If your condition is not already being medically assisted, switching from a computer screen to a tablet or a mobile phone will not help; you will only be prolonging the inevitable as you will be damaging your eyesight more. It is best to first consider medical help if you have not already done that, then the recommendations of the eye specialist on which screen will be better for your eye sight will be more valid than the recommendations from most of us who are not eye specialists but will speak from common knowledge without any form of diagnosis.