When you were in elementary school you probably performed classroom experiments that demonstrated how white light is composed of different wavelengths. The human eye perceives each light wavelength as a different color. That’s why when light travels through a curved or angled lens, such as a soap bubble, you see a rainbow of colors.
Colors with longer wavelengths, such as red and orange, have less energy, while colors with shorter wavelengths, such as blue and ultraviolet, have more energy. Since the wavelengths on the blue end of the spectrum, referred to as “blue light,” have higher energy, they are also more potentially hazardous to the eyes.
Where do you encounter blue light?
In short, blue light is everywhere. Since sunlight is the primary source of blue light, a great deal of exposure occurs when people are outside during the day. Also, due to the short wavelength of blue light, it scatters more easily in the atmosphere than the colors at the lower end of the light spectrum, which is why a clear sky appears blue in the daytime.
Man-made sources, such as fluorescent and LED lights, also emit blue light. Computerized devices such as laptops and tablets are particularly significant man-made sources of blue light. Considering how much time people spend looking at these electronic devices, eye doctors are becoming more concerned with the potential hazards to the eyes from prolonged use of these devices.
The hazards of blue light
1. The eyes are poor at blocking blue light
Although the human eye is capable of blocking ultraviolet light from reaching the retina, it is extremely ineffective at filtering blue light. In fact, less than one percent of ultraviolet light reaches the retina, while virtually all visible blue light does (However, this does not mean you should not be concerned about ultraviolet light. Sunglasses, in order to be effective, must block 100% of UV rays, as even a small amount is harmful to the eyes).
Given how ineffective the eye is at filtering blue light, and how intense this visible light is, eye doctors recommend avoiding too much exposure to it.
2. Blue light may increase the risk of developing macular degeneration
Macular degeneration is primarily an age-related disorder caused by the deterioration of the macula, the central area of the retina. The macula controls visual acuity, which allows people to be able to discern visual details. Without proper macular functioning it becomes very difficult to do common daily activities such as reading, driving, and recognizing faces.
Research has shown that excessive exposure to blue light causes damage to light-sensitive cells in the retina, which causes damage similar to that of macular degeneration. More research needs to be done in order to determine how much blue light is safe for the eyes. Nevertheless, many eye doctors are concerned about excessive blue light exposure from prolonged use of electronic devices, because it could possibly lead to an increased risk of developing macular degeneration.
3. Blue light contributes to eye strain
Since the high energy and short wavelength of blue light causes it to scatter more easily than other light wavelengths, blue light is more difficult for the eyes to focus. This is why looking at electronic screens, which emit significant amounts of blue light, tends to cause fatigue and strain on the eyes.
Protecting your eyes from blue light
If you spend many hours a day looking at electronic screens, there are two simple ways to protect your eyes from excessive blue light. One solution is to get prescription computer glasses that have a yellow-tinted lens that blocks blue light. These don’t darken your vision as outdoor sunglasses do, but they are only suitable for looking at nearby objects, and not suitable for general use, especially driving. If you don’t wear glasses, another solution is to get a blue light filter that is placed over the screen of your device.
To protect the eyes from blue light exposure in the daylight, there are various amber-colored lenses on the market that block UV and blue light. You will find that amber colored glasses, when worn in bright daylight, reduce glare and allow you to see more detail, which is why they are referred to as “high definition” eyewear. Also, some eyeglass centers offer anti-glare coatings that block UV and blue light. To find the best solution for blocking blue light, speak to your eye doctor to determine the best way to protect your eyes.
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