the sunshine beams in horizontally
out on the rock, a cormorant watches too
to help us climb up
sun shines on the garden shed
soon the sea will lapse in dark light
in the last hours before sunset.
|This is a Blanket Flower|
Excerpted from What is Colorblindness and the Different Types
People with normal cones and light sensitive pigment (trichromasy) are able to see all the different colors and subtle mixtures of them by using cones sensitive to one of three wavelength of light - red, green, and blue. A mild color deficiency is present when one or more of the three cones light sensitive pigments are not quite right and their peak sensitivity is shifted (anomalous trichromasy - includes protanomaly and deuteranomaly). A more severe color deficiency is present when one or more of the cones light sensitive pigments is really wrong (dichromasy - includes protanopia and deuteranopia).
5% to 8% (depending on the study you quote) of the men and 0.5% of the women of the world are born colorblind. That's as high as one out of twelve men and one out of two hundred women.
And here is a link to a free on-line test. Parents and teachers might find this website especially helpful as undiscovered vision deficiences can cause multiple difficulties for children .