Plain English Meaning

Each of your eyes has one tiny spot where it can't see anything. Normally the other eye covers for it. But in flight, if something sits in that spot in one eye and is hidden from the other eye too, you simply won't see it — even though you're looking right at it.

Full Definition

A small area in each eye where the optic nerve attaches to the retina, containing no light-sensitive cells. Any image that falls on this spot is not seen. Because the blind spots in the two eyes are in different positions, normal binocular vision usually fills in the gap — but if one eye is covered, blocked, or if an object aligns with the blind spot of one eye while a wing or canopy frame blocks the other, the object can disappear from view entirely.

Context Anchor

Encountered in night flying, night scanning , and discussions of how pilots should look for dim lights, , or in light.