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Let There Be Some Light

Contrary to popular opinion, your eyes need some exposure to the full spectrum of sunlight to be optimally healthy. Light waves from the sun are converted to electro-chemical energy in cells in your retina, and this energy is transmitted throughout your brain and body where it has positive health effects.

Energy from sunlight travels to your hypothalamus, which is an area in your brain that is about the size of a grape and acts as the micro-processing chip that governs almost everything that happens in your body. Your hypothalamus receives information from all regions of your body and uses this data to regulate your autonomic nervous system to keep you healthy. Depending on your moment-to-moment needs, your hypothalamus adjusts your heart and lung rates, the amount of blood that perfuses your skeletal muscles and digestive organs, and whether you sweat or shiver, just to name a few of the bodily activities that it controls.

There is no arguing that the health of your hypothalamus is dependent on the quality and quantity of light that enters your eyes. This is the primary reason why you shouldn't always wear UV-blocking sunglasses while outdoors.

You do want to protect your skin from burning, and you do want to wear sunglasses that block 99 to 100 percent of UV rays during outdoor activities that involve prolonged direct upward gazing or magnification of sunlight by water or snow - examples include playing tennis, being around water, and skiing.

But generally speaking, your eyes and health are best served by being regularly exposed to some sunlight. Even while indoors, during waking hours, it's best for your eyes and health to be in well illuminated spaces.

Here are some practical guidelines on light exposure for optimal health:

  • Unless you are looking directly at a sunny sky or are around water or snow for hours on a sunny day, avoid sunglasses. You can protect your eyes and health from damage caused by excessive exposure to UV rays with a sun hat and appropriate clothing that allow some indirect healthy exposure to light rays.

  • If your eyes are sensitive to sunlight, you can build up tolerance by spending a minute or two at a time "sunning" with your eyelids closed. This is as simple as looking up at a sunny sky for short spurts with your eyes closed to allow for indirect beneficial exposure for your eyes and skin. Again, always be sure that you don't burn.

  • While indoors, when possible, use full-spectrum lighting. There are many choices for full-spectrum lighting on the market - one that I can recommend that was developed in Finland can be found here: Chromalux Full Spectrum Light Bulb

  • During sleeping hours, avoid all artificial sources of light, including a night light. The darker your sleeping environment, the better your endocrine function and quality of rest will be.

  • If you find that your eyes feel dry without sunglasses or while indoors around plenty of natural light, try increasing your intake of omega-3 fatty acids, which can increase natural production of moisturizing tears from your lacrimal glands. Also work on increasing your frequency of blinking.

As a caveat, please remember that there are circumstances where one has to be extremely careful about getting too much exposure to sunlight. For example, those who lack pigmentation in their eyes have very low tolerance and may need protection against UV-rays most of the time while outdoors.

But for the vast majority of adults and kids, moderate exposure to sunlight and plenty of natural light while indoors will enhance vision and overall health.


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If a person has had cataract surgery, do the replacement lenses prevent the body from receiving the benefits of exposing the eyes to sunlight?

Loved this and totally agree. I never used to wear sunglasses since in the UK you dont really need to. However i recently went to a very hot country and at the beach...everyone was wearing sunglasses. i found it very hard to keep my eyes open - it was SO sunny! i was trying to eat and it was bothering me, lol.

THEN i realised - i needed sunglasses for times like those. i was the one squinting and having a hard time - but the people with sunglasses - even cheap ones - werent squinting and were just chilling - haha. :) I love sunlight on my eyes. feels good. people in the olden days never had them.

Thanks for all your great posts