Up to 90% of school leavers in major Asian cities are suffering from myopia ---short-sightedness, a study suggests. Researchers say the "extraordinary rise" in the problem is being caused by students working very hard in school and missing out on outdoor light.
Eye experts say that you are short-sighted if your vision is blurred(模糊的) beyond 2m. It is often caused by an elongation（拉伸） of the eyeball that happens when people are young. According to the research, the problem is being caused by a combination of factors - a commitment to education and lack of outdoor light.
Professor Morgan who led this study argues that many children in South East Asia spend long hours studying at school and doing their homework. This in itself puts pressure on the eyes, but exposure to between two and three hours of daylight helps maintain healthy eyes.
Cultural factors also seem to play a part. Across many parts of South East Asia, children often have a lunchtime nap. According to Professor Morgan they are missing out on natural light to prevent short-sightedness.
A big concern is the numbers of the students suffering from “high” myopia. One in five of these students could experience severe visual impairment(障碍) and even blindness. These people are at considerable risk—sometimes people are not told about it and are just given more powerful glasses—they need to be warned about the risk and given some self-testing measures so they can get to an ophthalmologist and get some help.
For decades, researchers believed there was a strong genetic component to the condition. But this study strongly suggests an alternative view. “Any type of simple genetic explanation just doesn’t fit with that speed of change; gene pools just don’t change in two generations. Whether it’s a purely environmental effect or an environmental effect playing a sensitive genome, it really doesn’t matter, the thing that’s changed is not the gene pool---it’s the environment.”
小题1:As is mentioned above, which factor mainly results in students’ myopia in South East Asia?

A．Genetic faults of the people.	B．Elongation of the eyeball.
C．The shortage of outdoor light.	D．Lack of research into the problem.

小题2:Which of the following statements do you think agrees with Professor Morgan?

A．A lunchtime nap is helpful in reducing myopia.

B．Glasses keep myopia from getting even worse.

C．It’s necessary to treat myopia with an operation.

D．It’s of vital importance to reduce educational pressure.

小题3:What’s the main idea of the last paragraph?

A．Gene remains the main cause of the long-standing problem.

B．The environment is to blame for the extraordinary rise in myopia.

C．Short-sightedness has nothing to do with changes in gene pools.

D．An environmental effect playing a sensitive genome counts.

小题4:What’s the best way to take care of your eyes according to the passage?

A．Equip the classroom with better lights.

B．Look at the sun from time to time.

C．Do eyes exercise regularly.

D．Spend more time in the open air.