When an eye recedes, the third eyelid usually slides out over the surface of the eyeball and becomes visible. The treatment of a sunken eye is directed toward the underlying cause.
Both eyeballs may recede when there is loss of substance in the fat pads behind the eyes. This occurs with severe dehydration or rapid weight loss.
There is a retractor muscle, which, when it goes into spasm, pulls the eyeball back into its socket. Tetanus produces spasms of the retractor muscles of both eyeballs, along with the characteristic appearance of the third eyelids.
When only one eye is involved, the most likely cause is a painful eye. Nonpainful causes include nerve damage following a neck injury or a middle ear infection. With this condition, called Horner’s syndrome, the pupil is small on the affected side. Finally, after a severe eye injury, the eye can become smaller and sink into its socket.