You may have a very slightly 'lazy eye' (I do) - it can be a lot less extreme (not at all noticeable to others) than the pointing-completely-different-directions that people imagine, and iirc is highly correlated with astigmatism.

Optician used to tell me to work the muscle by following my finger to my nose, trying to maintain a single image. At a certain point it will snap into two - the 'lazy' eye has given up and drifted slightly - the goal is to get the finger as close as possible. Obviously if you get very close or all the way, that's 'cross-eyed', but I just can't do it.