"Keep your eye on the ball" is the oldest advice in the game, and it's right — it's just rarely coached past the slogan. Your head is your aiming system. The swing is supposed to turn around a still head, not carry it toward the pitcher or yank it toward the pull side. When the head moves, the aim moves, and the barrel chases a target that keeps sliding.
Two ways the head leaves
There are two common patterns, and the camera tells them apart.
Riding forward with a lunge. A long or early stride drags your head toward the pitcher, so your eyes travel with your body instead of staying home over the ball. This is the head going forward, and it usually travels with a stride that fires early.
Pulling off toward the pull side. Your chest flies open early and your head spins off with it — you're looking at the third-base dugout (for a righty) before the ball ever arrives. This is the head spinning off, and it usually travels with the whole body opening as one block.
Both leak the same way: the eyes leave contact before contact happens.
What the camera reads
CoachVision measures head stillness — how far your head travels from your load through just past contact, in torso-lengths. Some travel with the stride is normal and fine; a big number means the head is riding a lunge (open side) or pulling off the ball (behind). It reads on both views, which is handy, because the two views catch the two patterns.
Here's the honest boundary, and it matters: this is skull motion, not gaze. The camera can't see your eyeballs. So "your head's pulling off" is a verdict that needs the number and the frames together — a still head reads quiet, but the read is about where your head goes, not where your eyes point. Pair it with the keyframes before you decide.
The fix — quiet the head at its source
Here's the key insight: the head usually isn't the cause — it's the passenger. Fix the move that's dragging it, and the head goes quiet on its own.
If the head rides forward, the fix is the stride: land early and soft so there's nothing pulling the head toward the pitcher. If the head spins off, the fix is separation: let the hips lead while the shoulders — and the head with them — stay closed a beat longer.
For pure habit, especially on a tee, Mirror Load Checks rebuild a quiet head from the ground up: slow loads in the mirror with your eyes and head staying dead still while your weight gathers back. Ten a day. And on tee work, the simplest cue in hitting: keep your eyes on the tee's stem after contact. If you can still see the stem when the swing's done, your head stayed home.
The camera reads your body, not the ball — "contact" is your hands' speed peak. So this measures your head, not your eyesight. Film one swing, check your head stillness, then quiet the move that's carrying it — and keep your eyes on that stem.