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Strabismus
Congenital weakness of eye muscles that can result in decreased vision in one eye
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Esotropia/Exotropia
Abnormal medial/lateral deviation of the eye
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Hypertropia
Abnormal elevation of an eye
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Saccades
(Scanning) Fixation jumps from one point to another
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Vergence
The axis of fixation converges when an object moves toward the eye, or diverge when it moves away
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What is seen in oculomotor (III) nerve palsy
- Ptosis
- Eye is down and out
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What is seen in trochlear nerve palsy
The eye is up and in
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What is the most commonly cranial nerve injured in head trauma
Trochlear due to how thin it is and how it wraps around the mesencephalon
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Patients with what eye muscle damaged often fall down the stairs
Trochlear (eye is looking up and in not down where it should)
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What nerves lie in and directly around the cavernous sinus
- III, IV, V1, VI, and V2
- All of the nerves that exit the superior opthalmic fissure plus V2
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Proptosis
Bulging of the eye
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Myasthenia gravis effects what muscles
The muscles that are used the most like the eye and eyelid
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What are often the first features affected when Botulinum toxin is introduced
Paralysis of eye muscles causing diplopia and ptosis
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What initiates voluntary eye movements, saccades
- Frontal eye field (Br. 8)
- This is in front of the premotor cortex in the frontal lobe
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What portion of the brain initiates smooth pursuit movements
The secondary visual cortex (occipital lobe)
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What are the brainstem centers for eye movements
- Paramedian Pontine Reticular Formation (PPRF)
- Rostral Interstitial Nucleus of the MLF
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What does the Paramedian Pontine Reticular Formation in the pons control, and what are its inputs and outputs to
- Horizontal gaze center
- Input from cortex, vestibular nuclei, sup. colliculus
- Output to ipsilateral abducens nucleus
- "Para=Beside=Horizontal"
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What does the Rostral Interstitial Nucleus of the MLF do, and what does it connect
- Vertical gaze center
- Connects eye muscle nuclei with each other and with the vestibular nuclei, and neck muscle motor neurons
- "Rostral=Up=Vertical"
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What are the effectors of the Rostral Interstitial Nucleus of the MLF
CN III, IV, VI
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Damage to the right frontal visual cortex affects movement of the eyes how
- There would be an inability to turn the eyes to the left (to the opposite side of the lesion)
- So the patient would be looking at the lesioned side
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A lesion to the Paramedian Pontine Reticular Formation (PPRF) would effect eye movement how
The eyes will look to the opposite side of the lesion
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Damage to the Medial Longitudinal Fasciculus (MLF) would effect eye movement how
- The eye on the side of the lesion doesn't adduct
- Eye will stay in the center
- Convergence however is in tact
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What is the pathway for voluntary eye movements
- Cortex
- Cross in brainstem
- Paramedian Pontine Reticular Formation (PPRF)
- Nucleus (specific nucleus of the eye muscle)
- Contralateral eye innervated
- Ipsilateral eye the tract crosses again
- Medial longitudinal fasciculus (MLF)
- Ipsilateral Oculomotor nucleus
- Ipsilateral eye innervation
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Dysarthria
Motor speech disorder
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Internuclear Opthalmoplegia (INO)
- Damage to the MLF
- In attempt to adduct the ipsilateral eye, it doesn't work
- Convergence of eye movement is intact however because the input for convergence doesn't travel in the MLF
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One and a half syndrome
- Damage to the abducens nucleus and MLF on one side with the abducens nucleus intact on the opposite side
- Patient can only look away from the lesion with the eye on the opposite side, no other horizontal movement remains
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Parinaud's Syndrome
- Lesion of the dorsal midbrain and vertical gaze center
- Loss of vertical gaze
- Dilated pupils
- Eyelid abnormalities
- Impaired convergence
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Mydriasis is innervated by what ganglion
- (Dilation of eye)
- Sympathetic
- Superior cervical ganglion
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Miosis is innervated by what ganglion
- (Constriction of eye)
- Parasympathetic
- Oculomotor/ciliary ganglion
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What muscle pushes the eyeball forward and what is its innervated by
- Orbitalis muscle
- Superior cervical ganglion (sympathetic)
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What is the pathway of the constriction of the eye
- Optic nerve
- Pretectal nucleus
- Edinger-Westphal nucleus (both sides)
- Ciliary ganglion
- Sphincter Pupilae muscle
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Horners syndrome
- Disruption of sympathetic pathway to the eye
- Ptosis
- Miosis
- Enophthalmus (eye going backward)
- Dry face on affect side
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What affect can a tumour on the apex of the lung have on vision
Horners syndrome due to the compression of the sympathetic trunk
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Argyll Robertson pupil
- Neither eye will constrict to light but does constrict on convergence
- Eyes are already constricted more then normal
- Commonly caused by syphilis, CNS complications
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Marcus Gunn Pupil
- Unilateral lesion anterior to optic chiasm
- Light in affect eye will not cause pupillary constriction in either eye but the unaffected eye will show constriction in both
- MS patients often display this
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The cornea reflex is innervated by what nerve
Trigeminal 1
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