welcome to health care magic
you have said that for the past 1 yr power has been increased from -5 to -5.5..
this is called myopia,,that means image coming far away are not reaching the retina
power has 2 dimensions one is cylindrical and another one is spherical,,spherical power goes on increasing with increasing age upto growing age that is approx 21..there is no curability in the sense she had to wear glasses for the life time..
LASIK treatment is one of the choice in which a small bit of cornea
is removed to decrease the size of power..this should be done after completion of growth only...practicing eye exercises may not help this cond.
for your kind information i will tell you some thing, in some forms of myopia like pathological myopia
degenerative changes may be seen in the posterior segment(retina) that is behind the iris....
dont be delay and consult ophthalmologist
to get check up..
she had to ware glasses/contact lens
...contact lens at this age is not required..
hope you understand my suggestion...