Abstract
A lens principle is described for night driving that does not encompass any tint directly over the pupil, but causes a shadow effect to fall across the pupil to eliminate the oncoming glare of headlights. This lens consists of a calobar green slab-off on a white lens. These lenses must be fitted on prescription so that the line of demarcation between the white and the green falls 3 mm to the left side of the night pupil. Research and tests on this lens are reported. The general acceptance of the lens on the individual fitted has been encouraging.