1. The eye

2. The Eye Aqueous humour vitreous humour

3. https://www.youtube.com/watch?v=0 rbCrJoTatE Link to good cow eye dissection video

4. The Eye - pupil The pupil is a circular hole in the iris. The black colour comes from a layer in the eye that stops internal reflections. In bright light the iris reduces the size of the pupil. In dim light the pupil is large.

5. The Eye - cornea The cornea is a layer of transparent skin on the front of the eye. It plays an important part in focussing the light (along with the lens)

6. The eye - retina The retina is a light sensitive layer at the back of the eye that sends messages to the brain via the optic nerve

7. The eye - lens The lens can change shape to focus both near and far objects

10. Near point The near point is defined as the closest point on which an unaided human eye can focus without straining. How far? Let’s try!

11. Near point The near point is defined as the closest point on which an unaided human eye can focus without straining. It is taken to be 25cm for a normal eye, but can change greatly with age.

12. Short sightedness (Myopia) – difficulty seeing distant objects If the eyeball is too long or the lens too powerful, rays are focussed before the retina. A person sees a blur!

13. Short sightedness (Myopia) can be corrected with a concave lens

14. Long sightedness (Metropia) – difficulty seeing close objects If the eyeball is too short or the lens is not powerful enough, rays are focussed behind the retina. A person sees a blur!

15. Long sightedness (Metropia) can be corrected with a convex lens

16. It is estimated that 75% of all people will need some kind of eye correction by the time they get old