Scientists say they are one step closer to solving the most common eye disorder in the world - myopia or short-sightedness.

An international genetic research project studying more than 13,000 twins has uncovered a key gene that causes the disorder.

A professor of ophthalmology at the Lions Eye Institute in Western Australia, David Mackey, led part of an international project to identify the exact genes responsible for myopia.

He says 13,000 people, all twins, took part in the study.

"We analyse usually around 600,000 DNA markers and find which markers tend to run more commonly with the feature that we are measuring - in this case myopia," he said.

"And in collaboration with the twin research group in London we have been able to identify one new gene associated with myopia, mainly in older people."

Professor Mackey says 3 million Australians suffer from the condition but there has been a myopia epidemic across Asia.

"Particularly Singapore, Taiwan, Hong Kong and now the large developing cities in China, [where] a majority of children when they finish high school are myopic, needing to wear glasses," he said.

"Now this is something that has happened really in the last 50 years and we are not sure what it is that led to this epidemic but we suspect that the east Asians are more genetically predisposed to getting myopia.

"Therefore understanding the underlying mechanism is of great importance, particularly if we are not having to supply glasses to the entire population of east Asia."

Professor Mackey says this gene is one of a dozen that need to be identified to help solve the bigger puzzle.

But he hopes the breakthrough will help develop new treatments and identify risk factors for the condition.

"One of these particular genes involved in the risk of myopia is something that we can actually develop a drug to intervene for, or we may be able to come up with other treatments, such as whether people should or shouldn't wear glasses all the time, whether they should get outdoors, or how much reading should they be doing," he said.

"All of these are factors that have been proposed as risk factors for developing myopia in those who are predisposed to get it."

Scientists at the Queensland Institute of Medical Research (QIMR) also took part in the research, which is published today in the journal Nature Genetics.