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.
Here are the 5 most common benign eyelid growths: Stye or Chalazion. A stye or chalazion is a blocked oil gland that causes that eyelid to be red, tender, and inflamed. Often, warm compresses applied directly over the swollen eyelid will help the oil gland to open, causing the swelling to subside.