Transitions® lenses will provide the same level of protection against UV rays as a pair of dedicated dark sunglasses. You can rely on them in most places to see comfortably in any lighting conditions including outdoor activities. 
However, if you spend long periods of time in high-glare conditions, a pair of polarized sunglasses would be the recommended choice for activities at the beach, water, snow and road. Transitions® lenses aren’t as dark as most sunglasses lenses and, depending on the size of the frame, may not provide the same facial coverage as a typical pair of sunglasses.  
If you spend a lot of time driving, you may consider keeping a pair of polarized sunglasses in the car. Wearing Transitions® lenses behind your windshield, which blocks UV rays, will prevent these lenses from darkening. 

Transitions ® lenses will maintain their quality and performance over the lifespan of your glasses (for at least 3 years). After this period, you may notice that it takes them longer to change from tinted to clear and start to see a slight yellow colouring around the edges.  

Remember – you should get a comprehensive eye exam every 1-2 years (which may be a great time to upgrade to a new pair of Transitions®).

Transitions® lenses start to darken within about 30 seconds of UV exposure and can continue to subtly darken for about 10 minutes. When you go back indoors, they should return to their clear state within about 5 minutes.

When photochromic lenses are exposed to UV light, molecules react by changing their structure (which is what causes the lens to darken). Transitions® lenses are the leading brand of light-intelligent lenses – a series of exclusive, patented formulas are each integrated into the lens surface, which cause the photochromic molecules to recalibrate constantly yet smoothly. This means your eyes are always exposed to the optimum amount of light, whether you’re in bright sunlight, under a cloudy sky, or indoors.

Yes, you can wear Transitions® lenses for reading outdoors and indoors. They are designed to tint in the sun and turn to clear inside, so you can enjoy great vision and UV protection without needing to switching glasses. They also include blue light filtering properties.

Transitions® lenses are as clear as normal lenses indoors. These lenses darken when they detect UV light, which is present outdoors when you’re not exposed to direct sunlight. Your lenses may become tinted on a cloudy day, depending on the amount of UV radiation present.