It is commonly known that UV rays from the sun can severely damage the eye. The main source of UV rays is the sun. They are normally located over the violent part of light spectrum that is visible to the eye. UV is classified into three major classes. That includes UVA, UVB, and UVC. UVA is easily able to pass through normal glass. Before are facts regarding sunglasses lens types.
Whether this form of UV is injurious to the eye or not is a matter of contention among scientists. However, the second class of UV rays is the most dangerous to the eyes. UVB causes the most damage to the eyes and are the reason it is important to wear sunscreen and sunglasses because they cannot pass through. UVC rays do not reach the earth because they are blocked by the atmosphere.
As such, it is important to wear sunglasses as a preventive measure against damage that UVB causes. Besides serving as a preventive measure, sunglasses also act as a corrective measure for various eye defects. For instance, people who have myopia or long-sightedness need glasses to be able to see better at close and long range respectively. In order for these glasses to work effectively, they need to have lenses.
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.
Bifocal lenses are made in a special way to be able to correct far-sightedness as well as short-sightedness. The lens in the upper part of the glasses is for correcting far-sightedness while the lower part has a lens for correcting short-sightedness. They are mostly prescribed for old people whose near-vision has deteriorated as a result of aging. Trifocal lenses add the ability to see objects that are a few feet away into bifocal glasses.
Photochromic lenses are made in a manner that they become dark when they come in contact with sunlight. This adaptation makes them suitable for individuals who would otherwise need to carry multiple sunglasses for different situations. They are available in all lens designs and materials. That means that one can find bifocals, trifocals, and hi-index lenses that are also photochromic.
Another lens design is the polarized lens. This is usually designed such that it reduces the glare coming from glass, snow and water surfaces. They make images to appear sharper and clearer. They are available in both non-prescription and prescription glasses and those who are sensitive to light can wear them indoors. These glasses are usually a good choice for patients who have undergone a post-cataract surgery.
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.
Whether this form of UV is injurious to the eye or not is a matter of contention among scientists. However, the second class of UV rays is the most dangerous to the eyes. UVB causes the most damage to the eyes and are the reason it is important to wear sunscreen and sunglasses because they cannot pass through. UVC rays do not reach the earth because they are blocked by the atmosphere.
As such, it is important to wear sunglasses as a preventive measure against damage that UVB causes. Besides serving as a preventive measure, sunglasses also act as a corrective measure for various eye defects. For instance, people who have myopia or long-sightedness need glasses to be able to see better at close and long range respectively. In order for these glasses to work effectively, they need to have lenses.
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.
Bifocal lenses are made in a special way to be able to correct far-sightedness as well as short-sightedness. The lens in the upper part of the glasses is for correcting far-sightedness while the lower part has a lens for correcting short-sightedness. They are mostly prescribed for old people whose near-vision has deteriorated as a result of aging. Trifocal lenses add the ability to see objects that are a few feet away into bifocal glasses.
Photochromic lenses are made in a manner that they become dark when they come in contact with sunlight. This adaptation makes them suitable for individuals who would otherwise need to carry multiple sunglasses for different situations. They are available in all lens designs and materials. That means that one can find bifocals, trifocals, and hi-index lenses that are also photochromic.
Another lens design is the polarized lens. This is usually designed such that it reduces the glare coming from glass, snow and water surfaces. They make images to appear sharper and clearer. They are available in both non-prescription and prescription glasses and those who are sensitive to light can wear them indoors. These glasses are usually a good choice for patients who have undergone a post-cataract surgery.
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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