First of all I would take this as a good sign rather than a bad sign. If you die have some serious disease of the heart, brain, eye or blood vessels normally it gets worse and new symptoms develop making diagnosis easy.
You have not developed frank MS, nor a brain tumor or aneurysm, nor occlusive carotid disease, etc.
I would look at it positively like this and be grateful. I have seen one or two people like this in my career when a definitive diagnosis was never determined. In them the episodes of blurred vision eventually stopped without any terrible disease appearing.
My suggest would be, if possible, to see a neuro-ophthalmologist, or if one not available a neurologist. Possible causes include disease of the heart, brain, eye and blood vessels.
Thanks for the fast reply. I have already seen a neurologist, neuro-ophtalmologist and cardiologist. The only problem they saw is some demyelinating lesions and they seem not to know how to react or where to look at. They have done many examinations in the past 3 years which I cannot even recall, and I always returned empty handed. Every year I go to MRI and the lesions are the same no change for past 3 years. After examination there are only 2 possible answers every time: "It COULD be MS" or "I don't know".
Recently I went to the dentist. She told me that I have an infection in one of my tooths and that it was there for about 5 years. She also told me that these periodic episodes could have been because of the infection. I got my tooth remowed last month, but 2 days ago I had another one(episode). I have several questions here. Could this infection spread to my brain? If yes how can I check this? Is it possible that my tooth gums are still infected because the dentist didn't give me any antibiotics, if yes how can I find that? Your last comment really cheered me up but I believe that everithing has a purpose even if its not a serious one. Thank you very much and I really do appreciate that you are trying to help. Best regards.
1. No not in your brain. 2. I'm not a dentist I don't know. 3. I think the tooth a very unlikely cause of your episodes of visual trouble