what do you call glasses that change in sunlight

Glasses that change in sunlight are called photochromic lenses or transition lenses. They have lenses that are made with special dyes that chemically change when exposed to the sun’s ultraviolet (UV) rays, causing them to darken and lighten. Photochromic lenses are convenient because they save you from having to carry around two pairs of glasses and having to switch between them to meet different needs. They are also a great help for those who always wear eyeglasses, as they reduce the need for two separate pairs of prescription eyewear. However, there are some drawbacks to photochromic lenses. For example, they may not darken well in the car because windshields block UV rays. Additionally, different brands have different levels of darkness and different reaction times.