Your son is having Hypermetropia
and not myopia
. His refractive error
is spherical 1.5 and cylindrical 2.5. He his having hypermetropic astigmatism
Hypermetropia is common in children because of small axial length of the eye ball, infact everyone is born with hypermetropia at birth. Hypermetropia is more common in children than myopia, and with growth of the eyeball many children may become normal without need for spectacles.
He has to wear specacles regularly and attend follow up for eye examination regularly once in 6 months as rapid changes in refractive power are known to occur in children because of rapid changes in the dimensions of the eye ball.
Chances for decrease in the refractive error are possible in your sons case.