Sight Explained

Solution Preview

We can approach this question from different angles: image formation, visual physiology, and neural pathway.

Let's start with image formation. Formation of images on the retina involves 3 basic process. First, refraction of light by the cornea and lens. Second, accommodation of the lens. Third, constriction of the pupil. Refraction is the bending of light rays. Light rays entering the eye are refracted at the anterior and posterior surfaces of the cornea. This allows the light rays to focus exactly on the retina. When an image is refracted on the retina, it is inverted and right/left reversed. The brain automatically turns it right side up and right side around! Interesting, eh? Accommodation is an increase in the curvature of the lens for near vision. When you view close objects, the ciliary muscle contracts which pulls the ciliary process and choroid forward toward the lens. This results in a shortening and bulging of the lens. Finally, ...