Wind, flying dirt and debris can cause itchy, irritated eyes. Cycling glasses can be worn to protect your eyes from these elements, can shield you from ultraviolet radiation and the sun, and can increase contrast to help you see pot holes, rocks, and other road conditions better. Lenses can be made to change color with the lighting conditions to accommodate the time of day and weather you ride in. They can even be fit with a prescription lens. Here is what to look for:
Ultraviolet Protection: Since cycling takes place outside, you need to make sure your eyes are protected 100% from ultraviolet radiation. (See UV and its Effects on the Eyes for more information on UV). If using polycarbonate or trivex lenses (recommended for impact resistance in case of fall or rocks/debris) UV is included even in clear lenses.
Frame Style: Since riding takes place at a certain speed, and since flying dirt and debris is common in this activity, the best type of frame is going to be a wrapped around style. This will shield the eyes from the wind, especially important for contact lens wearers, as wind can cause the contacts to dry. Also, a wrap around style will also better keep dirt and debris out of the eyes. To offer proper ventilation for this style, the frame must have "air holes" or channels at the top of the frame to prevent fogging. An upper sweat bar can also help control fogging. Also, a frame that has interchangeable lenses will benefit those who ride in varying light conditions. (see lens colors below)
Lens Color: Since riding make take place at different times of the day, or in various weather conditions, interchangeable lenses work the best. They allow you to swap out lenses to correspond to the lighting condition you are riding in. In bright sunlight, you can use a dark sunglass lens. A gray lens will be the darkest, but a brown or amber lens can help increase contrast so you can better read the terrain (i.e. pot holes, rocks, mud, etc.) When riding in low light or overcast days, a yellow or vermilion (rose) lens can be used to block glare in this lighting condition. At night, a clear lens can be used to shield wind and debris without compromising vision. A photochromatic lens is also designed for varying lighting conditions. This is a lens designed to change color with the amount of light outside. Thus, in bright sunlight, it will act as a true sunglass. However, in the early morning, late afternoon, or on overcast days, the lens will lighten up so that they still can be worn, but let more light through the lens so you can see.
Recommended Styles: Rudy Project has polycarbonate lenses, wrap around styling, air holes and interchangeable lenses, and some styles are available with a prescription insert or Direct in lenses and photochromatic lenses. Switch has magnetic interchangeable lenses so that you can quickly and easily pop out lenses. Numa also has direct in interchangeable prescription lenses. Bolle (Vigilante, Parole, and Vortex), Smith, Hilco Pro Sport Optics and Wiley-X Interchangeables make frames with wrap around styling and interchangeable lenses and prescriptions are available with some styles. Julbo also makes style with side shields for wind protection or just extreme wraps and most are available with prescription. If your eyes tear easily, you may want a full foam seal like the Wiley-X or 7Eye by Panoptx.