Sunglasses and vision protection

 By Lily Ding & Richard Li

As you might have known, a pair of sunglasses is one of the most important eyewear in everyday life. With the knowledge of your local optical, you can get the most out of your sunglasses, and they can improve the quality and comfort of your vision in many ways.


Why sunglasses

  1. When you are driving a car in a bright sunny day, the sunlight may shine directly into your eyes and the glare can come suddenly and be extremely distracting. If you do not have a pair of sunglasses in the car, this may make driving very dangerously. This is especially important in winter, when the reflection from the snow on the ground makes glare much stronger, as well as make the direction that the glare is coming from unpredictable.
  2. When your eye color (density of the pigmentation of your pupils) is lighter, you are more sensitive to lights. Probably you might have noticed that some people wearing sunglasses even in lightly cloudy days
  3. UV can damage the crystalline lenses of the eyes; it is one of the most important factors of cataracts, because UV light can travel through your cornea and cause opaqueness and reduce your vision ability. Wearing sunglasses means most UV is filtered out by the tinted lenses and the anti-UV coating which is required in all sunglasses nowadays in Canada. This is important for everyone from school children to the elderly, and recently many schools have started recommending that children wear sunglasses when playing outdoors to lessen UV damage to their crystalline lenses.


Sunglasses without prescription

  1. Several decades ago, most sunglasses did not have many features to correct your vision, so people considered sunglasses to be more of a fashion accessory than a necessity. However today we are much more aware of the damaging effects of UV light on our eyes, and sunglasses technology has adapted to these needs.
  2. For a small population of lucky people, they can wear sunglasses without prescription, because they have good distance vision.
  3. If you wear contact lenses, you can enjoy the convenience of wearing non-prescription sunglasses on top of your contact lenses.
  4. If you do not require any prescription in your sunglasses, the options listed below will still help you in selecting the best sunglasses for your needs, because they are available for all types of sunglasses with prescription or not.
  5. Everyone has preference in their style of sunglasses, and if you do not require prescription in your sunglasses, you are not limited in your choices of styles. For example, the size of the lens or the curvature of the frame front may affect the vision quality in prescription sunglasses.


Color of the tint / lens color of the sunglasses

  1. Black / grey: When describing the color of the lenses, black or grey are interchangeable, because any percentage of black can be described as grey. Most sunglasses have a grey tint, which may or may not be based on a blue tint. This tint filters all colors uniformly and simulates a visual condition of lesser sunlight, which most people find pleasant.
  2. Brown: Brown lenses are typically the second most popular choice in tint color. When you compare the color brown and grey side by side, relatively speaking, you may notice that grey seems more natural to look through, and brown lenses to be milder. A brown lens will of course render everything you see in a brown shade, which although not very natural it can be preferable. A brown lens also may go well with your fashion choice. Be sure to try both grey and brown to see which you prefer.
  3. Yellow: This shade is becoming more popular recently. It is lightly tinted (~50%), reducing UV rays while not darkening your surroundings as much, so you can see better through them than other lens colors, and you can wear yellow sunglasses day or night. Many people feel that a yellow lens retains much more color contrast than other tints, and golfers especially prefer it because it helps them locate the ball and see their surroundings. Additionally, yellow is a very bold fashion choice and can really make your sunglasses stand out in a cool way.
  4. Other colors: Green is one of the popular colors other than grey or brown. Most Ray Ban sunglasses have dark green, and it becomes the signature of the Ray Ban brand, but you can get them in any pair of prescription sunglasses. Vision wise green is the most neutral color to look through after grey. Sunglasses are also available in deep blue or pink, these colors are mostly for fashion purposes and personal preference, which is to say you probably already know if you like them or not.


Density of the tint

  1. In technical terms, 100% grey is a completely opaque lens with no light passing through, and 50% grey means half the light passing through. In most cases, 80% grey are popular choice for most people, which blocks most light, yet retain enough vision for you to discern details in your visual field. The percentage of tint is important when you are ordering sunglasses. If you cannot decide the tint percentage, ask your optician to show you some samples of different tint intensities.
  2. For professional purposes, such as long-distance driving or outside work, some people will request that their sunglasses be tinted as dark as possible. However one should be aware that on cloudy days or later in the afternoon your visual acuity may be reduced to less than acceptable, when there isn’t as much natural light around you.
  3. For some older sunglasses wearers, especially those who have had cataract operations, their visual acuity may be less than 20/20 even when wearing prescription lenses, as it is currently medically impossible to restore their vision to be better. If this describes you, it is advisable to wear sunglasses that are not tinted less dark, because if your tint is too dark it may reduce your visual acuity below acceptable levels and you will find it difficult to manage.


Polarized sunglasses

  1. One of the most popular options for sunglasses, polarized lenses provide you with even better protection against glare. The lenses are specially made with microscopic shutters that are invisible to the naked eye, and only allow light through the lens aimed directly at the eye, blocking away all other scattered light. As a result, though the intensity of light through this lens is reduced, contrast and clarity are perfectly preserved. In situations where you experience overwhelming glare, such as on a snow-covered mountain or a water surface, the difference is enormous. Polarized lenses are especially popular with fishermen, because they cut away all the glare from the surface of the water, allowing you to look directly through the water at the fish.
  2. When you are looking at the computers or other device with screens with polarized sunglasses, you may see distorted images. This is because the computer screen is also polarized, and there is distortion between any two polarized surfaces. In such situations, it is best to take off your sunglasses to look at the device’s screen.


Transition glasses

  1. Transition glasses are an alternative choice for outdoor activities. When activated by UV, the clear lenses will become sunglasses right away. When you move back to indoor, the lenses will be clear again. People like them because you do not need to carry two pairs of glasses when you take a walk or doing something outside.
  2. Transition sunglasses won’t change colors inside the cars, because most car windows can block UV significantly. Recently some transition sunglasses can be worn inside the cars, but the color change is not as good as the transitional sunglasses.


Clip-ons or cover-over sunglasses

  1. Clip-ons are very convenient to use, because you can simply add them to your glasses as you require them depending on the situation. If you are interested in clip-ons, it is better to purchase frames that include clip-ons. It is possible to purchase pre-made separate clip-ons, but difficult to find one that matches exactly your frame shape.
  2. Cover-over sunglasses is one type of non-prescription sunglasses in most cases. They are large sunglasses that fit over your glasses. You can easily put on the cover-over sunglasses when the light is too bright on top of your regular glasses. It especially the favourite eyewear for people who had cataract surgeries because it can block the light from both sides of the sunglasses.


Mirror tint

This is a specialized kind of tint for sunglasses, which has a completely reflective front coat like a mirror. It is excellent for reducing glare, and some like it better than a regular tint because of the distinctive look. The downside is that it is rather expensive.



If you have further questions, you can reach me at 3 for 1 Appleby Opticals, 2180 Itabashi Way, Burlington, Ontario L7M 5A5, phone 905-309-0544, email applebyopticals@gmail.com.

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