Normally, people only know photochromic lenses or bifocal lenses, and the photochromic bifocal lenses are hardly to be touched since most optical shop can’t supply those. But some customers have two different optical powers on their special prescription. If they want to add the transition sunglasses function to the bifocal lenses in order to protect eyes at the summer. So the photochromic bifocal eyeglasses are perfect choice.
Generally speaking, the separate photochromic lenses, also called transition lenses, which go from clear indoors to as dark as sunglasses outdoors. Their advanced technology adjusts to changing light, so you see clearly and more comfortably in virtually any light condition. They have a mid refractive index of 1.57, so they are much thinner than standard CR-39 lenses. To what degree the eyeglasses will turn dark depends on the thickness and the coating of the molecular organic element on the eyeglass lens. The thickness is very important to be considered when buying transition glasses. Always, choose the appropriate one because your eyes do matter.
Also, these bifocal eyeglasses are prescribed to people suffering from presbyopia and who also require a correction for myopia, hyperopia and/or astigmatism. Bifocal lenses are mostly crafted by molding a reading segment, used for near vision, into the primary lenses. Since these lenses are available with the reading segments in diverse shapes and sizes, the choices for buyers have also increased. One of the most popular ones is the D-segment which is generally 28 mm wide. Though these D-segment bifocal lenses offer better viewing qualities, an increasing number of users are going for progressive bifocal lenses.
Furthermore, the photochromic lenses material is generally recommended for low-to-moderate prescriptions, between +3.00 and -4.00. Although now 1.61 photochromic lens is available, if your prescription is much higher, and selecting it to avoid too thick. But unfortunately, the high index transition lens is unavailable with bifocal. Customers only buy the divided transition or bifocal one at the refractive index of 1.61 lenses.
In fact, the two lenses alone retail for over $180.00. If you don’t mind the online stores, there is a cheap eyeglasses website- PrescriptionGlassesOnline.net is proud to offer them to you for far less, as a package including a stylish new frame. Such as: lens package HP- Thin and Liter (1.57) Photochromic Bifocal Lenses, its promotion time and the lowest price is just $79.95. It is the fastest growing online community selling high quality yet cheap eyeglasses, bifocal eyeglasses and other eyewear.