1. -3.25 is not highly myopic. It's
simplySimply sleep myopia. High myopia starts around -6.00.
2. If prolonged computer use caused incrased myopia there would be a world epidemic of myopia as the world citizens do more and more computer work. There has been no increase of the incidence of myopia as the world becomes saturated with computers. So your theory doesn't fit with world experience. You should relax some.
3. Looking away from the screen periodically will reduce eye
strainStrains .
4. If you're really interested in keeping your eyes health see an eye physician (Eye MD ophthalmologist) every year.
JCH III MD