Basma is the first winner of our science writing competition, and entered the 10-12 year old category. She is 10 years old, her home country is Syria but is now living in the UK. Basma’s piece about the eye was a wonderful read, and very impressive for someone so young. Congratulations Basma. The following is entirely Basma’s work, enjoy…
Tremendously Admirable Human Eyes
Eyes form part of the sophisticated sensory systems which humans are born with, the main function of which is vision. The basic features of an eye are: the cornea, the iris, the pupil, the lens, the retina, the optic nerve, and the jelly-like substance that keeps the eye’s essential “organs” safe and that shapes the eye itself.
- CORNEA – The cornea is the transparent skin covering the outside of your eye.
- IRIS – The iris is the round coloured part of a person’s eye.
- PUPIL- The pupils of your eyes are the small, round, black holes in the centre of them.
- LENS – In your eye, the lens is the part behind the pupil that focuses light and helps you to see clearly.
- RETINA – Your retina is the area at the back of your eye. It receives the image that you see and then sends the image to your brain.
- OPTIC NERVE – The second cranial nerve, which provides a sensory pathway from the retina to the brain.
- SCLERA – the firm white fibrous membrane that forms the outer covering of the eyeball.
- LACHRYMAL GLANDS – the compound gland that secretes tears and lubricates the surface of the eye and the conjunctiva of the eyelid. (1)
Emotions can affect one’s eyes. When someone laughs hardly or cries, the muscles in their upper eyelids squeeze the lachrymal glands, as a result, tears are produced. (2) Eyes also adjust to how much light there is surrounding it; too much light could cause harm. When you walk into a room full of light after being in a dark room, your pupils shrink. It’s the same as looking up to the sun, pupils will grow smaller as your eye doesn’t want too much light. Looking up to the sun for a long time could cause blindness.
Irises are another matter. The colour of an iris is inherited from the person’s parents. But as human eye labs have discovered more information about eyes, research has proven that eye colour can change due to changes in the body such as puberty and pregnancy. Irises with little or no pigment (a material that gives a particular colour) will be blue; irises with some pigment will be green, and irises with a lot of pigment will be brown (3). Dangers occur when people take risks by placing plastic discs (contact lenses) on their eyes so that their eyes appear with different colours. It’s hazardous to take the discs on and off, especially people with fake long nails because if the discs are broken on the eye, then part of the eye will become scratched and this could lead to infection and disorder.
In year 6, we dissected pig eyes; one of the closest eyes to human eyes. After we cut through the tough outer layer (Sclera) with a scalpel, the jelly substance burst out. The lens was very interesting- when we put it onto a piece of newspaper, it zoomed in on the words like a magnifying glass!
DID YOU KNOW two eyes are better than one? It’s to help you judge how distant things are. When you look at something, your left eye sees the image differently from your right eye. The difference depends on how distant the object is. Your brain will receive both images and will immediately work out how far the object is. This ability is called depth perception. Some blind people can ‘see’ where they’re going by using the same methods as bats: they make clicking sounds and listen to the echo to judge distances to objects (4).
ANOTHER FACT: the cornea of your eye is the only part of your body with no blood supply? Your cornea needs to be translucent (so that you can see through it) or blood vessels will block your vision. Also like other tissue, your cornea requires oxygen to stay strong and healthy: oxygen in the air dissolves in your tears and spreads throughout the cornea (4).
- URL: https://www.collinsdictionary.com/dictionary/English
- URL: https://www.google.co.uk/search?q=botanica&ie=&oe=
- Clancy J, 2011, 1st Ed. The Human Body Close-Up. Quercus Publishing Plc, London
- Canavan T, 2015, 1st Ed. Body Works, Taking Control, The Brain and Senses, Franklin Watts, UK