The Eye

The Eye

The Eye

• Eyelids • Tear duct• Cornea – skin that covers front of eye. Lets

light pass into the eye.• Iris – changes in size depending on light

intensity. • Pupil – an opening through which light passes• Lens – focuses light onto the retina.

The Eye

• Retina – Has 2 vision receptors. One is sensitive to the colours of light, and the other to brightness

• Vision receptors join to Optic nerve - goes to the brain.

Converging and Diverging Lens

• Converging lens – the light comes together• Diverging lens – this lens bends light rays

outwards.

The Eye

• The lens in your eye acts as a converging lens and focuses light on the retina.

Converging and Diverging Lens

• The more curved the lens is, the more it bends the light rays ( think of thick glasses)

Problems with EyesLong-sighted (far-sighted)

• Difficulty focusing on close objects eg when reading.

• The image focuses behind the eye.

• Glasses can be worn to correct the problem.

Problems with EyesShort-sighted

• The focus of the image is in front of the retina.• These people can focus on close objects, but

have difficulty focusing on distant objects.

Problems with Eyes

• Colour-blindness– Cannot distinguish between certain colours– Eg people with red-green colour-blindness confuse

certain shades of red, green and brown.– Inherited.– Incurable

Independent Task

• Go to Mr Leitchs weebly• mrleitch.weebly.com• Complete 1.0 ‘parts of the eye’• Functions of the parts• Quiz