If you’ve ever gone to the eye doctor (so all of us, though some more than others), you’ve probably wondered whether or not you should ask about those little things that “float” across your field of vision.
You might have been more hesitant to ask about strange flashes or patterns that appear when you close your eyes – but is there any reason to worry?
The short answer is, not really – most visual hallucinations and other visual disturbances are the harmless result of normal eye function.
They’re technically called “phosphenes,” or sensations of light experienced when there is no light to explain them.
Queensland University of Technology School of Optometry Professor Katrina Schmid, explains why there is usually no harm in seeing these patterns when your eyes are closed.
“Our eyes don’t turn off in the dark, but instead they create very weak internal signals that mimic light. These signals are constantly being made by the cells at the back of your eyes.’
Basically, your eyes and your brain can’t get on the same page.
“The swirls and waves we see are made by changes in activity from these cells. The blobs may be coloured because the cells in your eyes that detect colour also show this activity. These signals are transmitted to the brain, and the brain interprets this random activity. Your brain doesn’t know they weren’t produced by real light, so we think we’re seeing coloured lights and patterns that are not there. It’s kind of an illusion!”
That said, if you notice these phosphenes more frequently or they change or last for longer periods, you might want to see a doctor.
Those symptoms could be a sign of retinal issues like detachment, or of certain neurological conditions.
But most likely, you’re totally normal.
At least as far as your eyes are concerned.
If you found that story interesting, learn more about why people often wake up around 3 AM and keep doing it for life.