The cornea refracts or “bends” light rays so that they pass through the pupil of the eye. The light rays passing through the pupil are then focused by the lens of the eye onto the retina (which acts like the film of a camera).
These light rays are changed by the retina into electrical signals that are transmitted to the brain via the optic nerve, which is like a “cable” connecting the eye to the brain. The brain processes these signals into “pictures” that we see.
What is eye pressure
Like a football or tyre, the eyeball also needs pressure to maintain its shape. In the eye a water-like fluid called aqueous maintains the pressure.
This fluid is made in the back part of the eye in an area called the ciliary body. It then circulates inside the eye providing oxygen and nourishment to eye tissues. It then drains out the front part of the eye in an area called the drainage angle (or ‘drainage canal’) and into the bloodstream.
Normally this fluid is made at the same rate as it is drained and the eye pressure remains stable. The eye pressure for most people ranges between10 to 21 mmHg (millimetres of mercury). However, if there is a problem with the drainage of fluid then it builds up and the eye pressure rises