What are Photochromic Lenses?
The most popular photochromic lenses on the market are called Transitions®. When Transitions lenses are exposed to UV light, trillions of photochromic molecules in the lenses begin to change structure and darken. This reaction changes the degree of darkening in relation to the amount of light that reacts with the lens. The Transitions photochromic technology is put into the lens through one of two types of processes.
Temperature can have an effect on the speed that the lenses change their color. In colder temperatures the photochromic change will be slower and obviously in higher temperatures the reaction is much faster.
Imbibing Technology
Now the lenses are not drinking or imbibing in the sense that you might first think of when the term imbibing is used. This technology uses heat to put the photochromic dye into the lens. After the imbibing is completed, a scratch-resistant coating is applied to the surface of the lenses.
There are surfaces of lenses that do not or are resistant to imbibing the photochromic dye into the lenses very readily. In these cases another method is used.
Trans- Bonding
In this method the photochromic technology is applied to the surface of the lenses since the dye does not penetrate into the lenses.
New Types of Photochromic Lenses
Most photochromic lenses darken as they are exposed to ultraviolet light (UV) . When people get into their cars these types of photochromic lenses do not stay darkened as car windshields block 99% of ultraviolet light. Therefore most photochromic lenses are not adequate for people when they are driving.
Transitions XTRActive® lenses contain a specially formulated photochromic dye that responds to both ultraviolet light and natural light. These lenses can stay moderately dark inside a car and provide a reasonable sunglass while driving.
Transitions Drivewear® lenses combine two different types of technologies. NuPolar® polarization eliminates glare from car hoods, roads, and other reflective surfaces such as water or snow. Transitions photochromic lens technology allows the lens to lighten or darken based on the light conditions a person is in at that moment.
Four Different Types of Transitions Lenses
Transitions
Lens Color Options- Clear to gray or clear to brown
Indoor Clarity- Clear
Outdoor Darkness- moderate darkness
Inside a Car- Clear or does not darken
Polarized- No
Transitions Vantage
Lens Color Options- Clear to Gray
Indoor Clarity- Essentially clear
Outdoor Darkness- Dark
Inside a Car- Essentially clear or does not darken
Polarized- Variable polarization as the lens darkens
Transitions XTRActive
Lens Color Options- Clear to grey
Indoor Clarity- Essentially clear
Outdoor Darkness- Very Dark
Inside a Car- Moderately dark
Polarized- No
Transitions Drivewear
Lens Color Options- Greenish yellow to copper to dark reddish brown
Indoor Clarity- Darkened
Outdoor Darkness- Very Dark
Inside a Car- Yes and is fully darkened
Polarized- Yes
Summary
Photochromic lenses are a useful option for people when they are choosing what kind of lens that they are looking for in a pair of glasses. There are now different types of lenses to choose from when deciding on a lens depending on what activities you usually like to do.
Leave a Reply