What Causes Recurrent Blurred Vision?

I am experiencing reoccurent episodes of blurred vision. It happens every few minutes and lasts 10-15 seconds every time. If I close one eye, my vision refocuses. I also have a full feeling in my left ear like it needs to pop, but won t. I have had 3 sinus infections in 3 months, normally I never get sick or sinus infections. I am very healthy otherwise. I just finished the 3rd round of antibiotics, this time with predizone added and all sinus issues have resolved, but the vision and ear issues have not gotten any better. What could this be?