Why more percent of children need spectacles in each successive generations??

We as human children are born with +4.00d power. This eye power helps us in better vision for distance and is essential for survival for both hunting and hunted animals to survive on earth. We have binocular vision meaning both eyes used together for focusing that give us depth sense. Thus, we are born hunters in order to survive on this earth.

But by evolution came agriculture to sustain us. Now we send our young toddlers to school at 3 years of age. Excelling at studies remain the aim. So nature improves our near vision. In the process our distance vision get blurry and we require minus power to look at the distance. Hence, in each successive generations population of myopia (minus power) is increasing.