Harmful UV radiation from the sun can damage various parts of the eyes including conjunctiva, lens and also the retina (nerve). Long-term exposure to sunlight increases the risk of cataract formation and also pterygia (a growth on the surface of the eye).
Apart from wearing a broad brimmed hat, one of the best ways to prevent unnecessary eye exposure to the strong ultraviolet rays is to wear protective sunglasses. So many kinds of sunglasses are available to choose from, ranging from cheap ones to designer ones that cost an arm and a leg. Some things to be informed about are:
CLIP-ONS: These are good for those who have to wear a prescription pair of spectacles to correct a refractive error and do not have a prescription pair of sunglasses. The clip-ons are convenient to use over the powered spectacles. The downside is that if they have a poor fit, they can fall off or scratch the spectacles they clip on to.
PHOTOCHROMATIC: These are lenses that darken when exposed to light and heat. They are a convenient option when you have a prescription pair of spectacles to wear. The prescription spectacles can be made photochromatic but you will need to inform your optical vendor about this choice when ordering your prescription pair. The downside is that these lenses sometimes take a little long to darken in sunlight.
GRADIENT: Two kinds are available. Conventional ones have a darker tint on the upper part of the sunglasses and a lighter tint on the lower part. The double gradient ones are dark on the top and bottom leaving the central part having a light tint. They are good for those who want protection from scattered light above and below but yet do not like their sunglasses to be dark.
MIRRORED: These sunglasses have a metallic coating on the lenses making them appear like mirrors. They are actually effective in filtering off light because they reflect the light rays. However, there is a tendency for the coating to get scratched if they are not taken of well.
POLARIZING: Sunglasses which are polarized are doubly effective in preventing glare by allowing only the vertical component of light to pass through. They eliminate the haphazardly scattered light rays that cause glare. Having sunglasses which are polarized that cut off such reflected light is definitely beneficial.
Here are some more tips to consider when getting a pair of sunglasses:
The ability to block off UV light does not depend on how expensive are the sunglasses, or how dark the sunglass lenses are.
Brand does not matter as much as the quality of the glass.
Choose a pair of sunglasses that has a CE mark, with 100% UV protection from UVA and UVB rays, or has a UV400 tag.
Ardent outdoor sports people would benefit from “wrap-arounds” that effectively prevent strong sunlight from passing through the sides.