The lenses used in sunglasses are very important for providing proper protection for the eyes. With the advancements in the glass manufacturing technology, different types of lenses are used in glasses. Each and every type caters to different needs. You have to know about the lenses to choose the glass for your purpose.
Lenses are made of plastic or glass. Plastic lenses are light weight made of plastic material that can be tinted with different colors of your choice. They block 80% of UV rays thus providing good protection from the sun. Glass lenses are more prone to scratches but they have excellent inherent optical quality.
Polycarbonate lenses are widely used in sunglasses these days. They provide 100% sun blocking. They are very light and they don’t shatter very easily. Polycarbonate lenses are perfect for sporty glasses and children sunglasses as they are scratch resistant.
High index lenses are made of high index plastic material. They are widely used for cosmetic purposes as they are very thin. Like polycarbonate lenses, the high index lenses provide 100% protection from the harmful rays of the sun. High index lenses must have anti reflective coating because the surface reflections increase with the increase in the index of the lens.
Aspheric lenses are best suitable for people who need to wear high prescription glasses. In this type of lens the thickness of the lens is evenly distributed compared to the conventional lenses. Thus they provide very clear vision and also give you a stylish look. For light weight glasses, aspheric lenses are made with the high index material.
Photochromic lenses have the property to control the light entering the eye irrespective of the conditions prevailing outside. When you alternate between indoor and outdoor you have to choose these lenses to reduce the strain on the pupil of the eyes.
Polarized lenses are perfect for an outdoor aficionado. They greatly reduce the glare by canceling the rays due to reflection from the flat surface. These lenses can be used when you are engaged in driving, golfing, skiing, and so on. Any glass must provide you protection from the harmful UVA and UVB rays of the sun. When you go out your eyes are exposed to the hard sun. So ensure that your lenses have proper UV coating.
If your lens is made of polycarbonate or high index plastic, then you need not worry about UV protection as these materials inherently block the sun. When you want your conventional prescription glasses to look thin and light weight you may consider the use of aspheric lenses or high index plastic lenses. Use of smaller frames may also add to the style.
Scratch resistant coating (SRC) is essential for all lenses to prevent the lenses from getting scratches very often. Polycarbonate and high index lenses come with this SRC coating by default.
Anti reflective coating (ARC) is essential for certain type of lenses like high index plastic to reduce the reflective rays. Glasses with this coating eliminated glare caused during driving in the night and staring at the computer. But glasses that have this ARC are prone to scratch and hence ARC and SRC are mutually exclusive. You cannot have both coatings on the same lens. To improve the look and to see the world in your favorite color, you can add tints to your lenses. Many adults are now tinting their lenses with their favorite colors. Tints can be effectively applied to plastic lenses. The tints will be absorbed uniformly in plastic lenses. Glass lenses cannot be tinted uniformly and are more difficult to tint.
High index plastic lenses are easier to tint than polycarbonate lenses. Lenses that have coatings such as ARC and SRC cannot be tinted as the color will not apply uniformly on the coating. If you want to tint, then you must remove the coatings, tint the lens and then reapply the coating. Tints may add style to your glass but you must ensure that your lenses are provided UV coating to protect your eyes. More than a fashion eyewear, the glass you wear must provide clear vision and proper protection for your eyes.