Can you tell me about surgery for enophthalmos?

Cause dependent. To answer that you need to know the cause of enophthalmos. If it's due to an orbital fracture then repairing the fracture can help. Other causes are oftern treated by re-volumizing the orbit, usually with a floor implant. If there is a prosthetic eye then soft tissue filler or fat transfer may be an option. There may be other treatments depending on the cause.