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 3 and in addition:
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 220.127.116.11).
3 BS EN 1836: 2005 para E2.
4 BS EN ISO 14889:2009 para 18.104.22.168.
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 Patients with a single vision prescription may be dispensed with single vision enhanced or accommodative boost lenses after confirmation with the prescriber. Not to do so could be considered prescribing.
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
C9.10.1 New Content Coming Soon