EYES I Flashcards
LIGHT REACTION
A light beam shining onto one retina causes _______ in that eye, termed the direct
reaction to light, and in the contralateral eye, the
consensual reaction to light.
pupillary constriction
Near reaction
When a person shifts gaze from a far object to a near object, the pupils constrict This
response, like the light reaction, is mediated by the
___________ nerve. Coincident with this pupillary
constriction, but not part of it, are (1) ________ of the
eyes, a bilateral medial rectus movement; and (2) _____, an increased convexity of the lenses
caused by contraction of the ciliary muscles.
occulomotor nerve
convergence
accomodation
EXTRAOCULAR MOVEMENTS
Nerve damage or injury to the muscle, due to head
trauma, congenital causes, or central lesions, can cause
aberrations in this yoked system and lead to ___________.
diplopia (double vision)
vision changes
Difficulty with close work suggests _________
(farsightedness) or _______(aging vision), and,
difficulty with distance vision, suggest ________
(nearsightedness).
hyperopia
presbyopia
myopia
vision changes
If painful, causes are usually in the cornea and anterior
chamber such as corneal ulcer, uveitis, traumatic
__________, and acute angle closure glaucoma.
hyphema
double vision
__________is seen in lesions in the brainstem or
cerebellum and with weakness or paralysis of one or
more extraocular muscles,
as in _________ diplopia from
palsy of CN III or VI
______diplopia from palsy of CN
III or IV.
Diplopia in one eye, with the other closed,
suggests a problem in the ocular surface, cornea, lens,
or macula.
diplopia
horizontal
vertical
VISUAL DEFECTS
Occlusion of a branch of the central retinal artery may cause a horizontal altitudinal) defect. Ischemia of the optic nerve can produce a similar defect.
horizontal defects
VISUAL DEFECTS
A lesion of the optic nerve and, of
course, of the eye itself, produces unilateral monocular blindness.
blind right eye (right optic nerve)
VISUAL DEFECTS
A lesion at the optic chiasm (such as a pituitary tumor), may involve only fibers crossing over to the opposite side.
Since these fibers originate in the nasal half of each retina, visual loss involves the temporal half of each field.
bilateral hemianopsia
VISUAL FIELD DEFECTS
A lesion of the optic tract, interrupts fibers originating on the same side of both eyes.
Visual loss in the eyes is, therefore, similar (homonymous) and involves half of each field (hemianopsia).
left homonymous hemianopsia
VISUAL FIELD DEFECTS
A partial lesion of the optic radiation in the temporal
lobe, may involve only a portion of the nerve fibers, producing, for
example, a homonymous quadrantic (“pie in the sky”) defect.
homonymous left superior quadratic defect
VISUAL FIELD DEFECT
A complete interruption of fibers in the optic radiation, produces a visual defect similar to that produced by a lesion of the optic tract.
left homonymous hemianopsia
Variations and Abnormalities of
the Eyelids
________ is a drooping of the upper lid. Causes include senescence, myasthenia gravis, damage to the oculomotor nerve (CN III), and damage to the sympathetic nerve supply (Horner syndrome).
A weakened muscle, relaxed
tissues, and the weight of herniated fat may cause senile _________.
________ may also be congenital
ptosis
VARIATIONS AND ABNORMALITIES OF THE EYELIDS
______ more common in the elderly, is an inward turning of the lid margin.
The lower lashes, which are often invisible when turned inward, irritate the conjunctiva and lower cornea
This is different from _______where there is aberrant inward growth of the eyelashes, but the eyelid position remains normal.
entropion
trichiasis
EYELID VARIATIONS AND ABNORMALITIES
In __________, the lower lid margin turns outward, exposing the palpebral
conjunctiva. When the punctum of the lower lid turns outward, the eye no longer drains well, and tearing occurs.
_______ is also more common in
older adults.
entropion
trichiasis
