Ocular Motility (Done) Flashcards
Abduction & Adduction are rotations about the ____ axis.
Z axis
Elevation & Depression are rotations about the ____ axis.
X axis
Incycloduction (intorsion) & excyclotorsion (extorsion) are rotations about the ____ axis.
Y axis»remember this is the upper portion of the eye that tilts inward or outward
Dextroversion is eye movements to the …
RIGHT
Levoversion are eye movements to the…
LEFT
What are all the actions of the Superior rectus?
Elevation, intorsion, and adduction
|»_space;23 degrees temporal to line of sight
What are all the actions of the Inferior rectus?
Depression, extorsion, and adduction
|»_space;23 degrees to temporal line of sight
What are all the actions of the Superior oblique?
Intorsion, elevation, and abduction
|»_space;54 degrees medial to line of sight
What are all the actions of the Inferior oblique?
Extorsion, elevation, and abduction
|»_space;51 degrees medial to line of sight
What is the Spiral of Tillaux?
describes the line of insertion of the recti muscles on the globe of the eye
Which rectus muscle inserts closest to the limbus? the farthest?
Medial rectus, and Superior rectus
Remember, MILF
What is Listing’s Law?
For 1 eye, the eye must rotate around axes to achieve a given direction of gaze
What 3 systems make it so that the fovea aligns with the object of interest?
- Saccades
- Pursuits
- Vergence system
Which 3 systems focus on holding the image in place on the retina?
- Fixation system
- VOR system
- OKN system
What is the Troxler effect? How is this overcome?
Describes the fading of the peripheral images when the eye is fixated on a central object
»MICROSACCADES stop this from happening
What are the 3 types of movements associated with fixation?
Microsaccades, microtremors, and microdrifts
Which of the 3 types of movements associated with fixation are non-intentional noise?»which one is intentional?
Microtremors and microdrifts are non-intentional noise, while microsaccades are intentional (help eliminate Troxler effect)
Which of the 3 types of movements associated with fixation is the fastest?
Microtremors
What is VOR?
stabilizes images on the fovea during brief head movements by producing an eye movement of equal magnitude to the head movement, but in the OPPOSITE direction
How fast is the VOR? What is the latency?
very fast–300 degrees/ sec with a very small latency of 15 msec
Does the VOR require a visual stimulus in order to occur?
NO. VOR will occur in response to head movement even if the eyes are closed
Will slow growing lesions cause nystagmus?
Generally, NO. Acute lesions will though
If there is damage to the inner ear, what symptoms often accompany this?
Oscillopsia, nausea, and vertigo
If caloric testing is performed, in what movement will the quick phase be if warm water is placed in the right ear?
Slow phase to the left, quick phase to the right
REMEMBER….COWS (cold opposite, warm same)
If caloric testing is performed, in what movement will the slow phase be if cold water is placed in the right ear?
slow phase to the right, quick phase to the left (COWS)
What is the Null point in regards to nystagmus?
the direction of gaze where the nystagmus has the lowest amplitude
Is end-point nystagmus physiological or pathological?
Physiological–no symptoms!
In which binocular dysfunction is latent nystagmus found?
Infantile esotropia
What happens to latent nystagmus when one eye is occluded?
there is an increase in velocity and amplitude
Name 4 types of pathological nystagmus.
- Spasmus nutans (resolves after 2-8 years)
- Convergence-retraction syndrome
- Gaze-evoked nystagmus
- See-saw nystagmus
What is OKN?
OKN maintains a stable image of a MOVING object on the fovea when the head is STILL.
ex. watching a train go by
The nasal to temporal OKN is absent in infants until _____ months of age
3-4 months of age
What is the approximate velocity and latency of saccades, respectively?
1000 degrees/sec and 200 msec latency
Which types of saccades are used while reading?
Microsaccades
Are saccades voluntary or involuntary?
BOTH. Sometimes voluntary, but sudden visual, auditory, or peripheral stimuli may elicit involuntary saccades.
What structure controls saccadic eye movements?
Frontal eye fields
If a patient is performing saccades to the left, which side of the frontal eye fields is controlling this action?
CONTRALATERAL
Damage to the right FEF’s results in impaired saccades towards the _____ side, resulting in the eyes turning toward the ______.
LEFT side, therefore eyes turn to the right side
A TBI to which frontal eye field will yield worse complaints by the patient?
Left side, because this will impact saccades to the right, which will, therefore, affect reading ability
Ocular flutter and opsoclonus are typically associated with _________ disease.
Cerebellar disease
Describe what pursuits are.
slow, tracking movements that allow continuous fixation of the fovea on a MOVING object»CANNOT perform pursuit on a stationary object!
What is the approximate velocity and latency of a pursuit?
Velocity is 50 degrees/sec and latency 125 msec
Which are of the brain controls pursuits? and which side of the brain?
PARIETAL lobe…Ipsilateral side!
What is Tonic vergence?
describes the eyes position of rest at distance without a stimulus to convergence or accommodation
What is Proximal vergence?
A person’s awareness of a near target
What is Fusional vergence?
initiated by retinal image disparity and helps the eyes compensate for a phoria to obtain bifoveal fixation and binocular vision
What is Accommodative vergence?
Initiated by blur and occurs in concert with changes in accommodation
What is the velocity and latency of vergence movements?
Velocity is very slow at 10 degrees/second, while latency is 160 msec
What are some subjective testing methods in order to determine the extent of double vision?
Maddox rod, red lens test, and Hess-Lancaster test
What does it mean if the diplopia experienced by the patient is comitant?
This means that it is likely secondary to a decompensated phoria
If a deviation is non-comitant, what must be performed?
Forced ductions!
If upon performing forced ductions, you find out it is a vertical muscle palsy, which test can you perform to isolate the muscle?
Parks 3 step
Where do we have the patient look if we want to isolate the inferior oblique?
up and in (O’s to the nose)
Where do we have the patient look if we want to isolate the superior oblique muscle?
Depression and looking inwards (O’s to the nose)
Where do we have the patient look if we want to isolate the superior rectus?
Elevation and looking away from the midline
Where do we have the patient look if we want to isolate the inferior rectus?
Depression and looking away from the midline
IO palsies cause patients to have a head tilt _________ side of the lesion.
Toward (same side as the lesion)–unlike a SO palsy
What is the affected muscle in Brown’s syndrome?
SO muscle and tendon or abnormality of the trochlea
What are some characteristics of Brown’s syndrome?
Typically unilateral, small hypotropia in primary gaze, limited elevation during aDduction
What are some characteristics of Duane’s retraction syndrome among all types?
globe retraction, narrowing of palpebral fissure w/ aDduction, and patients commonly present w/ esotropia in primary gaze
