I think i'm myopic and i use computers and mobiles a lot. now i'm seeing hundreds of tiny dots moving in a light screen such as white wall.

Urgent Ophthalmology: The sudden onset of floaters can be a sign of an impending retinal detachment, often followed by flashes of light and a curtain or veil across your view. An urgent dilated retinal exam will determine if this is a posterior vitreous detachment, a retinal tear, infection, vitreous hemorrhage or something else. A retina specialist is recommended if laser or other surgery is indicated. Do not delay!