About 58 percent of the teenagers in Changchun, capital of northeast China's Jilin Province, have poor vision, according to a survey released yesterday by the city's Disease Prevention and Control Center.

The number represented a record high for the past several years.

The survey involved 30,000 students at 24 primary and middle schools in Changchun during the first half of this month.

The survey found that 32.9 percent of primary school students had poor vision, representing an increase of 2.39 percent from the previous year. And 63.93 percent of middle school students had poor vision, up 3.73 percent over the previous year.

Reading for long periods and staring at computer screens without rest are believed to be the main causes of the increase, said Song Rizhe, director of the Changchun Disease Prevention and Control Center.

Changchun's teenagers suffer from problems like short-sightedness, far-sightedness and amblyopia, or dimness of vision. Short-sightedness is the most common problem.

"There are 52 students in my class, and of those at least 30 wear glasses. That does not include the people who wear contact lenses for the sake of appearances," Luo Jing, an English teacher at Changchun No. 6 Middle School, said.

Other classes at the school are similar, she added.

"About 70 percent of Chinese teenagers suffer from short-sightedness, but less than 5 percent of them are born susceptible to sight problems. The rest are affected by their environment," said Wang Chunsheng, an eye specialist of Changchun Children's Hospital.

The survey showed that about 45 percent of the students' free time was occupied by homework, while 60 percent of their weekends were spent taking extra classes.

Reading for long periods and staring at computer screens without rest are generally thought to harm the eyesight.

"I began to wear glasses when I was 11 years old. I am too tired every day. I spend almost all my time taking lessons and doing homework. And last Friday my parents went to visit my grandmother and didn't come back home that night, so I watched TV until dawn," said Cheng Qi, a junior school student said.

Meanwhile, medical professionals warned people against turning to the variety of medicines and surgical procedures appearing in television advertisements to correct their vision.

Wang Chunsheng, a specialist at Changchun Children's Hospital, said people would be better if going to formal hospital for eye examinations and treatment.

Wang also advised teenagers to moderate their study habits and to be conscientious about their eyesight while studying, watching TV and browsing websites. He said teenagers should avoid reading in the dark or in bed.

He also advised them to rest for 15 minutes after reading for over an hour and insisted that they get physical exercise.

(China Daily December 26, 2006)