It’s a fairly known fact that the Japanese work ridiculously long hours each and every day which may explain why they always seem to be sleeping in public whether it be on the trains or in their cars parked by the side of the road which is not too kind on the environment with their engines running unnecessarily.
Anyway, if they’re not falling asleep they are trying to stay awake and it appears to me that so many tend to use eye-drops to help with this. Sure, some (particularly in this hayfever season) use them for other purposes but I’ve never seen so many people openly use them in public. I think the reason for such regular use is not just lack of sleep but also over-heated office air which irriates their eyes making them dry and red and so eye-drops are the solution.
Personally, I absolutely hated them when I was younger and more-or-less had to be pinned to the sofa while my parents added a drop to each eye so I guess I can now be thankful that I don’t work for a Japanese company and so can maximise my sleep if I desire.