I am sometimes asked, “What’s wrong with UV light?”

Isn’t it just that… “light?”

UV is short for ultraviolet, which is short-wavelength, high-energy radiation, at the blue end of the spectrum. Without it, life on earth would not be possible. Plants need it to grow and produce food for us.

Our exposure to UV has increased dramatically with the shift from incandescent bulbs to fluorescent and LED lights.

Thus presenting the question, “What’s so bad about UV exposure?”

The answer is that too much exposure can cause skin cancer, cataracts, and macular degeneration. It also disrupts our sleep cycle.

Not only do we receive UV from lights, but we also get UV from computer screens and handheld devices. Use of these devices near bedtime can cause poor sleep.

At the same time, our UV exposure has been increasing, our exposure to infrared (IR) has been decreasing. IR is long-wavelength, low-energy radiation at the red end of the spectrum. Less time spent outdoors in sunlight means less IR exposure. IR is necessary for our bodies to produce ATP (adenosine triphosphate), which is the fuel that powers all of our cellular metabolic functions.

Incandescent, clear bulbs (no white coating) produce the IR our bodies need. The problem is, they use more electricity than LED lights, so they are more expensive to operate. A balance can be achieved by using a clear incandescent bulb in a “reading nook” or similar small space before bedtime. This allows the body to produce the melatonin it needs to go to sleep.

Tanning beds and “SAD” (seasonal affective disorder) lights produce high amounts of UV.

We use them more in winter when our natural exposure to sunlight (and IR light) is at its lowest. So, wintertime is when we benefit most if we “supplement” our normal room lighting with IR-producing, incandescent lights in the evenings.

There are also “blue-blocking” glasses that reduce the harm that UV light can cause to our bodies.

One of the most complicated vision-related topics is the risks and benefits of exposure to light, especially ultraviolet (UV) light. Like men and women frequently say about each other, “Can’t live with ‘em. Can’t live without ‘em.”

UV light is short-wavelength, high-energy radiation. Without UV light, there would be no life on earth. So we DON’T want to eliminate it. Plants need it for photosynthesis, which is how they grow and produce food for us.

Too much UV exposure causes skin cancer, cataracts, macular degeneration, and sleep disorders, and is implicated in many, many problems, including improper brain development. So we don’t want too much; we want to limit our exposure to it.

Add to the mix the societal shift to more and more UV exposure through LED lighting, and the UV radiating from all of our “devices,” along with less and less exposure to natural sunlight, and we start dealing with insufficient Infrared (IR) exposure. IR is longer-wavelength, lower-energy radiation.

There is significant evidence that IR is necessary to produce ATP, which is the energy “currency” of our cells.

We constantly manufacture and use ATP in all of our metabolic functions, from breathing and blinking to digestion and circulation. In fact, we manufacture approximately our own weight in this “energy currency” every day. That is, IF we get enough IR exposure. Lack of exposure to IR degrades all of the biological functions of our bodies.

Without sufficient ATP, we lack energy, our organ systems suffer and we age prematurely. So we need exposure to IR (especially “Near” IR).

Studies have shown that using our UV-emitting electronic devices up to bedtime (and even while in bed,) disrupts the sleep cycle by suppressing the production of melatonin (the “go to sleep” chemical). In nature, melatonin production decreases in daylight and increases when it gets dark. Now, we have so much artificial light that it affects our melatonin production, which affects our body clock. This explains at least part of the increase in sleep disorders that has occurred.

And, of course, everyone has heard of the dangers of too much “tanning bed” time. That is UV exposure. Protective goggles are required to minimize harm to the eyes.

On the other hand, “SAD” (Season Affective Disorder) lights have a high UV rating, which suppresses melatonin during the day, and helps to alleviate the “winter blues” that many experience due to the lack of light in winter.

They are meant for a limited-time exposure, with the appropriate time of day determined on a case-by-case basis.

Recent research indicates that the best or healthiest indoor lighting, especially for evenings, is incandescent lighting, with no “soft white” coating. The element should be visible. If possible (although this requires additional expense), it should be run on DC (battery power) vs AC, due to the “flicker” caused by AC. This incandescent lighting provides more near-IR, which stimulates the ATP production as well as Melatonin production.

Of course, we have been pressured to accept more LED lighting because it uses less electricity. But, for a couple of hours before bedtime, especially in a “reading nook” or similar small area, a DC-powered clear incandescent bulb has significant health benefits.

In addition, limiting our exposure to UV-emitting “devices” such as smartphones, tablets, laptops, especially before bedtime, can reduce the harmful effects of too much UV.

Editor’s Note: Dr. Daniel J. Kosterman is the owner of Dr. K’s 20/20 Vision Center in Eagle River.