Close your eyes right now, and see whether or not there are any patterns dancing there on the back of your eyelids.

Chances are, you see them – most of us do!

What are they, though, and why are they there?

Let’s get into it!

While some visual disturbances can be caused by medical conditions, most are harmless hallucinations that are the result of normal eye functioning.

Called “phosphenes,” they are sensations of light experienced by people even when there is no light to cause them.

Katrina Schmid, a professor in the School of Optometry and Vision Science, explains more.

“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.”

She goes into even more detail, all of which is quite interesting.

“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 a kind of illusion!”

They can be indicative of retinal issues, like retinal detachment, or neurological conditions. They can even be caused by rubbing your eyes too much.

“If what you’re seeing has changed, and the patterns of light become much more noticeable or hang around for longer, it could indicate a problem.”

So, while it’s likely nothing to worry about, you know your body best.

Go see a doctor if you’re worried!

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