to the American Academy of Pediatrics.Education officials here fear that if tablets and laptops become mandatory in the classroom, students could become even more device-dependent. They might also suffer from vision problems. Some parents, officials say, have expressed the concern that their kids will struggle to keep their focus on studying when using an Internet-connected device.Before making a complete transition to digital books, the government should study the health effects on students, said Jeong Kwang-hoon, chief of the online learning division at the Korea Education and Research Information Service, a government-sponsored institute that is working with private companies to create digital textbooks.Scaled-down ambitionsSouth Koreas education ministry never said explicitly that paper textbooks would disappear. But the 2007 plan spoke in sweeping terms about overcoming the limit of traditional learning, so education experts here assumed as much.Only last summer did the government unveil the specifics. South Korea said it would introduce the first set of e-textbooks nationwide by 2015 at the latest. The content would be accessible on any device on tablets or laptops, in classrooms or at home, on Apples or Samsungs, the homegrown electronics company whose rise corresponds with Koreas economic emergence. But the plan was scaled back, too, with officials saying paper textbooks still need a prime place in classrooms.There have been some changes in ambition, said Ra Eun-jong, the deputy director of textbook planning at the education ministry. In some way, paper and digital textbooks will be used together. But we still havent figured out the best mix. . . . It might just depend on the teachers personal style.Students in classes using digital textbooks at the beginning, they might be used only for a few subjects, such as science and social studies will be able to retrieve their homework from a cloud computing network, the education ministry says. Conceivably, they will be able to access their homework in any place with Internet service or cellphone service; they could even finish up their assignments on their smartphones while riding Seouls subway, where the service network reaches underground.At least 10 South Korean publishing companies are building digital textbooks. The crudest versions are much like copied pages of a traditional textbook; the pages are digital, but you cant play around with them. The more advanced versions, though, are packed with 3-D animation and video clips. Theres also the possibility that the textbooks can be updated in real-time although textbooks here are government-approved, and any changes would require a bureaucratic review.Most of these publishing companies have their background in traditional textbooks, and for the moment, their developers find themselves torn between an old model and a new one. Despite higher upfront development costs, e-textbooks, stripped of the costly printing process, are typically cheaper than traditional ones. South Koreas government has always insisted on affordable textbooks, unlike in the United States, where the market is more lucrative (South Koreas paperbound textbooks cost about $9). But the fear among publishers is that the move to e-textbooks will cause the entire industry to shrink.For now, one publishing executive says, companies are developing e-textbooks only because