### FOV - will it ever be perfect?

Except that the average person doesn't see quite 180 straight ahead

From Peripheral vision (the original article contains links to book references) :

"For a single eye, the extent of the visual field can be defined in terms of four angles, each measured from the fixation point, i.e., the point at which one's gaze is directed."

"These angles, representing four cardinal directions, are 60° superior (up), 60° nasal (towards the nose), 70-75° inferior (down), and 100-110° temporal (away from the nose and towards the temple). For both eyes the combined visual field is 130-135° vertical and 200-220° horizontal."

So the max values with central fixation is 170° monocular horizontal.

A bit less than 170°, but if you look at this image from the NASA Bioastronautics Data Book, you can see that the nasal FOV is ≥ 65° for each eye, so the monocular horizontal FOV would be between 175° and 180°.

doesn't turn quite 45 each way (most eye movements are within about 25)

From the first reference, the binocular horizontal FOV with central fixation is 200°-220°.

With 25° of rotation on each side, that gives a 250°-270° binocular horizontal FOV with eye rotation.

plus the vision that far in the periphery is ridiculously poor

Sure, but it's useful to sense speed or for the detection of moving objects. And as you can see here we can't read past a 20° FOV, recognize symbols past 40° and discriminate colors past 60°. So the quality of vision is already very poor even without considering the peripheral visual field.

If you add the 25° eye rotation, we shouldn't need more than 170°, but we still have 100° more than that.

There is really no point going anywhere near 270

The OP question was about perfect FOV. If you want a HMD that provides a perfect FOV for everyone, you need 270°. Probably even a bit more if we consider the data published in the NASA handbook (280° total).

If the goal is to provide a good enough FOV for the average people, then more data would be required to know what the average FOV is.

That's the same question than for visual acuity. With 16K displays per eye you would cover the average population, but for fighter pilots you'd need more than that (around 27K).