Clincial Evaluation Of Eye Movements Flashcards
Ductions
Movement when one eye is covered
Have patient cover one eye
Excursion of one eye
Versions
Excursions of both eyes
Simply with both eyes open
Pursuit
Keeps image on fovea, 30-40 deg/sec, parietal-temporal areas
Assess: follow finger
Slow eye movements
Parkinson’s can affect this
Saccades
Bring image on to fovea
Assess: switch fixation finger- nose note speed, accuracy
Bring an object of interest into your fovea (a rapid eye movement, designed to find whatever it is that is of immediate interest to you)
Vergence
Keeps visual fields overlapped, avoids diplopia/confusion
Assess: overcome prism
Convergence/divergence
Convergence Insufficiency
You read for a while and then things get blurry because your convergence ability is poor
Divergence
See a far object, not completely lined up. Minimal misalignment of objects in the distance. Maybe it’s a problem with the tendons that hold the eye in place (sags a little)
Vestibular Ocular Reflex
Maintains eyes on moving target
Assess: head shaking, pursuit at zero velocity
It compensates for your head moving. Notes position change of head and moves eyes in the opposite direction
Estropia
Crossing inward
Tropia: manifest misalignment, it’s there all the time.
Ocular Alignment Assessment
Have them focus on some object. Keep eyes right on the light switch or on that letter. Whenever he covers left eye, no movement. BUT when you cover the right eye, the left eye moves out, it’s crossed. (Because it’s not looking at the chart). You know the eye was in because it had to move out.
Method number 1 of measuring alignment
People who are born this way usually don’t have double vision
Cover/Uncover Test
You’ll A see you only look at the eye that’s uncovered. Don’t see any movement of the uncovered eye. His eyes are straight at this moment, no tropia (manifest malignment).
This test ends with your hand up still. Don’t pay attention when you drop your hand
Allows brain to regain fusion
Cross Cover Test
You see movement, the eye that is uncovered moves in. The way was out, it’s moving in to cover the target
Unmasks any latent misalignment. Doesn’t allow brain to regain function
Difference between phoria and tropia
Phoria: a latent misalignment. Can control it. Big ones eventually might turn into tropia’s and can’t control
Tropia: Can’t control misalignment
Measuring how big the misalignment is
Each rectangle is a stronger prism
if you hold it in the right direction, you can bend the light, make up for whatever he’s doing and movement goes away
Measured in diopter. Can measure the amount of misalignment with the prism
It’s quantifiable. Can follow things over time by making those measurements
Right 3rd nerve Palsy
Ptosis
His eye doesn’t move down, it moves laterally
Doesn’t move down , up or in
Pupil will usually be dilated, it’s a dead giveaway
Oculomotor Nerve
Parasympathetic: ciliary body/iris sphincter
Levator palpebrae
inf, sup, and med recti, inf. Oblique
Origin of posterior communicating artery
Close to the CN III
Hits CN III first if you have an aneurysm
Right 4th Nerve Palsy
Remember this: how does the superior oblique muscle attach to the eyeball?
This intorts and depresses the eye
If it isn’t working like it should, eye goes up and extorts
Eye will be extorted a little bit, ONLY problem when the eye is in adduction and depression. Don’t really see torsion, you see a lack of depression and adduction
MOST COMMON palsy from a head injury. Usually get better over a couple months
6th Nerve Palsy
Lack of abduction of eye
You’d be estropic, his eye would be turned in a little bit
Not noticeable when you look toward the lesion
Internuclear Ophthalmoplegia
Ipsilateral adduction deficit
Contralateral abduction deficit (nystagmus)
Can be caused by a very small lesion
- younger person: MS
- older person: lacunae infarct
Gaze Palsy
When neither eye moves in a direction
Parinaud’s Dorsal Midbrain Syndrome
Patient can’t look up
Pupils won’t cooperate either
It’s a vertical gaze palsy
Light/near dissociation (light reaction is absent but accomodation is present)
Lid retraction
Convergence-retraction nystagmus
Miller Fisher Variant of Gullain Barre
Anti-GQ1b Ab
Ophthalmoplegia
Areflexia
Post-infectious (campylobacter)
Tends to target intermodal spaces on occulomotor cranial nerve
Myasthenia Gravis
Ptosis
Ophthalmoplegia
Fatiguable ptosis and variable ptosis
problem with antibodies that bind to receptor sites
Ptosis and/or double vision
60-70% become generalized
30-50% develop myasthenic crisis
Respiratory distress due to muscle weakness
75% mortality rate prior to immunotherapy
