THE OBJECTIVE SIDE:
Ultraviolet light (UV for short), though invisible, affects everybody who can see. Over time UV will damage skin and eyesight.
Normal visible light consists of vibrations with a wavelength between 700 Nano-meters and 400 Nano-meters, a Nano-meter being 1000 times smaller than a millimetre. UV light consists of vibrations even smaller than this, between 400 and 100 Nano-meters.
UV light can be divided into:
- UV A light: 320 to 400 nMeters.
This may cause skin damage over time. - UV B Light: 290 – 302 nMeters.
This causes sunburn and eye damage. - UV C light: less than 290 nMeters
of little concern, does not enter atmosphere.
UV B is the biggest concern for eye and skin care. UV B causes skin to sunburn and eyes to suffer photokeratitis damage.
SUNGLASSES:
Sunglasses should protect against UV light. There is some debate whether UV A is harmful, but UV B definitely causes problems. Ideally glasses should protect against UV A and UV B light.
The UV 400 label on a pair of sunglasses means they block out all UV light, both UV A and UV B. the ‘400’ refers to the 400 Nano-Meter wavelength of UV light.
OTHER TERMS:
Polarized Glasses: These are designed to block out reflected light, such as glare. As such they are an advantage with skiing or with beach condition where sun reflects off water and snow. Their only minor disadvantage is that they can block computer monitors and displays.
Blublockers: these glasses (actually a brand name) block some blue light as well as offering UV protection. Blocking blue light, which is the visible light next to UV light, can improve vision contrast. Always check the UV certification, however, as there are many fake products on the market.
Always check that Polarized glasses have UV protection as well.
And the most important subjective factors?
COMFORT: Find a pair that feels comfortable. If you like how they feel you are far more likely to wear them! When you’re new to wearing any types of glasses you may not know what to look for here; being used to something is part of feeling comfortable with it. Likewise, if you’re used to your old pair you find similar glasses seem comfortable because they feel familiar, even if better options come along. Consider other options, though maybe the earlier pair of glasses actually were a good choice all along.
APPEARANCE AND EFFECTIVENESS: Find a pair of glasses that look right for your face. Of course, you don’t want to compromise on anything else here, but if the glasses leave a lot of surrounding skin exposed any UV protection is compromised; you skin will be open to sun damage. Covering more of your eye area with the glasses tends to be better, but you can always use a hat and sunscreen to help as well. If you do like the way you look with a pair of quality UV sunglasses try finding a way of adding protection to your skin with shade, hat, sunscreen and anything else that works for you.