Eye Movements I & II Flashcards
There’s a kind of eye movement called pursuit. What is it?
Dr. Caldwell refers to this as “foveating.” It is the act of putting both foveas on an object to track it.
Describe the type of eye movement called saccade.
Rapid and ballistic movements – which can be as fast as 700° per second – during which visual input to the cortex ceases.
While reading, we focus on a point and see ______ letters to the left and ________ letters to the right. We move about eight letters at a time.
4; 15
Explain the movement patterns of nystagmus.
Nystagmus means slow movement one direction (say, left), followed by rapid, saccadic movement in the opposite direction (so, right)
Nystagmus is described as either ___________ or ___________.
right-beating (fast right); left-beating (fast left)
The pupils ___________ during convergence.
constrict
Smooth pursuit can go as fast as ___________.
50° per second
Saccadic eye movements are controlled by what nucleus?
The frontal eye field (FEF)
The vestibular-ocular reflex can be tested by ____________.
asking someone to fixate on a point and then rotating their head
Rapidly jerking eye movements are called _____________.
opsoclonus
Opsoclonus does not result from ___________.
brain or nerve damage; it is a paraneoplastic disorder
Know the difference between INO and MLF lesions.
Ok!
The fovea covers about ______ of the visual field.
5°
Why do the pupils constrict during accommodation?
To increase depth-of-field
The ____________ drives the saccadic eye reflex.
superior colliculus
Where is the frontal eye field?
Just anterior to the head position in the primary motor cortex
Damage to the __________ will result in a temporary ability to generate saccades. Loss of the _________ results in decreased accuracy of the saccades. Loss of both results in permanent inability to generate saccades.
frontal eye field; superior colliculus
True or false: horizontal saccades are generated ipsilaterally.
False
Reflexive saccades are mediated by the __________ lobe.
parietal
Ipsilateral vestibular activation leads to activation of the ______________ motor nuclei.
contralateral
Internuclear neurons serve as ____________ for horizontal gaze movements.
pattern generators
Internuclear ophthalmoplegia, a condition common in multiple sclerosis, presents with what defect in eye movement?
Inability to coordinate medial and lateral recti in horizontal gaze but still able to converge eyes (indicating that the medial recti are intact, but the MLF is damaged).
