Excerpt from article by Environmental Working Group
Love the Sun and Love your Eyes too!
How to protect your eyes from UV rays
- Buy a good pair of general-purpose medium to dark sunglasses with large lenses and wraparound design (Health Canada 2010). UV can enter the eyes from the side. As well, light shining from a source behind the head can be reflected off the inner surface of sunglasses and into the eyes, making the shape of the curved sunglasses particularly important (Behar-Cohen 2014). Daily-use outdoor sunglasses should block 60 to 92 percent of visible light and UVA rays and 95 to 99 percent of UVB rays.
- Wear sunglasses from morning to night.
- Wear a wide-brimmed hat or visor and avoid bright midday sunlight.
- Don’t wear lightly-tinted “cosmetic” sunglasses when outdoors. They do not protect the eyes sufficiently.
- Don’t wear sunglasses made for prolonged sun exposure for driving because they are deeply tinted and can block up to 97 percent of visible light, 98.5 percent of UVA rays and at least 99 percent of UVB rays. Overly dark lenses interfere with the driver’s view of traffic signs and signals.
When shopping for sunglasses, you will likely be presented with options for different types of lenses and coatings that don’t increase UV protection but may offer other benefits. These include:
- Polarized lenses that limit glare from external reflective surfaces such as water. These lenses consist of three sandwich layers: external tinted glass, a thin layer of polarizing film and internal non-polarizing glass. On some lenses polarized film is on the lens surface.
- Photochromatic lenses that incorporate light-reactive materials that undergo a reversible chemical process when exposed to UV. These lenses darken in the sun and fade indoors.
- Anti-reflective coatings that are applied on the outer or outer and inner lens surfaces to reduce glare and prevent the lenses from mirroring the images of people who converse with the wearer.
For more information on Protecting you eyes from the Sun, check out this excellent article from the Environmental Working Group.