How is visual field testing of each of the 4 quadrants best conducted?
visual field by confrontation
sit in front of patient and close opposite eye
count fingers in each of 4 quadrants
bring fingers in towards center of visual field
compare against own visual field
What is the name of the diagnostic tool that tests for metamorphopsia?
Amsler grid (square grid)
What are the small object tests for optic nerve dysfunction?
test each eye separately
If optic nerve is damaged, what is the one of the first things besides vision loss, that becomes noticeable in a vision test?
loss of seeing red color
test each eye separately
to patients, red objects will appear more faded than in normal eye
afferent along optic nerve (CN II); splits at optic chiasm; both enter pretectal nuclei; enters Edinger-Westphal and 3rd cranial nerve nuclei; efferent along parasympathetic fibers of 3rd cranial nerve to pupillary muscles of both eyes
What is the swinging flashlight test?
3 to 5 seconds in front of each eye with rapid change from one eye to the other (in dimmed room)
normal = initial pupillary constriction followed by variable amounts of redilation
abnormal = slow dilation without initial constriction (due to optic nerve damage or large retinal lesions)
know the difference between afferent and efferent defects
What is left afferent pupillary defect if light is shone into left and right eyes separately?
when light is shone into right eye right eye constricts left eye constricts i.e. no efferent defect
when light is shone into left eye right eye constricts a small amount left eye constricts a small amount i.e. afferent defect prevents left eye from 'seeing' and reacting to the penlight
What is left efferent pupillary defect if light is shone into left and right eyes separately?
when light is shone into right eye right eye constricts left eye does not constrict i.e. efferent defect in left eye, cannot effect a pupillary change (CN III palsy)
when light is shone into left eye right eye constricts left eye does not constrict i.e. efferent defect prevents left pupil from constricting
What is the term for unequal pupils?
An abnormally dilated pupil is usually due to an efferent defect. T/F?
CN III palsy - unable to constrict pupillary muscles despite afferent pathways being intact
can be due to compression of CN III from trauma, hernia or aneurysm
What is the most common cause of pupil abnormality?
dilated pupil with droopy eyelid (ptosis) and double vision
Why is pupillary constriction affected first during any type of compressing defect on CN III?
pupillary nerves are on outside of CN III
What is Adie's tonic pupil?
ciliary ganglion dysfunction in an otherwise healthy person
0.1% pilocarpine will constrict pupil (does not normally constrict pupil)
What class of medications are used to treat abnormally dilated pupils?
works against parasympathetic system
What is the name of the syndrome with unilateral miosis?
ptosis, miosis, anhidrosis due to sympathetic chain dysfunction
miosis = small pupil anhidrosis = lack of sweating
Horner's syndrome can be due to life threatening causes. T/F?