O beijo que você deu.

Taking Care Of Your Eyesight

You tune up your engine every six months, defrag your hard drive with Swiss precision and wax your snowboard to a perfect sleek smoothness. But what about your eyes? Do you give your most sophisticated and delicate physical equipment the same care you give your gadgets?

Your eyes are your first interface to the world. But they need to be maintained, especially in a world replete with hazards. Here's all you need to know if you want to keep your vision as sharp as an eagle's.

measuring eyesight quality

You've heard the term 20/20 to describe healthy vision. But do you know what it means? It's a standard devised to measure someone's eyesight relative to the average. If you have 20/20 vision, it means that from 20 feet away, you can see what the average person sees from 20 feet.
Few people have this supposedly "normal" vision, considering that 61% of Americans wear some form of corrective lenses.

People with poor eyesight have a higher second number. A person with 20/40 vision can only see from 20 feet what a person with normal vision can see from 40 feet. 20/200 vision is considered legally blind in the U.S.

You can also have better-than-average vision, like 20/10. This is measured with eye charts containing letters that diminish in size, such as the Snellen eye chart.

A few online vision tests exist, but they have the credibility of personality quizzes. You should only trust a professional's opinion.

causes of eye damage

Your eyes are under constant attack by numerous harmful elements. Luckily, your eyes have good defense mechanisms that neutralize them. But even the most stalwart shield will fail after being hit with enough bullets; it's long-term exposure that damages your vision.
The following factors can damage your eyes in the long run:

Ultra-violet rays
These come from the sun and man-made sources, such as tanning booths and electric welding arcs. UV rays can burn the cornea and damage internal components of the eye like the lens and the retina. This increases the risk of cataract and other eye disorders.

Smoking
The chemicals in cigarettes can harm the most sensitive part of the retina, called the macula. Your vision can be irreversibly damaged when cells of the macula die or tiny blood vessels burst through it.

Intensely bright lights
With repeated prolonged exposure, they can overload and damage the sensitive light receptor cells in the retina.

High blood pressure
It causes hypertensive retinopathy, which can damage the eye's blood vessels.

Diabetes
High blood sugar, left untreated, can damage the blood vessels in the back of the eye.

Debris
If left untreated, debris caught in your eye can scratch the cornea and other surface tissue.

Laser pointers
Hand-held laser pointers could burn a tiny spot in your inner-eye components.

Computer screens
Computer Vision Syndrome (CVS) is a well-documented condition that affects hundreds of millions of computer users. The symptoms, including blurred vision, fatigue, headaches, and seeing spots, are usually assuaged by taking breaks and by placing the computer screen directly in front of you, four to nine inches below eye level. So far, research has not shown that there is any permanent damage from CVS in adults. However, it can stunt children's normal eye development if they spend too much time in front of a screen. Apart from corrective lenses, there are special glasses that reduce the constant refocusing needed by your eyes, and thus eliminate eye fatigue.

types of eye problems

There are dozens of eye problems, but some are far more common than others. Here are the main ones:

Astigmatism
This is the most common eye problem, caused by a misshapen cornea or lens that refracts light incorrectly onto your retina. Almost everyone has astigmatism to a degree, but some require attention. Resulting in blurry vision and headaches, it is easily corrected with lenses or refractive surgery.

Farsightedness
Like astigmatism, farsightedness is the inability to properly refract light. But with farsightedness (also called hyperopia), one can't see objects up close. It affects 25% of people and is also corrected with lenses.

Nearsightedness
This problem is like farsightedness, but with the inability to see distant objects (also called myopia). It affects 20% to 30% of the population.

Glaucoma
Caused by excessive internal pressure of the eyes, it can damage the optic nerve, thus harming vision to the point of blindness. It can be treated by surgery or, depending on where you live, by medicinal marijuana. It affects about 3 million Americans, though most don't know about it until they lose their vision.

Cataracts
A buildup of protein in the lens of the eye causes it to become cloudy, resulting in blurry or double vision, nearsightedness and night blindness. More than 50% of adults over 65 develop cataracts to a certain degree.

Night blindness
Poor functioning of retinal cells makes them less sensitive to light. The result is low vision in the dark, making it dangerous to drive at night. Night blindness can be caused by cataracts or poor light adjustment, but most often by vitamin A deficiency.

Beyond poor sight, these problems result in headaches and migraines if left undiagnosed. Getting your eyes checked out regularly and using proper corrective lenses can help you regain clearer vision.

Will getting older and wearing glasses make your eyes weaker?

eyesight quality & age

The fact that your eyesight quality diminishes with age is just as normal as wrinkles and aching joints. Like all tissues in your body, the muscles around your lens that make the eye refocus degenerate, causing blurred vision. It usually starts after the age of 45. The only treatment is wearing corrective lenses.
Macular degeneration is another age-related eye problem affecting seniors, and it seems to be hereditary. The macula, a light-sensitive part of the retina, is broken down, resulting in fuzzy vision, distortion of lines and shadowy areas in one's field of vision. There are several treatments for macular degeneration, including drugs. An eye care specialist should be consulted when picking one.

the lazy eyes myth

There is a myth that wearing glasses or contact lenses makes your eyes lazy, since they're not "exercising" regularly. You may perceive that your natural vision worsened after a few months with glasses, but that's just your perception: Your brain got so used to the crystal clear world with glasses, that not wearing them seems a lot different in contrast.

eye exams

The frequency with which you should have your eyes examined depends on your age.
These are the standard guidelines:

Adults 20 to 49: every three to five years
Adults 49 to 64: every two to four years
Seniors over 65: every one to two years
People with diabetes, glaucoma, and HIV or AIDS should have their eyes checked with greater frequency.

tips for healthy vision

There are many things you can do in your day-to day routine to keep your eyes at full throttle. These include:

Wear sunglasses with UV protection
Read with plenty of light in the room
Don't smoke and avoid smoky environments
Wear eye protection when working with saws, chemicals or flames
If your eyes are red, dry or itchy, use eye drops
Visit your eye doctor regularly
Eat well, including lots of carrots (beta-carotene is used in the photochemical reaction that turns light into nerve signals in your retina)
In fact, here's a test to determine if you need more beta-carotene (a precursor of vitamin A). Make a small white circle on a black background. Stare at it for 30 seconds, then look away. The spot should be "burned" in your vision for a while. The longer the spot takes to go away, the more vitamin A you're missing.

the eye of the beholder

Like most things in life, people don't realize the value of what they have until it's taken away. Your eyes are too precious to wait for them to fail you. Take good care of them so you can always take in the sights of the world.

Resources:
http://my.webmd.com
www.nei.nih.gov
www.nlm.nih.gov
www.allaboutvision.com
http://science.howstuffworks.com
www.quitnow.info.au
www.med.wright.edu
www.hc-sc.gc.ca
www.jnj.com
www.agingeye.net
www.kellogg.umich.edu
http://abclocal.go.com

posted by Mauricio @ 2:42 PM |