The human eye belongs to a general group of eyes found in nature called “camera-type eyes.” Instead of film, the human eye focuses light onto a light sensitive membrane called the retina. The cornea is a transparent structure found in the very front of the eye that helps to focus incoming light. Behind the cornea is a colored ring-shaped membrane called the iris. The iris has an adjustable circular opening called the pupil, which can expand or contract depending on the amount of light entering the eye.

this experiment shows us  the Nearsightedness /myopia

People who are nearsighted have what is called a refractive error. In nearsighted people, the eyeball is too long or the cornea has too much curvature, so the light entering the eye is not focused correctly. Images focus in front of the retina, the light-sensitive part of the eye, rather than directly on the retina, causing blurred

vision.

Farsightedness (Hyperopia)picture 2

Farsightedness occurs when your eye is too short lengthwise and does not bend light correctly. This causes an image to focus behind the retina instead of directly on it, so the image is blurry.