Eyes Off the UV!

Written by: editor Mar,20 2012 16:38 PM

Going outdoors in the day? At minimum, don’t forget to slap on some sunscreen and put on your sunglasses.

 



Going outdoors in the day? At minimum, don’t forget to slap on some sunscreen and put on your sunglasses. Unfortunately, people often neglect wearing sunglasses as compared to sunscreen because of the immediate effects experienced from not wearing sunscreen. Without sunscreen, one can easily get sunburned, and the subsequent pain can last for days. In the meantime, many people have found themselves without an issue when not wearing sunglasses. We tend to forget that our eyes do experience sunburn as well, but we often confuse it with tiredness from the day. A big culprit of sunburned eyes would be the lack of protection against the sun’s UV-rays. Let’s have a look at the types of UV-rays present, and how they can affect our eyes.


UV-A (wavelengths from 320 to 400nm)

UV-A is relatively harmless; however, as this ray can pass through the cornea and reach the lens, excessive exposure can lead to damage to the lens, leading to the development of cataracts and macular degeneration. It can also cause the darkening of the skin surrounding the eyes.


UV-B (wavelengths from 290 to 320nm)

UV-B rays are also known as burning rays, and its implication is exactly as named. Absorbed 100% by the cornea, short-term excessive exposure can cause photokeratitis or “snow blindness”, which is the painful inflammation of the cornea, marked by symptoms such as swollen eyelids, grittiness, blurred vision, tearing, redness, headache, halos around lights, and temporary loss of vision. While the risk is higher in places with snow in high altitudes or arc welders, one can also experience it when exposed to reflected light from water or sand. Prolonged exposure can cause the eyes to develop cataract, pterygium (eye growths) and pinguecula (eye degeneration).
 

UV-C (wavelengths from 200 to 290nm)

Despite posing the least threat as they are absorbed by the ozone layer, UV-C rays happen to be the most dangerous among the three rays if exposed to them directly. The cornea is susceptible to this ray, and when exposed to it, it creates a foreign body sensation, tearing, and pain in the eye that can appear between 30 minutes and 12 hours after exposure. It can also cause corneal cell damage which can lead to blindness. UV-C rays are also present in welding arcs and in the reflection of sunlight from snow at high altitudes.

Unfortunately, we cannot live hiding in the dark (even for general health reasons). There is, however, a way to reduce the harmful effects of the UV-rays towards our eyes – sunglasses. But not just any sunglasses! Here are some tips for choosing comfortable sunglasses with optimal protection against the sun.

High UV protection. The darkness of a lens does not indicate the effectiveness of filtering UV-rays. Always use sunglasses with at least UV400 filter tint as they offer the best protection against the sun.


Wraparound design. Sure, standard sunglasses have the front of our eyes protected against the sun. But in reality, we don’t look straight into the sun, so the rays can get in from the openings on the top, bottom, and sides, too! Wraparounds give an all-round protection

Well-fitted. The frames should snugly fit on the nose and ears instead of rubbing or pinching them, and your eyelashes should not come in contact with the frames. It is important that they fit securely so they don’t end up slipping!


Evenly-distributed weight.
Especially for non-spectacle users, finding one that doesn’t carry too much weight on certain spots will help you get comfortable with your sunglasses in no time. Find one whose weight is evenly-distributed between your ears and nose so you don’t end up with a headache at the end of the day.

Materials. Material is important as they affect the comfort, durability and safety of the sunglasses. Polycarbonate is a good example of lens material, as they are durable and lightweight, not to mention they automatically come with UV protection. In the meantime, common types of frame materials are metal, nylon, and acetate and zyl. Ask the optician for the best type of material for your type of lifestyle.

Lens colour. Some people think that the choice of lens colour is purely cosmetic, but what they often miss is that the colour does actually have its function. For one, it can effect colour perception. Grey, brown and green are popular choices of lens colours as they distort colour perception the least. Of course, certain sports would fare better with different coloured lenses, such as yellow for skiers and target shooters as they reduce haze and increase contrast for a sharper image.

Of course, there is no point getting the right sunglasses without using it during the right occasion. Whether child or an adult, never forget to wear sunglasses during noon, summer, when on the beach or boating, or when you’re skiing on high altitudes. Besides, you’d look funny wearing sunglasses at night!

 


Eye Guide

 


 

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