Photochromic lenses respond to ultraviolet (UV) exposure. They can darken outdoors and become lighter again when UV exposure is reduced. The change is gradual, not an instant switch.
What to expect indoors and outdoors
| Setting | What to expect |
|---|---|
| Indoors | With less UV exposure, lenses generally become lighter. Allow time for the tint to fade after coming inside. |
| Outdoors | UV exposure can activate a darker tint. The amount of darkening and time taken can vary with the lens and conditions. |
| Inside a car | Lenses may not darken reliably behind a car windshield, which filters UV. Bright sunshine through the windshield does not necessarily produce the same tint as being outdoors. |
A note about driving
Do not assume photochromic lenses will provide a dark sun tint inside a car. If in-car sun comfort is your priority, ask us about the specific lens option before ordering.
This guide describes general expectations, not a guaranteed tint level or transition time. For products with multiple lens options, it applies to the photochromic option.