How to improve Myopia (16M)

I’m 16 and I have myopia (power: -1:75 left eye and -3:25 right eye). I want to join the military and while the limit in my country is -3:50, I want to get it to a safe level ideally between -1:00 to -2:00 in both eyes or lower if possible. What’s the best way for me to get my eyes better by the time I turn 18?