Abstract: A lens that transmits light expressing a transmission curve which has a low cut-in wavelength in the vicinity of 400 nm, rising gradually in terms of percentage of light transmitted, to a maximum in the vicinity of 509 nm and then descending in equal manner, in terms of wavelength and percentage of light transmitted, to a high wavelength cut-off in the vicinity of 600 nm, and method of manufacture. The overall transmission curve expresses essentially a Gaussian configuration. The transmission curve is congruent with the rod mediated portion of the electromagnetic wavelength spectrum for the human eye, also described as scotopic in character and believed to be operative in maximizing the inhibition of melatonin secretion, a substance produced by the human pineal gland.