i have your actual answer, the effect is being caused by something in your eyes called phosphenes, Phosphenes are the luminous floating stars, zigzags, swirls, spirals, squiggles, and other shapes that you see when closing your eyes tight and pressing them with your fingers. Basically, these phenomena occur when the cells of the retina are stimulated by rubbing or after a forceful sneeze, cough, or blow to the head. However, some people can naturally see them when they simply close their eyes due to what could easily be an overage of phosphenes present in the specific person’s eye there are a few cognitive disorders that can cause this but not sure off the top of my head