FAQ: Sunglasses & Protecting Your Eyes from the Sun

If the sun doesn't bother my eyes, do I still need to wear sunglasses?

Yes. The sun has damaging UV rays that can cause:

Photokeratitis, basically "Sunburn of the cornea", which can cause temporary vision loss that can result is referred to as "snow blindness."
Pingueculae
permanent retinal damage.

What exactly are UV rays?

Ultraviolet (UV) rays are located just past the violet portion of the visible light spectrum; sunlight is the main source.

UV light is broken into three different types: UVA, UVB and UVC. UVA has longer wavelengths and passes through glass easily; experts disagree about whether or not UVA damages the eyes. UVB rays are the most dangerous, making sunglasses and sunscreen a must; they don't go through glass. UVC rays do not reach the Earth because its atmosphere blocks them.

When do UV rays affect my eyes?

Most people think that they're only at risk when they're outside on a sunny day, but UV light can go right through clouds, so it doesn't matter if the sky is overcast. The sun's rays are strongest between 10 am and 2 pm.

Glare and reflections can give you trouble, so have your sunglasses ready if you'll be around snow, water or sand, or if you'll be driving (windshields are a big glare source).

The following put you at additional risk: sunlamps, tanning beds and parlors, photosensitizing drugs, and living at high altitudes or near the equator.

What are my options to prevent damage to my eyes?

You must wear sunglasses to prevent damage to your eyes. While some contact lenses provide UV protection, they don't cover your whole eye, so you still need sunglasses.

Look for sunglasses that protect you from 99 percent to 100 percent of both UVA and UVB light. This includes those labeled as "UV 400," which blocks all light rays with wavelengths up to 400 nanometers. (This covers all of UVA and UVB rays.)

Also, you may want to consider wraparound sunglasses to prevent harmful UV rays from entering around the frame.

Vision Terms Glossary

Anterior Chamber - the-fluid filled space inside the eye, between the iris and the cornea
Aqueous Fluid - a thick watery substance that fills the anterior chamber of the eye
Astigmatism - a condition where the surface of the cornea is not completely spherical, which can result in blurry vision
Binocular Vision - the blending of two images into one, the separate images in both eyes blend into a single image to be seen
Blind Spot - an area in the visual field which corresponds to an area of the retina where no visual cells are present, resulting in a part of your field of vision that cannot be seen. All vertebrates have a blind spot
Cataracts - an eye disorder in which the lens of the eye clouds, leading to vision loss, and blindness unless treated
Central Retinal Artery - the vessel that carries blood into the eye and supplies the retina with nutrition
Choroid - the layer of the eye filled with blood vessels that provides nourishment to the retina
Ciliary Muscle - a muscle in the eye that controls lens shape for seeing objects at various distances
Cones - a type of cells located in the retina that provide color vision
Conjunctiva - the thin moist membrane that lines the inner surface of the eyelids and the outer surface of the sclera
Conjunctivitis (Pink Eye) - an infection which causes inflammation of the conjunctiva, it can easily be treated with antibiotic eye drops
Cornea - the transparent dome shaped front part of the eye that covers the iris, pupil, and anterior chamber, and is part of the eye's focusing system
Dilation - a process where the pupil is temporarily enlarged with special eye drops, so an eye doctor can get a better view of the inside of the eye
Farsightedness (Hyperopia) - a defect of the eye that causes the ability to see faraway objects more clearly than close objects, can be easily treated with glasses or contact lenses
Glaucoma - a disease in the optic nerve of the eye that causes vision loss, and can progress to blindness
Intraocular Pressure - the pressure of the fluid inside of the eye, the pressure varies among individuals
Iris - the colored ring of tissue surrounding the pupil that controls the amount of light entering the retina
Legal Blindness - a visual acuity of 20/200 or less, and can be caused by disease, injury, genetic defects, and poison, it does not necessarily mean that a person is completely blind, there may be some vision left
Lens - a transparent, curved structure in the eye that helps to refract light to be focused on the retina
Macula - an oval shaped yellow spot located in the center of the retina, responsible for central vision, or vision for fine work and reading
Nearsightedness (Myopia) - a defect of the eye which causes the ability to see close objects more clearly than faraway objects, can be easily treated with glasses or contact lenses
Optic Nerve - the main nerve in the eye that transmits visual messages from the retina to the brain
Peripheral Vision - the ability to see objects outside of the direct line of vision
Posterior Chamber - the space between the back of the iris and the vitreous, it is filled with aqueous fluid
Presbyopia - a condition in the eye gradually loses its ability to focus on near objects, the condition is associated with aging, and occurs in most all people over the age of 45
Pupil - the black sphere located in the center of the iris, that has an adjustable opening at the center and controls the amount of light that enters the eye
Retina - the light-sensitive layer of tissue that lines the back of the eye, and sends visual messages through the optic nerve to the brain
Rods - a type of cell located in the retina that provides the ability to see objects in dim light or darkness
Sclera - the white of the eye, it is tough, fibrous, and protects the entire eyeball
Uvea - the middle of the three layers of the eye, similar in appearance to a wrinkled grape
Visual Field - everything at any given time that causes light to fall on the retina (what you can see at any given time)
Vitreous - a transparent mass of gel that sits behind the lens and in front of the retina

What are the different kinds of lenses that are available?

With so many lenses available, it is difficult to find ones that will protect your eyes if you don't know what each one will do.

Both polarized lenses and anti-reflective coating cut reflected glare. Polarized lenses in particular are popular with those who play water and snow sports. Read more about polarized lenses and anti-reflective coating

Mirror-coated lenses limit the amount of light entering your eyes, so you're more comfortable.

Gradient lenses are tinted from the top down, so that the top of the lens is darkest; they're good for driving. Double gradient refers to lenses that are also tinted from the bottom up: the top and bottom are darkest and the middle is clear (or close to it); double gradients are not very useful for driving, because they make it difficult to see the dashboard.

Photochromic lenses adjust their level of darkness based on the amount of UV light they're exposed to.