Why don't my baby's eyes move together yet?

Two questions, months apart

First, at a few days corrected: why don't her eyes coordinate yet, and is that all right for a preemie.

Then again at three months: she's crossing her eyes a lot today, why.

Both ordinary questions, and the answers differ mainly because of her age.

Why it happens early on

The muscles that move the eyes and the coordination between them are still developing. Early on she can't reliably aim both at the same point, so they drift, cross, or occasionally do different things.

It's most noticeable when she's tired, when something is close to her face, or when she's trying hard to focus.

Newborn vision is also short range — roughly the distance from your arms to your face, which is not a coincidence. She isn't trying to track something across the room, so the misalignment matters less than it looks.

When it should have settled

Broadly by around four months, and for a baby born early that means four months corrected rather than four months old.

That distinction matters. Ours was born seven weeks early, so measuring from her birthday would have had us worrying two months before there was anything to worry about.

Past that point, persistent crossing or drifting is worth having looked at properly. Not urgently — but it's one of the things where early assessment genuinely helps, so it shouldn't drift on for months.

An eye that turns and stays turned, rather than drifting now and then is something that should be checked.

And a white or cloudy appearance in the pupil — including in a photograph, where one eye shows white instead of the usual red-eye reflex. That one gets checked quickly, and it's worth knowing about because a photo is often how it's first noticed.

Also worth mentioning: a sudden turn in a baby whose eyes had been straight.