I filmed 25 reels in one session and could use 7. The other 18 had eye drift: I was looking just beside the lens. Across 4,684 measured frames, 90.8% drifted in the same direction, and it got worse over the 90-minute session.
The cause
I was aimed at the self-view preview beside the lens, with bigger glances to read the next line, and my posture drifted as the session went on.
The fix
Close the self-view. Nothing to look at but the lens.
Put the script in a narrow column right under the lens, so reading looks like eye contact.
Re-sit halfway through a long session.
Test before you batch
Film 15 seconds, watch it back muted, then shoot the batch. A quarter-second glance is fine. Half a second is noticeable.
The rest of my setup
Glasses glare: dim the screen, raise it above the lens, and tilt your glasses down slightly. Check a still: no screen shapes in the lenses.
Light: one soft light just above the camera, off to one side. Background lamp turned down.
Eye line: camera at eye height, notes directly under the lens.
Mic: top of the mic below your chin in frame.
Framing: eyes about a third of the way down the frame.
Captions: off. The edit adds them.
Pace: say the hook at normal speed so the keywords transcribe cleanly. Keep the gaps between items short.