It might sound a silly question but have you had a full ophthalmic assessment by a consultant opthalmologist? They should use eye drops and various eye scans. I had similar symptoms to you on one side and they went on for years. Not all the symptoms were the same as yours though. I saw GPs and optometrists as I was suffering from headaches, eye pain, facial pain, even tooth pain on affected side. Eventually a hospital consultant diagnosed Corneal Epithelial Basement Membrane Dystrophy. This was causing recurrent corneal erosions and constant foreign-body sensation and pain in my eye which radiated all over my face/head on that side. I think I also had migraine which was complicating the symptoms and causing after-images. I had a procedure under local anaesthetic on my left eye called alcohol delamination which resolved the problem wonderfully. The condition can recur apparently, as there is a genetic component, but I am happy for now. Worth investigating, if nothing else. It seems to be hard for doctors to spot. Good luck! I know how awful head and eye pain is
Have you found an aswer ?
Also look up "macular pucker"
Go over ALL your medications with your pharmacist, the prescribing doctor, other doctors, and google it yourself with the word "toxicity" and see what you learn. I had similar symptoms and it turned out to be a too high dose of medication for atrial fibrillation. Good luck