Can a weiss ring floater cause fog?

No: A floater is a shadow created by something floating inside the eye. A weiss ring may retain its ring shape or break or twist, but can only create a shadow of its shape. If you see a fog, you may be seeing shadows created by other floaters or even floating blood. If this is new, you need to see your eye md asap.

Yes: A weiss ring is a finding in vitreous detacent. During vitreous detachment, there can be some bleeding, which in turn can cause spots or fog, the foggy vision occurs because the blood speeds around, but is too little an amount to block vision. You sould be seen by an ophthaologist to rule out a retinal tear or detachment..