" Vision is the gateway in seeing wondrous things"


Overview of the anatomy and physiology for vision:

A fascinating organ of the human body that enables the sense of sight are the eyes, It allows us to observe and learn about the surroundings of this world, it is the most valuable sense from the other four. The eye allows one to interpret shapes, colors and dimensions of objects by processing the light they reflect or emit. The processes of vision is very complex but yet very simple to understand, the cornea is the clear dome at the front of the eye, it is like a window that allows the light to enter. So as the light waves of an object is being reflected in entering the cornea, it is then processed through the pupil, the circular opening in the center of the color iris. The iris determines the amount of light entering by dilating or constricting the pupil. For instance the pupil will shrink to block of to much light for entering, as for when it is dark they pupil will enlarge allowing more light to enter. The light then reaches the crystalline lens, which focuses the light rays onto the retina by bending them, at this point the images are turned backwards ( reversed ) and turned upside down ( inverted ). Behind the lens and in front of the retina there's a chamber called vitreous body, which contains a clear gelatinous fluid that makes up 80% of the eyes volume. the light passes through to the retina, it alines the back two- thirds of the eye and it is responsible for the wide range of vision. Within the retina it contains millions of specialized photoreceptor cells known as rods and cones that convert light rays into electrical signals that are transmitted to the brain through the optic nerve. Respectively, rods and cones provide the ability to see in dim lights and to see in color. The cones are located in the macula at which is in the center of the retina, this is where the eye provides the best vision. The macula is constructed by the fovea, a small depression in its center that contains the highest concentrations of cones cells. This is why macula is responsible for central vision, color distinguishing and for fine detail. The outer portion ( peripheral retina ) where the majority of the rods are located allows for night vision and seeing movement and object to the side ( this is where we get " peripheral vision " ). The optic nerve receives signals from the photoreceptor cells to the brain. Each eye transmits a slightly different portion of an image, that is inverted and later corrected and combined by the brain.







Vision Anatomy
Vision Physiology

Sources