Eye and vision – basic principles
How it works
The human eye is a sense organ that absorbs light stimuli and converts them into electrical signals. Important structures are the cornea, lens, pupil, iris, retina, optic nerve and vitreous body. The lens focuses the image (accommodation), the retina contains light-sensitive sensory cells (rods for brightness, cones for colors). The brain processes the signals into an image. Light enters the eye through the cornea and the pupil, is refracted mainly by the cornea and additionally by the lens, and is focused on the retina. The iris regulates the amount of light by changing the size of the pupil. Vision disorders such as nearsightedness and farsightedness arise due to deviations in the optical system.
The eye absorbs light. The cornea and the lens refract the light so that a sharp image is formed on the retina. The iris controls the amount of light by changing the size of the pupil, and the lens focuses the image. Rods and cones perform different tasks in vision.
An example
Which structure regulates the amount of light that enters the eye by making the pupil larger or smaller?
Try it yourself now
50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Biology. The topic assignment may vary by federal state.