Thanks for all of the information.
Single vision glasses are definitely much easier to use. Shame I only have them for computer use.
Sunday has been a good day. Sat was the first day I felt close to normal. I chopped some wood for kindling and it was fine; had to do it mid-week and the noise (in a shed) left my ears ringing and head fuzzy for some hours. Sat's chopping noise had no effect.
[Mon] Brain is back to almost normal function again. Several people commented at work. My manager said that last week it was very clear that I was not myself, not functioning. Clarity of thought is lovely to have.