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Two movable structures composed of skin and two types of muscle: striated and smooth
Eyelids
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Protect the eye from foreign bodies and limit the amount of light entering to the eye.
Eyelids
They serve to distribute tears that lubricate the surface of the eye
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The ___ eyelid is larger, more mobile, and contains tarsal plates made up of connective tissue
Upper
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Secrete an oily substance that lubricates the eyelid
Meibomian glands
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The eyelids join at two points. What are they?
- Lateral (outer) canthus
- Medial (inner) canthus
-
Contains the puncta and caruncle
Medial canthus
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Two small openings that allow drainage of tears into the lacrimal system
Puncta
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A small, fleshy mass that contains sebaceous glands
Caruncle
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The white space between open eyelids
Palpebral fissure
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The point where the sclera meets the cornea
Limbus
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T or F: When the eyelids ope, the upper eyelid should be between the upper margin of the iris and the upper margin of the pupil
True
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T or F: The lower lid should rest on the upper border of the iris.
No sclera should be seen above or below the limbus
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Are projections of stiff hair curving outward along the margins of the eyelids that filter dust and dirt from air entering the eye
Eyelashes
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A thin, transparent, continuous membrane that is divided into two portions.
Conjunctiva
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Lines the inside of the eyelids
Palpebral conjunctiva
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Covers most of the anterior eye, merging with the cornea at the limbus
Bulbar conjunctiva
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Consists of glands and ducts that lubricate the eye
Lacrimal apparatus
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Located in the upper outer corner of the orbital cavity just above the eye, produces tears
Lacrimal gland
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Sequence of tears from the eyes
Eyes - puncta - lacrimal canals - nasolacrimal sac - nasolacrimal duct - nasal meatus
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The six muscles attached to the outer surface of each eyeball
Extraocular muscles
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Innervation of the muscles of the eyes is supplied by three cranial nerves:
Oculomotor (III), trochlear (IV), abducens (VI)
-
A dense, protective, white covering that physically supports the internal structures of the eye
Sclera
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The window of the eye
Cornea
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Permits the entrance of light, which passes through the lens to the retina
Cornea
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Consists of muscle tissue that controls the thickness of the lens, which must be adapted to focus on objects near and far away
Ciliary body
-
A circular disc of muscle containing pigments that determine eye color
Iris
-
Controls the amount of light entering the eye
Iris
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For near vision, the pupil ____
Constrict
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For far vision, the pupil ____
Dilate
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Biconvex, transparent, avascular, encapsulated structure located posterior to the iris
Lens
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______ attached to the ciliary body support the position of the lens
Suspensory ligaments
-
Functions to refract light rays onto the retina
Lens
-
Refractive ability of the lens can be changed by a change of
shape of the lens
-
Changing the shape of the lens is controlled by the
Ciliary body
-
The lens ___ to focus on close objects and ____ to focus far objects
bulges, flattens
-
Contains the vascularity necessary to provide nourishment to the inner aspect of the eye and prevents light from reflecting internally
Choroid layer
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Receives visual stimuli and send it to the brain
Retina
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Highly sensitive to light, regulate black and white vision, and function in dim light
Rods
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Function in bright light and are sensitive to color
Cones
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A cream-colored, circular area located on the retina toward the medial or nasal side of the eye
Optic disc
- Can be seen using ophthalmoscope
- Normally round or oval in shape, with distinct margins.
-
A smaller circular area that appears slightly depressed is referred to as the
physiologic cup
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A retinal depression located adjacent to the optic disc in the temporal section of the fundus
Fovea centralis
Surrounded by the macula, which appears darker than the rest of the fundus
Highly concentrated with cones and form the area of highest visual resolution and color vision
-
Located between the cornea and iris
Anterior chamber
-
Located between the iris and lens
Posterior chamber
-
Contains several chamber that maintain structure, protect against injury, and transmit light rays
Eyeball
-
Helps cleanse and nourish the cornea and lens as well as maintain intraocular pressure (IOP)
Aqueous humor
-
Located in the area behind the lens to the retina. It is the largest of the chambers.
