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.
Since UVB rays can damage the eye, it is always necessary to wear sunglasses as a protective measure. Other than acting as a protective gear for UVB rays, sunglasses also help prevent a number of defects of the eye. For example, people who have eye conditions such as long-sightedness or myopia require glasses to see well at long and close range respectively. Lenses are necessary in order for these glasses to work well.
There is a wide range of lenses, which are used to achieve different effects when worn. Some examples of sunglass lens types include aspheric, bifocal and trifocal, Hi-Index, photochromic, polarized, polycarbonate, and progressive. Aspheric lenses are made with a complex front surface that changes in curvature gradually from the center towards the edge. They are designed to correct small distortions in vision. They are convenient to wear and carry because they are lighter and thinner.
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.
When light from the sun hits photochromic lenses, they become darker. This makes them convenient for people who require multiple sunglasses for various conditions. These lenses can be found in all lens materials. For example, one can find trifocal, bifocal or high-index lenses that are photochromic. Most people regardless of the age prefer photochromic lenses.
Polarized lenses are designed to reduce the glare that comes from surfaces such as water surfaces, glass, and snow. This makes images to appear clearer and sharper. One can get them in both prescription and non-prescription sunglasses. They can be worn indoors by people who are sensitive to light. Post-cataract surgery patients make very good candidates for glasses with polarized lenses.
Polycarbonate lenses on the other hand are a good option for individuals who are always active. These lenses are made such that they are able to withstand impact and are very durable. They are commonly bought by most parents for their kids since kids commonly 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.
Since UVB rays can damage the eye, it is always necessary to wear sunglasses as a protective measure. Other than acting as a protective gear for UVB rays, sunglasses also help prevent a number of defects of the eye. For example, people who have eye conditions such as long-sightedness or myopia require glasses to see well at long and close range respectively. Lenses are necessary in order for these glasses to work well.
There is a wide range of lenses, which are used to achieve different effects when worn. Some examples of sunglass lens types include aspheric, bifocal and trifocal, Hi-Index, photochromic, polarized, polycarbonate, and progressive. Aspheric lenses are made with a complex front surface that changes in curvature gradually from the center towards the edge. They are designed to correct small distortions in vision. They are convenient to wear and carry because they are lighter and thinner.
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.
When light from the sun hits photochromic lenses, they become darker. This makes them convenient for people who require multiple sunglasses for various conditions. These lenses can be found in all lens materials. For example, one can find trifocal, bifocal or high-index lenses that are photochromic. Most people regardless of the age prefer photochromic lenses.
Polarized lenses are designed to reduce the glare that comes from surfaces such as water surfaces, glass, and snow. This makes images to appear clearer and sharper. One can get them in both prescription and non-prescription sunglasses. They can be worn indoors by people who are sensitive to light. Post-cataract surgery patients make very good candidates for glasses with polarized lenses.
Polycarbonate lenses on the other hand are a good option for individuals who are always active. These lenses are made such that they are able to withstand impact and are very durable. They are commonly bought by most parents for their kids since kids commonly damage sunglasses.
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