The Retina

What is The Retina?

The Retina is at the back of the eye, and is the part of the eye that is responsible for detecting light and dark, as well as colour.

The Retina (Shown Right), contains millions of light sensitive cells called Rods and Cones. Rods are responsible for detecting light at various intensities, and cones are responsible for detecting colours. There are three types of cone, which detect different colours of light (Red, Green, Blue)

When these rods and cones are exposed to light they each transmit a signal through the Optic Nerve (The Light Spot at the Centre of the Diagram), which is then processed by the brain.

This remarkable system of perceiving light can distinguish between over 120 million colours, in normal vision.

The Human eye is in fact an external portion of the brain, and normally in humans the eye is also responsible form more than 90% of the sensual input to the brain.

See Also :

• Colour Blindness
• Retinopathy

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