Photochromic lenses darken and lighten based on the light conditions you're in, and allow you to combine the functionality of both sunglasses and eyeglasses into one pair of frames. Using a light-reactive chemical that darkens when in contact with UltraViolet rays, photochromic lenses darken in sunlight and then lighten when you are back indoors. If you move from indoors to outdoors frequently, exercise in changing light conditions, or are a minimalist who prefers to only carry one pair of glasses, photochromic lenses may be right for you.
Photochromic lenses are a combination of eyeglass and sunglass lenses that darken or lighten in tint as light conditions change. In short, when you're inside, the lenses lighten and become typical, clear eyeglass lenses, and when you're outside, in bright sunlight, they darken to become sunglasses. The term photochromic comes from the Greek words photo, meaning light, and chroma, meaning color. They're also called light adaptive, variable tint, or photochromatic lenses, and sometimes they're called by the brand name "Transitions® Light Intelligent Lenses™". If you're interested in photochromic lenses for your everyday, clear prescription glasses, read more about Transitions lenses.
Photochromic lenses are clear indoors, but a chemical reaction within the lens causes them to darken after about 30 seconds of exposure to ultraviolet (UV) radiation from sunlight. After moving indoors, the lenses become clear again within a few minutes. Photochromic lenses are available in a range of materials, lens colors, and with various lens treatments, including anti-glare coatings, and are commonly used with progressive and bifocal lenses.
Photochromic lenses are eyeglass lenses that darken when exposed to UV light, while Transitions® Light Intelligent Lenses™ are a particular brand of photochromic lenses that offer 100% protection from UVA and UVB light. In other words, all Transitions® lenses are photochromic lenses, but not all photochromic lenses are Transitions®. At FramesDirect.com, the majority of photochromic lenses we sell are Transitions® Light Intelligent Lenses™.
Prescription sunglasses are better for long periods of time in the sun, while photochromic lenses are better while moving between indoors and outdoors all day. But there are pros and cons on both sides of the Transitions® Light Intelligent Lenses™ versus prescription sunglasses debate. Both can block 100% of UVA and UVB rays. Both light-adaptive lenses and prescription sunglasses lenses will work in most optical-quality frames, including designer styles from top brands. In fact, sports eyewear brand Oakley makes its own line of photochromic sunglasses perfectly suited to cycling, running, and skiing outdoors in changing light conditions.
When trying to decide between photochromic glasses and prescription sunglasses, first consider what you spend the majority of your time doing:
Note: Photochromic performance can be influenced by temperature, so lenses can also take longer to adjust in the cold.
Many people appreciate the opportunity to accessorize with bold sunglasses, while others find it a hassle to switch between prescription sunglasses and regular glasses.
When it comes to photochromic lenses, cost earns a check in the “pro” column.
Photochromic glasses can reduce eye strain by continuously adapting to changing light conditions. This means:
In most cases, no, but special photochromic lenses like Transitions® XTRActive® lenses do work in the car. Most car windshields come standard with a UV-blocking layer, which will filter out the necessary ultraviolet rays to trigger darkening in photochromic lenses. Unless you have photochromic lenses that change automatically, without the need for UV light, your photochromic lenses will not work behind the wheel. On a similar note, you can wear photochromic lenses while night driving, as they will remain normal eyeglasses and allow you to see. As they need UV light to darken, the lenses will stay clear during late nights on the road and there's no added harm or benefit to wearing them as opposed to regular eyeglasses.
While photochromic lenses are useful for an outdoor barbecue or going for a walk, they have some drawbacks.
Yes, although most photochromic lenses do not get quite as dark as traditional sunglasses. Many wearers with smaller frames may not enjoy as much coverage as those with larger frames. If you opt for photochromic lenses, we encourage larger glasses that cover a wider area and will provide the maximum amount of protection as they darken.
Grey lenses are the best color for photochromic lenses. This traditional lens color offers protection from the sun's rays while boosting contrast across the board. Brown and green lenses offer slightly better blue and green contrast and may be better suited for the water, while grey lenses are better for all-around protection.
Photochromic lenses and polarized lenses offer two different light-filtering technologies. Polarized lenses cut glare on bright, sunny days from reflective surfaces like water, snow, and street signs, while photochromic lenses adapt to the light settings you're in by darkening or lightening based on the presence of UV rays. Some companies offer photochromic lenses with polarization, or you may want to choose one over the other—we've outlined the pros and cons of both to help make the decision easy.
Polarized lenses are engineered to block light that bounces off surfaces like cars and water in the form of horizontal wavelengths, thus preventing glare. When you're looking for glare reduction and crisp vision for sports, driving, and outdoor activities, polarized lenses may do the trick. Filtering these wavelengths decreases strain on your eyes, so you're more comfortable in bright, high-glare environments.
Polarized lenses don't offer protection from UV rays on their own, so you'll need to make sure the sunglasses you choose come with 100% UV protection. And they're not ideal for all conditions—polarization can make it difficult to see your phone or GPS screen, and pilots usually aren't allowed to wear them while flying. When the weather gets chilly, polarized lenses can make it difficult to see icy patches on the slopes. Some people experience nausea or dizziness while wearing polarized lenses, and others simply prefer non-polarized lenses.
Common applications for polarized sunglasses include:
Photochromic sunglasses lenses automatically adjust to the light conditions so the ideal amount of tint can pass through the lenses. If you'll experience varying light conditions in your activities, photochromic lenses might be the right choice. While a darker tint doesn't mean more UV protection—only the UV treatment on the lenses can offer that—it does mean your eyes are as comfortable in the bright morning sun as they are on a slightly overcast day, because the tint adapts as necessary.
Most photochromic lenses are not ideal for driving as windshields block the UV light that makes the lenses darken. And photochromic lens performance may decline after a few years, making them slower to respond.
Common applications for photochromic sunglasses include:
Photochromic lenses are better for people who go from indoors to out frequently, and who prefer to carry one pair of frames instead of both eyeglasses and sunglasses. Polarized sunglasses reduce glare from reflective surfaces like water or snow, and work best for people who work or exercise in bright, sun-drenched conditions. While the two types of lenses are often compared, they serve distinct purposes and work best in different scenarios.
Whether you're on the water, trail, road, or elsewhere, sunglasses are essential to protect your eyes and keep you from squinting against bright conditions. Polarized or photochromic lenses—or both—prevent eye strain in a variety of circumstances so you can enjoy the ideal protection anywhere you wander. These lenses, paired with 100% UV protection, keep your eyes comfortable and healthy year-round.
Contact one of our experienced opticians if you have any questions about photochromic lenses.
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