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HOW THE EYE WORKS
HOW THE EYE WORKS
A cross section of the human eye
The image cast on the retina is upside down, then turned right side up by the brain.
A close up of a tiny part of the retina. The retina contains millions of rods and cones.
Rods Cones
THE BLIND SPOT
Close up view of one area of the retina
RETINAL RODS
Rods allow us to see in low light environments. There are many more rods than cones in each retina in order to receive the most energy from the available light.
Cones have the ability to receive the separate wavelengths of white light into the array of different colors. The retina contains three types of cones that are each capable of “seeing” hundreds of colors.
RETINAL CONES
Color Blindness (deficiency) results from cones not sending accurate signals to the brain or not sending any signals at all because they are not responding to the light energy received on the retina.
In 1975, Dr. Ishihara’s developed a test for color blindness that consists of several colored plates with numbers or patterns in them. State the number you see on each plate.
