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Eye Movements—Donna L. Hill, M.D., UF and Shands Jacksonville

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  • 1. Eye MovementsEye Movements Donna L. Hill, MDDonna L. Hill, MD Neuro-ophthalmologyNeuro-ophthalmology Departments of NeurologyDepartments of Neurology and Ophthalmologyand Ophthalmology UF&Shands JacksonvilleUF&Shands Jacksonville
  • 2. Normal Eye MovementsNormal Eye Movements • Objective: FoveationObjective: Foveation • Extraocular musclesExtraocular muscles • Muscle innervation – CNs III, IV, and VIMuscle innervation – CNs III, IV, and VI • Cranial nerve nucleiCranial nerve nuclei • Three primary types of movementsThree primary types of movements • Pathologic eye movementsPathologic eye movements
  • 3. Objective: foveationObjective: foveation • fovea – most sensitive portion of retinafovea – most sensitive portion of retina • we need to orient, either voluntarily orwe need to orient, either voluntarily or reflexively, to important stimulireflexively, to important stimuli • accomplished by directing our eyes to a targetaccomplished by directing our eyes to a target so that it is projected onto the foveaso that it is projected onto the fovea • to maintain foveation, we depend onto maintain foveation, we depend on visualvisual feedbackfeedback as the primary source ofas the primary source of information on eye movement accuracyinformation on eye movement accuracy
  • 4. Extraocular musclesExtraocular muscles • Superior rectus – moves eye upSuperior rectus – moves eye up • Inferior rectus – moves eye downInferior rectus – moves eye down • Medial rectus – moves eye in (a-d-duction)Medial rectus – moves eye in (a-d-duction) • Lateral rectus – moves eye out (a-b-duction)Lateral rectus – moves eye out (a-b-duction) • Inferior oblique – moves eye up when it is in an adducted position;Inferior oblique – moves eye up when it is in an adducted position; also extorts the eye.also extorts the eye. • Superior oblique – moves eye down when it is adducted; also intortsSuperior oblique – moves eye down when it is adducted; also intorts the eye.the eye. left
  • 5. Isolating Extraocular MusclesIsolating Extraocular Muscles
  • 6. CN IIICN III
  • 7. CN IIICN III • Superior division - Superior rectus muscle - Levator palpebrae superioris muscle • Inferior division - Medial rectus muscle - Inferior rectus muscle - Inferior oblique muscle - Parasympathetic innervation to pupil
  • 8. CN IVCN IV CN VICN VI
  • 9. CN VICN VI
  • 10. Coordination of Eye MovementsCoordination of Eye Movements • Separate systems exist to control each differentSeparate systems exist to control each different subtype of eye movement: saccades, smoothsubtype of eye movement: saccades, smooth pursuit, and vergencepursuit, and vergence • May be nuclear or supranuclear controlMay be nuclear or supranuclear control • May be reflexive or voluntaryMay be reflexive or voluntary • Separate systems exist to govern vertical andSeparate systems exist to govern vertical and horizontal eye movementshorizontal eye movements
  • 11. Targeting Eye MovementsTargeting Eye Movements 1.1. Saccades: Quick, darting conjugateSaccades: Quick, darting conjugate movements which direct the eyes to a newmovements which direct the eyes to a new target.target. 2.2. Smooth pursuit: A slower conjugate movementSmooth pursuit: A slower conjugate movement which allows for tracking of a moving object, orwhich allows for tracking of a moving object, or of a stationary object while we are moving.of a stationary object while we are moving. 3.3. Convergence: A dysconjugate movement ofConvergence: A dysconjugate movement of both eyes toward the midline to allow forboth eyes toward the midline to allow for focusing on a near object by adjusting the anglefocusing on a near object by adjusting the angle between the eyes.between the eyes.
