Doctor's Column

  • Dr. Nadia is committed to helping you make the right lifestyle and fashion choices in regards to the health of your eyes. If you have any questions you would like her to answer, please submit them through our email submission form on the right.
Important Facts about UV Light

1. What is UV light?

UV light stands for ultraviolet light. Ultraviolet light is invisible light with a frequency ranging between 100 nm and 400 nm. UV light includes UVA, UVB and UVC and is emitted by the sun. UVC is the highest frequency UV light and is naturally filtered by the Earth’s ozone layer. UVA and UVB however are not filtered by the ozone layer and require some other type of protection. UVA is often linked with aging whereas UVB is linked with retinal burns.

2. Why is UV light bad for the eyes?

Ultraviolet light can cause many changes to ocular tissues such as cataracts, macular degeneration, corneal burns, conjunctival thickening as well as skin cancers and tumors of the eyelids. An important function of the lens is to absorb UV light and prevent it from reaching the highly sensitive tissue of the back of the eye (retina). UV protection is especially important in young children because their ocular lens filters only 5%-25% of UV light depending on age and in post-cataract removal patients since their lens implant is highly transparent. In these two demographic groups, macular changes or macular degeneration are an increased concern.

3. How can you protect yourself from UV light?

You can protect yourself from the damages of UV light by using sunscreen on your face and wearing a brim hat to keep sunlight away from your face. On a bright sunny day, be sure to wear sunglasses that block 100% UVA and UVB or photochromic lenses. Photochromic lenses such as Transition lenses are clear indoors and turn grey or brown when activated by UV light. When coupled with a high-quality lens material that naturally blocks UV light, Transition lenses provide nearly 100% UV light protection.

4. Do computers, phone screens and tablets emit UV light?

No, digital devices emit blue light, not UV light.

5. Why is blue light bad for your eyes?

High-energy visible (HEV) blue light is bad for the eyes for a couple of reasons. Blue light has a very high frequency and therefore very high energy, which can damage the inner tissues of the eye, specifically the retina. Increased exposure to HEV blue light has been linked with photochemical injury to the retina in what we call macular degeneration. Blue light also causes light scatter and glare into the eye, which can cause eyestrain and headaches.

6. What can you do to protect your eyes?

You can reduce your use of devices that emit blue light. If that is not an option, the next best way to protect your eyes from the damages of high-energy visible blue light is to wear lenses with a powerful anti-reflective coating such as Crizal Sapphire. Crizal Sapphire filters blue light reflecting from digital device screens and thereby decreases glare, eyestrain and headaches. This leads to increased comfort during digital device use. Another coating that I recommend and it's specifically geared towards those who spend a lot of time using digital devices is Crizal Preventia. This particular one blocks harmful blue light, which may cause macular degeneration, and allows good blue light to go through. Our sleep cycles are regulated by blue light and Prevencia takes this into account. If you spend a lot of time on digital devices and find yourself having a hard time falling asleep at night, you can try Prevencia to see if it helps.