Last night I suffered a less than hour-long bout of scintillating scotoma. It’s a weird kind of snow crash in your visual cortex where part of your field of vision is replaced by sparkly geometric patterns. It happens to me once every few years and is sometimes associated with a headache, sort of migraine lite. The scotoma is quite disorientating, particularly when the affected bit is at the centre of whatever you’re looking at, like last night. I was probably a pitiful sight, squinting out of one corner of my eye at the laptop as I laboured half blindly to download the latest Escape Pod — I needed something to do when I retired to bed. After listening to the Neal Asher story, I got up and took some ibuprophene against the headache that followed the scotoma.
Inspired by Oliver Sachs’s essay “Stereo Sue”, I’ve recently taken up using a contact lens again after many years. Maybe the unfamiliar stereoscopic calculations have taken their toll on my brain. I have a good left eye and a near-sighted right one, so for most of my life my brain has just disregarded the blurry input from one eye and made do with the good signal. The minute I popped in a lens, everything came out in glorious 3D again. I’ve reached the point where objects extending toward me scare me when I’m not wearing a lens, since I can’t see exactly how far away they are the way I’ve recently learned to.