Sunglasses or sun glasses are a visual aid that has feature lenses colored or darkened to prevent direct strong light from entering the eyes. Some call them sun-cheaters. As we all know that most people find sunlight either too bright at times or their eyes feel uncomfortable.
Medical experts and eye doctors highly recommend wearing some kind of protection to protect your eyes from the ultraviolet rays that could possibly lead to cataract or some other eye problem. Color shade glasses have become very popular among all ages and for all season, though summer times or at beaches it is more comforting to wear them all the times. It is undoubtedly popular as fashion accessory among celebrities, models and working and non-working people.
Film lighting is typically stronger than natural light and you will often see Hollywood stars protecting their eyes with high quality designer sunglasses in various color shades and style.
Sam Foster first introduced inexpensive mass-produced sunglasses in 1929. They first became polarized in 1936, when Edwin H. Land began experimenting with making lenses with his patented Polaroid filter.
These lenses can improve visual comfort and visual clarity by protecting the eye from glare. Excessive exposure to ultraviolet radiation (UV) can cause short-term and long-term ocular problems such as photokeratitis, snow blindness, cataracts, pterygium, and various forms of eye cancer.
For regular use it is often recommended to wear green, gray, yellow or brown color lenses. Gray lenses are considered neutral because they do not enhance contrast or distort colors. Brown and green lenses cause some minimal color distortion, but have contrast-enhancing properties. Orange and yellow ones have the best contrast enhancement at depth perception but cause color distortion. Golfers and shooters for its contrast enhancement and depth perception properties commonly use yellow ones.
Some people prefer to wear polarized to reduce glare such as from water and fishing people often go for these, as the ability to see beneath the surface of the water is very important.
Sunglass lenses and frames are made from the material either glass or plastic. Plastic lenses are typically made from acrylic, polycarbonate or Polyurethane. Glass lenses have the best optical clarity and scratch resistance, but on the other hand are heavier than plastic ones are more likely to break or get scratching. They can also shatter or break on impact. Plastic lenses are lighter but are more prone to scratching. Polycarbonate plastic lenses are the lightest, and are also almost shatterproof, making them good for impact protection. CR-39 is the most common plastic lens, due to their low weight, high scratch resistance, and low transparency for ultraviolet and infrared radiation.