Bounty mutineers myopia
Bounty mutineers myopia,The descendents of sailors who took part in the infamous mutiny on the Bounty are helping unearth the causes of short-sightedness, say Australian researchers.
Professor David Mackey from the Lions Eye Institute and colleagues have been studying the eyesight of people on Norfolk Island, where almost half of the population can trace their ancestry back to nine Bounty sailors and their Polynesian wives.
Over the past five years, they have found that rates of short-sightedness, or myopia, are lower among people related to the Bounty sailors, nine of whom settled at Pitcairn Island after the mutiny in 1789 and later moved to Norfolk Island, 1,600 kilometres north-east of Sydney.
All 1,275 permanent residents of the island aged over 15 years were invited to participate in the Norfolk Island Eye Study. The most recent paper from the study is published this month in the journal Investigational Ophthalmology and Visual Science.
"We found the rate of Pitcairn group myopia is approximately half that of the Australian population, and as a result would be ranked among one of the lowest rates in the world," said Professor Mackey.
By contrast, other Norfolk Island residents had approximately the same rates of short-sightedness as the Australian population - around 16 per cent.
Genetics and environment
Professor Mackey says these differences show genetic factors contribute to short-sightedness. However, it is also becoming apparent that spending too little time outdoors also raises a person's risk of becoming short-sighted.
To untangle these genetic and environmental factors, Professor Mackey and colleagues used an ultraviolet light fluorescence photograph to measure Sun exposure to the white of the eye.
In 10 per cent of the Norfolk Island population, this area develops raised, bloodshot growths on the front of the eyes called pterygia. The condition is sometimes called surfers' eye, and is thought to result from exposure to ultraviolet light.
On Norfolk Island, the researchers found the amount of autofluorescence on a person's eye correlated with the amount of time they spent outdoors.
Comparing the eyes of Norfolk Island residents with Pitcairn ancestors and those without, Professor Mackey and his colleagues could find no differences.
"We couldn't show a sign difference in the outdoor activity between the two groups," he said.
The researchers are now studying the genes of Norfolk Island residents to see if they can identify the genetic factors that affect short-sightedness.
"It's the ideal situation. With any disease that involves genes and environment, you can identify the people who are at high genetic risk and intervene by reducing the environmental risk," he said.
"In this case, the advice to people with high-risk genes might be to get outdoors more in their teenage years to reduce their chances of myopia."
source: yahoo
