What is UV?
Everyone speaks about the harmful effects of UV. But do you really know what UV is and what are the effects of UV on your eyes?
UV is an abbreviation of Ultra-Violet Light. This UV is emitted from the sun and can reach speeds of 299,000 kilometres per second and they are invisible to the human eye. UV damage is as serious as it sounds. Although it is true that UV has beneficial effects on the body like stimulating the production of Vitamin D in the body, it is only needed in really small amounts like 15 minutes/3 times per week under the sun as advised by the World Health Organization.
UV rays are classified into 3 categories, UVA, UVB & UVC.
UVC is thankfully absorbed by the earth’s atmosphere. So what are the damaging effects of UVA and UVB?
- UVA – This makes up around 95% of the UV that reaches the human eyes. UVA penetrates the cornea and the crystalline lens to reach the retina. Although there hasn’t been conclusive studies on the effects of UVA, the most possible effect could be oxidative stress
- UVB – 90 % of UVB is absorbed by the earth’s atmosphere. The remaining UVB rays which have not been absorbed by the earth’s atmosphere is the most dangerous of them all. UVB rays can result in all kinds of damages to the skin and eyes.
Over exposure to UVB can cause the following forms of eye diseases:
Photokeratitis – The most classic form of Photokeratitis would be snow blindness where people who are skiing at high altitudes are exposed to high levels of UV as it is reflected off the snow and onto their eyes. This causes the corneal epithelium, the top layer of the cornea to suffer burn-like damage. Although it is a really painful ordeal, it usually resolves on its own within a couple of days
Pterygium – Prolonged UV exposure causes the conjunctival cells to grow into the Corneal area. The cornea needs to be transparent for light to pass through. Since the conjunctival cells become deformed and opaque when they intrude the corneal space, one will slowly start to lose their vision. Cosmetic surgery is needed to remove the growth. However, the growth tends to recur
Cataracts – Cataracts are one the most common causes of vision loss in the world. Especially in third world countries where people are exposed to excess UV but lack the education on the harmful effects of UV and access to proper protection. Technology has made it easy for cataracts to be removed and replaced with new lenses. However, there are risks associated with such surgeries as well.
UV damage is serious and real. We are not able to see or feel UV but it doesn’t mean that we are not getting UV damage. Protect your eyes now with sunglasses and contact lenses that provide UV protection.
Stay Healthy & Stay Happy!