Types of Tints for Sunglasses

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Depending on the hobbies you enjoy or the type of work you perform, sun wear may be a very important part of your life. The type of sunglasses you need depends on several factors, including your answers to the following questions: 

  • What do you do for a living? Do you work outdoors most of the day? Do you work indoors but spend a significant amount of time shopping outside, playing with toddlers or mowing the yard?
  • Do you take any medications that cause you to be light sensitive? Certain medications, such as oral contraceptives, diabetic drugs, heart medications or even antihistamines can make some of us photosensitive.
  • What types of things do you do outdoors? Playing volleyball on the weekends may be quite different than serious vacationers that are planning to hike a mountain top or invade the tropics.
  • What times of day do you typically drive a car? Are you getting in and out of your car several times per day? Many of us make the trek to school in the morning and afternoon all the while battling blinding glare during sunrises or sunsets. Others may be driving during the day for business and tend to catch a lot of glare off commercial roads and buildings.

When you consider all the different scenarios of daily living, you can see how one pair of sunglasses may not work in all cases. Sun protection is available in many forms.

Consider the following items when buying your next pair of sunglasses.

  1. Impact resistant material:  If you play high impact sports, make sure your sun lens is made of polycarbonate. Polycarbonate is a thin, plastic, impact resistant material. It won't break or shatter when struck with a significant amount of force. This is important for us all, but vitally important for people with good vision in only one eye.
  1. Polarized lenses:  Sunlight can be absorbed or reflected in several different directions. Sunlight that is bouncing off horizontal surfaces such as water, land or the hood of a car is usually reflected back in a similar horizontal direction. This reflection produces an agitating source of glare that not only creates visual discomfort but can also cause a potentially blinding glare. Glare has the potential to create a very dangerous situation, especially while driving. Polarized lenses contain a laminated filter that allows only vertically oriented light to pass through. This blocks the horizontally oriented light so glare is almost eliminated. The most common colors of polarized lenses are gray and brown. However, depending on the manufacturer, many other colors may be available.
  2. Photochromic lens:  Photochromic lenses are lenses made of glass, plastic or polycarbonate that darken when exposed to glare from ultraviolet light. A photochromic lens is a great choice for people who want to have one pair of eyeglasses that function as both prescription lenses and sunglasses. If you have a job where you are running inside and outside to and from a vehicle, a photochromic lens may be much easier than removing sunglasses every time you go in and out of the sun. Photochromic lenses make for great sun protection. However, it is important to note that some brands of photochromic lenses may not become very dark in the car. The windshield has built in UV protection and can prevent the UV light from coming in and changing the tint.
  1. Polarized photochromic:  Lenses are now available that change from light to dark, but also become polarized to better block glare. However, some people are bothered by a polarized lens and do better with a solid tint.
  2. Standard solid tint:  A solid tint does not protect against glare like a polarized lens, but it limits the amount of light that gets to the eye. A solid tint can be made almost any color and tends to cost less than a polarized lens product.
  3. Gradient tint:  A gradient tint is made with a darker color at the top of the lens and gradually lightens up to the bottom of the lens. Some people prefer gradient lenses to enable better light when reading through the bottom of the lens where a bifocal or progressive lens has reading power. Many people consider a gradient tint more of a fashion detail.
  4. Anti-reflective treatments:  Anti-reflective coating, also known as glare-free technology, is added to almost all clear lenses, making the lenses look invisible, decreases annoying glare and cuts down on scattered light and reflections. However, on sunglasses, it is often applied to the back side of the lens. This minimizes glare from reflected sunlight that bounces back into your eyes from unwanted visual obscurations from the sun.
  5. Anti-fog treatments:  In some areas of the country, as soon as you open your car door and step outside, your sunglasses fog up. Current anti-fog treatments are excellent at fixing the problem.
  6. Mirror coatings:  Mirror coatings double as cool fashion accessories.  However, they are also very good at reducing the brightness of the light, such as when water or snow skiing. The mirror is applied to the surface and acts to reflect light rays from all surfaces.
  7. Blue light protection:  Prevencia by Crizal is a newer application to eyewear that offers blue light protection. New research suggests that a certain wavelength of blue light could be harmful to certain individuals at risk for retinal disease such as macular degeneration.  Blue light has a very short wavelength and not only does it provide basic illumination to our world, blue light also helps to increase feelings of well-being. But exposure to large amounts of blue light can be harmful to the eyes.

Source:  Mclean, Karlean. Sun lens checklist, Eye Care Business, pp 58-60, Jan 2015.

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