Monday, May 9, 2011

Cleveland "Spring" and the Rhythm of Life

Wow! We know it's a cliche, but how about our Cleveland weather?! Have you ever seen so much rain? Have you ever gone that long in Cleveland with that little sunshine? We laughed when we saw a Tweet from a patient who thanked Seatle for visiting, but could they please take their lousy weather back to the Pacific Northwest! (Look for us on Twitter @drdarrellwhite and @Skyvisioncenter).

It seemed like everyone around Skyvision Centers was a little down and blue in March and April so we got to wondering how the eye is involved in our daily rhythm (Circadian Rhythm), and how our eyes are part of the light cycle that can cause Seasonal Affective Disorder--the blues from the blizzards and the gray skies.

The retina contains the photoreceptors we all learned about in high school, the Rods and the Cones. These are the cells that react to light and send information to the back of our brain where we actually "see". Think of the eye as the "image collector", kind of like a digital camera or the Hubble Space Telescope. The light information collected by the Rods and the Cones goes directly to the vision center of the brain.

There is a third light sensitive cell or photoreceptor in the retina, the Photosensitive Retinal Ganglion Cells (pRGC). These were just discovered in the 1990's! Kind of unreal to think we are still making such fundamental discoveries about anatomy of the eye. These pRGC's also react to light, but they do NOT send information to the vision center of the brain. Instead, these cells are responsible for the reaction of our pupils to light (the pupil gets SMALLER in bright light). They also send information to the part of the brain called the Hypothalmus which is responsible for our daily light/dark rhythm. The pRGC's respond most vigorously to light in the blue/violet color range, and if they don't "see" enough WE can get the blues!

So there's the science behind light and mood. Check back and we'll tell you how some people use this information to fight the blahs and the blues.

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