Thank you for your interest and kind comments. Actually the device triggers a phenomenon called "phosphenes." I think that happens in the visual cortex. The rods and cones of the eye are actually a part of the brain; the phosphenes may also begin in the eye itself. In the first sentence of my post above, the word “patent” is highlighted. That is an active link to the patent itself on google patents. The second paragraph of the patent has a pretty good description of what "phosphenes" are. You can also look up the word on Wikipedia, however that source needs some rewrites.

The use of this device has strongly influenced my artwork and has increased my sensitivity to pareidolia <<Also an active link.