Myopia in students is caused by the continuous eye movements due to reading books with the head tilted downwards which, mechanically, also by the force of gravity, cause an increase in the eye’s axial length, causing the focus of the image before the retina. The eye of our progenitor, hunter-gatherer, has not evolved to endure this effort.
The spread of myopia in the Eskimo people, in one generation, can only be explained by the reading effort that young people have faced with compulsory schooling.
To reduce this effect, I would recommend studying with the book on a reading desk, in order to keep the head horizontal, canceling the effect of gravity on the eye, otherwise present if tilted downwards