Third eye representation in the tarot

In the Dark Grimoire, there is a demon (?) with a third eye on the 8 Swords.

https://www.pinterest.com/pin/407012885049795986/

I just noticed something. These are so many Devil cards with third eyes. I just observed that the Devil in the Golden Dawn Magical Tarot has one.

In the New Golden Dawn Ritual Tarot companion book by the Ciceros, it states:

TNGRT said:

The Devil has a large third eye in his forehead, symbolic of the fact that inner vision is greater than the sensory vision of two normal eyes.

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I think one possible explanation of the preponderance of third eyes in Devil cards is because Atu 15 corresponds to the path of Ayin, the Hebrew letter whose meaning is eye.

Found another one: the genie in the Deviant Moon's 9 of Cups card has a third eye.