Sunglasses With Transition Lenses: Pros and Cons

By David Turbert for the American Academy of Ophthalmology.

If you wear glasses you’re familiar with the hassles of dealing with the sun. You carry your glasses and sunglasses wherever you go, switching back and forth each time you go outside and head back in. A simple alternative is to wear glasses with photochromic or “transition” lenses. These lenses automatically darken in bright sunlight and return to a regular tint in dimly lit environments.

Light-adaptive lenses have improved in recent years

Photochromic lenses have been around for decades. Years ago, all transition lenses were made of glass and came in a single color: grey. But today’s photochromic glasses are available in a rainbow of lens colors and are made with various materials.

These lenses contain proprietary dyes that undergo chemical changes and darken when exposed to UV light. Photochromic technology has come a long way since the very first transition lenses, which darkened when silver chloride or silver halide in the glass lens reacted with UV light.

Are photochromic lenses worth it?

Glasses with photochromic lenses certainly offer convenience, but they have some drawbacks too. Think about the advantages and disadvantages of these sunglasses before you buy.

Pros of transition lenses

• They are convenient. You can use these glasses under most circumstances, whether indoors or outside. 
• They offer continuous UV protection. You will no longer forget your sunglasses or not bother to put them on for a trip outside.
• They won’t get lost as easily. You and your children are less likely to lose glasses when you don’t have two pairs to keep track of.
• They are available in many styles and colors, and can meet the prescription needs of most people. If you need shatter-resistant lenses, bifocals, progressives or have other specific needs, there’s almost certainly a photochromic lens for you.
• They can save you money. You may not need to buy prescription eyeglasses and prescription sunglasses as well.

Cons of transition lenses

• They darken and lighten to varying degrees depending on the brand. Some lenses also take longer than others to adjust to brightness. Discuss your needs and options with an eyecare professional.
• These lenses can take longer to adjust in cold weather.
• They don’t darken as well inside cars. Auto glass has some UV protection, which can prevent photochromic lenses from darkening. Some lenses are designed to help solve this problem.