Categories of sunglasses
There are four main categories for sunglasses.
|0||The lenses of category 0 are either clear or have a very light tint. Mainly used for safety glasses|
|1||The lenses of category 1 are for fashion purposes.|
|2||The lenses of category 2 are for general purposes. They provide some protection from visible light and from UV rays.|
|3||The lenses of category 3 provide extra protection from visible and UV light. These lenses will only allow less than 20% of visible light to penetrate the lens. This means that they will block out 80%+ of light.|
|4||The lenses of category 4 provide a high level of protection from visible and UV light. These lenses are too dark, so they are prohibiting when driving. Lenses of this category will allow less than 10% of light to transmit through the lens. They are to be used for specific situations only, like activities on a high altitude. They aren’t suitable for everyday activities.|
Also, consider buying sunglasses with UV 400 protection (also known as 100% UV protection). Sunglasses with UV 400 block all light rays with wavelengths up to 400 nanometers, meaning that no UV light will pass through the lens. This covers all of UVA and UVB rays.
Overexposure to ultraviolet light is thought to be a cause of cataracts, retinal damage and other eye problems.
Do sunglasses protect against blue light?
Common sunglasses do not offer sufficient protection from the blue light. Blue light can’t be blocked neither from common tinted lenses, as they are not manufactured for this purpose. The best solution to protect your eyes outdoors, from UV radiation, as well as blue light, is to prefer good quality polarized sunglasses.
What polarized lenses are?
Polarized lenses can block efficiently the glare from light reflecting off any smooth surface like water, snow, and glass. Polarized lenses can keep out horizontal light. This light contains damaging short-wave blue rays. So, polarized lenses can filter some of the blue light.
Polarized lenses to block blue light.
To better protect our eyes from the harmful effects of the blue light, it is recommended to use sunglasses with polarized lenses. This lens coating provides effective protection from these harmful light rays.
Always, read carefully the specifications of the manufacturer. For instance, SPY Optic has developed lenses, that claim to provide 100% UV and blue light blockage. Also, they claim that these lenses let the good long-wave blue light rays pass. Another company, named Costa, claims to have produced lens technology that goes beyond polarization. These lenses filter out the harsh yellow and harmful blue light.
For better eye protection, always look for similar specs on the manufacturer’s brochure. You better prefer polarized sunglasses with UV 400 protection. Also, seek for lens technology that absorbs the High Energy Visible (HEV) blue light. That’s the short wave blue light you want to avoid.
Are polarized sunglasses better for your eyes?
The short answer is yes…Polarized sunglasses can give you extra protection and comfort, in everyday activities, like driving or fishing. But remember: polarization has nothing to do with UV light absorption. The first thing you have to consider is the UV protection of the sunglass. Only buy high-quality sunglasses, with UV 400 filter. A polarized lens is a bonus.
Limits on polarized sunglasses
Polarized sunglasses aren’t suitable for reading the screen of a smartphone, or any other LCD screen, like dashboards on the road. Also, polarized lenses block some light, so it is better to be avoided while driving and there is limited sunlight. In addition, prefer sunglasses of the optimum darkness for everyday use. Polarized sunglasses tend to be darker than tinted ones.