- Posted on: Sep 21 2020
If you wear glasses, chances are you’ve been asked the question “Would you like your lenses to turn dark when you go outside?”. You may even be wearing photochromic lenses now! These lenses have been around for decades, and new advances in lens design make them better than ever. In this blog, we’ll discuss how photochromic lenses work, what options are available, and whether or not they are a good choice for your next pair of glasses.
What are photochromic lenses?
Photochromic lenses are optical lenses that change from light to dark when exposed to UV. These lenses use UV-reactive molecules which are either soaked into the lens material or bonded to the surface of the lens, depending on the material it is made of. When UV is present, the structure of the molecules changes, causing the lens to darken. Because the molecules are activated by UV and not light, they do not darken in the car, where most UV is blocked by the windows. Additionally, temperature has an affect on these molecules. According to Transitions.com, when the lenses become cold the molecules begin to move slowly. This means that it will take somewhat longer for the lenses to adapt from dark to clear. When the lenses become warm the molecules speed up and become more reactive. This means that they will fade back faster. It can also mean that if you’re outside on a hot sunny day, but sitting in the shade, your lenses will be quicker to detect the diminished UV rays and lighten in color. If you are outside on a sunny day in a cold climate, and then move into the shade, your lenses will adjust more slowly than they would in a warm climate.
What options are available?
When photochromic lenses were first introduced in the 1960’s, they were only available in grey with glass lenses. As technology has evolved, photochromic lenses are now available in every lens material and several different colors. At Mountain View Optical, our preferred brand of photochromic lenses is Transitions™. In this blog, we will discuss products available in the Transitions™ portfolio.
Transitions® Signature® GEN 8® lenses respond to UV, not natural light. They will turn dark outdoors, but remain clear while indoors or in a vehicle. They are available in the following colors:
- Graphite Green (grey-green)
Transitions® XTRActive lenses will become extra dark outside, and are more effective than Transitions® Signature® in hot climates. Additionally, this product responds to both UV and natural light, so lenses will achieve 50% transmission behind a windshield. These lenses have a slightly perceptible “hint of tint” indoors. They are available in the following colors:
- Graphite Green (grey-green)
Transitions®️ Vantage®️ lenses are a variable polarized lens. Like the other types of Transitions®️ lenses, they turn dark when exposed to UV, however these lenses have the added benefit of becoming polarized in their darkened state. They do not darken behind the windshield. They do have a slight “hint of tint” indoors. These lenses are only available in Grey.
Transitions® Drivewear® lenses are sunglasses that start with an olive green lens that changes to copper behind a windshield and dark reddish-brown when exposed to UV outdoors. They are polarized in all stages of activation. These unique lenses give the wearer the right amount of contrast for any outdoor lighting situation.
ACUVUE® OASYS with Transitions™ are contact lenses with Transitions® photochromic technology built in. Like Transitions® eyeglass lenses, these contact lenses will turn dark when exposed to UV, reducing the stressful impact that light can have on your eyes by helping your vision recover from bright light. These lenses provide added comfort and convenience, but they should not be considered a replacement for sunglasses. While they do absorb 100% of UV rays, they do not protect the uncovered portion of the eye or surrounding skin, which is susceptible to UV damage. They are only available in Grey.
What color should I choose?
Grey: Grey is the most popular photochromic lens color. It is the darkest option, so it will provide the most comfort on a bright, sunny day. Like all photochromic lenses, they block 100% of UV.
Brown: Brown lenses are lighter than grey, and help to enhance contrast. They are a good choice for days when the sun is not as bright, or for anyone who prefers a warmer tint. Like all photochromic lenses, they block 100% of UV.
Graphite-Green: Graphite-Green is a grey-green lens that provides more natural color perception than other tints. Like all photochromic lenses, they block 100% of UV.
Sapphire, Amethyst, Emerald, and Amber do block 100% of UV, but these colors are primarily for style and will not have as great of an impact on visual comfort as the colors listed above.
Who should wear photochromic lenses?
Almost everyone will benefit from the comfort and convenience of photochromic lenses. This is especially true for children and anyone who spends time outdoors.
Children: Most kids spend a lot of time outdoors, but their glasses may not be protecting them from UV. Children’s eyes are more susceptible to UV, so it is especially important that they wear protective glasses or sunglasses. Photochromic lenses block 100% of UV, and enhance comfort on bright, sunny days. To learn more about protecting your child’s eyes, read our blog here.
Outdoor Enthusiasts: Anyone who spends time outdoors will enjoy the convenience of photochromic lenses because they eliminate the need to change glasses or carry a second pair. Wearers can easily move from indoors to outdoors without thinking about their glasses.
Protecting your eyes from blue light
If you have read our blog Blue Light and Your Eyes, you know that exposure to blue light can lead to digital eye strain and eye fatigue. Photochromic lenses have the added benefit of filtering more blue light than a clear lens. According to Transitions.com:
Indoors, Transitions® Signature® lenses filter 1.4x more harmful blue light than a basic clear lens. Outdoors, they reduce exposure to the sun’s harsh glare, and filter more than 8x more harmful blue light than clear lenses.
Indoors, Transitions® XTRActive® lenses filter at least 2x more harmful blue light than clear lenses, and 8x more harmful blue light outdoors. And Transitions® Vantage® lenses filter at least 2x more harmful blue light indoors than clear lenses, and over 6x outdoors.
This may help to reduce eye fatigue and enhance overall comfort.
Photochromic lenses are a great way to upgrade your glasses. New technology has made them better than ever, with faster response to changes in light indoors and out. If you have not tried photochromic lenses, or it has been a long time since you wore them last, consider upgrading your next pair of glasses to include Transitions® photochromic technology. To make an appointment with an optician, please call or text (907) 328-2920. Thank you for taking the time to read our blog, and please stay tuned for new blog entries every week at www.mountainvieweyes.com.
Written by: Gina Stafford COA, LDO, ABOC