1. China: According to the Regulations on Conscription in People's Republic of China (PRC), minors under the age of 18 and people with diseases and disabilities cannot join the army. As for people with high myopia, the current regulations are that people with myopia 1500 degrees or above or whose corrected vision is not up to standard after wearing contact lenses are not allowed to join the army.
2. South Korea: In South Korea, people with high myopia can perform military service, but they will be assigned to different arms according to their eyesight. Generally speaking, people with high myopia who have certain military capabilities can still serve as soldiers.
3. Singapore: In Singapore, people with high myopia can perform military service, but they need a comprehensive physical examination to determine whether they are suitable for military tasks. If they have poor eyesight, they may be excluded from deploying weapons that require good eyesight.
It should be noted that these regulations may also change with the progress of technology and the changes of military needs of various countries. It is recommended to consult the local recruitment department for the latest policies and regulations.