Headache and Nausea While Using a Microscope: Causes and Solutions

Question
I wasn't sure which category to post this question in, but I hope you can help me. I'm wondering why I get a headache and feel nauseas (kind of like motion sickness) when I use the microscope to look at slides? There is nothing really wrong with my vision, I do have floaters in my eyes that are triggered by bright light - they can sometimes be a problem when I look in a microscope...but other than that, everything's good with my vision.
It's very frustrating when I sometimes have 50 slides to look at, and by the time I am done with the first slide I feel like I'm gonna throw up. I don't know what to do. No one else using the same microscope seem to have this problem. I have used other microscopes in the past without having this issue (but they have been better microscopes).

Answer
it looks like you are inducing a little motion sickness.....  people tend to build up tolerance to a task, where it goes away with practice.... the other thing you can do is take breaks and go back and forth with focusing on things outside the microscope in between.....