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Volume 23       January 30, 2012

Publication for our patients.

-- Kanizsa Triangle --
In this optical illusion, the brain sees two triangles even though they aren't actually there. This is a subjective or illusory trick where the triangles are implied by the image. Notice that the triangle implied by the black circles looks whiter than the background even though it's the same color. This is caused by the large contrast between the black circles and lines and the white background. If you cover the black circles, you will see that it is the same white color.

Our ability to see color is controlled by photoreceptors in the retina called cones. There are three different types of cones sensitive to different wavelengths in the color spectrum. They pick up short, medium, and long wavelengths of light for Blue, Green, and Red, respectively. It's similar to how televisions work with RGB color generation. Each color of light has a different combination of these wavelengths that give it its unique appearance. Each cone is stimulated with each color and the brain combines the three cone signals to perceive that color. If one of the cone types isn't working properly, you have color-blindness. More men are born color-blind than women (8% vs. 0.40%). The sample color test shows the number 7 for normal color vision. A color-blind person would not see the number at all. One gentleman we saw didn't know he was color-blind until he finally had an eye exam at age 30!

In a recent survey, 4,000 Bay Area physicians across all specialties were asked "Whom would you send your family member or whom would you go if faced with a medical problem?" More than 13,000 votes were cast. The results are listed in the February issue of Marin Magazine. We are honored to announce that Dr. Ella Faktorovich has been selected as one of the Top Ophthalmologists in the Bay Area.


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