Tuesday, December 30, 2008

Scientists working on next generation of artificial retinas

McClatchy reported that researchers at the Doheny Eye Institute at the University of Southern California are testing artificial retinas that they hope can restore partial sight to people who've lost their vision to the most common causes of blindness, retinitis pigmentosa (RP) and macular degeneration.

RP ruins peripheral vision, while macular degeneration causes a blurred or blind spot in central vision. Both conditions irreparably damage the retina, the light-sensitive patch at the back of the eye that converts images into signals and relays them the brain.

Scientists now aim to create sensitive devices that can be implanted in the eye and will let previously blind people recognize faces and read large print. These artificial retinas are still experimental and won't be available for commercial use for years, however. Currently, the Argus Two artificial retina is being tested on 17 blind people in the U.S. and Europe. In the meantime, scientists at the Energy Department's National Laboratories are creating a third-generation artificial retina, and hope to begin human trials in 2011

Tuesday, December 23, 2008

Artificial corneas and retinas

The Miami Herald reports that in developing countries, the need for donor corneas largely exceeds the supply, making the laboratory-developed artificial cornea all the more important.

Researchers from Miami's Bascom Palmer Eye Institute have been at the forefront of its development. Eduardo Alfonso, M.D., interim chair of the institute, explained that doctors prefer donor corneas, because artificial ones are still in the testing phase, though results in the past few years have been good. And, like the human cornea, the synthetic cornea is made in the same curved shape.

Even though artificial corneas are not yet perfect, Alfonso and his team are also starting new projects, including development of an artificial retina and artificial vision technology, in which images processed by the brain would use information that doesn't come from the eyes -- especially useful for those who are completely blind.

Wednesday, December 17, 2008

Tuesday, December 16, 2008

Blind and dream

I have been asked this question before and have struggled to give a rational answer.

In the New York Times Really? column, Anahad O'Connor raised the question of whether people who don't see images during the day might see them when they shut their eyes at night.

According to studies led by a psychologist at the University of Hartford...people born without the ability to see report no visual imagery in their dreams. Instead, they experience a heightening of taste, touch, and smell. They also report a higher percentage of dreams that involve mishaps related to traveling or transportation, perhaps reflecting one of their biggest daytime concerns: safely finding their way around.

Researchers also say that people who go blind before age five rarely experience visual imagery in their dreams. Those who lose their vision after age five, however, often continue to see in their dreams, though the frequency and clarity diminish over time.

In regards to dreams, my favorite quote is by a former President of India, Dr Abjul Kalam “Dreams are not what you see in your sleep, but dreams are that, which do not allow you to sleep”. Fantastic!

Friday, December 12, 2008

Patch versus Drops in treating Lazy eye

In the New York Times Well blog, Tara Parker-Pope wrote that a study published in the Archives of Ophthalmology compares patch therapy for amblyopia with .a weekly regimen of medicated eye drops that essentially work as a patch by blurring vision in the stronger eye.

Mitchell M. Scheiman, O.D., FCOVD, of the Pennsylvania College of Optometry in Philadelphia, (now called Salus University) and colleagues, conducted a randomized study of nearly 200 children, and found that giving the eye drops on the weekend worked about as well as wearing a patch for two hours a day. The eye drops, which contain atropine, work by preventing a muscle in the stronger eye from constricting. As a result, when a child tries to read or focus on something close, the good eye is blurred. The child's weaker eye is forced to focus and work harder, which helps it strengthen over time.

Thursday, December 11, 2008

Diabetes-related eye diseases may skyrocket over next four decades

The New York Times reports that, according to a study published Dec. 9 in the Archives of Ophthalmology, diabetes-related eye diseases will skyrocket over the next four decades, with elderly Hispanics and blacks hit hardest because of higher rates of Type 2 diabetes.

In particular, the report projects that the number of adults 40 and older with diabetic retinopathy -- the leading cause of blindness among working-age adults -- will reach 16 million in 2050, up from 5.5 million in 2005. In addition, the study estimates that the number of diabetics with glaucoma will quadruple to 1.4 million, while the number with cataracts will more than triple to 10 million. Study author Jinan B. Saaddine, M.D., M.P.H., of the Centers for Disease Control and Prevention (CDC), said the findings are a call for to do more to prevent diabetes to start with.

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