SIGHT

The sense of sight serves to capture the light stimuli that affect the interior of our eyeballs, where photoreceptor cells are found. These stimuli are interpreted in the visual area of the brain to form the image we see through the eyes.

CorneaThis is the see-through skin that covers the front of your eye. It is clear like glass and it has no blood vessels in it.

ScleraThis is the tough skin which covers the outside of the eyeball. We call it the 'white' of the eye.

IrisThe iris controls the amount of light that enters the eye. The iris is the coloured part of your eye.

Pupil This is the hole in the coloured iris. It lets light into your eye.  It gets very small in bright light, and bigger in dull light.

The lensThe lens focuses light onto the retina. It changes shape to make sure that the 'picture' on the retina is as clear as possible.

Retina This is like a movie screen which shows the picture you are seeing - upside down, remember? The retina has two lots of cells called 'rods' and 'cones' Rods can 'see' black and white.  Cones can 'see' colours. They turn the picture into an electrical message for the brain. 

Optic nerve The electrical messages from the retina travel along the optic nerve to your brain. It's a bit like the cable that carries all the TV pictures from your aerial to your TV so that you can see the programs. The great thing is that our eyes take these 'movies' all the time and we don't need any film or camera.

Vitreous humour 
This is a thicker jelly-like liquid which fills the larger part of the eyeball and keeps it in shape. 

Choroid

Is the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera.

Ciliary musclesThese are a circle of tiny muscles around the lens. They change the shape of the lens by squeezing and relaxing. They squeeze to look at nearby objects, and relax for far away objects.

BIBLIOGRAPHY

• http://www.cyh.com/HealthTopics/HealthTopicDetailsKids.aspx?p=335&np=152&id=1730
• http://tulandar5.wixsite.com/florihospital/2nd-floor-interaction
• http://kidshealth.org/en/kids/eyes.html
• http://www.biology-online.org/dictionary/Sight