Also known as: Eye test - color, Vision test - color or Ishihara
color vision test - Present from birth (congenital) problems in
the light-sensitive cells (cones) of the retina (the light-
sensitive layer at the back of the eye) - Diseases of the optic
nerve (the nerve that carries visual information from the eye to
the brain) - Achromatopsia -- complete color blindness, seeing
only shades of gray - Deuteranopia -- difficulty telling the
difference between red/purple and green/purple - Protanopia --
difficulty telling the difference between blue/green and
red/green - Tritanopia -- difficulty telling the difference
between yellow/green and blue/green A color vision test checks
your ability to distinguish between different colors. How the
test is performed You will sit in a comfortable position in
regular lighting, and your health care provider will explain the
test to you. You will be shown several cards with multicolored
dot patterns. In the patterns, some of the dots will apear to
form numbers or symbols. You