EYEGLASSES LENS TINTS
Pink, or commonly referred to as rose, is a fairly popular color used to tint lenses. Many people get them to improve visual comfort in harshly lit environments like offices with fluorescent bulbs.
However, these patients would usually be better off with a good quality anti reflective coating on their lens which would reduce glare from harsh lighting better than the colored tint.
Yellow tints have had a fairly steady reputation to be useful for 3 purposes:
Blue light absorption: Yellow tints absorb blue wavelengths, so they could reduce glare or scattered light outside.
Shooting: The research on this is inconclusive. For some shooter it seems to help, for others, it does not.
Night Driving: These can be found in gas stations all over the nation, and on amazon sold to people in order to improve night driving vision. We actually recommend against using these for night driving though. At night, light levels are already low, and any tint (by definition) is going to further reduce the amount of light through the lens. Patients who are looking for improved night driving would be much better served with an anti reflective coating.
Brown tints are commonly used as sun lenses. Like yellow, they are good at absorbing the shorter, blue wavelengths which can cut reflections and improve contrast on sunny days.
Gray tints are the most common outdoor tints used for sunglasses. It provides an even reduction of light transmission across the whole visible light spectrum. This allows colors to be seen as they truly are - just dimmer. We recommend gray over brown or green for anyone with color deficiencies because of this.
Green tints have gained some popularity for sports like golf, tennis and baseball possibly because they don't block as much light as brown or gray, and match the color sensitivity of the human eye more so than some of the other colors. We are not aware of research proving the claims that green tints will help improve vision for specific outdoor sports better than another color.
Solid tints refer to the tints evenly cover the entire lens. These are the most common types of tints for indoors and outdoors. There is a grading scale of 1 to 3 which indicates the darkness - or the amount - of tint in the lens. A grade 1 tint is mild/light, grade 2 tint is medium and grade 3 tint is dark. Ask our optical team which grade looks like and feel free to stop in and try a few before putting these tints into your eyeglasses.
Gradient tints are cover the surface of the lens unevenly. The color tint is most intense on one side (usually the top), then gradually fades towards the opposite side of the lens. This can be helpful in sunglasses if you need to do reading outside but don't want to look at text through the tinted area. Gradient tints come with a scale of 1 to 3 just like the solid tints and are available in most every color outlined above.
Photochromic tints enable the lens to change how much light passes through based on the amount of light exposure. This technology was invented in 1964 and began with Corning's PhotoGray lens. Over time, the science evolved and changed and we now have dozens of options to choose from based on your needs.
The lenses darken with exposure to UV light from 300 to 400 nm through the use of a molecule, Indolinospironaphthoxazine (ISN) which breaks apart and absorbs light photons during UV exposure and then returns to it's normal structure without the light.
Plastic photochromic lenses don't always darken as well as glass photochromics, especially in hot weather and tend to wear out earlier. However, their lightweight makes them much more comfortable and therefore more popular than their glass material counterpart.
Photochromic lenses are available with polarization, and in gray, brown and green tints. They do not generally darken in the care with the windows up because you glass windows block the UV light already. Therefore, they shouldn't be considered sunglasses for all occasions.
There are some factors that affect the effectiveness of the photochromics.
Amount of Light: The greater the amount of light, the more they will darken. With the amount of overcast we get in Bellingham, do not be surprised if your photochromic lenses are only about halfway dark even in the middle of the day.
Temperature: You might be surprised to learn that photochromics generally work better with colder temperatures.
Previous Exposures: Photochromics often have what is called "exposure memory" which means that they'll work best after a period of using them. If you don't use them for months, they will lose the memory and thus you will have to break them in again with a few more indoor/outdoor wearing cycles.