How does normal vision work

The function of the eye is comparable with that of a camera:

Rays of light reflected by objects (images that we see) meet the eye and pass through the cornea to the lens.

It functions like the lens of a camera and brings the rays of light together. The lens of the eye is flexible and can influence the focus by changing shape.

The iris assumes the function of an aperture. It can contract or expand, depending on how strong the light is. This causes the pupil to contract when the light is bright and also ensures good vision by causing it to expand when there is less light.

The cornea, lens and vitreous body of the eye refract the rays of light in such a way that they meet a focal point on the retina.

The retina can be compared to the film in a camera. Mirror-inverted images of our surroundings are created on its surface.

Sensory cells in the retina direct incoming information to the brain via the optic nerve. The mirror-inverted images are then rotated in the visual centre so that we see our surroundings as they really are.

Vision defects occur when the focal point is not directly on the retina. If it is in front or behind the retina, our surroundings appear blurry. If the eye is too long (Short-sightedness) or too short (Long-sightedness), the cornea and the lens do not refract the light precisely on the retina. In addition, if deviations in the shape of cornea or the lens are present ( Astigmatism, Presbyopia) the focal point changes and incorrect images are created.