How Do Transition Lenses Work?
- In the late 1960s, Corning developed prescription lenses that become dark in the sunlight. These lenses were only made in glass. Approximately 30 years later, Transitions initiated the manufacturing and distribution of these lenses in plastic, making these lenses very popular.
- Transition lenses have special dyes that allow them to self-adjust when the amount of available light changes. These patented dyes are photochromic; they are affected when exposed to ultraviolet (UV) rays produced by the sun. Specifically, the exposure of these lenses to UV rays causes the lenses to darken. As the presence of UV rays increases, the lenses change accordingly and become darker.
- The lenses tend to undergo the most change during the day. When you step outside on a sunny day, lenses automatically become clearer. They ultimately adjust to allow a suitable amount of light to enter your eyes. This is a gradual process and practically unnoticeable to the wearer. However, glasses tend to darken more rapidly than lighten. At night or when indoors, when UV rays are no longer present, the lenses are as clear as regular reading glasses.
- While indoors, lenses do not change when lights are turned on because Indoor lighting does not contain the necessary UV rays light to activate the dyes. Although sunlight contains UV rays, when sunlight comes through a window, the rays are blocked. As a result, lenses would not darken as much when sunlight comes through a window or the windshield of a car. In addition, lenses are affected by temperature and tend to darken less in heat. After several years of use, transition lenses become less effective.
- A separate pair of sunglasses may no longer be needed with transition lenses, since these lenses serve the same purpose and also provide additional benefits. Similar to sunglasses, transition lenses provide protection from UV rays, which can be damaging to your eyes. Transition lenses can even become as dark as most sunglasses on a bright sunny day. However, transition lenses have many more advantages than sunglasses. Specifically, transition lenses reduce the eye strain and fatigue caused by squinting. These benefits occur because of the reduction in glare provided by the lenses. Glare is excessive brightness that can occur during the day or at night. Night driving is further complicated by the glare of streetlights or oncoming cars. This can leave the driver vulnerable to accidents.
