A single vision lens is a lens that serves only one purpose. It is usually used for either reading or for seeing in the distance. The most common material that a single vision lens is made out of is CR39 (plastic), however, they are also available in glass or photochromatic or Transition Lenses (a plastic that darkens in the sun).
A bifocal lens is most commonly described as the lens with the line on it. The top section is used for the patient to see in the distance. The bottom section, which is called the seg (segment), is used for reading. There are different types of bifocals, but the most commonly used is called the 28mm D-Seg.
A progressive lens is one that increases in power gradually towards the lower portion of the lens. It is not divided into sections, hence has no visible lines on it. When looking straight ahead, you should be able to see in the distance. When you move your eyes towards the bottom of the lens, you should be able to read. In between, you should be able to look at intermediate distances clearly. This lens blends from your distant vision to your reading.
Transitions lenses are designed to be worn all day long, outdoors and indoors. And you can get them in virtually every frame, style, size and prescription. They’re even great for children. Transitions don’t just make everything look great, they also reduce eye fatigue and strain.
And block 100% of UV light.
They change effortlessly, but the technology behind them is anything but simple. A complex formula of photochromic molecules make light, dark and every shade in between possible.
Anti-Reflection lenses are recommended for all ages. Benefits include; comfortable night-time driving by reducing glare from headlights, taillights and street lights. Anti-Reflective lenses are clean, clear, and glare-free so they’re virtually invisible to those around you. People see you instead of your glasses. Anti-Reflective lenses mean fewer headaches and less eye fatigue caused by reflections from computer screens and daytime lights. It provides protection against glare, scratches, smudges, dust, water, UV and other enemies of clear vision.
Polarised lenses do what no other lens or lens treatment can - block blinding glare. In addition, polarised lenses can enhance visual acuity, colour contrast and visual comfort, and block 100% of harmful UVA and UVB light.
When light hits a reflective surface, such as water, snow, even cars and buildings, the light can become polarised, resulting in glare that can interfere with your vision. Only polarised lenses can remove this glare, working like a venetian blind to block out horizontal light waves .