Japan's government thinks that their students' eyesights are being damaged, and more specifically, they are being damaged due to smartphone usage.
In a recent survey conducted by Japan's Ministry of Education, Culture, Sports, Science and Technology, it was found that the number of students with vision below the standard 1.0 score (which is equivalent to 20.20 vision) has reached an all-time high of 25.3 percent. Furthermore, over 67 percent of high school students and more than 34 percent of elementary students did not meet the bar.
Japan's government related this to the trends of “increased time spending staring at [smartphone] screens…and mobile games.”
It's important to note that smartphone gaming is incredibly huge in Japan. To put it into perspective, the country is the world's third largest gaming market, per market researcher Newzoo. To add, a large amount of those gamers are playing mobile games (41 percent of men and 32 percent of woman).
While we are seeing increased usage of screens, it has not been proven that more screen time ruins your eyesight, but experts have issued warnings that extended periods of exposure to blue light emitted from these devices (such as smartphones) can cause a lot of fatigue or eye strain.
China is right there with Japan in terms of getting tough on this matter. The country has threatened to take action to protect eyesight of children, including bringing regulation to online games and new releases, as well as limiting game time.