Chapter 2. Biological Eye  Designs

Chapter 3. Eye
 Design Illustrations
A. Plant light sensing
1. Grass, simple vines, 
and stems
2. Flowers
B. Lower animal eyes
1. Flatworms
2. Clams and Scallops 
3. Nautilus
4. Shrimp
5. Crab
6. Octopus and 
   giant squid
7. Spiders
8. Scorpions
8. Brittle Star 
C. Insect eyes 
1. Bees
2. Dragonflies
3. Butterflies
4. Flies
5. Ants
6. Moths
7. Beetles
8. Wasp
D. Fish eyes 
1. Shark
2. Flounder
3. Four-eyed fish 
E. Amphibian eyes
1. Frog
2. Salamander
F. Reptile eyes
1. Boa constrictor 
2. Rattle snake
3. Lizard
4. Turtle
5. Crocodile and 
    alligators
G. Bird eyes
1. Eagles
2. Hummingbirds
3. Owls
4. Ostrich
5. Cormorants
H. Mammal eyes
1. Whales
2. Elephants
3. Lions, tigers, and 
   other cats
4. Monkeys
5. Rats and mice
6. Bats
7. Tarsier
I. Human eyes
1. Iris
2. Lens
3. Retina

Chapter 4. Eye 
 Reproduction

Chapter 5. Optical 
 Systems Design 

Chapter 6. The Eye Designer

Related Links

Appendix A - Slide Show & Conference Speech by Curt Deckert

Appendix B - Conference Speech by Curt Deckert

Appendix C - Comments From Our Readers

Appendix D - Panicked Evolutionists: The Stephen Meyer Controversy
 

 
 
 
 
 
 
 
 

EYE DESIGN BOOK
Chapter 3
Section G
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3. EYE DESIGN ILLUSTRATIONS
G. Bird eyes
      Birds need more complex vision systems than many land animals. Some birds use the sun and maybe even star patterns to navigate. Some bird eyes provide very good distant vision. Large hunting birds, such as vultures, can spot an animal carcass from 3,000 or 4,000 meters. Eagles may see a fish or evidence of a fish at the same distance. At that height, most humans cannot even see the bird. Most birds are far-sighted, and accommodation of the eye is superior to most eyes mentioned so far. Of all the larger animals, birds have the highest density of photoreceptors. For example, the eyes of the hawk have 1 million photoreceptors per square millimeter. This is a higher density than many of the CCD image detectors used in today’s video cameras. Smaller sparrow eyes have 400,000 photoreceptors per square millimeter, double the density of photoreceptors in the larger human eye. 

1. Eagles

Eagles need to see long distances with good resolution in order to hunt. They have closer sensor spacing than human eyes, so they are able to see more details at a given distance. Their image processing is carried out using a much smaller brain than that of humans. They can respond quickly to what they see, such as when they swoop down to pick up a small rodent.We have heard that eagles can see a fish at five miles, but they are probably seeing a  reflection of a fish jumping out of the water. One expects they would see less overall color than humans. Even with a variety of pigments in their eyes, they can sense polarized light. Eagles have excellent vision near their central viewing angle.        Some small, remote-piloted vehicles have been patterned after the eagle. They are not as versatile as an eagle's seeing capability for equivalent eleva-  tions and equivalent overall size. Most do not have the dynamic range of sensing and are usually only relaying images to a command area, not fully pro- cessing images for internal decision making. (Newspaper Ad, unknown source, Trad. Photo)       The remarkable Hawk Eye is probably similar to that of the Eagle and other similar birds. Figure 3.38a illustrates a very sophisticated optical design in a very small package for specific needs of the Hawk. (Reference: Figure 5.12, p. 91, Animal Eyes, Michael F. Land, Dan-Eric Nilsson, Oxford Animal Biology series, Oxford University Press, 2002- Please see their book for more details )

Figure 3.38 Eagle Eyes. Fig 3.38a Telephoto Hawk Eye

2. Hummingbirds
      Hummingbirds can see  flowers at a distance and very small parts of a flower at close range. This indicates they have good focusing ability for near and far objects. They probably have extended UV spectrum color vision like insects, as well as vision to sense polarized light. Their brain has the ability to control three-dimensional navigation and coordinate rapid movements of their wings to their eyes, so they can take full advantage of their eyesight. (P. 185, Readers Digest, Exploring the Secrets of Nature, 1994) 

Fig 3.39 Hummingbird Eyes.

Fig 3.39b Hummingbird Eyes.

3. Owl
     Owls locate their target or meals with their precise directional sensing using the difference of the time it takes for sound to reach each of their two ears. They then turn their eyes to the direction from which the sound originated. Owls learn to do this while  quite young. However, as they grow, the capability has to be modified as the ear separation grows. Here there must be some special compensation, in the brain, indicating intelligence to compensate for increasing ear separation.
     Owls have sensitive eyes for hunting at night, they tend  to have a large aperture (large NA or small f/number) eye. large for their overall body size. Owl eyes do not rotate as much as human eyes do, but an owl's head can turn a considerable angle to accomplish the same purpose. They also have good stereo vision and depth perception because of the owl's eyes being separated by a significant distance. (Fig. 3.40 from P. 93, Readers Digest, Exploring the Secrets of Nature, 1994 and fig. 3.41 adapted from p. 105, fig 40 Vision in the Animal World, R. H. Smythe, Macmillan Press, 1975) 

Figure 3.40a Owl Eyes.

Figure 3.40b Owl Eyes.

Figure 3.41 Optical Cross  section of Owl Eyes to  illustrate capability to Focus

4. Ostrich       The ostrich has the largest eye of any bird. It also has the longest neck of any bird. This allows it to move its eyes close to smaller targets. It does not have the same needs for extremely high resolution or acute eyesight as the high flying eagle and other smaller birds, since it does not fly. (Pg. 126 The Illustrated Encyclopedia of the Animal Kingdom, 1970, Danbury Press) 

Figure 3.42 Ostrich Eyes.

Figure 3.42b Ostrich Eyes.

5. Cormorants        The cormorant eye must have the ability for optical correction in a land based camera eye. When it dives in water it must focus to catch a fish. It can maintain good focus over a wide range in air and water. Its brain can make fine control decisions based on rapid processing of the eyes-output. This is especially true as it tracks a fish in the water from the air and then dives after it, moving to readjust its vision very quickly as it swims under the water. The adjustment requires optical design adaptation when in the water because of variable pressure and different focus requirements. (P. 323, Readers Digest, Exploring the Secrets of Nature, 1994)

Figure 3.43. Cormorant Eyes.

6. Falcon

The Falcon eyes must have the ability for high-resolution and dynamic correction while diving at almost 200 miles per hour. Some have said that it has eight times the resolution of human eye where it is able to see at 160 feet what humans see at 20 feet. It is somewhat similar to the eagle. It achieves the best combination of speed and visual resolution. It is able to target distant prey such as other birds and intercept them in flight. As it intercepts them it uses its clenched claws to disable the prey and then it swoops under them to recover the kill before it falls to earth. For many years people have trained Falcons as hunters. Figure 3.43f illustrates the Falcon (From Today's Chemist, page 11, Jan. 2002).

Figure 3.43f Falcon Eyes.