Why does Charles Bonnet Syndrome happen?

Why does Charles Bonnet Syndrome happen? Well, it happens because when a person has full sight, there are messages which run all the time from the retina in the eye to the visual cortex in the brain. So the eye acts like a camera and the brain interprets what it is you're seeing. as sight diminishes those messages slow down or stop entirely but for some reason that we still don't understand the brain doesn't stop it doesn't quieten down it fires up and creates its own images and what is seen depends on which part of the brain is firing at that moment so if it's the part that interprets patterns and colour, that's what you see, or animals, that's what you see, or even images of people. These can vary with everybody. Some people see very complex images like whole landscapes and other people see patterns, words, musical notes, numbers, maps, but they're incredibly irritating because you don't know when they're going to arrive, you don't know when they're going to go and even if they're something simple like numbers they cover everything in the room. They are also very very vivid. Totally silent, no other senses involved but extremely vivid. One lady said to me she'd had no sight for six years but it was like looking at a gardening documentary when suddenly there was colour again and she could see even a raindrop on a leaf.