Mr Venki Sundaram
Consultant Ophthalmic Surgeon
MD FRCOphth MRCOphth BMBCh BSc

About the eye

The human eye is an incredible organ that is responsible for the conversion of light signals into meaningful images that can be interpreted as vision by the brain.

There are several structures within the eye that have a vital role in this process (see Image 1):

Cornea – this is the clear window at the front of the eye, which allows light to enter.

Iris – this is the coloured part of the eye with the hole in the middle known as the pupil.

Lens – this is a clear, convex structure within the eye that helps to focus images onto the retina.

Vitreous – this is the clear, jelly like substance that forms the majority of space within the eye.

Retina – this is the light sensitive tissue at the back of the eye that captures light signals and coverts them into electrical impulses that are sent to the brain. It is the most active tissue in the human body, responsible for processing millions and millions of pieces of visual information over a lifetime.

Macula – this is the central part of the retina and is responsible for central vision.

Fovea – this is the very centre of the macula area and is responsible for providing fine vision.

Choroid – this is a rich network of blood vessels that provide essential oxygen and nutrients to the retina.

Optic nerve – this is the main nerve that leaves the back of the eye and conveys electrical signals from the retina to the brain.

Sclera – this is the tough, white outer coating of the eye that helps to maintain its shape.

Human eye diagram

Image 1 – Basic structure of the human eye