NoIR filters can help people minimize eye discomfort and maximize visual resolution. Filter shade number 21 ‚ medium gray ‚ allows in 32% of visible light, has 100% ultraviolet protection and has a soothing color which sharpens focus and provides excellent glare protection. It is often recommended for people with post-operative cataracts. The standard fit-over style frame may be worn over most prescription frames or worn alone. It features side shields with temple lapped construction to keep out extraneous light and wind and it has curved temple pieces for a non-slip fit. Frame measures 5 1/2″ temple to temple.