Two years ago, I found I was losing vision on the left side of my left eye. The optician identified a bad cataract, and I went for surgery - and it made NO difference whatsoever. I certainly had had a cataract, but further investigation and an MRI scan revealed the weirdest coincidence - that I also had a meningioma (a non-cancerous tumour inside the skull) exerting pressure on the optic nerve. Either the cataract or the meningioma, alone, would have produced the sight loss I was suffering. Subsequent MRI scans show (a) that the tumour isn't getting any bigger but (b) neither radiotherapy nor cranial surgery can improve the situation. My right eye's OK and I'm passed fit to drive, so all I can do is keep having regular MRI scans and opt for surgery or radiotherapy if the tumour shows signs of growing again. Fingers crossed!