This document summarizes key differences between cow and human eyes. It discusses the external tissues, eye movements, cornea, refractive errors, corrective lenses, lasik surgery, iris, pupil, lens, accommodation, presbyopia, cataract, retina, color vision, optic nerve, blind spot, glaucoma, and causes of bloodshot eyes. Differences between men and women in terms of color vision deficiencies are also noted.

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 Cow Eye Human Eye Orbit

5. Eye movements http://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

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

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.

17. Cataract www.nih.nei.gov

18. Retina

19. Color Vision

21. Where’s my blind spot?

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

23. Glaucoma