Now his vision in left eye sometimes goes "grey" and for a few minutes he can't see anything out of the top half of his eye.
Anyone else have this problem?
Have you thought of detached retina? https://patient.info/health/retinal-detachment-leaflet
one of the symptom seems quite similar to what you describe.
Treat it as an emergency!
My friends husband had exactly the same thing, about a year ago. She persuaded him to go into the Opticians in town. When the optician looked at it, he said it was an emergency. He was in hospital by the end of the day and operated on immediately. It was something to do with an artery leading to the brain (I think). he was told, the visit to the Optician had saved his life. So go to an optician TODAY. Hope this hasn't allarmed you, but just felt I should tell you this, as your symptoms are identical. Dont go to A&E in a panic. they will not have an opthamologist at their disposal. The optician has all the right things to identify your symptoms. Good Luck.
No didn't think of that! Thank you for your response!!
Thank you for your thoughts! Very helpful!!