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 F
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3. EYE DESIGN ILLUSTRATIONS
F. Reptile eyes
      Reptiles have a rich history, including some very large animals that are now extinct. The eyes of extinct creatures may have been more complex than many eyes of previously discussed animals. In some cases, reptile eyes may have features beyond the capabilities of the amphibian. This is partially evidenced by the order of hunting, where the reptile hunts the amphibian.

1. Boa constrictor 
     The boa constrictor is nonvenomous and has color vision, some also have extended infra-red (IR) vision well beyond where humans  can see. This enables it to sense temperature differences of less than 0.03 degrees centigrade at a significant distance, and thus find live targets in dense rain forests. Their IR vision system is being studied by the military to see how such a detector, useful for night vision, can function without being cooled to a very low temperature. (Figure 3.32 from p 204, Readers Digest, Exploring the Secrets of Nature, 1994) (Figure 3.32b from p 61, and figure 3.32c from p 64, Reptiles & Amphibians) 

Figure 3.32 Boa Constrictor Eyes. (For large graphic,  click on small graphic)

Figure 3.32b Emerald Tree Boa Eyes.

Figure 3.32c  Rainbow Boa Eyes.

Figure 3.32d shows an organ of a Boa IR vision system. It has been well known that snakes have thermal vision. Scientists at Florida Institute of technology are one of the groups analyzing that vision. This research could result in better IR vision for scientific, industrial, safety, and medical applications. The vipers system is roughly 10 times better than typical cooled infrared detector system presently available. Some very large IR systems may approach and exceed the Boa resolution, but they are not practical for many applications. The organ detects IR energy and relays it to the brain that creates a map or image of the field of view. As a result, these snakes are able to see well beyond human vision clear out to approximately 8-12 micron wavelengths. Snakes may use the visual system to calibrate the thermal vision or vice versa. The organ may have unusual topography that may function as a spectral filter. (reference: Biophotonics International, May 2002, page 28)      In a recent example of scientists looking to snakes, such as that shown below in Figures 3.33a-d, to provide clues for IR radiation detection, scientists from Iowa State University have used a scanning probe microscope to analyze IR reception in beetles. More recently, they have focused their efforts on micro structural and thermal properties of Burmese and ball python pit organs. These pit organs are located near the eye. They have infrared receptors that allow them to hunt using thermal imaging. This research could provide new thermal imaging optical designs. (Today's Chemist at Work, March, 2002, page 10)       Work is still going on to understand the IR vision systems of these snakes. Other snakes may look slightly similar, such as the Garter Snake.

Figure 3.32d IR eye. Figure 3.32e Garter Snake. Fig 3.33a Rattlesnake Eyes.

2. Rattlesnake
      The rattlesnake is a smaller pit viper that lives in drier, less vegetated areas of the earth. They need to see small living targets in open areas. These snakes can sense very small  temperature differences of about 0.05 degree centigrade and find warm targets to  attack without visible light. These targets, invisible to human eyes at night, require vision in the infrared spectral range. Because of their vision in the infrared (IR) spectral region, these snakes have the ability to hunt and attack at any time. This compact and efficient IR vision capability is also desirable for current military equipment developments. (Rattlesnake photos by Bruce Chambers) 

Figure 3.33b Aruba Island Rattlesnake.

Figure 3.33c Aruba Island Rattlesnake.

Fig 3.33d Western Diamondback Rattlesnake

3. Lizard       Like salamanders, lizards come in all sizes and shapes, from several inches to several feet long. Their eyes have interesting coverings, including eye sockets for protection and scanning like airborne military optical systems. A primitive version of a lizard (Rhynchocephidia) has a well- developed third eye, something on the order of a salamander eye. Another unusual lizard (Sphenodon) also has a third eye. It would be interesting to research how they benefit from the third eye.       The color-changing chameleon is able to look and focus in different directions with each eye. Some have interesting  camouflaged eyelids and eyes that can point in random directions to look at separate fields of view. This means it must have different parallel imaging processing systems for each eye. Since it has a narrow field of vision, the eye must scan to follow targets. There are many design variations in lizard eyes.

Figure 3.34 Lizard Eyes. (By Bruce Chambers) Figure 3.35 Gecko Lizard Eyes  (Pg. 61, Eyes Of Nature,  National Audubon Soc, 1968,  Nelson Doubleday)

Figure 3.34b Madagascar Velvet Gecko Eyes. p 20, Reptiles & Amphibians

Figure 3.34c Madagascar Ground Gecko Eyes. p 22, Reptiles & Amphibians

Figure 3.34d Baja California Rock Lizard Eyes. p 41,  Reptiles & Amphibians

Figure 3.35b Panther  Chameleon Eyes, p 48 Reptiles & Amphibians

Figure 3.35c  Tokay Gecko Eyes, p 23 Reptiles & Amphibians

Figure 3.35d Common  Wonder Gecko Eyes, p 26 Reptiles & Amphibians

4. Turtles
      Turtles do not see as well as humans. Their retina is made up primarily of cones. Eye lenses are flat for land turtles, and more spherical for sea turtles. Special oil ducts emit droplets in  turtle eyes. This oil is used for optical color filtering, much like filtering in some bird eyes. Their vision is best in the yellows, oranges, and reds. If disturbed, they can retract their head into their bodies to protect their eyes. Turtles lay eggs in the same area year after year. Some may even travel with their eyes closed. They must have significant navigation capability in addition to vision as we know it. This would indicate some intelligence beyond that connected to visual capability. (P. 168, Readers Digest, Exploring the Secrets of Nature, 1994) 

Figure 3.36b New  Guinea Snapping Eyes, p 71 Reptiles & Amphibians

Figure 3.36c Reimann's Snakeneck Turtle Eyes, p 77 Reptiles & Amphibians

Figure 3.36d Painted  Wood Turtle Eyes, p 81 Reptiles & Amphibians

5. Crocodiles and alligators       The crocodile has an extra upper eyelid and protective membrane in front of the iris, in addition to the considerable protection of thick skin on its head surrounding the special eye socket. Its eye has a special pupil, called a stenopeic pupil. This acts like a pinhole camera when in bright light during the day, thus allowing a greater depth of field. At night there is a greater effective opening of the pupil to  allow much more light to go into the eye. When light strikes the crocodile's eyes, they will reflect orange light, due to the  pigment color in their reflective rod retinas. Pigments may reflect different color than those the animal sees, because of the different sensitivity of photoreceptors. Like many creatures, crocodiles have a limited area of high-resolution vision. Their eyes are set high on their heads so the body of the crocodile can be hidden in the water and the eyes can still see through air so they can hunt land-based creatures.

Figure 3.36a Turtle Eyes. Figure 3.37 Alligator Eyes (By Bruce Chambers)

Figure 3.37b American  Alligator Eyes, p 82 Reptiles & Amphibians

Figure 3.37c Schneider  Smooth-Fronted Caiman Eyes, p 83 Reptiles & Amphibians

Figure 3.37d Alligator Eyes

Figure 3.37e Alligator Eyes

     (Figures 3.32 through 3.37, where cited, from Reptiles & Amphibians, used by permission of the photographer and copyright owner Ryu Uchiyama, and the publisher, Chronicle Books, San Francisco, CA 94105)