I wear contact lens more than twenty years, and I have 近視 more than 1000 degree.
If you want to wear the contact lens, the optical company will give you try first. In the first time, I wore them only less than one hours in the optical company, then on the next week, I wore them more than one hours, the time of wearing the contact lens increase few hours a week then until a months, I could wear it for the whole day.
But you should have good personal hygenie and follow the procedures, for example, you should not wear too long hours in the first month, you should wash your hand completely before touching the contact lens. You should not re-use contact lens if they are disposable, or you should complete clean the contact lens for non-disposable type.Don't forget to check the eye more freqently at the optical shop or doctor in the first year.
The above information is just my personal experience. You can consult the professional if you are worry about it.