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Israeli researchers show that summertime babies more prone to myopia
Posted By Nicky Blackburn On August 28, 2007 @ 3:15 pm In | No Comments
The more light a newborn is exposed to after birth, the worse the myopia will be. The answer, according to Prof. Michael Belkin of Tel Aviv University: sunglassesProf. Michael Belkin, a professor at Tel Aviv University’s Goldschleger Eye Research Institute, makes sure his grandchildren wear sunglasses, even as babies. He advises all parents to do the same.
He ought to know. Belkin has been researching the eye for over 30 years, and is one of the foremost professors in this field. In his latest research – a collaboration with researchers from Hebrew University and the Technion-Israel Institute of Technology led by Dr. Yossi Mandel, a senior ophthalmologist in the Israel Defense Forces Medical Corp – Belkin showed that babies born during the summer months of June and July have a 24% greater chance of becoming severely shortsighted than those born between December and January.
The reason: early-life exposure to natural light. According to Belkin, the body has a mechanism that causes the eyeball to lengthen, causing shortsightedness, when exposed to prolonged illumination. Hence, the more light a newborn is exposed to after birth, the more the eyeball lengthens and the worse the myopia will be.
The mechanism is associated with melatonin, a pigment secreted by the pineal gland, which sets our body’s internal clock and permits it to participate in ‘Circadian rhythms’, though scientists are not sure exactly how it operates.
Myopia – where distant objects appear blurred – is a very common condition worldwide. In Israel 17.3 percent of the population entering the military (which is compulsory), suffer from shortsightedness. By the time they leave three years later, the occurrence has risen to 25%.
In some countries, like Japan and China, 50% of children starting school are shortsighted, rising to 80% at the end of high school.
While there are many factors involved in short-sightedness, including genes, intelligence (yes, people in bottle top glasses are often smarter than their peers), and years of study (80% of students at religious yeshivot are short-sighted, while 60-70% of professors at Tel Aviv University suffer the condition), the new study shows that in severely myopic individuals – where the numbers rise above five or six – the season of birth can also have a major impact.
The first indications of this came when Dr. Uvall Cohen, one of Belkin’s students, carried out a study of chickens. Cohen discovered that he could control the degree of shortsightedness in the chickens by the controlling the amount of light the chicks experienced in their first weeks of life.
“This gave us the idea that sunlight might affect the growth of the eye,” says Belkin.
The next step was to examine people. With the HU and Technion researchers, Belkin and Mandel began studying data on young people aged between 16-23 admitted to the IDF.
The scientists took data on almost 300,000 people, making it one of the world’s largest epidemiological surveys in any field, and retroactively correlated the incidence of myopia with their month of birth.
They took into account birth complications, weather, infectious agents, socioeconomic status and education. They also registered the eyesight of siblings born during other months.
The results, published this month in clinical eye journal, Ophthalmology , were clear. A child born in the winter or fall, will have better long-range eyesight throughout its lifetime and less chance of requiring thick corrective glasses than those born in the summer.
Belkin points out the graph in his report, which visibly indicates the rise in severe myopia in children born during the summer months, when there is an average of 4.2 more hours more sunlight per day than in winter. “You don’t need to look any further than that,” he says. “This was the largest study of its kind, and the results were conclusive. It’s got nothing to do with the stars, or your horoscope, it’s to do with the season.”
He also believes that this research is likely applicable to babies born anywhere in the world.
Belkin is a leading figure in ophthalmology research worldwide. He was one of the founders and first director of the Goldschleger Institute, established more than 25 years ago at the Sheva Medical Center in Tel Aviv, and is Incumbent to the Fox Chair of Ophthalmology.
His main area of research is lasers and their applications for curing eye disease such as glaucoma and age-related macular degeneration – the leading causes of blindness. He also recently co-authored a report with Dr. Zohar Habot-Wilner, also of the Goldschleger Eye Institute, which showed a link between obesity and the occurrence and development of all four of the major eye diseases that cause blindness – cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy. Belkin expects to publish a new report on stem cells and lasers in the coming months.
Belkin is also a board member of a number of companies creating promising treatments, including Proneuron, stem cell therapy company TheraVitae and El-Vision, which is developing a diagnostic device for the eye. One of his ideas, for a microscopic surgical implant to treat medically uncontrolled glaucoma, is now being commercialized by the company Optonol.
“Slight myopia is not really significant, but severe myopia, where numbers rise above five or six is already a disease that can lead to visual problems that cannot be solved by glasses alone,” says Belkin. “The eye in childhood is much clearer than when we are older so it’s vital that our children start to wear sunglasses from birth onwards, particularly those in hot, sunny countries. Severe myopia, cataracts and retinal degeneration are partly due to UV light from the sun. It’s cumulative and it adds to the severity. I have little doubt that they can be partially corrected by using sunglasses in childhood.”
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