I have tried both the powder you mix into the food as well as the wipes. I think the powder (which is more expensive) doesn't work too well but, the wipes have made a difference. I wipe/wash Theodore's face every morning using damp cotton rounds and then I wipe the folds along his nose and under his eyes with the Angel's Eyes wipes. After wiping with the wipes I dry the area with a tissue. I have seen a noticeable improvement.
Angle's Eyes wipes
Angle's Eyes wipes