I was blown away to hear of the third eye on chameleons heads and I had just took a pic of the back of my bearded dragons head so I triple cropped it and there it was. The 3 Rd eye !!! I haven't looked at Seymores head yet that's my veiled chameleon. Really cool.
Just a link for those that stumble on this and want to know more.
This is why we tell new keepers "No light at night, no, not even the expensive red one, no he won't get too cold." In chameleons, this special scale can sense red light and, it will disrupt their sleep.