An Eye Twitch

Sometimes when I get stressed, I get this… twitch in my eye. It's very annoying because, while I know that people can't see it, I feel like they can and I keep rubbing and touching my eyelid, which people can see, which then brings attention to it. It started around the time I was in my late thirties and hasn't really stopped since. Every time I'm stressed, which is always before a big case, it just starts going and I've tried to train myself to ignore it. But it most of the time, it doesn't work and I just end up making my eye red.