${\displaystyle K_{\text{B}\text{,v}}=\frac{{\Phi }_{\text{B}}}{{\Phi }_{\text{v}}}=\frac{{\displaystyle \int {\Phi }_{\text{e}\text{,}\lambda }(\lambda )}\cdot B(\lambda )\cdot \text{d}\lambda }{K_{\text{m}}\cdot {\displaystyle \int {\Phi }_{\text{e}\text{,}\lambda }(\lambda )}\cdot V(\lambda )\cdot \text{d}\lambda }}$

where λ is wavelength, Φ_e,λ(λ) is spectral radiant flux, B(λ) is the blue light hazard spectral weighting function, V(λ) is the CIE spectral luminous efficiency function for photopic vision, and K_m is maximum luminous efficacy (≈ 683 lm·W⁻¹)

Note 1 to entry: The term "luminous radiation" refers to optical radiation weighted with the CIE spectral luminous efficiency function for photopic vision, V(λ).

Note 2 to entry: The use of this term is only reasonable if parts of the optical radiation are in the visible range and thus Φ_v ≠ 0.

Note 3 to entry: The blue light hazard efficacy of luminous radiation is expressed in watt per lumen (W·lm⁻¹), possibly with a metric prefix.