At the age of 8 yrs ,power is too much .Myopic power is inherited from either mother or father side & is basically hereditary in nature ,maximum increase in myopic power takes place between 13 to 21 yrs in male & between 13 yrs to 19 yrs in female because maximum body growth takes place between these periods. There is no direct medicine to check the increase in myopic power but with the help of balanced diet ,green vegetables & seasonal fruits  one can slow the speed in the increase of myopic  power,one can take the help of yoga pranayam, swimming, gym &these things definitely slow the speed of increase in myopic power.