The Eyes Explained – How do We See?

Did you know that the human eye is responsible for 80% of all the information that our brain receives? The human eye is vital to the way that we live our lives and go about our daily activities, so understanding how our eyes work is important as well.

When the light reflects off of the objects around us and into our eyes, we are able to see them. The light enters the eye through the cornea, is focused through the lens, and is reflected onto the retina. Since the cornea is curved, the image is reflected upside down, and then reoriented before being transmitted into the brain through the optic nerve.

The iris is the coloured portion of our eye, and surrounds the pupil, which together control how much light enters the eye. This is why when you go from a dark room into the outdoors your pupil constricts, letting less light into the eye so that you aren’t blinded by the sun. Vice versa, when going from a bright space into a dark room your pupil dilates to let in as much light as possible. The light that reaches your eye is then reflected and formed into images on the retina.

The retina is a small, complex area at the back of the eye which the images we see are reflected onto. The retina is made of rods and cones which are sensitive to light. Cones are responsible for daylight vision, as they are sensitive to the colour and light we see around us. Rods are responsible for night time vision, and are only sensitive to light, which is why we do not see colour in the dark. The retina gathers the light we see and transmits the images that are formed to the brain through the optic nerve.

Eye Problems

Problems in the eye occur when one or more of these parts is not formed or functioning properly. Some common eye problems that can be remedied with prescription glasses are short sightedness, when you can only see objects up close, and long sightedness, when you can only see objects at a distance. Short sight occurs when the eyeball is too long, or the lens is too thick, and the light reflected does not reach the retina, but focuses just in front of it. Long sight occurs when the eyeball is too short or the lens is too thin, and the light reflected reaches past the retina, and focuses behind it.

Understanding how your eyes work means that you can know exactly what is going on in your eye, and you can protect and maintain your vision to the best of your abilities. Having regular eye exams is the best way to have these deformities diagnosed and optimize your eye health.