This is very funny topic, I started to laugh right after the first sentence:
The first problem you can have is - eyes problems.
What kind of problem can you have if you work on some farm, or some field, or you are digging wholes? Every job have some risks, potential health problems, you need to find a way to protect yourself somehow. Maybe by this topic trading is unhealthy, but for sure its less unhealthy than some other jobs you can do to make some money for yourself and your family.