Sometimes a section of the vitreous pulls the fine fibers away from the retina all at once, rather than gradually, causing many new floaters to appear suddenly. This is called a vitreous detachment, which in most cases is not sight-threatening and requires no treatment.
However, a sudden increase in floaters, possibly accompanied by light flashes or peripheral (side) vision loss, could indicate a retinal detachment. A retinal detachment occurs when any part of the retina, the eye’s light-sensitive tissue, is lifted or pulled from its normal position at the back wall of the eye.