Transition Lenses have increased in popularity since they were developed by Transitions Optical, Inc. in the 1990s. They are high-tech lenses that operate as clear, regular eye glasses indoors and at night but automatically darken into tented sunglasses when the light conditions outdoors indicate the need for protection. They block 100% of harmful UV rays and keep your eye protected. Advances in photochromic technologies have allowed Transition lenses to be produced in almost every lens design and material, such as bifocals, progressives, shatter-resistant lenses, and high-index materials.