Over the last few weeks I have noticed that now and again, my 3yo daughter's eyes cross. I can't be sure which eye it is but they just go crossed and turn inwards. I first noticed it a couple of weeks ago when I was sitting opposite my dd in a bright cafe for a drink. It was the morning but my dd was washed out and tired. The other times I've noticed it have been after nursery when she's tired. I know tiredness can cause it but I have been quite alarmed as they've never done this before until recently . Any advice gratefully received