Black on Yellow, Best Visible Contrast

By: Pamela Ravenwood

As we age, our eyesight changes, and sometimes in ways that can be a nuisance. One common vision change due to aging is a reduced sensitivity to contrast. When objects are of the same color, such as shades of white on other shades of white, it becomes more difficult to delineate the two. Decreased focus, decreased depth perception, decreased color judgment, sensitivity to glare and the need for more light are also symptoms of aging eyes.

Having declining vision isn't always due to aging. Poor color vision has several causes. They include:

* Inherited disorder. In most cases, the genetic information that results in color deficiency is passed along from mother to son. However, the abnormal gene passed along by the mother could come from the mother's father - maternal grandfather. In such cases both the grandfather and grandson would be affected. About 1 in 12 males are born with some degree of color deficiency. Most females possess genes that counteract the deficiency. Inherited color deficiency usually causes a difficulty in perceiving red and green. The severity of your color deficiency doesn't change over your lifetime. You inherit a mild, moderate or severe degree of the disorder.
* Diseases. Some conditions that can cause color deficits are diabetes, glaucoma, macular degeneration, Alzheimer's disease, Parkinson's disease, chronic alcoholism, leukemia and sickle cell anemia.
* Some medications. Color vision can be altered by certain medications, such as some drugs used to treat heart problems, high blood pressure, infections, nervous disorders and psychological problems.
* Chemicals. Exposure to some potent chemicals in the workplace, such as carbon disulfide, fertilizers and styrene may cause loss of color vision.

We notice our eyesight changing most often when reading or driving, but some people, who use a computer daily, also find it difficult to see the keyboard. This is due to its ivory keys on an ivory board.

If this has become your problem, don't despair. Keyboard manufacturers, such as Key Connection, are recognizing this as an issue. With this, new keyboard designs include keyboards that have yellow keys with large black type.

Why yellow?

Yellow, most commonly used in highlighters is the most visible color to the human eye. The reason has to do with the wavelengths of color. Visible light ranges from red, the color with the longest wavelength, through orange, yellow, green, blue, and indigo to violet, the color with the shortest wavelength. Yellow and green are right in the middle of the spectrum's wavelengths, therefore, our eyes are most sensitive to these colors making them the easiest to see. This is even true for people who are colorblind.

For those who are colorblind, green, yellow, orange, and red are all perceived as yellow or grey. However, when the color actually viewed is yellow, the yellow appears brighter than the perceived "yellow" that is seen in place of red or green.

So if we notice yellow and green more quickly than other colors, then why are stop signs and most emergency vehicles painted red? The choice of red has more to do with tradition than visibility. Because yellow has been proven to be more visible, many communities have started to paint their fire equipment and ambulances a very bright yellowish-green, which helps motorists see them coming in which they are able to get out of their way more quickly.

So if you are one of those people who are using their computer less and less because it has become difficult to see the keys, no worries. There is a solution and declining eyesight doesn't have to be a nuisance any more with the growing amount of choices.

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