Eye movement disorders - classifications Flashcards
what are the 4 general categories of eye movement disorders?
binocular diplopia, diplopia sub-type INO, gaze palsy, and nystagmus
what is binocular diplopia?
patient see double with both eyes open - goes away when they close one eye (eyes are out of alignment)
what is diplopia sub-type INO?
internuclear ophthalmoplegia = specific type of EOM anomaly that may or may not have diplopia in some positions
what is a gaze palsy?
fusion is usually present but the eyes cannot move into certain positions of gaze
what is nystagmus?
specific type of unsteady fixation characterized by slow movement in one direction and a fast movement in other direction
what are the 3 main layers/levels that control eye movements?
supranuclear level, premotor level, and the final common pathway
what is the supranuclear level for controlling eye movements?
structures in the cortex for saccades, pursuits, OKN, and VOR (cortical and subcortical) and control pre-motor nuclei
what is the pre-motor level for controlling eye movements?
organize eye movements by coordinating the nuclei that control the muscles = riMLF, PPRF, vestibular nuclei
what is the final common pathway for controlling eye movements?
the cranial nerves that control movements = CN3, CN4, CN6
what are 3 locations that pathology can occur for EOM functions?
in a muscle, in the synapse between a nerve ending and the muscle, and in the orbit
what are 3 locations that pathology can occur for a nerve that controls EOMs?
in the brainstem nucleus (midbrain or pons), interstitial compartment in the brainstem, and in the space where the axons exit the brain
what are the 4 locations of pathology for the pre-motor structures that control EOM location?
PPRF (horizontal), riMLF (vertical), vestibular nuclei (CN8), MLF (internuclear)
what are the 4 locations of pathology for the structures that control and maintain fixation?
semicircular canals, CN8, vestibular nuclei, and cerebellum (especially the flocculonodular lobes)
what are the 3 locations of pathology for the higher order supranuclear structures?
superior colliculus, frontal eye fields (frontal lobe - saccades), occipital eye fields (pursuits)
what is the general symptom/sign for pathology in the orbit, EOM, or synapse?
diplopia
what is the general symptom/sign for pathology in the nucleus or nerve?
diplopia
what is the general symptom/sign for pathology in the pre-motor structures?
INO
what is the general symptom/sign for pathology in the supranuclear structures?
gaze palsy
what is the general symptom/sign for pathology in the vestibular system and CN8?
nystagmus
what structures are present in the orbit?
EOMs, nerves, fascia, connective tissue
what structures are present in the orbital apex?
superior orbital fissure and optic canal
what structures are present in the nerve?
subarachnoid space, circle of willis, cavernous sinus, superior orbital fissure and posterior orbit
what structures are present in the nerve nucleus and interstitial axons (midbrain)?
descending pyramidal system rostral to the decussation and red nucleus (motor system)
what structures are present in the nerve nucleus and interstitial axon (pons)?
descending pyramidal system rostral to the decussation, vestibular nuclei, and cerebellum is nearby
what structures are present in the pre-motor (brainstem)?
MLF, SC, vestibular system, and cerebellum
what structures are present in the pre-motor (supranuclear)?
frontal and occipital lobes
what structures are present in the vestibular system and CN8?
facial nerve, auditory system, descending pyramidal system rostral to decussation
what are the associated signs and symptoms for the orbit?
space-occupying lesion and CN5
what are the associated signs and symptoms for the orbital apex?
space-occupying lesion and CN2
what are the associated signs and symptoms for the nerve?
aneurysm, space-occupying lesion and inflammation
what are the associated signs and symptoms for the nerve nucleus and interstitial axons (midbrain)?
contralateral voluntary somatic movement and incoordination
what are the associated signs and symptoms for the interstitial axons (pons)?
contralateral voluntary somatic movement, incoordination, dysmetria, imbalance, and dizziness
what are the associated signs and symptoms for the pre-motor (brainstem)?
incoordination, dysmetria, imbalance and dizziness
what are the associated signs and symptoms for the pre-motor (supranuclear)?
aphasia, psychological, and VF defects
what are the associated signs and symptoms for the vestibular system and CN8?
contralateral voluntary somatic movement, facial asymmetry, reduced auditory sensitivity
