>>16776026
this is basically it

1. Brains ability to filter gets interrupted or modified
2. Information from the eyes that is typically filtered out is read as 'real' by the brain
3. Brain attempts to make sense of it
4. ????
5. Hallucinations

This image demonstrates what i mean, the pillars of faces are formed by natural imperfections of your visual system being read as real. The structure of the pillars are always present, your brain just filters them out like your optical blind spot.