1. Ishara Mills-Henry, Ph.D. MIT

2. Human Eye

3. Cows versus Humans What can they see and what can we see?

4. External Tissue of Eye Rene, C. Eye 20: 1119-1129; (2009) Cow Eye Human Eye Orbit

5. Eye movements http://www.michaelbach.de/ot/mot_eyeJitter/index.htmlhttp://www.michaelbach.de/ot/mot_eyeJitter/index.html from Pinna B & Spillmann L (2002) A new illusion of floating motion in depth. Perception 31:1501–1502.

6. Cow Eye

7. Cornea – Refractive Errors Pictures taken from www.essilor.com.au

8. Myopia – Nearsightedness Hyperopia - Farsightedness Pictures taken from www.essilor.com.au

9. Corrective Lenses Myopia concave lens will correct the problem by focusing the light farther onto the surface of the retina. Hyperopia a convex lens will refract light rays allowing them to focus directly onto the retina.

10. Lasik

11. Iris and Pupil Pupil changes size to adjust for light levels (like an aperture)

12. Let’s take a peak inside…

13. Lens

14. Accommodation Close one eye and stare at a point about 20 feet away. Keep focusing on the point and raise one of your fingers into your line of sight just below the point. How does your finger look? Now, change focus: look at the tip of your finger instead of the point 20 feet away. How does the distant image look?

15. Accommodation Far Away Objects – The zonule fibers provide tension to the lens giving it an elongated shape. Close Objects – Ciliary muscles contract Relaxes the tension of the lens leading to a rounder shape changing the focal length of the eye. This brings objects that are closer to the eye into focus.

16. Presbyopia Limited lens accommodation

17. Cataract www.nih.nei.gov

18. Retina

19. Color Vision

20. Optic Nerve Where’s my blind spot? Why is it so hard to find?

21. Where’s my blind spot?

22. Why is it so hard to find? Right Eye Left Eye

23. Glaucoma

24. Bloodshot eyes Inflammation of blood vessels on sclera (white of eye) Causes Conjunctivitis (pink eye) Dry eye Eye strain Alcohol induced

25. Why more men than women? 1 in 12 people have some sort of color deficiency. About 8% of men and 0.4% of women in the US. Some types of color vision deficiency are sex–linked diseases