eye Flashcards
the eye is
sensory organ of vision
palpebral fissure
the elliptical open space between the eyelids
the lower eyelid margin is at the ____-
limbus
the corner of the eye is the _____
canthus
exposed part of the eye has a transparent protective calling which is the _____
conjunctiva
the palpebral conjunctiva ….
lines the eyelids and is clear with many small blood vessels
tears drain into the ______
puncta
4 straight (or rectus) muscles are . . .
superior, inferior, lateral, and medial
2 slanting (or oblique) muscles are the . . .
superior and inferior
movement of the extraocular muscles is stimulated by _________
3 cranial nerves
cranial nerve VI ________ the eye
innervates
cranial nerve IV __________ the eye
innervates superior oblique muscle
Cranial nerve III innervates ______
all others; superior, inferior, medial rectus and inferior oblique
sensitive to touch, contact with a wisp of cotton stimulates a blink in both eyes
cornea
cranial nerve ___ carries the afferent sensation into the brain
V
cranial nerve __ carries the efferent message that stimulates the blink
VII
has dark pigmentation to prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina
choroid
functions as a diaphragm, varying the opening at its centre, controlling the amount of light admitted into the retina
iris
size of the ____ is determined by a balance between the parasympathetic and sympathetic chains of the autonomic nervous system
pupil
a transparent biconvex disc located just behind the pupil
lens
posterior to the cornea and anterior to the iris and lens
anterior chamber
lies behind the iris to the sides of the lens
posterior chamber
the visual receptive layer of the eye in which light waves are changed into the nerve impulses
retina
area in which fibres from the retina converge to form the optic nerve
optic disc
normally include a paired artery and vein extending to each quadrant, growing progressively smaller in calibre as they reach periphery
retinal vessels
located on the temporal side of the fundus,
macula
_____ transforms the light stimulus into nerve impulses that are conducted through the optic nerve and the optic tract to the visual cortex of the occipital lobe
retina
all _____ ______ collect to form the optic nerve, but they maintain this same spatial arrangement with nasal fibres running medially and temporal fibres running laterally
retinal fibres
the right side of the brain looks at the _____ side of the world because _____ fibres cross over at the optic chiasm
left, nasal
the normal constriction of the pupils when bright light shines on the retina
pupillary light reflex
pupillary light reflex is a subcortial _________
reflex arc
stimulation of the blind eye causes no response because the sensory afferent in cranial nerve ____ is ______
II is destroyed
the adaptation of the eye for near vision
accommodation
when visual acuity falls it is essential for nurses to assess the risk for
falls, social isolation, and the impact on relationships
the leading cause of blindness in Canada, the breakdown of cells in the macula of the retina resulting in loss of central vision and area of clearest vision
age related macular degeneration
lens opacity, results from a clumping of protein in the lens
cataract formation
increased intraocular pressure
glaucoma
leading cause of visual impairment in people younger than 65, is highest in diabetic patients with concurrent proteinuria
diabetic retinopathy
medications that have ocular adverse effects
systemic and topical
blind spot in the visual field surrounded by an area of normal or decreased vision, occurs with glaucoma and with disorders of optic nerve pathway
scotoma
the inability to tolerate light
photophobia
perception of two images of a single object
diplopia
most commonly used and accurate measurement of visual acuity
snellen eye chart
in the snellen eye chart exam the larger the denominator the ______ the vision
poorer
if pt moves card away while reading this could be a sign of
presbyopia
the confrontation test measures
peripheral vision
corneal light reflex assess’s the
parallel alignment of the eye axes by shining a light toward the pt eyes
the cover-uncover test detects
small degrees of deviated alignment by interrupting the fusion reflex that normally keeps the two eyes parallel
diagnostic positions test assess’s
any muscle weakness by leading the eyes through six cardinal positions of gaze
a fine oscillating movement best seen around the iris, assessed in addition to parallel movement
nystagmus
PERRLA
Pupils are Equal, Round, Reactive to Light, and Accommodate
red reflex with the ophthalmoscope is caused by
the reflection of ophthalmoscope light off the inner retina
normal range of finding for the optic disc are
creamy yellow-orange to pink, round or oval, distinct and sharply demarcated
normal range of findings for the retinal vessels include
a paired artery and vein pass through each quadrant, arteries are brighter red than veins, arteries and veins show a regular decrease in calibre as they extend to the periphery
