The Biophysical Modeling of the Human Sight

— The eye has multiple roles in vision. It contributes to the formation of images of the outside world, adaptation to different light-intensities, transformation of light into electrochemical signals and then nerve impulses and to preliminary evaluation of visual information. For an object to be seen clearly the rays of light from each of its points have to be focused on the retina. When distant objects are viewed the image of near ones is indistinct and blurred, owing to the light rays being focused behind the retina, and diffused light circles being formed on it. The pupil is the aperture in the centre of the iris for the passage of light entering the eye. The pupil helps produce distinct images of objects on the retina. The retina is the internal membrane of the eye in which are located photoreceptors, rods and cones sensitive to light rays, and the nerve cells with their numerous processes that make up the nervous apparatus of the eye. We describe the biophysical model of the action potential. The minimum number of light quanta required to cause excitation in the eye in darkness is one. The trichromacy theories based on the assumption that the retina contains three types of colour-sensitive photoreceptors, or cones, is that most widely accepted.