There may be many reasons.
Here's one.
A migraine. Yes, even without the headache. I didn't know this either. Vision goes blurry for a while in the center, then moves outward over time, then disappears. All in 20-30 minutes.
Turns out that's one manifestation of a blurry view in one eye.
I always suggest seeing a doctor. Vision is very important, and you don't want to muck around with it!
Here's one.
A migraine. Yes, even without the headache. I didn't know this either. Vision goes blurry for a while in the center, then moves outward over time, then disappears. All in 20-30 minutes.
Turns out that's one manifestation of a blurry view in one eye.
I always suggest seeing a doctor. Vision is very important, and you don't want to muck around with it!