Vision

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Vision

• The Human Eye

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Light

• Light is electromagnetic energy
• Not all light is visible to humans
• Light is broken down into colors via prisms
• Light is measured in wavelengths
• The main colors of the spectrum are Roy G. Biv

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Electromagnetic Spectrum
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Color Wheel
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The Parts of the Human Eye

• Blind Spot
• Optic Nerve
• Cornea
• Iris
• Lens-focuses light on retina
• Pupil-opening in center of eye that adjusts to
  allow light to enter
• Retina-inner surface of the eye that contains
  rods and cones

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How do we see?

• Step 1 Light enters the eye through the pupil
• Step 2 Light reaches the lens, which focuses the
  light
• Step 3 Light is now visible on the retina where
  it is changed to chemical and electrical impulses
  by rods cones
• Step 4 Impulses are sent to the optic nerves in
  the brain

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Rods v Cones
Rods Photoreceptors that are sensitive to the
brightness of light they allow use to see in
black and white (120 million) Cones Photoreceptor
s that provide color vision (6 million)
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Herman Grid
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Dark Light Adaptation

• Dark Adaptation the ability to adjust vision to
  lower lighting when entering a dark light place.
  This process usually takes up to 45 minutes.
• Adaptation to bright light happens much more
  quickly than adaptation to dark light.

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Why do we see color?

• Trichromatic

• Opponent Process

Answer A combination of both theories
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Color Wheel
Complementary Colors- Those colors across from
one another on the color chart
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Color Vision

• Afterimages
• The visual stimulation that occurs after the
  original has been removed
• The colors across from one another on the color
  chart become visible after the original is
  removed.

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Afterimages

• Stare at the following images for approximatley
  45 seconds
• I will advance each slide to a white slide. When
  that slide appears, you will see an afterimage
  (the colors here will be the complementary colors
  from the original image)

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Color Blindness

• Complete or partial inability to distinguish
  colors resulted from a dysfunction in the cones
• Hereditary
• 8 of men suffer from it
• Less than 1 of women suffer from it

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Take the Colorblindness test

• http//www.toledo-bend.com/colorblind/Ishihara.asp
  
• http//colorvisiontesting.com/online20test.htm