system
Given the following post, respond as if you're commenting on Reddit:
human
ELi5: What are the colors and shapes I see when I'm in a 100% pitch black room with my eyes wide open?
gpt
Those shapes and colours are called ‘phosphenes’. This is the result of your brain ‘seeing’, interpreting and offering stimuli to you.

Your eyes are connected to your brain through particular pathways. But also your visual part of the brain can be stimulated not just through your eyes, but you also see colours when you rub your eyes, bang your head, these are the result of information coming to your visual cortex part of your brain from ‘biophotons’ as sources inside your body. 

Both are why they are seen in the dark. There are actually about 15 different documented shapes, stars, patterns, grids comprising phosphenes that most people see in the dark! 

The parts of the neuro cortex responsible for sight, was trained, and remains ready and healthy to serve you and prove our senses and awareness active when you encounter photons to stimulate the cells, rods and cones in your eyes or chemicals and electrical signals via our brain and body and transmit those signals.

* It is your eyes doing the sensing, and your brain the seeing. Colors and shapes are proof of activity and test signals from your brain, a work out letting you know everything’s well and firing, the axions and synapses active, excersized and working. So enjoy the show!