Eye Movement Disorders Flashcards
Four classifications of eye movement disorders:
- Bino diplopia
- INO (internuclear ophthalmoplegia)
- Gaze palsy
- Nystagmus
Bino diplopia -
Both eyes open, pt sees double all the time or sometimes
Misalignment of eyes
INO -
Specific type of EOM that may or may not be accompanied by diplopia in some positions of gaze
Gaze palsy -
Fusion usually present but the two eyes together cannot move into certain positions of gaze
Nystagmus -
Unsteady fixation: slow movements (pursuits) in one direction followed by fast movements (saccades) in the other direction
Layers of neurological systems for the control of eye movements:
- Muscles
- Final common pathway (CN)
- Pre-motor nuclei (organizes eye movements)
- Supranuclear structures (control the nuclei)
- Systems to maintain fixation
How many pairs of muscles to control eye movements?
6 pairs = 12 EOMs
Pathology of EOMs locations:
- Muscles
- Synapse btwn muscles and nerves
- Orbit
Pathology of a nerve ( EOMs locations)
- Brainstem nuclei (midbrain or pons)
- Interstial compartment
- Space from exit of axons from brain to muscles
Pathology of pre-motor structures (nerve nuclei > nerves > EOMs locations)
- PPRF (horizontal)
- riMLF (vertical)
- Vestibular nuclei (CN8)
- MLF - internuclear
Pathology of structures that control nuclei and EOMs to maintain fixation (pre-motor) locations:
- Semicircular canals
- CN8
- Vestibular nuclei
- Cerebellum (esp flocculonodular lobes)
Pathology of supranuclear (pre-motor > nerve nuclei > nerves > EOMs locations)
- Superior colliculus
- Frontal eye fields (saccades)
- Occipital eye fields (pursuits)
Symtoms/signs by location of pathology:
EOM, orbit, synapse, nerve, nerve nuclei
Diplopia
Symtoms/signs by location of pathology:
Pre-motor structures
INO and gaze palsy
Symtoms/signs by location of pathology:
Supranuclear structures
Gaze palsy
