In a quirk of history, descendants of the mutineers from the English ship the Bounty have some of the lowest rates of near-sightedness in the world, according to Perth researchers.
The Lions Eye Institute studied 800 of the sailors' descendants on Norfolk island, 1600km north-east of Sydney, and their findings could hold the key to understanding how genetics impact our eyesight.
Professor David Mackey, who led the study, said Norfolk Island is unique because almost half the islanders trace their ancestry back to nine British mutineers, 12 Tahitian women and six Tahitian men.
The islanders who descended from this group have a rate of myopia (near-sightedness) that's half that of the Australian population.
In 1789, the Bounty sailors led by Fletcher Christian (played by Mel Gibson in the 1984 film The Bounty) set their captain William Bligh adrift in the South Pacific and, along with their Polynesian wives, settled at Pitcairn Island. In the 1850s they moved to Norfolk Island.
"One component of the study has found the prevalence of myopia on Norfolk Island is lower than on mainland Australia,” Prof Mackey said in a press release.
"But there was a two-fold higher prevalence of myopia in people without Pitcairn ancestry. We found the rate of Pitcairn group myopia is approximately one-half that of the Australian population and as a result would be ranked among one of the lowest rates in the world.”
Now Professor Mackey wants to analyse the genetic differences between the Norfolk islanders and the broader population to try determine the cause of myopia.
"It could actually have come from both populations," Professor Mackey told ABC radio.
"I imagine the English sailors would have had to have very good vision, as would the Polynesian sailors. It may be that they were from populations that had low rates of myopia to start with and this has been transmitted to their descendants."
The researchers also looked at the participants' time spent outdoors and found those with more sunlight exposure were less likely to have myopia.
About 16 percent of Australians over the age of 40 have myopia.
The study was published in Investigative Ophthalmology and Visual Science.
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