Let’s follow together the journey of light inside the eye.
The reflected light from objects entering the eye through the cornea, the pupil and the lens, ending his run on the retina.
The cornea is the first lens that meets the light, its function properly and to converge the light rays within the eye.
The iris carries at its center the pupil, constitutes a diaphragm which, as a function of ambient light, is capable of regulating the amount entering the eye thus affecting also the depth of field.
Doing so makes the iris so that the light shine, as needed, cones only (distinct vision in bright light) or rods (vision in white and black, slightly distinct but useful to orientate in low light).
The crystalline is a flexible lens, and allows you to focus on objects.
The light then reaches the retina capable of transforming a light signal into an electrical signal.
To be perceived the images it is necessary that the electric impulse is transported to the brain to be processed and this is done via the optic nerve.
The eye and the camera
Given the structure and operation, the eye is often compared to a camera, as you can see in the im age below:
- Cornea: the outer and fixed lens.
- Iris: the diaphragm that adjusts the amount of light that penetrates inside the chamber.
- Lens: the group of movable lenses useful to focus.
- Retina: the sensor of digital cameras capable of transforming a light signal into an electrical signal.
- Optic nerve: the connecting cable through which the nerve stimulus is delivered to the brain.
- Brain: the computer, where the image is processed and finally perceived.