What makes my vision randomly blur?

Dry eyes: This is mostly commonly due to dryness that leaves the natural oil layer of the eye's surface to predominate and blur your vision when you blink like an oil slick over water. Try over the counter artificial tears 4-6 times a day.

Dry?: A common cause of vision fluctuations is dry eyes. An easy test is to try otc artificial tears 4x/day and see if the vision improves. If it does, you should see an eye md for definitive treatment.