It is common knowledge by now that UV rays from the sun cause a lot of damage to the eye. UV rays are located above the violet portion of the visible light spectrum and its main source is sunlight. There are three main categories of UV, that is, UVA, UVB, and UVC. UVA has a longer wavelength, which allows it to pass through normal glass easily. The information below is worth knowing about sunglasses lens types.
Scientists have not proved whether UVA can damage the eye or not. On the other hand, the second type of UV rays is extremely dangerous to the eye. This type is the UVB. It is advisable for people to wear sunglasses since these rays are not able to pass through glass. The UVC rays are blocked by the atmosphere and for this reason, they are not able to reach the earth.
In order to prevent the harm caused by UVB, it is necessary to put on sunglasses. Apart from sunglasses being used as a protective mechanism against light, they can also be used to correct various eye defects. An example is where people who are short- or long-sighted wear glasses to correct defect in their vision. These glasses require lenses for them to work properly.
There are different types of lenses which give different effect when a person wears them. These types of sunglass lens include progressive, polycarbonate, polarized, photochromic, Hi-index, trifocal and bifocal. A complex front surface is used to make aspheric lenses. This surface gradually changes its curvature from the center towards the edge. These lenses are meant for correcting minor vision distortions. Due to their light weight and thinness, they are suitable for carrying and wearing.
The correction of far-sightedness as well as short-sightedness is done by bifocal lenses. The lens located in the lower part is meant for correcting short-sightedness while that in the upper part of the glass are for improving long-sightedness. Their prescription is mostly for the elderly people because vision develops defects as one ages. Trifocal lenses incorporate into bifocal lenses the ability to see objects that are located only a couple of feet away.
Photochromic lenses are designed in a way that they darken when they are hit by sunlight. This feature is very convenient for most people that would otherwise have to carry multiple sunglasses for different conditions. These lenses are available in all materials and lens materials. For instance, it is possible to find high-index, bifocal, and trifocal lenses that are photochromic. They are a popular choice for people of all ages.
Polarized lenses are made in a way that they decrease the reflection that comes from surfaces like glass, snow and water surfaces. This helps the wearer to perceive objects more clearly and sharper. Polarized lenses are available as prescription as well as non-prescription sunglasses. They are worn by people who are sensitive to light. People who have recently undergone surgery for cataract find these products very suitable.
Active individuals should go for polycarbonate lenses. This is because these lenses are impact-resistant and resilient. Most parents buy their children these lenses because kids always damage sunglasses.
Scientists have not proved whether UVA can damage the eye or not. On the other hand, the second type of UV rays is extremely dangerous to the eye. This type is the UVB. It is advisable for people to wear sunglasses since these rays are not able to pass through glass. The UVC rays are blocked by the atmosphere and for this reason, they are not able to reach the earth.
In order to prevent the harm caused by UVB, it is necessary to put on sunglasses. Apart from sunglasses being used as a protective mechanism against light, they can also be used to correct various eye defects. An example is where people who are short- or long-sighted wear glasses to correct defect in their vision. These glasses require lenses for them to work properly.
There are different types of lenses which give different effect when a person wears them. These types of sunglass lens include progressive, polycarbonate, polarized, photochromic, Hi-index, trifocal and bifocal. A complex front surface is used to make aspheric lenses. This surface gradually changes its curvature from the center towards the edge. These lenses are meant for correcting minor vision distortions. Due to their light weight and thinness, they are suitable for carrying and wearing.
The correction of far-sightedness as well as short-sightedness is done by bifocal lenses. The lens located in the lower part is meant for correcting short-sightedness while that in the upper part of the glass are for improving long-sightedness. Their prescription is mostly for the elderly people because vision develops defects as one ages. Trifocal lenses incorporate into bifocal lenses the ability to see objects that are located only a couple of feet away.
Photochromic lenses are designed in a way that they darken when they are hit by sunlight. This feature is very convenient for most people that would otherwise have to carry multiple sunglasses for different conditions. These lenses are available in all materials and lens materials. For instance, it is possible to find high-index, bifocal, and trifocal lenses that are photochromic. They are a popular choice for people of all ages.
Polarized lenses are made in a way that they decrease the reflection that comes from surfaces like glass, snow and water surfaces. This helps the wearer to perceive objects more clearly and sharper. Polarized lenses are available as prescription as well as non-prescription sunglasses. They are worn by people who are sensitive to light. People who have recently undergone surgery for cataract find these products very suitable.
Active individuals should go for polycarbonate lenses. This is because these lenses are impact-resistant and resilient. Most parents buy their children these lenses because kids always damage sunglasses.
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