If it's anxiety related, it could possibly be a conversion disorder, where you have a really high anxiety level, and then you suddenly get symptoms like temporary blindness, or vomiting. But then these are just temporary.
But if you think your eyes are strained that maybe a cause too. You should see a specialized doctor like a neurologist or an ophthalmologist. But for the mean time you should do relaxation techniques, like Deep
breathing exercises (for almost every problem, systematically useful) and
Bates method (eye relaxation techniques).
I hope this info helps mLuciej