How Well Do You See Colors?

Do you have "color vision deficiency," otherwise known as color blindness?

It affects about 32 million Americans -- eight percent of men, 0.5 percent of women -- but there are now new websites and smartphone apps to help people identify difficult-to-see shades and hues, the Wall Street Journal reports.

Head injury and eye problems like macular degeneration, glaucoma, cataracts or retinal disease from diabetes also can affect color vision, as can Alzheimer's, according to the American Optometric Association. Changes in the aging eye may also make it harder for older adults to see differences between one dark color and another.

Saying a person is "colorblind" is really a misnomer, because most can see some colors, but not all. "People think you're living in a black-and-white TV show and that's not true. There are all different degrees, from mild to severe. And you can see colors-they're just different,"  Terrance Waggoner, an ophthalmologist consulting on color vision for the U.S. Navy, told the Wall Street Journal.

The vast majority of colorblind people have trouble seeing red or green -- or a mix of these colors --  due to an inherited genetic defect that affects the color-sensing cells, or cones, at the back of the eye. About 75 percent have trouble seeing green, the Journal reports. Because red and green make brown, people with red-green blindness often have trouble telling the three colors apart.

Unfortunately, inherited color vision problems cannot be treated. Yet. In 2009, University of Washington scientists restored red-green vision in two colorblind squirrel monkeys by injecting the missing gene into their retinas, but whether this would be safe or effective for humans remains to be seen.

However, there are now smartphone apps, such as Colorblind Avenger, HueVue and Colorblind Helper, that can assist with identifying or harmonizing colors.

Vision experts tell the Journal they wish other things could change to help those who have trouble seeing shades of red and green. Some examples: Battery chargers that blink orange for empty and green for full, and hotel keycards that flash green for entry and red for stop.

Photo: viZZZual.com via flickr