Ophthalmic lenses, tints and coatings

Ophthalmic Lenses & Tints and coatings

C 9.1.1 BS EN 1836:2005 attributes filters for sunglare use into 5 groups, according to their range of luminous transmittance (Tv).

C 9.1.2 Filters suitable for road use and driving shall be of categories 0, 1, 2 or 32 and in addition:

  1. the spectral transmittance of filters suitable for road use shall be not less than 0.2 x Tv for wavelengths between 500 and 650 nm; and
  2. the relative visual attenuation coefficient Q of filters of categories 0, 1, 2 and 3 suitable for driving and road use shall be not less than 0.8 for red and yellow signal lights, not less than 0.4 for the blue signal light and not less than 0.6 for the green signal.
    Sunglare filters with a luminous transmittance of less than 75% are not suitable for use in twilight or at night.3,4

Filter Category – Description Range of luminous transmittance

0 – Clear or very light tint- From over 80% to 100%
1- Light tint –  From over 43% to 80%
2- Medium tint –  From over 18% to 43%
3- Dark tint –  From over 8% to 18%
4 – Very dark tint – From over 3% to 8%

1Category 0 applies only to photochromic filters in the faded state, to gradient filters with a luminous transmittance >80% at the reference point, and to filters that have a luminous transmittance >80%, but where a specific protection against any part of the solar spectrum is claimed.
2 Therefore lenses with a luminous transmittance of <=8% are not intended for driving or road use (BS EN ISO 14889:2009 para 4.5.2.3).
3 BS EN 1836: 2005 para E2.
4 BS EN ISO 14889:2009 para 4.5.2.4.

 

C 9.2.1 New content coming soon

C 9.3.1 New content coming soon

C 9.4.1 New content coming soon

C 9.5.1 Download the ABDO Guide to Fitting and Lens Design

C 9.5.2  New content coming soon

C 9.6.1 New content coming soon

C 9.7.1 New content coming soon

C 9.8.1 New content coming soon

C9.9.1 Blue Light Guidance for ABDO Members

C9.9.2 New Content Coming Soon

C9.10.1 New Content Coming Soon