How does light enter the eye and form an image?

Question

anonymous · Answer

The light enter through the cornea, pupil, vitreous and impact to the retina. In this zone are two different photoreceptors: rods and cones. Rods detect only the presence or absence of light without distinguishing between colors, thus giving black and white vision (as at night). Cones detect colors in the images but are less sensitive, i.e. they require more light to function. These receptors are channels of ions (K+) when the light interact with them, they are closed only for a short time and this repeatedly creates a pattern of signal (open-close-open-close). In the other hand the accumulation of ions produce a difference of charge (remember that ions have a charge). These differences of ionic charge are transmitted through optic nerve and afterward to the occipital zone of the brain. In this part the neurons are available to transform and interpret the electric signal into images.    
I hope it would help you

anonymous · Answer

thank you!!! that was really helpful!