitis, keratitis, posterior synechiae, and drugs such as pilocarpine)
What is the diagnostic triad associated with sudden acquired retinal degeneration?
(Acute vision loss, normal fundus, and flat ERG)
What is the typical signalment for a SARDs patient (age, sex, intact status, and BCS)?
(Middle aged to older, spayed females, over conditioned)
Why would a dog with progressive retinal atrophy be hesitant on nightly walks be the first sign?
(Because rods degenerate first so dim light vision becomes diminished first)
What are the fundic changes that can be seen via ophthalmoscopic examination of a dog with progressive retinal atrophy?
(Vascular attenuation, tapetal hyper-reflectivity, and optic nerve atrophy)
What disease is a common rule out for retrobulbar optic neuritis and how can you rule it out?
(SARDs, r/o with ERG)
