Oct. 7 - Half of China's youth suffer from myopia, second only behind Japan, a Chinese ophthalmologist has warned.China also has the largest myopic population in the world, with more than 300 million people wearing glasses to correct nearsightedness.This accounts for nearly a quarter of the total population, ten percent higher than the world average, according to Ge Jian, director of the renowned Ophthalmic Center at Sun Yat-sen University in Guangzhou.Ge attributed the high rate of myopia to the strain on the eyes caused by large amounts of schoolwork, excessive television viewing and playing of computer games.He also warned that 85 percent of prescription glasses in China were substandard because there are a lack of trained specialists in the field."In China, the public, doctors and optometrists are not well-trained in optic knowledge. One can have very different eye test results in different hospitals or opticians," Ge said, adding that the country urgently needs ophthalmologists.