This time the eye problem isn't Optic Neuritis but rather Retro-bulbaric Neuritis which is a very specific form. That's the science bit... I was lost there. It means that instead of the usual visual disturbance with no pain I have a lot of pain with no visual disturbance.
It took an afternoon at A&E at Moorfields Eye Hospital to establish this. I'm not exaggerating. I was there for over four hours!
I'm off to bed now to take a cocktail of drugs which I suspect will knock me out until morning. I'm hoping they'll stop me waking up in pain when I move my eye in my sleep at any rate.