Such a progressive myopia
is something to be worried about. there are a couple of things that need to be checked to make sure that our eyes are ok and remain so
1. is there any progessive change in the shape of the eye (serial topography)
2. is your eye structurally normal or is there some type of what we call blue sclera syndrome
3. what is the intra ocular / eye pressure
4. what is your retinal status
is something that mainly comes at this age because of poor vision in wither eyes. if vision is not corected then the squint will come back even after operative corection. so the primary concern is vision.
if it is possible do upload all your previous ophthalmic reports so that a better opinion can be formed.
hopw this helps