Can you tell me if an eye doctor checks your eyes and says they are perfectly healthy, what can cause floaters in your vision?

Commonly floaters. are from the loss of clarity of the gel-like substance inside your eye (vitreous). This is a natural process in most patients and does not require treatment. Your doctor was checking for retinal tears or retinal detachments that can sometimes be associated with new floaters. Retinal issues would require treatment. Be well. .
Normal aging. Floaters can sometimes be the sign of a problem like a retinal tear, but more commonly they can be a normal sign of changes in the vitreous gel in the eye as we get older. Always have floater-like symptoms evaluated by your eye doctor. You can have otherwise healthy eyes and still have floaters. It's important to let your eye doctor know right away if your floater-like symptoms get worse.