Ocular Motor Disorders Flashcards
Not all ___ ___ is caused by muscle problems. Not all ___ ___ cause double vision.
- double vision
- muscle problems
When assessing double vision, things to consider.
- is it constant or intermittent?
- is it horizontal or vertical?
- is it comitant or non-comitant?
Instead of using plegia and paresis, ____ and ____ are used to describe the state of muscle function. What do these suffixes mean?
- tropia= happens all the time, paralysis or over action of the muscles.
- eye drifts even when the person is focusing on a target..if long standing they may “Suppress” the sight in one or both eyes.
-phoria= intermittent and during rest, the rest position of the muscles.
Prefixes indicate the direction of misalignment. What do each of the following mean?
- Eso
- Exo
- Hyper
- Hypo
eso= inward (crossed eyes), esophoria or esotropia
exo= outward (wall eyed), exophoria, exotropia
hyper= upward, hyperphoria or hypertropia
hypo=downward, hypophoria or hypotropia
Which cranial nerve and nerve fibers constrict and dilate the pupil?
Cranial nerve III constricts the pupil through its PARASYMPATHETIC fibers taht supply the smooth muscle of the ciliary boddy and the sphincter of the iris.
Cranial nerve III dilates the pupil through its SYMPATHETIC fibers that supply the smooth muscle of the ciliary body and the sphincter of the iris.
Clinical Presentation of Aquired CNIII Palsy
- sudden onset of binocular horizontal, vertical, or oblique diplopia
- ptosis
Clinical presentation of Congenital CN III Palsy
- found in young children
- may not complain of diplopia because they suppress the second image or because they have superimposed amblyopia
- parents notice ptosis or strabismus
- amblyiopia
Eye Exam Findings of CN III Palsy
- partial or complete ptosis
- pupil may be dilated and poorly reactive, or dilated and non-reactive to light
- deficits in ipsilateral adduction, elevation, and/or depression
CN III is considered complete if _______?
if impairment of the majority of function of all the somatic branches of oculomotor nerve is present and ptosis is complete or almost complete.
Complete CN III Palsies are usually associated with _____, _____, and ____.
- large angle extropia
- hypotropia
- ptosis
complete= eye down & out with ptosis
Complete CN III Palsy involving the pupil indicates what type of cause? How about not involving the pupil?
- Compressive lesion (tumor or aneurysm) will almost always involve the pupil.
- Ischemic palsy (microvascular disease) will not likely involve the pupil.
CN III Palsy Differential Dx
- Vasculopathic: HTN or DM
- Tumor
- Congential
- Aneurysm
What is the “Parks Three Step” in isolating the paretic EOM.
- ) Which eye is highest in the primary gaze?
- ) Which head turn increases vertical disparity?
- ) Which head tilt increase vertical disparity?
What is unique about CN IV?
- has the longest intracranial course and is the only cranial nerve that has a dorsal exit from the brainstem.
- this renders it prone to injury from blunt head trauma or compression from changes in intracranial pressure, brain tumors, or swelling anywhere along its course.
CN IV Palsy Clinical Presentation
- binocular vertical diplopia and/or subjective tilting of objects (torsional diplopia)
- objects viewed in primary position or especially in down gaze appear double (going down flight of stairs)
- pt may adapt an anomalous head position to avoid diplopia because torsional and vertical diplopia improve with head tilting to the side OPPOSITE the paralyze muscle.*
