Photochromic lenses often end up being referred to as "transitional" lenses . "Transitional " is a trademarked product that is photochromic.
Photochromic coating darkens the lenses when one is out in the sunlight and will then lighten up to be completely clear when one enters a dark space (or indoors)
They are extremely useful for everyday wear as they quickly adjust and adapt to the current light conditions, helping you through your busy day.
These lenses are sensitive to ultraviolet rays, so how dark they get is directly related to how much UV rays actually reach the lenses. This is important to know, because when one is driving the lenses will not get as dark as you might like on a very sunny day as there is no direct exposure.
In contrast, on a cloudy day, being outside one will discover that the photochromic lenses are quiet dark due to the exposure to the UV rays.
It is also important to point out that photochromic lenses can darken and lighten pretty quickly as needed but do not darken completely more like 85-90% but do clear up to 0.
This is a direct contrast to polarized lenses, which will stay dark under all circumstances. Photochromic lenses offer great flexibility and will protect the eyes from UV rays but are not a replacement for polarized sunglasses as these offer the best and most complete protection for the eyes.
At Eyewearinsight.com though we do offer as a premium "progressive (Freeform) Transition ® Lenses (1.56)" we otherwise offer photochromic lenses coating of our own brand at a very discounted rate.
As always if you find that our quality does not measure up please contact us and we will be happy to assist you further; but we have yet to get a complaint and in fact find that our quality measures up quite nicely to "brand names". Our customers always come back for another pair if not two..and even buy for their family members.