In the vast majority of patients who are properly selected for under eye treatment by an expert injector, juvederm or restylane will work beautifully and safely to reduce under eye darkness. In some cases, a filler is not the treatment of choice, especially if the skin is particularly thin in that area, or if the cause of the underlying darkness has not been determined (see a dermatologist for this). The filler can cause a Tyndall effect which is the eye seeing a bluish tinge where the filler was injected ; if this were to happen, an antidote called hyaluronidase can safely be injected by a dermatologist or plastic surgeon to dissolve the filler and clear up the Tyndall effect. Dr. Benjamin Barankin, Toronto Dermatology Centre.