Photochromic lenses are those eyeglass lenses that are clear or almost clear indoors. These are lenses that automatically darken when they are exposed to sunlight. Sometimes other terminologies are used for calling photochromic lenses. These include "variable tint lenses", "light intelligent" and "light-adaptive senses". The ultraviolet radiation released by the sun activates the molecules that cause the darkening of photochromic lenses. As ultraviolet rays carry out the penetration in the clouds, the darkening of the photochromic lenses will take place on sunny and overcast days. Usually, in an automobile, photochromic lenses will not darken as a windshield glass causes blockage of many ultraviolet rays.
Materials and designs of photochromic lenses
Recent improvements in technology let the activation of some photochromic lenses with both visible and ultraviolet light, which results in some darkening behind the automobile's windshield. Photochromic eyeglass lenses are offered for sale in nearly every design and lens material. These include bifocals, progressive lenses, and high-index lenses. Photochromic lenses, an added benefit, protect the eyes of their users from a hundred percent of the harmful type B ultraviolet and ultraviolet-A rays. Because a person's lifetime exposure to ultraviolet radiation and sunlight has been related to cataracts in the later phase of their life, it is a decent idea to use photochromic lenses for the eyewear of children and eyeglasses for adults. Polycarbonate is the safest material for children's lens, offering up to ten times the effective resistance of the other lens materials.
Adding an anti-reflective coating to photochromic lenses improves their performance even more. anti-reflecting coating lets more light pass-through photochromic lenses for better vision in low-light conditions like driving at night. It eliminates harmful reflections of sunbeams and the rest of the light from the lens' backside inside bright conditions. Although photochromic lenses are more expensive than pure eyeglass lenses, they provide people with the convenience of decreasing the need for carrying prescription sunglasses to pair with them wherever they go.
Blue light and photochromic lenses
Besides shielding people's eyes from glare in outdoor environments, there is an additional advantage of photochromic lenses--- they help protect people eyes from dangerous blue light. In general, blue light is the visible light that ranges from three hundred and eighty to five hundred nanometers. Sometimes, blue light is further divided into blue-turquoise (approximately four hundred and fifty to five hundred nanometers) and blue-violet light(about three hundred and eighty to four hundred and fifty nanometers).
By shielding human eyes from blue light, photochromic lenses play their role in protecting human eyes from eye problems. This is because excessive exposure of the human eye retina to blue light can harm light-sensitive cells found like those present in human beings' eye retina, which has been responsible for causing permanent loss of vision under experimental conditions. Photochromic lenses also help protect human eye health by ensuring that human eyes do not suffer from digital eye strain. This is because blue light is also responsible for contributing to digital eye strain and causing oxidative stress in the human eye retina. Photochromic lenses protect the human eyes from that blue light.
Digital eye strain refers to a set of vision and eye problems. These problems encompass headaches, eye fatigue, blurred vision, irritated and dry eyes. For protecting your eyes from blue light, you should contact an eye care specialist and discuss with them the exposure of your eyes to blue light and ask him which kind of photochromic lenses will meet your particular eye needs. If you want to prevent eye problems caused by ultraviolet radiation and blue light. Then you should order photochromic lenses from a photochromic lenses exporter.
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