The Eye The Eye The Eye Eyelids Tear

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 Eyes Long-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 Eyes Short-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