Prescription Sunglasses vs Photochromic Lenses: Which Is Best?

You’re driving down the road with your eyeglasses on, sunglasses perched crookedly over them—glasses wearers can likely relate to this less-than-chic scenario. You need your glasses to see clearly, but heading outdoors means squinting through the harsh rays from the beating sun. Deciding between sunglasses and clear vision isn’t the struggle it once was with the availability of both prescription sunglasses and photochromic, or light-adaptive lenses.

What Are Photochromic Lenses?

Photochromic lenses are often known by the popular brand name Transitions®. These lenses are clear indoors, but a chemical reaction within the lens causes them to darken after about 30 seconds of exposure to ultraviolet radiation from sunlight. After moving indoors, the lenses become clear again within a few minutes. Adaptive lenses are available in a range of materials, lens colors, and lens treatments such as anti-glare coatings. Some adaptive lenses become polarized as they tint. Even some prescription progressive and bifocal eyeglasses can use Transitions do photochromic lenses work

Should I Get Transitions Lenses or Prescription Sunglasses?

There are pros and cons on both sides of the Transitions lenses versus prescription sunglasses debate. Both can block 100% of UVA and UVB rays. Both light-adaptive lenses and prescription sunglasses lenses can be used in most optical-quality frames, including designer styles from top brands. Other considerations include:

Type of Activity

When trying to decide between the two, first consider what you spend the majority of your time doing.
Adaptive lenses are convenient for quick trips in and out.
For activities that include time on the water or snow—where bright light may reflect back at you—prescription sunglasses with polarized lenses may be better suited to the job.
Adaptive lenses react differently to glare from shiny surfaces such as snow and water, so they may not darken enough to meet your needs.
Photochromic performance can be influenced by temperature, so lenses can also take longer to adjust in cold temperatures.


Many people appreciate the opportunity to accessorize with bold sunglasses, while others find it a hassle to switch between prescription sunglasses and regular glasses.
Carrying a pair of each means you may be more likely to leave a pair of glasses somewhere.
You may forget to bring sunglasses when you need them.
Children who wear eyeglasses, especially, can benefit from glasses that automatically change to suit light conditions.


When it comes to Transitions lenses, cost earns a check in the ‘pro’ column.
Transitions lenses last for about three years—longer than the life of a typical eyeglasses prescription. After about three years, the lenses may not get as dark and could show signs of yellowing.
While you’ll pay an upgrade charge for the photochromic treatment, buying only one pair of prescription glasses saves you money overall.
A pair of Rx sunglasses can cost as much as, or more than, a pair of regular prescription glasses.
With prescription sunglasses, you’ll replace two pairs of glasses rather than one each time you update your prescription.


Photochromic glasses can reduce eye strain by continuously adapting to changing light conditions. This means:
Reduced sensitivity to the light, no squinting into the sun
Full protection from UV rays every time you step outdoors
Transitions lenses change in response to the brightness outdoors, so you will benefit from an ideal amount of tint on cloudy days as well; prescription sunglasses may be too dark for a semi-cloudy day.

Disadvantages of Photochromic Lenses

While photochromic lenses are useful for a walk outdoors or BBQing with family, there are some drawbacks.
A common complaint is that small-framed eyeglasses with variable tint lenses are not large enough to comfortably block the sun. For the best protection, sunglasses should wrap around to cover the whole eye to effectively block stray UV rays.
Variable tint lenses will not be as dark as sunglasses and may not provide enough protection on a bright day. Sunglasses can block up to 85% of light, while Transitions lenses block a maximum of 75%.
You may find that Transitions lenses are not ideal for outdoor photography as the display on your camera may be difficult to see.
You may need to remove your glasses when you pose for outdoor portraits to avoid dark lenses in your photo.

Do Transitions Lenses Work in the Car?

Most light-adaptive lenses do not work in the car. Photochromic lenses darken as a response to the ultraviolet rays from the sun. Since windshields have filters built into the glass to block UV rays, your lenses will not react. Transitions® Drivewear™ lenses work with both visible and UV light and will darken behind the wheel, but are not recommended for nighttime driving.

The sun’s UV rays can cause cataracts and damage the retina, so wearing UVA/UVB protective sunglasses each time you go outdoors is more than just a fashion statement—it’s a necessity. The choice between prescription sunglasses or light-adaptive lenses is up to you. If Transitions lenses aren’t right for you, avoid the doubled-up look with a pair of designer prescription sunglasses.

high index lenses

#FDAnswers: I have a strong prescription. What lenses do I need?

Full disclosure, this post is personal. I have terrible vision. I started wearing glasses when I was about 8 years old. By the time I was 11, I was begging my Mom for contact lenses. This was in the 80’s when high school girls and secretaries in movies would take their glasses off and suddenly be transformed from invisible to gorgeous. Glasses were not pretty – that’s the message I received loud and clear. Thus began a lifelong struggle with glasses, I would only wear them at home, if at all, never in public, and half the time I fell asleep with my contact lenses on. Even as the decades passed and glasses became the fashion accessory du jour, I couldn’t enjoy them. Why? Because my vision is so bad my lenses looked like the proverbial coke bottles, and turned my eyes into blinking little beads.

So that brings us to today. My prescription is -8 in my right eye and -11 in my left. I can’t see ANYTHING without glasses or contacts, but I have found a way to wear my glasses without feeling completely self conscious – three words: High Index Lenses. If your prescription is crazy high like mine, you should get the thinnest possible lens, which is the High Index 1.74. Anything +/- 6 you definitively need them. Another trick I’ve learned is to ask for no edge polish. When your lenses are VERY thick, polished edges call even more attention to them.

Here’s one of our expert opticians, Amanda, talking about the benefits of High Index 1.74 lenses.


If your prescription is between +/- 2 and 6, you could get the High Index 1.67 lenses. The 1.74 are the thinnest, but they aren’t available with tinting or progressives, so you may need the 1.67 if you’re looking for those add-ons. The other varieties of lenses – plastic and polycarbonate – aren’t great if you have a prescription that’s +/- 3. High Index lenses are a bit more expensive but well worth avoiding the coke bottle look!

All our high index lenses come with scratch resistant and UV coatings for no additional cost. You can learn more about all the lens types we offer at here.

Also see How Do Glasses Work?