I was checking out some VR and AR today and this got me thinking, again, about the pfhor visual anatomy.
What on earth is the point of a third eye? Well, what's the point of two? We only need one to see.
The advantage of two eyes is that it gives us a little bit more depth perception by expanding our cone of vision slightly to the left and right. We could say our line of sight is right inbetween the eyes, but with three eyes in a triangle position at a slightly convex angle, that line of sight is moved to the spot inbetween all three eyes. So, not only is there a bit of a wider cone to the left and right, there is also better perseption of what's above and below the pfhor in their cone of vision. What the pfhor have achieved is still being able to see ahead while their head is tilted up or down. Amazing, isn't it? This kind of eyesight is probably better adapted for spending life in the more 3D environment of a low-gravity spaceship than being a landlubber with gravity that pins you down to the planet's center.