Explain the structure and the functioning of human eye.
For people with normally functioning eyes, the following sequence takes place:
- Light reflects off the object we are looking at.
- Light rays enter the eye through the cornea at the front of the eye.
- The light passes through a watery fluid (aqueous humor), and enters the pupil to reach the lens.
- The lens can change in thickness to bend the light, which will focus it onto the retina at the back of the eye.
- On the way to the retina, the light passes through a thick, clear fluid called a vitreous humor. The vitreous humor fills the eyeball and helps maintain its round shape.
- The light then reaches the back of the eye and hits the retina. The retina translates the light into electrical impulses which are then carried to the brain by the optic nerve.
- Finally, the visual cortex (or Centre) of the brain interprets these impulses as what we see.
- Blind spot: The small circular area in the retina where the optic nerve enters the eye that is devoid of rods and cones and is insensitive to light. — called also optic disk.