Could Blurry Vision And Headache Be Due To Sinus Infection?

My 16 year old son has had blurry vision, headaches, confusion, puffy forehead, pushing feeling behind eyes and pain and pressure from above the eyes, and short 1-2 second earaches. He has this in 1 to 2 week episodes off and on since last spring. When he doesn't have the episodes he is better , but the vision is still not quite right. Been to optimologist (eye specialist) several times. Conclusion ...Vision definitely impaired, but it is not the eye itself, rather something hindering the interpretation from the eye to the brain possibly. He has had both a cat scan of the sinus and an MRI of the brain. Neurologist appointment at the end f January. Ice cold rags on his eyes helps. We think the Vicks helps too. The Cat scan and MRI were clear. My first question is if those test were clear , could there still be a sinus infection possible? Next question, when he has a headache and his eyes are burning, or he says feels very sore should I just wait it out till the neurologist at the end of January or do I keep going back to the primary doctor who doesn't seem to have an answer?