When buying a new pair of glasses, you often come into these terms when picking the lenses. Here is what these options mean:
Photochromic - Optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet radiation.
Anti-Reflective - Reduce glare and reflections on the surface of your lenses.
Polarized - Special chemical applied to filter light to help give you clearer, more accurate vision, and alleviate some eye strain.
Polycarbonate - Made of strong lightweight plastic. More thin and withstand impact. (Good for Children or Sports Eyewear). Built in UV Protection.
UV Protection - Shield your eyes from UVA and UVB rays.
Scratch Coating - Generally needs to be applied to Polycarbonate lens to prevent scratches which is very easy on lenses made of Polycarbonate.
High Index - Thinner and lighter than regular glasses. Recommended for people with strong prescription.
Another set of terms you see is Single Vision, Bifocal, Trifocal, and Progressive. Essentially, "Single Vision" means the lenses address a single distance properly (whether it's near or far" while Bifocal and Trifocal splits your lenses into different sections (usually top/mid/bottom) for different distance viewing. And "Progressive" is the more gradient like where from the top of the lenses to the bottom of the lenses it slowly help address vision from far to near.
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