Describe the process involved in focusing an image onto the

Describe the process involved in focusing an image onto the retina for objects near and far and how that process is controlled. Identify the common defects in our ability to focus light on the retina and how they can be fixed.

Solution

Eye lens work as biconvex lens. When light rays enter the eye, the curved surfaces bend them. Bending the light rays is necessary in order to focus an image and emit the light just behind the lens. The image is then focused on the retina. Then the image is formed which is inverted. When viewing distant objects, lens is made thin and flat. For nearer vision lens become thicker and rounder.

Myopia is a defect in which far away objects are not clear in vision but nearby objects can be seen clearly.

Hyperopia is a defect in which far objects are seen clearly but nearby objects are not seen clearly.

Astigmatism is a condition in which light is not focussed evenly on retina.