light stimulus 2

The eye is a sense organ because it contains:

Receptors (photoreceptors: rods and cones)

Other tissues that allows the receptor cells to work effieciently.

Its own bloody supply and physical protection.

An image is formed when rays of light are focused onto the retina.

Lens have the ability to produce an image of objects at different distances. (accomodation)

As people get older lens become less elastic and loses its ability to change shape. This makes harder to refocus quickly on objects at different distances.

What happens to people when they become older?

If too much light fell on the photoreceptors they would not recover in time to allow clear vision.

What happens if too much light fell on the photoreceptors?

The Iris contracts or expands to control the amount of light that enters the eye.

Research Choose a visual problem: myopia, cataracts,

lazy eye, astigmatism, hyperopia, blindness or color blindness.

What is/are the cause/s?What are the symptoms?Do they have a treatment?

Design a presentation to expose this visual problem for the rest of the class.