Table 1 Sunglasses category limits, adapted from ISO 12312-1:2013
From: Are sunglasses appropriate for driving? Investigation and prototype for public testing
Filter category | Visible spectral range |
|---|---|
Range of luminous transmittance \(\tau_{\mathsf{v}}\) 380–780 nm | |
0 | \(\tau_{\mathsf{v}}\) > 80% |
1 | 43% < \(\tau_{\mathsf{v}}\) ≤ 80% |
2 | 18% < \(\tau_{\mathsf{v}}\) ≤ 43% |
3 | 8% < \(\tau_{\mathsf{v}}\) ≤ 18% |
4 | 3% < \(\tau_{\mathsf{v}}\) ≤ 8% |