Start Eyes not accommodating

Eyes not accommodating

This is known as presbyopia and is one reason that older people often need reading glasses.

If you look at your reflected image on the flat side of the balloon, you will notice that it becomes smaller if you pull the edges of the balloon outwards.

For the eye, light from distant objects is focused onto the retina at the back of the eye.

The eye is about the size of a table tennis ball, so the focal length needs to be about 2.5 cm.

The afferent pupillary defect becomes obvious when the flashlight is moved from the normal to the affected eye, and the affected pupil Sequence Direct response (pupil illuminated).