I'm 17 and I have a -2.25 and -2 prescription. It may not be A LOT but I work on my computer a lot. Assignements, studying, gaming, almost 5-6 hrs a day. Plus we are attending online schools as well.
I follow the 20:20:20 technique as well but my eyesight worsened -0.25 as per my yesterday's eye checkup.
Any advice on preventing it?