Eye functions(external)
Cone-shaped cavity formed by the skull that houses and protects the eye ball.
The Orbital Cavity
Sensitive to dim light
Rods
Nickname for Hyperopia
Farsighted
Lens of eyes gradually becomes cloudy
Frequently occurs in people over 70
Causes a painful, gradual blurring and loss of vision
Pupil turns from black to milky white
Rx – surgical removal of the lens
Cataracts
Circular opening in the choroid coat that
allows light to enter the eye.
Pupil
Movable folds of skin that protect the eye
The Eyelids
Sensitive to bright light and color
Cones
Nickname for Myopia
Nearsighted
Leading cause of vision loss An incurable eye disease
Happens when the small central portion of your retina, called the macula, wears down
Risk factors: Age (55 and over); Genetics—family history; Race—more common in Caucasians; and Smoking
Symptoms: partial loss of vision, abnormality where straight lines appear wavy, blurred vision, loss of central vision
Treatments range from medications, injections into the eye and laser surgery
Macular Degeneration
Circular clear area in front center of the
sclera; “window of the eye”; is transparent and
permits the passage of light rays
Cornea
Produce tears which cleanse and lubricate the eye.
On retina, known as blind spot, nerve fibers form optic nerve here
Optic Disc
Light focuses behind the retina because the eyeball is too short Objects ; must be moved farther away from the eye to be seen clearer Convex lenses help.
Hyperopia
Complication of diabetes that affects the eyes
Caused by damage of the blood vessels of the retina
Symptoms include: Spots or (floaters); Blurred vision;
Impaired color vision; Dark or empty areas in vision and Vision loss ; Can result in blindness
Diabetic Retinopathy
Carries impulses formed by the retina to brain for interpretation.
Optic Nerve
Prevents large particles from entering the eye
Inner most layer of the eye; light rays reflect here to form an image; contains rods and cones
Retina
Irregular curvature of the cornea or lens, causing blurred vision and eye strain
Astigmatism
Ishihara test
Cones are affected
Genetic disorder that is carried by female and transmitted to males
Usually have difficulty
distinguishing between reds, greens and occasionally blues
Color Blindness
Crystalline structure located behind iris and
pupil; separates anterior and posterior chambers;
focuses images on the retina.
Lens
Protective membrane that lines the inside of the eyelids and covers the sclera
Conjunctiva
Tough, outside layer; "white of the eye"; helps maintain shape of the eye.
Sclera
Nickname for Presbyopia
"Old-sightedness"
Inflammation of the conjunctiva
Symptoms are redness, pain, swelling, and discharge
Highly contagious
Rx: antibiotic eye drops
Conjunctivitis or pink eye
Colored, muscular layer that surrounds the pupil.
Iris