Introduction

The eye is an organ which has the ability to detect and respond to light. It is widely considered the most valuable of our senses as it allows us to observe and learn from our surroundings. Everyday activities such as writing, driving a car, watching telly or cooking can be carried out more efficiently with functional eyesight. 

The complex anatomy of our eyes makes it possible for us to interpret the dimensions of a variety of objects, for example, their shape, colour and size depending on the type of light they emit. Different components of the eye allow us to detect light when it is either very bright, or dim. However, the ability to see is eliminated when no light is present.

Light waves are emitted from objects which first enter the eye through the cornea. It then continues through the pupil which is an opening in the centre of the coloured aspect of the eye, the iris. It then progresses through the vitreous humour, a clear gel which makes up 80% of the total volume of the eye. The final component of the pathway is for the light to focus onto the retina, which contains the rod and cone cells. 

 Eye picture is courtesy of Wikimedia Commons. This image is in the public domain thus free of any copyright restrictions.