What is UV Light?
UV radiation is defined as the portion of electromagnetic spectrum ranging between 100 nm to 400 nm.The sun is the primary source of UV radiation,although there are some secondary sources as the suntanning beds,electric sparks,welding arcs,halogen desk lamps,etc.UV radiation can be divided into three parts: UVA(315-400 nm) ,UVB(280-315 nm) ,and UVC(100-280 nm).Shorter the wavelength,the more harmful are the effects.
How UV Light is harmful?
UV radiation is not a part of visible light spectrum therefore, its harmful effects cannot be felt unless some tissue damage has developed. Considering short penetration depth of UV radiation, the major organs at risk are the skin and the eye. Scientific evidence show that large exposure to UV radiation can cause serious ocular complications as Photokeratitis and photoconjunctivitis. Even a small exposure to UVB radiation can cause cataract, Pinguecula, pterygium, and squamous cell carcinoma of the cornea and conjunctiva.
How to protect our eyes from UV damage?
Ideally, the best protection is to avoid being outdoors during hours of high UV radiation. However various forms of personal protection such as UV blocking spectacle lenses, UV blocking contact lenses, polarized sunglasses, photochromic eyeglasses and prescription sunglasses can help.
What is a UV protected eyewear?
For people not requiring any refractive correction,can wear regular sunglasses with UV- 400 protection. Nowadays,plano eyeglasses also come with a UV filter. A UV-400 protected eyewear can block upto 400 nm of wavelengths and additionally they block upto 75% of visible light emited from the sun as UVA and UVB radiation. Similar facility is available for the people needing refractive correction. Prescription sunglasses are also available with bifocal and progressive correction as well.
What are Photochromic lenses?
Photochromatic/Photochromic is a lens coating given to provide a transition between outdoor exposure and the indoors on the basis of amount of UV light absorbed. Eyeglasses with Photochromic treatment can be worn indoors as well as outdoors. Indoors serve as a regular prescription spectacle whereas on the outdoors it darkens as a sunglass.
What are Polarized lenses?
Polarized lenses reduce glare from highly reflective surfaces such as water, glass or snow. These lenses reduce glare because of their vertical polarization orientation. At any angle other than the horizontal, these lenses filter out the glare thereby protecting the eye from potential strain. Therefore polarized sunglasses can be even more effective than a regular non polarized sunglass.
Do I need UV protection in my eyewear?
The answer to this is definitely YES!! Any plastic or glass lens with UV coating can provide maximum protection. With sun being the primary source of UV light, sunglasses are definitely important but we should not forget that even indoor lights such as halogen bulb, LEDs, computer rays,do emit some amount of UV radiation. Hence,any eyeglass with UV protection is a must for everyone. A UV protected eyewear is best for maintaining the health of your eyes.
REFERENCES
2. Backes, C., Religi, A., Moccozet, L., Behar-Cohen, F., Vuilleumier, L., Bulliard, J. L., & Vernez, D. (2019). Sun exposure to the eyes: predicted UV protection effectiveness of various sunglasses. Journal of exposure science & environmental epidemiology, 29(6), 753-764.
3. https://www.arpansa.gov.au/understanding-radiation/what-is-radiation/n on-ionising-radiation/ultraviolet-radiation
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