UV400: ultraviolet protection
UV400 describes filtering of ultraviolet light up to 400 nanometres. A darker tint alone does not establish UV protection. Check the protection stated for the actual lens.
UV400 & VLT Guide
UNDERSTANDING YOUR LENSES
UV400 & VLT: protection and lens brightness.
Two different measures help explain your lenses: UV400 describes UV protection, while visible light transmission (VLT) describes how much visible light passes through.
VLT: how light or dark the view is
A lens with 15% VLT transmits about 15% of visible light. Lower percentages give a darker view; higher percentages let more light through. VLT does not measure UV protection or polarization.
VLT in everyday light
Darker view · Lower VLTBrighter view · Higher VLT
VLT reference bands; each band is expanded for readability, not drawn to a linear scale.
About the VLT values: The VLT values shown for TINHAO lenses are measurements of specific samples tested in the TINHAO laboratory. Lenses of the same model may show slight variations between production batches. These values are provided as a reference and may differ slightly from the lens you receive.
Over 80–100% Cat. 0 reference
Clear or very light tint, with very little reduction in daylight brightness.
Over 43–80% Cat. 1 reference
A light tint for softer daylight, overcast conditions or shade. Limited reduction of strong sunlight.
Over 18–43% Cat. 2 reference
A medium tint for moderate sunlight and everyday outdoor conditions.
Over 8–18% Cat. 3 reference
A dark tint for bright sunlight, including bright conditions near water or at the beach.
Over 3–8% Cat. 4 reference
A very dark tint for exceptional brightness, such as intense sun on snow. Not suitable for road use or driving.
When bright light feels uncomfortable
A lower VLT can provide a darker view in bright daylight. The darkest lens is not always the most comfortable as light levels change. For cataracts or persistent light sensitivity, ask an eye-care professional for advice suited to your vision.
Photochromic lenses
Transmission changes between lighter and darker states. Where both values are available, the product guide shows a range. UV exposure and temperature affect the response; UV-blocking windshields can limit darkening.
These scene descriptions are general guidance. Reference bands follow EN ISO 12312-1 filter-category ranges and do not establish product certification. VLT alone does not establish driving suitability; signal recognition and other requirements also apply. A high VLT or yellow tint is not by itself a claim of suitability for night driving. Refer to the lens information for the actual variant.
Learn more: ISO 12312-1 · Filter categories and driving · UV protection
