Preparation H is often used under the eyes to reduce the swelling associated with puffy eyes, but VentureEyeCare.com recommends that the product be used only as directed. If the cream gets into the eye, it can cause irritation and possible blindness.
Preparation H is designed to be used on hemorrhoids. The main ingredient, phenylephrine, constricts blood vessels causing blood to be squeezed out, therefore causing the hemorrhoid to shrink. In principle, this should work similarly on puffy eyes, explains Dr. Skromme of VenturaEyeCare.com. The cream can help constrict the blood vessels, squeeze out the fluid, and reduce the swelling.
Preparation H is commonly used by models and actresses to reduce eye puffiness, explains Dr. Skromme. However, regular use under the eye can actually have the opposite of the desired effect. Used with regularity, the blood vessels can try to counter the phenylephrine and actually dilate, further increasing the puffiness of the eyes.