Are photochromic lenses good as computer glasses?
Photochromic lenses, which are relatively transparent with a subtle tint when worn indoors but darken when exposed to sunlight, have the added benefit of filtering blue light.
Computer glasses can potentially make looking at a monitor more comfortable if you experience digital eye strain. These glasses typically have an intermediate prescription that can help you focus at a computer distance (about 20 to 40 inches). Some computer glasses have a blue-violet light filter that may improve overall viewing comfort. So, depending on the prescription of your lenses, photochromic lenses may work well as computer glasses.
What are photochromic lenses made of?
Photochromic lenses were originally made of molecules composed of trace amounts of silver chloride (the same chemical compounds used to develop film). When this silver chloride was exposed to ultraviolet light, the molecules become silver metal, allowing the lenses to absorb visible light and turn darker in the process.
Unlike film exposure, photochromic lenses were also made with copper chloride, which strips the silver of its chloride electron. This allowed the lenses to return to their original, non-absorbing state in the absence of ultraviolet light.
More modern photochromic lenses often contain organic molecules called naphthopyrans instead of silver chloride. Naphthopyrans change their molecular structure when ultraviolet light strikes them, making the lenses darken.
So, are photochromic lenses good for computer use?
Photochromic lenses are versatile --- they function as glasses and sunglasses in one pair of spectacles. In addition to blocking ultraviolet (UV) rays, they have the added benefit of filtering blue light and reducing glare. It is just fine to wear your photochromic lenses at the computer if the prescription helps you focus clearly on your monitor.
