January 27, 2012
By David Blyweiss, M.D.
In This Issue:
- Why you need eye protection in any season
- The rays you can see.. and the ones you can’t
- How to pick protective lenses that do their job
Now, I realize it’s the end of January – and the days are still pretty short. Depending on where you live, you might be wondering why I’ve chosen this time of year to talk about protecting your eyes from the sun.
It is specifically because it’s winter that I’m sending you this issue, actually. To clear up a common misconception many people have about when the sun is dangerous – and when it isn’t.
Your eyes are fragile. And unlike other parts of your body, damage done to this most-sensitive area can be irreversible. Your eye’s lens doesn’t repair itself when damaged, and cells and proteins that are lost may never be replaced.
This is one part of your body you truly can’t afford to neglect. Taking supplements formulated for your eye health is one important step. But there’s another form of protection that you can’t buy in a bottle…
Because exposure to the sun is a critical way to get Vitamin D – one of the most essential vitamins for your immune system – I’m all in favor of soaking up a little sun every day. And yes, you should take reasonable precautions to protect your skin, but I am not a big fan of excessive sunblock if it also blocks you from absorbing the good of the sun.
When it comes to your eyes, however, my tune changes dramatically. Wearing protective eyewear, even in winter and cloudy weather, is essential. Choosing the right protection means understanding why you need it, and knowing what to look for when you buy shades.
There are two types of rays to watch out for – blue rays that you can see, and the UV rays that are invisible to you. Each one requires a certain type of protection. And each one wreaks a different kind of havoc on your eyes.
For the fragile mechanisms of your eye, UV rays have no positive benefits whatsoever, none. Which means wearing protective lenses whenever you are outside in the daytime is a must… even on a cloudy day, as UV rays are not filtered by clouds. Over time, exposure to UV rays can cause cataracts.
There are three types of UV rays:
- UVA rays, which have long wavelengths and can pass through glass. While these are not the most harmful of the three types, it is still recommended that your eyewear carries protection against them.
- UVB rays are the most harmful to your eyes, although they don’t go through glass. Protecting against these rays is critical during outdoor activities.
- UVC rays are the most intense of the three. Fortunately, they are blocked by the Earth’s atmosphere.
Glare and reflections can also magnify and intensify the exposure, which means you need protection when swimming, skiing or walking along the beach in particular. And of course, if you use tanning beds or sunlamps, live at a high altitude or near the equator, or are on any medications that make you more sensitive to light, you’ll need the highest levels of protection available.
Unlike UV rays, blue rays are visible – they are what make the sky blue! But they also cause a photochemical reaction that produces free radicals in your rods, cones and RPE (Retinal Pigment Epithelium), a layer of cells that protects the retina and when damaged, can cause macular degeneration.
The darker your eye color, the more natural protection you have against blue rays. The lighter your eyes, the more protection you need. This is because melanin – the substance giving eyes their color – traps the light rays before they can damage the macula. In fact, blue eyes transmit as much as 100 times as much light to the back of the eyes as dark colored eyes do!
Since UV rays are invisible, so is UV protection. But blue ray blockers are visible as a yellow or amber tint that alters the appearance of blue and green colors. But the tint doesn’t affect the way other colors appear. In fact, blue ray blockers can improve color contrast, and have become popular as sports glasses because they improve outdoor vision and reduce glare more effectively than UV protection alone.
While there is some controversy over the hazard vs. benefit of blue light, science is coming down on the side of caution. However, if you have conditions such as Seasonal Affective Disorder (SAD) or bipolar disorder, you might want to check with your physician or an ophthalmologist to get a more specific recommendation.
The best way to protect your eyes is to wear sunglasses. However, not all sunglasses will provide you with equal protection from UV and blue light rays. For maximum protection, you should look for sunglasses that:
- Block 99-100% of UVA and UVB rays
- Block blue light rays
- Contain large lenses that fit close to your eyes
You don’t necessarily need brand name, big bucks lenses to get this protection. But glasses that offer protection should be clearly marked when purchased. If you purchase a used or vintage pair of frames – or you’ve had your sunglasses so long and you want to double check them – you can take them to just about any optical store and ask them to tell you. Most will have a UV meter and can let you know in minutes, free of charge.
Please don’t compromise protection for style. Frames should be large enough to offer full protection, preferably wrap-around to keep rays from leaking around the edges.
And finally, if you wear contact lenses, check with your optometrist or optician about the protection in the lenses, and what you need to augment with to achieve optimal protection.
Roberts JE., Ultraviolet radiation as a risk factor for cataract and macular degeneration. Eye Contact Lens. 2011 Jul;37(4):246-9.
Algvere PV, Marshall J, Seregard S., Age-related maculopathy and the impact of blue light hazard. Acta Ophthalmol Scand. 2006 Feb;84(1):4-15