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Half of Americans Have Vision Problems
 The BBC reports that a study conducted by the National Eye Institute (NEI) reported in the Archives of Ophthalmology found that half of Americans suffer from a vision problem of some kind. Most of the problems are a myopia or astigmatism according to the study. The numbers were a big jump from previous studies.
"Clinically important refractive error affects half of the U.S. population 20 years or older," wrote Susan Vitale and colleagues at the institute, one of the U.S. government's National Institutes of Health.
They analyzed data from the National Health and Nutrition Examination Survey on 12,000 people aged 20 and older between 1999 and 2004.
More than 33 percent were nearsighted and 36 percent had astigmatism, which causes fuzzy vision, the team reported. Another 3.6 percent were farsighted, meaning they can see at a distance but not up close.
"Our estimated prevalence of myopia was higher than the 25 percent reported in previous U.S. studies and similar (in persons under 40 years) to that of ethnic Chinese persons in Singapore," they wrote.
Medpage Today's article on the study has the percentages of the most common causes of vision problems. They are:
Hyperopia, 3.6%
Myopia, 33.1%
Astigmatism, 36.2%
A HealthDay article about the NEI study notes that most people's vision problems are solved with corrective lenses.
Photo source: National Eye Institute, National Institutes of Health
Posted on August 11, 2008
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Single Nucleotide Polymorphisms Responsible for Human Eye Color Differences
The BBC reports that genetic scientifics have discovered that just a few letters of the six billion contained the human genetic code are responsible for eye color.
Differences in eye colour are largely down to "single nucleotide polymorphisms" (SNPs - pronounced "snips"); variations in the sequence of letters that make up a single strand of human DNA.
SNPs represent a change of just one letter in the genetic sequence. These changes, or mutations, in our DNA can have important consequences for how the gene gets physically expressed.
All the SNPs are located near a gene called OCA2. This gene produces a protein that helps give hair, skin and eyes their colour. And mutations in OCA2 cause the most common type of albinism.
According to the study there is not a specific gene for eye color instead it is the combination of these SNPs that results in different eye colors.
Dr. Richard Sturm from the University of Queensland - one of the scientists who discovered the SNPs - said that "The SNPs we've identified in themselves are not functionally causing the eye colour change, but they are linked very, very closely to something that is."
This early genetic work determining how the genome helps determine things like eye and hair color is significant because it could be a major stepping stone to more significant genetic findings.
Posted on December 20, 2006
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Scientists Hope Simple Eye Scans Could Detect Alzheimer's
The BBC reports that scientists have discovered that infrared lights could be used to identify people with very early stages of Alzheimer's disease. Scientists have developed a test that checks for deposits of beta-amyloid. Early tests have been successful in mice.
During the trial, a brief pulse of infrared light into the eyes of four mice with Alzheimer's and four without accurately identified which had the condition.
Dr Goldstein and his team envisage the test could be used to detect the disease at its earliest stages as well as to track disease progression and monitor how people respond to Alzheimer's treatments.
Currently there is no simple test to make a diagnosis of dementia and it can only be confirmed with certainty by looking at someone's brain in a post-mortem examination.
The scientists believe the technology, known as quasi-elastic light scattering, may detect the very earliest stages of amyloid deposits in the lens, even when they appear completely clear to the naked eye.
It might help with prevention and finding a cure if doctors are able to diagnose alzheimer's in its very early stages. However, it would also be very alarming to have such a serious diagnosis from a simple eye exam.
Posted on July 25, 2006
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