The first two wave types, P and S , are called body waves because they travel or propagate through the body of Earth. The latter two are called surface waves they the travel along Earth's surface and their amplitude decreases with depth into Earth.
The causes are many and can have bacterial infection, seborrheic dermatitis of the face or even a scalp, rosacea, allergies, and in very rare cases, the lice. If the itchy eyelids is brought about by seborrheic dermatitis then you may develop dry, flakey patches of skin on the eyelid.
Excess skin on the lower eyelid causes wrinkles and bulges. On the upper eyelids, an extra fold of skin can hang over the eyelashes and get in the way of seeing. The fat that cushions the eyeball from the skull can also cause bulges in the upper and lower eyelids.