Examination of Ocular Movement and Pupillary Function Flashcards
what is convergence?
visual axis = not parallel
point of fiation = closer than infinity
eyes adduct –> <–
where do the L retus, I rectus, S rectus & M rectus converge at?
Annulus of Zinn
where do M & L rectus muscles move to?
M & L rectus
* Adduct/adbduct the eye
* rotation of eye around vertical axis
where do S & I rectus muscles move to?
S rectus - upward along lateral axis
I rectus = depresses eye, adduct the eye
where is the origin of S & I oblique?
S oblique = lesser wing of sphenoid bone
I oblique = medial inferior rim of bony orbit
What are the innervations of the EOM?
LASOT
Lateral rectus abducense nerve (CN VI)
Superior oblique trochlear nerve (CN IV)
the rest = CN III (oculomotor nerve)
what are the functions of the I oblique?
elevates the eye
abducts the eye
extors the eye
ues
is there always a light tension in the EOM whern the eye is in primary position?
yes
in times of paralysis, which direction does the eye deviate to?
- toward direction of the intact muscle
- paralysis distrupts tonic innervations => lack of tension
during inspection of the eye, what should be observed?
relation of limbus of the eye to the lid margins as the px gazes straight ahead
what is the hirschburg test & what is it for?
aka Corneal light reflex test
to check for ocular malignment
what should we take note when doing the hirschburg test in children/pedia px?
medial canthus looks diff so it might look like Strabismus
what is seen in ocular malalignment?
- abnormal relation of corneal limbus to margin of eyelids
- noncorrespondence of points of conreal light reflection
after inspecting the eyes in primary position & range of movement, what test is done?
Cover-uncover test
what is the normal presentation in normal px in doing Cover-Uncover test?
eye is covered and uncovered
we shouldnt see any movements of the eye from mid-position
what are alignment problems with vertical axis?
- Esotropia = abnormal eye tends to deviate inward
- Exotropia = abnormal eye tends to deviate outward
what alignment problems with horizontal axis is seen in Cover-uncover test?
- Hypertropia = abnormal eye tends to deviate upward
- Hypotropia = abnormal eye tends to deviate downward
what are the 3 muscles used in Accommodation reflex?
Convergence = Medial recti msucles
Pupilloconstriction = Pupilloconstrictor muscle of the iris
Lens thickening = Ciliary muscle (Smooth muscle, parasympathetic)
what are the determinants of pupil size?
- local disease of the eye
- drugs
- emotions
- sleep/drowsiness
- age
- autonomic nervous system = parasympathetic & sympathetic
what is the action of the eye during parasympathetic & sympathetic denervation?
Parasympathetic = pupillary dilation
Sympathetic = pupillary constriction
what are the 4 abnormal findings in pupillary exmination?
- Anisocoria = diff color of the eye
- Hippus = oscillation of th eborders of the pupil
- Keyser-Fleishcer ring = brownish to gray-green rings
- Dilation lag = one pupil dilates slower than the other
Dilation lags notes what?
there is sympathetic innervation problem of the eye
Horner’s syndrome, Adie’s tonic pupil
what is checked in direct & consensual pipillary light reflex?
dilation & constriciton of pupils at the same time if one eye is only receiving the stimuli
Normal: one eye directly receives the light => other pupil should consen
what is checked in direct & consensual pipillary light reflex?
dilation & constriciton of pupils at the same time if one eye is only receiving the stimuli
Normal: one eye directly receives the light => other pupil should consen
what happens in direct & consensual light reflex?
- direct light reflex = direct constrictin of the pupil stimulated by light
- consensual light reflex = constriciton of the opposite pupil
what eye test is done to check for problems w/ direct or consensual light reflex?
swinging flashlight test
what is an important abnormality seen in swinging flashlight test?
Relative afferent pupillary defect OR
Marcus-Gunn pupil
Problems of the optic nerve
what muscles are affected by Ptosis?
- Superior tarsal msucles - carotid sympathetic nerve
- Levator palpebrae muscle - CN III
Can paralysis cause a more severe ptosis than superior tarsal msucle paralysis?
yes
in what clin conditions can you see ptosis?
congeintal ptosis
Myasthenia gravis
Horner’s syndrome
