Nearsightedness has nearly tripled among preschool children in Hong Kong, and experts say they believe videogames and computers are partly to blame, a report says.

A study by the city's Chinese University found that 6.3 percent of kindergarten students were myopic in 2006-2007, compared with 2.3 percent a decade earlier, the South China Morning Post reported.

Researchers say they believe computers and portable videogame devices popular among Hong Kong children might be contributing to the problem.

Professor Dennis Lam, one of the study's organizers, says using videogames on public transport and spending too much time in front of televisions and computers were affecting young children's eyesight.

Hong Kong already has one of the world's highest rates of myopia, with earlier studies finding 17 percent of early-grade primary school students and 53 percent of primary school graduates are nearsighted.

About 800 kindergarten pupils were involved in the Chinese University study, which also found the average prescription for glasses was noticeably stronger a decade earlier.