Hey Tou Chiu: Sight

When asked the question “How do we see?” many would say – “we use our eyes!” This is true; however the eye is not as simple as it looks.

We see things when we process the light rays that reflect into our eye. The light rays first pass through the surface of our eye (cornea) and then to through the pupil. Here the pupil can regulate the amount of light that can pass through into the inside of the eye. If the outside environment is dim, more light will be allowed to pass through to enable us to see clearly. On the other hand, if the outside environment is bright, then the pupil will allow less light to the back of our eye – the retina. The rays of light then become electric impulses and get sent to the brain to be processed and we are then able to see.

Some people may ask – “How do we see color?” The answer is simple. There are photo receptor cells in the retina which respond to dim light and color. They are known as rod and cone cells. Others may also wonder why we can still see an upright image when the image created on our retina is actually inverted. This is actually because our brain “knows” that the picture on our retina is inverted which is not what we usually sees, so it “adjusts” the picture so that we can see it with the right way up.