What is this white thing that i get at the outer corner of my eyes during the working hours of the day (can be wiped out with the finger tip or tissue paper) .what is the reason of this? ( ps: i also have myopia ?

This is most likely dried or drying mucus which is produced by the eye to maintain moisture in the eye. When the eye dries the mucus comes out of the tear solution and gets stuck on the lid as a white blob. Increase tears and fluids when working to avoid drying of your eyes and this will disappear.

If you can wipe it away, it is likely precipitated lipids and glycoproteins from dry eye syndrome. Try aggressive use of artificail tears.