Visible Light Transmission (VLT) indicates how much visible light passes through a laser safety lens. It is expressed as a percentage and affects how bright the environment appears while wearing the eyewear.

Higher VLT values allow more visible light through, while lower values create darker lenses.

The required laser protection often determines the achievable VLT. Some filters provide excellent visibility alongside high protection, while others require darker lenses to attenuate specific wavelengths effectively.

VLT should not be confused with Optical Density. A lens with high VLT can still provide excellent laser protection if designed for the appropriate wavelength.

Balancing protection with visibility helps users perform tasks comfortably while maintaining appropriate eye safety.