Eye Movements Flashcards
What are types of disconjugate movements?
Convergence, divergence
What are the three parts of the accommodation reflex?
Convergence eye movement, pupils constrict, lenses bulge
What is the convergence pathway for accommodation?
Occ cx -> SC -> vergence center in midbrain near CN 3 -> R/L CN 3 subnuc for med rec -> convergent eye mvmt
What is the Argyll Robertson pupil?
Complication of neurosyphilis, no pupillary constriction to light but to accommodation
Where are the vertical and lateral gaze centers located?
Vert: rostral midbrain near CN 3
Lat: caudal pons near CN 6
How do pineal gland tumors (pinealomas) affect eye movements?
Affect vergence, accommodation, vertical gaze centers in midbrain deep to SC
How would a patient’s eyes appear if he had obstructive hydrocephalus?
Unopposed down-gaze, unopposed convergence = “setting-sun” sign
What is the PPRF?
Paramedian pontine reticular formation, horizontal gaze center in pons near CN6; moves eyes horizontally ipsilaterally
What is the MLF?
Connects eye movements for conjugate mvmts and carries fibers from vestibular complex
What are the two outputs of the CN 6 nucleus? What are the effects of a CN 6 nuc lesion?
Ipsilateral lateral rectus m & contralateral CN 3 via MLF
Lesion: ipsi eye medially deviated, contra eye can’t adduct when following medially
What deficit occurs with left MLF lesion? How can this be distinguished from L CN 3 lesion?
L eye can’t adduct when tracking to right; with CN3 lesion, also can’t converge
What is internuclear ophthalmoplegia?
MLF lesion, often caused by MS, complaint is diplopia
Where are the eye fields?
Frontal (saccades - post part middle frontal gyrus), occ eye field, temporal eye fields
What is the purpose of the frontal eye fields?
Shift gaze to contralateral side directly through contra PPRF, indirectly through ipsi SC (to contra PPRF)
How do lesions of frontal eye fields present?
“Look at lesion” due to unopposed contra FEF
