The Two-Quanta Hypothesis as a General Explanation for the Behavior of Threshold Values and Visual Acuity for the Several Receptors of the Human Eye

Abstract

With the aid of the three methods for the determination of the number of absorbed quanta necessary for light perception described in previous papers, it is found from extensive threshold measurements with flashes for foveal and peripheral vision that a “red cone” in the periphery probably gives rise to a light impression when two quanta are absorbed in it within a time τ.For the foveal cone systems a light impression is caused for every wave-length by the absorption of two quanta within a time τ and within an angular distance of 2–4 minutes. The different kinds of receptors proved to be capable of reacting in mutual dependence on each other, and the conclusion is drawn that all receptors send a nerve impulse to the nerve connection when one quantum is absorbed.A light impression will occur when a second quantum is absorbed after the first absorption within τ sec. within a receptor within a distance D of the first receptor.Experiments on the visual acuity demonstrate that for all wave-lengths, for foveal as well as for peripheral vision, the dependence of the visual acuity on the intensity agrees with the two-quanta theory.