When it comes to cycling glasses, the options are vast. From dark tints to boost contrast in bright sunshine to clear lenses for indoor riding, there’s a choice to suit any environment.
The best option for riders who need bifocals may be a pair of photochromic glasses. These specialized lenses react to sunlight and lighten or darken automatically to prevent UV exposure to your eyes.
What are Photochromic Glasses?
Photochromic glasses, or transition lenses, are eyeglasses that darken automatically in response to UV light. They are an excellent option for people who often go outdoors and want the convenience of having one pair of eyeglasses that will protect them from UV rays indoors and out.
Photochromic lenses contain particular molecules that darken when exposed to UV radiation. When you are outside, these molecules darken the lens so that you can see better in bright sunlight. They will then change back to a clear state when you are inside or in the shade. This process takes a few minutes to complete.
Most pairs of photochromic bifocal cycling glasses also feature polarized lenses to reduce glare from the sun. For outdoor enthusiasts who enjoy jogging, bicycling, kayaking, or any other activity that involves being outside, they are a great option.
Some downsides to photochromic lenses are that they can take a little longer to darken when you first wear them, are more complex than regular glasses, and only work in certain temperatures. However, many of these issues can be overcome with new technology and by choosing a quality pair of frames. Most people who wear photochromic glasses find them very convenient and helpful, so it may be worth checking out a pair.
Photochromic lenses are transparent indoors but darken on exposure to ultraviolet (UV) light. They also fade back to their clear state once they are no longer exposed to UV light. Photochromic lenses are available in prescription and non-prescription forms, catering to various needs.
The first photochromic glasses were made of glass and coated with microscopic silver crystals that reacted to wavelengths of UV light by becoming opaque and darker. When the lenses were no longer in contact with UV rays, a compound embedded within the glass would take over and reverse this process. Today’s photochromic lenses use a different technology, but the principle is the same: the lenses are composed of molecules that react to UV light by reversible color change.
When the lens is exposed to UV rays, these molecules transfer an electron from silver metal to a copper compound within the lens, which causes it to appear darker. Once the lens is no longer in contact with UV rays, these molecules return to their original form and become transparent again.
Because they offer complete protection from harmful UV rays, Photochromic lenses are a convenient and affordable option for anyone who frequently moves indoors and outdoors. They are handy for active individuals who might need more time to find and put on a separate pair of sunglasses between activities like hiking or biking.
Unlike other optical lenses, transition lenses are clear until exposed to sunlight or UV light, when tiny molecules in the lens darken the tint. Depending on the brand, this can take 2 to 3 minutes. After the UV rays have faded, the lenses return to their original state.
The lenses can be used with prescriptions, including those for refractive errors and bifocals, and come in various colors. They shield the eyes from damaging UV rays, which have been linked to macular degeneration and are known to produce cataracts. They also help filter blue light emitted from digital devices and can improve visual comfort for people using their computers, phones, and tablets for long periods.
Transitions lenses are available in most frames, including those for bifocal wearers, and can be customized with your choice of frame color, design, and material. They’re also lightweight and durable. You can add an anti-reflective coating for additional glare protection.
Aside from the convenience of having a single pair of glasses that work in all lighting conditions, transition lenses offer UV protection and glare reduction and help filter blue light from digital screens. They’re an excellent option for people who want to eliminate the need to carry multiple pairs of eyeglasses or sunglasses.
If you’re starting to experience near vision problems like squinting when reading or are tired of constantly switching between multiple pairs of glasses, bifocal lenses might be right for you. Bifocal lenses contain two prescriptions in one lens, allowing for clear near and distance vision without needing multiple glasses.
Benjamin Franklin invented bifocals in the 1760s after becoming frustrated with constantly switching between his distance and reading glasses. He cut his original pair of glasses in half lengthwise, using the upper portion for distance vision and the bottom for close viewing. He then glued the halves together to create his bifocal lenses, which contained distance and near vision in one pair of glasses.
Today’s bifocal lenses are available in various designs, including flat-top bifocals and round seg bifocals. The flat-top bifocals feature a small segment in the middle of the lens, usually shaped like a half-moon or a letter D on its side. The bottom of the segment contains a visible line that can distract some wearers. Round seg bifocals are less common and consist of a minor, round segment blended into the rest of the lens and not visible to most people.
Bifocal lenses can take time to adjust, as the visible line can distract or limit the field of view. However, bifocal lenses offer many advantages over wearing separate glasses for different purposes.