What Causes Constant Ringing Noise In The Ears And Poor Vision?

Question: I am experiencing ringing/hissing in the ears that is also portrayed by 'eye tinnitus' or visualow in the left eye. This all began, I believe, after I had a root canal in Dec. 2016, followed by the removal of the root, and the tooth extracted I immediately noticed that my left side of the mouth was numb and worsened after eating or drinking, followed by facial tingling, slight droopiness in my left eye at times, In Aprll lasts year I noticed odd whirling/swirling in my left eye that would come and go, followed by ringing in my ears/with hissing, which caused visual snow that appears to me only as if viewing a TV screen with static - no picture - or similar to an electrical storm in my left eye. It worsens when the ringing in my ears worsen, so I have made many adjustments in my diet (caffeine for one). Stress makes it worse, as well.
i have seen a neurologist, have had an MRI, been examined by a neuro-opthlamologist, and they do not see what could be causing this. I also have tried homoeopathy with minimal results. I have found several web sites that portray exactly what I am experiencing but offer little help, Some say that removing metal in my dental work could help; some say it's due to a hidden infection in the area where I had dental work (an endodontist cannot confirm this)/. Please share any hepful advice you can.