  • 12. Variety of pathways contribute to saccadicVariety of pathways contribute to saccadic control and smooth pursuitcontrol and smooth pursuit
  • 13. SaccadesSaccades • Under the control of three different areasUnder the control of three different areas in the brain:in the brain: – voluntary saccades - frontal eye fieldsvoluntary saccades - frontal eye fields (Brodmann’s area 8)(Brodmann’s area 8) – reflexive saccades to complex stimuli -reflexive saccades to complex stimuli - parietal lobes (Brodmann’s area 7)parietal lobes (Brodmann’s area 7) – reflexive saccades to elementary stimuli -reflexive saccades to elementary stimuli - superior colliculisuperior colliculi
  • 14. Voluntary Saccades (Voluntary Saccades (horizontal)horizontal) results inresults in saccade tosaccade to contralateralcontralateral spacespace
  • 15. CEREBRAL HEMISPHERE MIDBRAIN PONS PPRF PPRF VI VI FEF FEF IIIIII Voluntary Horizontal SaccadesVoluntary Horizontal Saccades
  • 16. MIDBRAIN PONS VI VI IIIIII LR MR MR LR Yoking MechanismYoking Mechanism
  • 17. Reflexive SaccadesReflexive Saccades - to complex stimuli originates in area 7 of the parietal lobe - to elementary stimuli originates in superior colliculi dorsolateral prefrontal cortex involved in planning of eye mvts
  • 18. Smooth PursuitSmooth Pursuit Two types:Two types: 1.1. Voluntary (actually termed “smooth pursuit”)Voluntary (actually termed “smooth pursuit”) movements - originate in the temporo-movements - originate in the temporo- parietal lobeparietal lobe 2.2. Reflexive - which are under vestibularReflexive - which are under vestibular nuclear control alone and constitute what isnuclear control alone and constitute what is called the vestibulo-ocular reflex (VOR).called the vestibulo-ocular reflex (VOR).
  • 19. VoluntaryVoluntary Smooth PursuitSmooth Pursuit • originates near the angularoriginates near the angular gyrus - Area 39 at the temporalgyrus - Area 39 at the temporal parietal occipital junctionparietal occipital junction • cells in this region are able tocells in this region are able to compute the speed andcompute the speed and direction of a moving objectdirection of a moving object • results in ipsilateral smoothresults in ipsilateral smooth pursuitpursuit IPSI
  • 20. Optokinetic ReflexOptokinetic Reflex • Combination of saccades andCombination of saccades and smooth pursuit that allow trackingsmooth pursuit that allow tracking of targets in turn (e.g. countingof targets in turn (e.g. counting sheep as they jump over a fence).sheep as they jump over a fence). • smoothly pursue one target, thensmoothly pursue one target, then saccade in the opposite directionsaccade in the opposite direction to pick up the next targetto pick up the next target • parieto-temporal junction (smoothparieto-temporal junction (smooth pursuit area) projects down topursuit area) projects down to ipsilateral vestibular nucleus,ipsilateral vestibular nucleus, inhibits it allowing ipsilateralinhibits it allowing ipsilateral smooth pursuitsmooth pursuit • then, the FEF of thethen, the FEF of the samesame hemisphere generates a saccadehemisphere generates a saccade back (contralateral) to the nextback (contralateral) to the next target
  • 21. Reflexive Smooth Pursuit - VORReflexive Smooth Pursuit - VOR • maintains gaze on amaintains gaze on a target despite headtarget despite head movementmovement • reflex arc –reflex arc – semicircular canalsemicircular canal opposite the head turnopposite the head turn detects motion anddetects motion and activates the ipsiactivates the ipsi vestibular n. whichvestibular n. which deactivates itsdeactivates its inhibitory input on theinhibitory input on the ipsilateral VIipsilateral VI • results in eyes turningresults in eyes turning opposite to the headopposite to the head turnturn VIII deactivates (-) input p339 Medical Neuroscience, Nadeau et al
  • 22. ConvergenceConvergence • When areas of the occipital cortex detect aWhen areas of the occipital cortex detect a discrepancy in the retinal projection from eachdiscrepancy in the retinal projection from each eye and amount of blur, a signal is sent toeye and amount of blur, a signal is sent to initiate convergence.initiate convergence. • To bring a near object into focus actuallyTo bring a near object into focus actually involves convergence, accomodation (lensinvolves convergence, accomodation (lens curvature increases) and pupillary constriction.curvature increases) and pupillary constriction. Together, these 3 movements are called theTogether, these 3 movements are called the near triad.near triad.
