Transitions lenses are optical lenses that darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet (UV) radiation. In the absence of activating light the lenses return to their clear state. Transitions lenses may be made of glass, poly carbonate, or another plastic. They are principally used in eyeglasses that are dark in bright sunlight, but clear in low ambient light conditions. They darken significantly within about a minute of exposure to bright light, and take somewhat longer to clear.
In one sort of technology, molecules of silver chloride or another silver halide are embedded in transition lenses. They are transparent to visible light without significant ultraviolet component, which is normal for artificial lighting. In another sort of technology, organic photochromic molecules, when exposed to ultraviolet (UV) rays as in direct sunlight, undergo a chemical process that causes them to change shape and absorb a significant percentage of the visible light, as they darken. These processes are reversible; once the lens is removed from strong sources of UV rays the photochromic compounds return to their transparent state.
Pro and cons of transition lenses:
- Transitions lenses darken within few seconds and turn clear again just as fast. They maintain about 5-percent residual tint when indoors.
- Protect the eye from harmful UV rays. Reducing exposure to UV rays lowers the risk of cataracts and other age-related eye issues.
- This lens is available in brown and gray variable.
- Transition can apply to all forms of lenses, such as single, bifocal, and progressive lenses.
- At Vincent Optical we recommend transitions lenses for situations where you are indoors and outdoors within minutes.
- Transitions lenses are ideal for children who have difficulty juggling more than one pair of lenses.
- They don’t work in a car because the windshield blocks the UV rays that are necessary to initiate the lenses’ darkening mechanism. However, newer technology are available now for more car friendly transition lens option.
- Walking in from outdoor they require some time for them to become clear, in some cases you are forced to remove your glasses to see.
Our qualified and experienced optician and staff will ensure that you are provided with the best options for all of your eye wear needs. Simply contact us at Vincent Optical for more information.