The prevalence of poor vision among young schoolchildren in Beijing has declined in recent years, a report released on Tuesday showed.

But it said more efforts are needed to protect youngsters' eyesight, since myopia is occurring earlier.

The report, issued by the Beijing Municipal Health Commission, said the rate of poor eyesight among primary and middle school students in Beijing from 2017 to 2018 was 59.5 percent, down two percentage points compared with five years ago.

For first grade primary school pupils in the capital, the rate of shortsightedness was 34 percent.

Experts said the widespread use of mobile phones and portable electronic devices has a bad influence on pupils and may trigger close-range eye fatigue, the primary cause of myopia.

"Once myopia occurs, it will be incurable," said Wang Ningli, head of the Ophthalmological Center at Beijing Tongren Hospital, adding that all eye specialists can do is try to prevent nearsightedness from happening and then correct defective vision through eyeglasses or other means afterward.

Wang called for more efforts to be made to prevent myopia, with participation from parents and society as a whole.

The capital's top education authority released a 10-point guideline last month about preventing myopia among pupils as a move to improve eye healthcare services and boost awareness of such conditions among parents and children.

The guideline said teachers at schools were the principal people responsible for implementing the rules, which include banning some electronic devices from classrooms.

It also said primary and middle school students need to have at least an hour of exercise a day at school, as well as regular eye exercises.

Parents should realize that nearsightedness is a serious threat to health, the guideline said. Sufficient sleep should be ensured so that students can better protect their eyesight.

The myopia rate among young Chinese is one of the highest in the world－at 70 percent for high school and college students and nearly 40 percent for primary school pupils－according to a World Health Organization report in 2017.

The number of nearsighted people in the country has hit 600 million, nearly half the total population, according to the WHO.

In August last year, with myopia levels rising, the Ministry of Education coordinated with seven other departments, including the National Health Commission, to issue a guideline laying out measures to tackle the problem among school pupils.

Among young Chinese, the overall myopia rate was estimated at 53.6 percent last year. It was 36 percent for primary school pupils, 71.6 percent for those in senior high school and 81 percent for college students, the National Health Commission said in May.