Whew! Panic over. So it wasn't glaucoma or a detached retina or a brain tumour or anything - just an ocular migraine.
I called my doctor's surgery, and they said they could fit me in at 11. The symptoms cleared up almost as soon as I left work, and by the time I'd traipsed all the way over to my doctor in Whitechapel - a remnant from the five years I lived in the east end - I was fine. My vision was still a little blurry, and I had a very faint headache, but was otherwise perfectly well.
Still, she poked around, shining a bright light into my eyes, asking me if I could see her fingers wiggling, getting me to read some fine print, demonstrating to an intern - seventeen bloody times - how to handle the opthalmoscope.
And all the while I felt a bit of a fake: "I'm fine now, but I was really worried at the time. I thought it might be glaucoma."
"Is there a history of glaucoma in your family?"
"Um, not that I'm aware of, no."
"So why would you think...?"
"Well," I confessed shamefaced, "I read something on the web that...."