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.
Allergies: People with eye allergies can have itching, swelling and watery eyes. When eyes are rubbed, this releases histamine into the lid tissues and the tears. This is significant, because some evidence indicates that histamine can cause eyelid twitching.