I would like to describe you about floaters in detail.
We have a thick jelly like fluid in the posterior part of our eye called vitreous, which is attached to the retina of our eye. With age, in patients with high spectacles power or rarely without any cause, this vitreous can get separated from the retina, causing floaters. These are a normal phenomenon and in most patients they settle down with time, but might persist in some patients. In case of a complete vitreous detachment, there is no problem. An incomplete detachment can sometimes cause a pull on the retina, causing a small hole, which would need to be lasered to prevent complete vitreous detachment and blindness. Dilating pupil is the way to examine the retina to look for any potential holes. It is not a treatment for floaters. In fact dilating pupil will compromise your vision.
On the other hand alphagan-P eye drops are prescribed for patients of Glaucoma and not vitreous detachment. If you have glaucoma, you would need proper treatment and periodic evaluation.