Vitreous chamber
-
Refers to what a person sees with one eye
Visual field
- Divided into four quadrants:
- Upper temporal
- Lower temporal
- Upper nasal
- Lower nasal
-
Occurs as light rays strike the retina, where they are transformed into nerve impulses
Visual perception
-
Causes pupils to constrict immediately when exposed to bright light
Pupillary light reflex
-
Exposure to light in one eye results in constriction of the pupil in the opposite eye
Indirect or consensual reflex
-
A functional reflex allowing the eyes to focus on near objects
Accommodation
-
Used to measure pressure within the eye
Tonometry
-
Normal eye pressure
10 - 21 mmhg
-
Processes sharp, clear, straight-ahead vision
Macula
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A clouding of the usually clear lens of the eye, causing a person to see as though looking through a frosty or foggy window
Cataract
Other symptoms include fading or yellowing of colors, sensitivity to light and glare, seeing halos around lights, double vision in a single eye
-
Used to test distant vision acuity
Snellen chart
-
It is used if the client cannot read or has a handicap that prevents verbal communication
E chart
-
A hand-helf instrument that allows the examiner to view the fundus of the eye by the projection of light through a prism that bends light 90 degrees
Opthalmoscope
-
Each lens is labeled with a negative or positive number, a unit of strength called
Diopter
-
Indicate a negative diopter and are used for myopic (near-sighted) clients
Red numbers
-
Indicate a positive diopter and used for hyperopic clients
Black numbers
-
Is used if neither the examiner nor the client has refractive errors
Zero lens
-
Normal distant visual acuity
20/20
-
Is present when the second number in the test result is larger than the first (20/40)
Myopia
The higher the second number, the poorer the vision
-
Use this test for middle-aged clients and others who have difficulty with near vision or with reading
Test near visual acuity
-
Normal near vision acuity
14/14
-
Is indicated when the client moves the chart away from the eyes to focus on the print
Presbyopia (impaired near vision)
Caused by decreased accommodation
-
Normal visual field degrees are approximately as follows:
- Inferior: 70
- Superior: 50
- Temporal: 90
- Nasal: 60
-
This test assess parallel alignment of the eyes
Corneal light reflex test
-
This test detects variation in alignment or strength and slight deviations in eye movement by interrupting the fusion reflex
Cover test
-
Normally keeps the eye parallel
Fusion reflex
-
A term used to describe misalignment that occurs only when fusion reflex is blocked
Phoria
-
Constant misalignment of the eyes
Strabismus
-
A specific type of misalignment
Tropia
- Esotropia - an inward turn of the eye
- Exotropia - an outward turn of the eye
-
Assesses eye muscle strength and cranial nerve function
Cardinal fields of gaze test
-
An oscillating movement of the eye, may be associated with an ear disorder, multiple sclerosis, brain lesions, or narcotics use.
Nystagmus
-
Drooping of the upper lid
Ptosis
May be attributed to oculomotor damage, myasthenia gravis, weakened muscle or tissue, or a congenital disorder
-
Retracted lid margins, which allow for viewing of the sclera when the eyes are open
Hyperthyroidism
-
Raised yellow plaques located most often near the inner canthus
Xanthelasma
A normal variation associated with increasing age and high lipid levels
-
An inverted lower lid
Entropion
May cause pain and injure the cornea as the eyelash brushes against the conjunctiva and cornea
-
An everted lower eyelid
Ectropion
Results in exposure and drying of conjunctiva.
-
Redness and crusting along the lid margins suggest
Seborrhea and blepharitis
An infection caused by staphylococcus aureus
-
A hair follicle infection, causes local redness, swelling, and pain.
Hordeolum
-
An infection of the meibomian gland, may produce extreme swelling of the lid, moderate redness, but minimal pain
Chalazion
-
Protrusion of the eyeballs accompanied by retracted eyelid margins
Exophthalmos
A charac. of Graves disease
-
A sunken appearance of the eyes may be seen with
- Severe dehydration
- Chronic wasting illness
-
Generalized redness of the conjunctiva
Conjunctivitis
-
Areas of dryness in sclera
Allergies or trauma
-
An excellent place to look for signs of jaundice or icterus
Sclera of the eye
-
Yellowish nodules on the bulbar conjunctiva are called
Pinguecula
Harmless nodules common in older clients and appear first on the medial side of the iris and then on the lateral side
-
Cultural consideration
Dark-skinned clients may have sclera with yellow or pigmented freckles
-
A local, noninfectious inflammation of the sclera
Episcleritis
Nodular appearance or redness with dilated vessels
-
Bright red areas on the sclera
Subconjunctival hemorrhage
Caused by sneezing, coughing, vomiting. Harmless and disappears in 1-2 weeks
-
Cyanosis of the lower lid suggests a
lung disorder
-
Excessive tearing may indicate a
lacrimal sac obstruction
-
opacities of the lens are seen with
Cataracts
-
A normal condition in older clients, appears as a white arc around the limbus
Arcus senilis
No effect on vision
-
Inequality in pupil size of < 0.5 mm occurs in 20% of clients
Anisocoria
Normal finding
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