Another misconception.

There is no "field of view" thru these 1x (unmagnified) sights if employed properly. They're designed to shoot with both eyes open where your field of view runs fully from left to right, not just thru an aperture. The dot is "just out there" in your normal binocular vision.

Close the front cover. FOV thru the sight just dropped to zero yet the dot is still out there on the target and you'll still hit it. You should not see the sight itself, just the dot if both eyes are open.

If you're closing one eye both covers have to be open, of course, but you also give up the benefits of binocular vision and target acquisition. But even here there is no benefit having the sight up close to your eye as the body tends to block much more of your vision. Thru the lens FOV is undeniably greater but total FOV is less because the sight is blocking more of it when it's close. But you shouldn't be closing one eye anyway.

Takes very little practice to acquire the both eyes open technique and most folks can do it with iron sights as well.

Cross-eye dominant guys will need more practice.

-- Chuck