Floaters are due to translucent/opaque objects floating around in the vitreous cavity of the eyeball. When light shines into the eye, these objects cast shadows on the retina, causing the perception of floating objects in the visual field.
Most commonly, the floaters are bits of degenerated vitreous gel. They may also be caused rarely by things like blood or blood cells if there is inflammation in the eye.
If your mother suddenly got new floaters, she should make an appointment to see an eye doctor soon, preferably within a day or 2.
This is because the sudden onset of new floaters may be associated with a retinal tear/hole, which if present may lead to a retinal detachment and loss of vision.
Laser treatment for floaters themselves is generally not recommended. However, if a retinal tear is found on examination, that retinal tear needs to be sealed as soon as possible with a special 'Argon' laser to prevent it from progressing to a retinal detachment. This 'Argon laser retinopexy' does not get rid of the floaters, it just seals the hole so fluid cannot get in.