While I was still in A&E had friend had texted me. (I'd asked A&E did they know whether any optometrist in Fife was open on Christmas Eve. They couldn't say.)
God bless her, my pal phoned her optometrist - Superdrug. She texted me to say that the branch in my town was open and she'd made an appointment for me.
The Superdrug optometrist gave me a very thorough check. It turned out that the problem was a rather spectacular but pain-free ocular migraine. The more stressed I got, the more zig-zag lines and black bands appeared across my left eye. It had gone on for hours. The ocular migraine had triggered a very large floater which also impaired my vision. I had no idea that this could happen. (I'm not usually a wimp, but I was terrified that I was going blind - I'm in my 60s, so the right age for a detached retina.)
After I knew what was wrong and calmed down, the zigzags stopped. (The floater stayed with me for a few months but gradually broke up/floated to the bottom.)
When I asked the Superdrug optometrist how much I owed, her answer was "Nothing. We're charging the NHS, since we're doing their job for them.)
I don't have a lot of faith in the Vic A&E. In 2013, they misdiagnosed my late husband's full blown stroke as a TIA, simply because they didn't scan him straight away. (When I asked about the scan: "Oh, they''ll fit him in when they have the time.) By the time another doctor came on, the 4 hr window for the clotbuster drug was gone, and DH was left with life-changing disabilities.