NoIR filters can help people minimize eye discomfort and maximize visual resolution. Filter shade number 21 - medium gray - provides infrared protection in addition to 100% ultraviolet protection. It allows in 28% of visible light and it is considered a soothing color filter that sharpens focus and provides excellent glare protection. It is often recommended for people with Glaucoma or are Pre-Cataract.
This clip-on style lens can be attached to an existing pair of glasses and flipped up when not in use. Lens measures 132mm x 52mm (5.20" x 2.05").