Dear Cecil, this can also happen if you are alcoholic. At a certain point of alcohol consumption (quite a lot really), the pressure increases on the eyes and can cause this effect. Often the symptoms appear as dots and lines that look like spiders, but the effect depends upon the individual. Increase the dosage level and you get images which are often composites of people you know, or other images. This is where you get the expression “seeing pink elephants”. The effect is dependent on light level and disappears with a sufficiently high light level. Another effect at this level is the hearing of sound which is usually musical and combines melodies that are known to the individual which is not affected by light but is a resonance from another sound (car engine). Increase the dosage again and you are into delerium tremens (shaking hands and inability to hold things steadily in the hands). The basic cause of these effects is the putting of unacceptable pressures on the brain and nervous system which effectively scrambles the “wires” of the nervous system such that the brain (in an anethetised condition at this point) cannot control the senses, and can lead to death from heart failure, kidney failure or liver failure. It can also affect the brain as the condition destroys brain cells.
Welcome to the Straight Dope Message Boards, Burghfield, we’re glad to have you with us. As JZesbaugh noted, when you start a thread, it’s helpful to other readers to provide a link to the column in question. Saves searching time and helps keep us all on the same page. You did provide the date, which is helpful, and I’ve added the link at the bottom of your post. No biggie, you’ll know for next time; and, as I say, welcome.