  • 23. Pathologic eye movementsPathologic eye movements • MuscleMuscle – Trauma, entrapment, inflammation, infiltrating diseasesTrauma, entrapment, inflammation, infiltrating diseases • Neuromuscular JunctionNeuromuscular Junction – myasthenia gravis, botulism, organophosphate poisoningmyasthenia gravis, botulism, organophosphate poisoning • Cranial nuclei or nerveCranial nuclei or nerve – Brainstem: stroke, hemorrhage, multiple sclerosis, tumor, traumaBrainstem: stroke, hemorrhage, multiple sclerosis, tumor, trauma – Subarachnoid space: Increased intracranial pressure, aneurysm,Subarachnoid space: Increased intracranial pressure, aneurysm, meningitis, sarcoidosis, autoimmunemeningitis, sarcoidosis, autoimmune – Cavernous sinus: Tumor, sinus thrombosis, pituitary apoplexy,Cavernous sinus: Tumor, sinus thrombosis, pituitary apoplexy, sphenoid sinusitis, carotid-cavernous fistula, Tolosa-Huntsphenoid sinusitis, carotid-cavernous fistula, Tolosa-Hunt syndromesyndrome – Orbit: Trauma, tumor, infectionOrbit: Trauma, tumor, infection
  • 24. right cranial nerve III palsyright cranial nerve III palsy
  • 25. right cranial nerve VI palsyright cranial nerve VI palsy
  • 26. Gaze PalsyGaze Palsy • inability to look in a particular direction (ie.inability to look in a particular direction (ie. neither eye can look right)neither eye can look right) • lesion in the FEF, the PPRF, or the CN VIlesion in the FEF, the PPRF, or the CN VI nucleusnucleus – Lesion in the FEF – unable to look contralaterally,Lesion in the FEF – unable to look contralaterally, eyes deviate toward the lesion, can be overcome witheyes deviate toward the lesion, can be overcome with VORVOR – Lesion in PPRF or CN VI nucleus – inability to lookLesion in PPRF or CN VI nucleus – inability to look ipsilaterally with either eyeipsilaterally with either eye
  • 27. CEREBRAL HEMISPHERE MIDBRAIN PONS PPRF PPRF VI VI FEF FEF IIIIII Voluntary Horizontal SaccadesVoluntary Horizontal Saccades
  • 28. Left MLF lesion – intranuclear ophthalmoplegiaLeft MLF lesion – intranuclear ophthalmoplegia
  • 29. MIDBRAIN PONS VI VI IIIIII LR MR MR LR Yoking MechanismYoking Mechanism
  • 30. • Dr. Tariq Bhatti and his patients for clinical imagesDr. Tariq Bhatti and his patients for clinical images • Dr. Angela McSwain, Dr. Nadeau’s text, Peter Duus ( “Topical Diagnosis inDr. Angela McSwain, Dr. Nadeau’s text, Peter Duus ( “Topical Diagnosis in Neurology”), and Frank H. Netter (Ciba Collection of Medical Illustrations, Vol 1)Neurology”), and Frank H. Netter (Ciba Collection of Medical Illustrations, Vol 1) • Dr. Nancy Newman and Dr. Valerie Biousse, Neuro-ophthalmology EmoryDr. Nancy Newman and Dr. Valerie Biousse, Neuro-ophthalmology Emory UniversityUniversity AcknowlegdementsAcknowlegdements