Your eyes are amazing machines
but it takes only one small imperfections in the shape of your cornea or the lens to cause fuzzy focusing. Doctors call these imperfections astigmatism, and They're often inherited from parents. Glasses and contact lenses (or corrective surgery) can fix the problem.
WHY DO I BLINK?
humans blink automatically to flush away the stream of cleansing tears produced by ducts in the corners of our eyes. Adults blink about 15 times per minute, but our rate of blinking slows when we read or focus on a distant object. No matter how hard we try not to blink, the need to flush the eyes eventually trumps our willpower as anyone who lost a staring contest will tell you.
WHY DO I CRY!
That depends on the kind of crying you're talking about. Our eyes produce tears of three types...
BASAL TEARS ; flow constantly to keep our eyes from drying out. Our bodies produce about five to ten ounces (148-295 ml) of basal tears each day.
REFLEX TEARS; protect our peepers from irritants in the air , such as smoke and dust.
EMOTIONAL TEARS; flow when our brain registers sadness or stress. Which triggers the release of body chemicals called hormones that turn on the waterworks. Some scientists believe that emotional tears help rid our body of bad chemicals that build during stress which is why you feel better after "having a good cry". With the possible exception of elephants and gorillas ,humans are the only animals that shed tears of this type.
WHY ARE MY TEARS SALTY?
Sodium chloride the most common type of salt is in all your body's fluids :blood,sweat,and (yep) tears contain a little less than one percent salt.
WHY DO MY EYES STING WHEN I SWIM IN THE OCEAN BUT NOT WHEN I CRY?
because seawater contains about three times more slat than your tears. The higher concentration of salt can cause a mild stinging in your eyes even if you wear a mask.
WHAT DOES EACH PART OF MY EYE DO?
Cornea; The eyes protective transparent cover the cornea is similar to the protective glass on a camera lens. It blends the light entering your eye to ore focus the image before it reaches your lens.
PUPIL ; Muscles in the iris control this hole in the center which like a camera shutter allows light to enter the eye and strike the lens. In bright sunlight the pupil contracts to let in less light. In darkness it opens wide to let in as much light as possible.
SCLERA The whites of your eyes sclera from a proctective cover about the size of a ping-pong ball.
LENS Like a projector in a movie theatre , the lens focuses light onto the retina. It's suspended in a muscle that changes the shape of the lens to focus on objects near and far faster than any computerized camera.
OPTIC NERVE; This cable carries visual information from your retina to the brain. Your brain processes the information and translate it into what you're actually seeing.
You must be logged in to post a comment.