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The Anatomy of the Eye, click on image to enlarge








The Eye

The eye is a most interesting, complex organ allowing us to see the light of the world around us.

Anatomy of the Eye

Each eye has:
  • 120 million black and white receptors called Rods.
    • These are nocturnal, work mainly at night.
  • 6 million color detectors called Cones
    • Diurnal, work during the day
    • There are three kinds of cones red, green and blue
    • Cones need brighter light
    • Cones respond to more vivid, sharp images
  • A fovea - the central point of the Retina packed with cones.
  • A blindspot - with no light sensors, where th eoptic nerve leaves the eyeball.
    • The blind spot is at about 20 degree angle from the fovea (plus or minus 5 degrees). Interestingly this matches the tilt of the earth.

  • Cells called BiPolar cells send collect information from the rods and cones to send to the brain for processing
    • Bipolar cells carry information from many Rods, or just one Cone. The information from the Cone is precise (from one cone), while the info from the rods is sent as a packet - one signal from many sensors so the image is fuzzy - but it is much better at detecting movement.
Is the theory of Cones and Rods correct?
click on image to enlarge
source
Phototransduction, neurobiology of color detection

Message processing

For most of the body, the senses coming in on one side of the body are processed in the opposite half of the brain. A sensation in the right hand is processed on the left side of the brain.

In the eye, Cones from the right ey are processed only on the right side of the brain. Cones from the left ey are processed on the left side only.

Messages from the RODS are sent to both sides of the brain. The rods near the nose are processed on the opposite side of the brain. The rods closer to your ears are processed on the same side of the brain.

Visual Perception

Optical illusions play with our ability to focus in reality, to see what is there.

  • Visual Perception Magicians know the hand is quicker than the eye. Researchers are finding out how this happens. This is a guide to the latest research in visual perception and illusion.

Reflexes of the Eye

Superior Underwater Vision in Sea Gypsies

Prior to this research it was thought there was no change possible in Pupil contraction reflex.

Moken youngsters can spot tiny shells, clams and sea cucumbers four metres beneath the surface of the crystal-clear Andaman Sea without resorting to goggles.

Ordinarily, human eyesight becomes blurry under water because the eye is structured to see through air. But the Moken nomads, who tie stones to their waists so they submerge long enough to forage for seafood, can constrict their pupils to pin-prick size and spot pearls measuring only 1.5mm in diameter. They also squint in order to squeeze the lenses of their eyes, which temporarily thickens them and improves focus under water.

Source: Original no longer available

Eye dilation

Dilated pupils are less focused, but gives a wider lens providing easier access to peripheral vision, and subconscious mind.
  • This is the wide eyed look, over used in the first Harry Potter movie and by Marilyn Monroe.
  • This is a sign that someone has momentarily turned off the conscious brain and is accessing the right brain. In ¿hypnotism, this is a time where one can easily place hypnotic suggestions.
  • This is a part of the freezing limbic response
  • This is a defocused eye, seen when someone is deep in thought.
  • The pupil momentarily expands when encountering things we like.

Constricted pupils are focused.

  • This is a reaction to too much light.
  • This is a blocking response - the eyes reducing the amount of incoming information allowing the conscious mind to focus without interference from the right brain.
  • Eyes constrict to focus.
  • This is a focused eye, seen when someone is intently observing
  • The pupil momentarily contracts when encountering things we find stressful or disagreeable.

Things to ponder

  • If we live more and more in light, 24 hours a day, are we losing our ability to use our nocturnal senses?
  • over the age of 45, we being to lose or decrease in our ability to focus on what is immediate and right in front of us (the need for reading glasses). Does this give us more ability to see the bigger picture, force us to focus on things farther than us (far sighted).
  • When you look at black and white photos, you are using RODS only.
  • If you block the vision between your two pupils and over the nose - you are seeing only on the same side with not crossover. Is your "THIRD EYE" the part closest to the nose where the sensory data crosses over?
  • What happens if you used colored lenses to block the vision - does rose colored glasses really change what you sense or feel?
  • Lower ranking people are taught to lower their gaze. Higher ranking people look directly. Usually customs have the person lower the head, which is a form of blocking. The lower ranking person then is watching the higher ranking person with peripheral vision. Investigate brain and perception effects of this.

Eye color

Says Dr. Rick Sturm, the IMB researcher who led the study: "... the model of eye colour inheritance using a single gene is insufficient to explain the range of eye colours that appear in humans. We believe instead that there are two major genes -- one that controls for brown or blue, and one that controls for green or hazel -- and others that modify this trait." (Credit: Image courtesy of University of Queensland)Science Daily

Improving Eyesight

  • Improving Eyesight
  • Increased intakes of omega-3 fats may reduce the risk of both types of Age-related macular degeneration. 1
    • Wet AMD, occurring when blood vessels grow abnormally beneath the macular, are reduced by 35%
    • Dry AMD, occurring when normal tissue in the macula slowly disappears, is reduced by 32 percent, respectively.

Medieval Facts about the Eye

The eye was considered to be ruled by three Zodiac Signs
  • Aries Ruled the eyes as a part of the head
  • Cancer Ruled the eyes as a sac in the body (Glaucoma and diseases relating to the fluids in the eyes)
  • Aquarius is co-ruler of the eyes according to Eileen Nauman in particular the rods and cones and retina

  • The Sun Rules the Right Eye
  • Distant galaxies that fade in and out of site were considered to be bad omens for the eyes.

Sources


Related pages:

  • Photic Sneeze Reflex About a quarter of the people in the world sneeze when they go out into the bright sunlight, yet most people either have it or have never heard of it. Historical figures such as Aristotle and Francis Bacon had this reflex, but for most of us it is just a curiosity. Find out what's happening here.
  • Colors Art Color Theory classifies colors as warm: yellow, red, and browns or Cool: violet, blue, green, and grey. Science experiments are demonstrating this is not just a mental illusion. This is the Directory for color, its symbolism and significance.
  • Visual Perception Magicians know the hand is quicker than the eye. Researchers are finding out how this happens. This is a guide to the latest research in visual perception and illusion.
  • Perception Perception involves what and how we deal with input from the senses. Areas such as Attention, Emotion, and Empathy.
  • Observing Others Over half the people at any give time will not notice even the most blatantly obvious things in their environment. We must constantly remember to observe the world around us. These are notes from the Academie seminar on learning to be more observant.

Last edited November 5, 2009 (history)
 
   

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