1. Vision of Fish
By Andrew McDonald

2. Outline Introduction Challenges of water Absorption of light
Refraction of light
Anatomy of eye
Light regulation
Jim Lavarakas

3. Introduction
Optics : the collection of light and formation of an image by the lens
Accommodation : focusing of images on the retina

4. Eyes of Fish Much like human eyes But no eye lids
Many sizes and colors

5. Anatomy of Eye
Sclera
Cornea
Lens
Iris
Retina
Optic nerve

6. Powerful Eyes Spherical lens High refractive power High quality
Receptors: cones and rods

7. Problems With Seeing Under Water
Light refraction
Suspended particles
Light
absorption

8. Suspended Particles Sediments Microorganisms Plant growth
Fast-moving water
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9. Light Absorption The dimming of light as it passes through water
Red wavelengths absorbed rapidly
Blue wavelengths absorbed slowly
Deep ocean is blue

10. Light Refraction Snell’s window Cone of Vision
Water bends 48.6 degrees
Freshwater pools
Snell’s window

11. Light Regulation To limit light Iris contraction Smaller eyes
Migration of visual cells
Cornea filter pigments
Swim away from light

12. Light Regulation For more light: Walleye Mirrors in back of eye
Larger eyes
Swim toward light

13. Conclusion Some similarities w/ humans Different environments
More obstacles
More diverse
Altered behaviors