Healthy Eyes and Ears
Sclera: white part of the eye. Made of tough, fibrous tissue that protects inner layers of eye
Cornea: Transparent tissue that
bends and focuses light before it enters the lens
Iris: Colored portion of the eye
Pupil: “Black” hole through which light reaches the inner eye . In bright light, the pupil
constricts. In dim light, the pupil enlarges or dilates
Lens: transparent and helps refine the focus of image for the retina
Retina: inner layer of eye wall. Contains rods and cones.
Cones allows us to see color (“C” color)
Rods allow us to see dim light.
Vision
20/20 Vision: Images are produced clearly and sharply on your retina. You can stand 20 feet
away from Snellen eye chart and read the top eight lines
20/60 Vision: Must be 20 feet from the chart to read it the way a person with normal vision can
read it from 60 feet
Vision Problems
Nearsightedness (myopia): the inability to see distant objects clearly
Farsightedness (hyperopia): the inability to see close objects clearly
Glaucoma: cloudy, impaired vision from high pressure inside the eye
Cataracts: foggy vision from lens becoming clouded and cannot focus light
*LASIK surgery: used to precisely change the shape of the dome-shaped clear tissue at the front
of your eye (cornea) to improve vision
Keeping Eyes Healthy
1) Include foods with Vitamin A – such as carrots and sweet potatoes. Helps us to see in dim
light
2) Protect eyes with safety goggles. Wear sunglasses that block UV light
3) Rest eyes regularly
4) Get regular eye exams
5) See medical professional with issues regarding eyes immediately (don’t wait!)
Outer Ear/Auricle: channels sounds into auditory canal
Tympanic Membrane/Eardrum: barrier between outer and middle ear
Malleus/incus/stapes: (hammer, anvil, stirrup): connect eardrum to inner ear
Eustachian tube: connects eardrum to throat
Cochlea: a spiral-shaped canal filled with fluid that helps with hearing in middle ear
Vestibule/Semicircular canals: control balance
How do we hear?
1) Sound waves enter external auditory canal, cause eardrum to vibrate
2) Eardrum vibrates malleus, incus, stapes and vibrates fluid inside cochlea
3) Impulse sent to brain and interpreted as sound
4) Semicircular canals and vestibule maintain balance
Keeping ears healthy
**Keep all foreign objects (including cotton swabs) out of ears
Types of Hearing Loss
1) Conductive Hearing Loss – sounds waves not passed from outer ear to inner ear due to
blockage or injury (ie from middle ear infection)
2) Sensorineural Hearing Loss – inner ear damage causes problems with neural pathways from
ear to brain (usually more permanent than conductive hearing loss)
- Tinnitus: a condition in which a ringing, buzzing, whistling, roaring, hissing or other
sound is heard in the ear in the absence of external sound