Occulomotor + visual loss disorders Flashcards
Ampylopia will be present in acquired (paralytic) or congenital (non-paralytic/comitant) strabismus?
Non-paralytic. It is the result of the brain suppressing 1 of the images it perceives as wrong.
Define these two suffixes:
- trophia
- phoria
- trophia refers to a misalignment of the eyes that is always present
- phoria refers to misalignment of the eyes only present with disrupted fusion (i.e. when one eye is covered and uncovered, then you will see the error)
Which muscles are responsible for intorsion of the eye?
And extorsion?
sup. rectus + sup. oblique = intorsion
Inf. rectus + inf. oblique = extorsion
You’ve got compression of CNIII somewhere along its course. What will be damaged first, pupillary light reflex or occulomotor function?
PLR will be damaged first bc the PSNS fibers run along the periphery of CNIII
Eventually, the eye will drop down and out due to loss of all but LR and SO
Ptosis will also be seen due to fibers of CNIII innervating the levator palpebrae
Your obese 50 yo pt’s pupillary light reflex is intact, but they have lost occulomotor fxn. What is going on?
Microvascular CNIII palsy due to DM and HTN
Your pt loses vision transiently for seconds at a time in ONE eye. What could be causing it?
Papilledema
Your pt loses vision transiently in BOTH eyes. What could be causing it?
Basilar artery insufficiency
Your pt loses vision transiently for 5-10 minutes at a time in ONE eye. What is this called and what could be causing it?
Amourosis fugax- TIA
Your pt describes recurrent scintillating scotoma (arch shaped visual blurring concentric to focal point). What does this event often precede?
Migraine headaches
Your pt describes pain with their changes in vision. What is on the differential?
Closed-angle glaucoma, uveitis, optic neuritis, endopthalmitis
Your pt does NOT describe pain with their changes in vision. What is on the differential?
Cataracts, CRA/CRV occlusion, retinal detachment
This could cause a gradual, progressive loss of vision.
Brain tumor
This could cause a sudden loss of vision in one eye:
Vascular etiology- adult
Optic neuritis- Younger pt
A RAPD suggests a lesion of the optic nerve, chiasm, or tract anterior to:
LGN
Homonymous hemianopsia will be caused by:
Where would you find the lesion, relative to the visual field loss?
A lesion in the optic “tract” posterior to the LGN. It will present as visual field defect in the same field of both eyes, opposite to the side of the brain w/ the lesion. The closer you get to the occipital cortex, the more congruent the homonymous hemianopsia will be bc the affected fibers are closer together in the cortex for painting the “visual picture”.
