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Volume 10       January 23, 2008

Innovation. Leadership. Passion for Perfection.

  Eye Health

Omega-6 fatty acids need to be included in the diet to promote healthy tear film. Too much of the omega-6 fatty acids, however, especially in relation to omega-3 fatty acids may not be healthy. A healthy diet should consist of roughly one omega-3 fatty acids to four omega-6 fatty acids. A typical American diet, however, tends to contain 11 to 30 times more omega-6 than omega-3 fatty acids. In contrast, a Mediterranean diet is made up of the more appropriate balance between omega-3 and omega-6 fatty acids. The Mediterranean diet includes a generous amount of whole grains, fresh fruits and vegetables, fish, olive oil, and garlic; plus, there is little meat, which is high in omega-6 fatty acids. There are different kinds of omega-6 fatty acids. If you are taking omega-6 fatty acid supplement, make sure it is gamma-linolenic acid (GLA). GLA comes from several plant-based oils including evening primrose oil (EPO), borage oil, and black currant seed oil. It may decrease inflammation that may help dry eyes.

  What's new in vision correction procedures

Corneal conditions such as keratoconus, for example, can be successfully treated with corneal surgery - Intacs or corneal transplant. But, a new procedure that does not involve surgery is now on the horizon. This procedure is called collagen cross-linking. An eye drop of riboflavin is given followed by ultraviolet light exposure for 30 minutes. The UVA light interacts with riboflavin, producing reactive oxygen that creates strong chemical bonds between and within corneal collagen fibrils making them stiffer. Results from international studies show that progression of corneal conditions can be prevented and even reversed, in some patients. Three FDA clinical trials are expected to be launched by the end of the month.

  Tech Corner

Until recently, many scientists in the field of artificial intelligence would have told you that human visual cortex is so complex that a computer is unlikely to simulate it. A recent study from MIT, however, proved them wrong. The researchers designed a computer system that allows the machine to recognize objects in pictures as accurately, or even better, than human brain. Unlike previous artificial intelligence designs that were guided by computer architecture, this system endeavored to include the key mechanisms of visual signal propagation and neural computation in the brain. The result? Twenty four human volunteers were asked to determine whether there was an animal in 1,200 images flashed before them for 20 ms each. The photos ranged from close up to cluttered landscapes containing a small animal. Subjects answered by pushing "yes" or "no" button. The computer was asked to do the same. Humans registered correct answers 80% of the time. The computer scored 82%.

  Fun Eye Facts

Today, we use the eye chart in a doctor's office to check visual acuity. In ancient times, patients were asked to identify constellations and celestial bodies of the night sky to determine their vision. The second star from the end of the handle of the big dipper is actually a double star, made up of "Alcor" (4th magnitude) and "Mizar" (2nd magnitude). They are separated by 0.2 degrees or 12 minutes of arc, which is equivalent to approximately 20/200 or the "big E" on today's eye chart. Used by both ancient Persians and Native Americans, an old saying on the Arabian Peninsula was, "He can see Alcor but can not see the full moon" (that is, a person who could see trivial details by not the big picture). Only people with extremely sharp vision could determine different phases of Venus or distinguish between quarter-phase and half-phase of the moon (American Journal of Ophthalmology, December 2006).

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