A modified formula for calculating the disability glare effect from street lighting lanterns.

Holladay and Stiles suggested that the effect of a glare source on contrast sensitivity is the same as that of a luminous veil whose luminance is G =KE ftl., where E is the glare illumination in the palne of the pupil of the eye in Im/ft2, is the angle of the glare source from the line of sight in degrees and n and k are constants.