Light get reflected from the objects on which it falls and that light that gets reflected has different wavelengths and this gives the color to the object. This light that is reflected from the object passes through the pupil in your eye and fall on the retina at the back of the eye. The retina is a collection of photosensitive cells. Behind the retina the photosensitive cells are in the form of rods and cones. The visual pigments in retina absorb the light differently based on the wavelength. The light that falls on the retina is transmitted to the nerve cells and the nerve cells send message to the brain so that the brain interprets the image that is seen. The light that is passed through the pupil is focused on the retina through a lens which is a tissue. If that light that is passed is not focused properly then you have visual problems like short sight and long sight.
[tags]Pupil, Retina, Iris, Cornea, Photoreceptors[/tags]