Photoreceptor Optics — Theoretical Principles

The purpose of this paper is to familiarize the reader with the fundamentals of photoreceptor optics, defined here as the science that investigates the effects of the optical properties of a photoreceptor, i.e. its size, shape, refractive index, orientation and arrangement, on the absorption of light by photopigment (MILLER, 1974; SNYDER, 1974a). Most photoreceptors of those vertebrates and invertebrates with a high degree of acuity and sensitivity can be described roughly as long narrow cylinders with a diameter comparable to the wavelength of light in the visible, and an index of refraction greater than the surrounding medium. Our general concern here is with the consequences of confining photopigment within such a cylinder.