Raccoon eye/eyes (also known in the UK and Ireland as panda eyes, though that term commonly refers to excess or smeared dark make-up around the eyes, or to dark rings around the eyes) or periorbital ecchymosis is a sign of basal skull fracture, a craniotomy that ruptured the meninges, or (rarely) certain cancers. Bilateral subconjunctival hemorrhage occurs when damage at the time of a facial fracture tears the meninges and causes the venous sinuses to bleed into the arachnoid villi and the cranial sinuses. In layman's terms, blood from skull fracture seeps into the soft tissue around the eyes. Raccoon eyes may be accompanied by Battle's sign, an ecchymosis behind the ear. These signs may be the only sign of a skull fracture, as it may not show on an X-ray. They may not appear until up 2–3 days after the injury. It is recommended that the patient not blow their nose, cough vigorously, or strain to prevent further tearing of the meninges.
Racoon eyes may be bilateral or unilateral.  If bilateral, it is highly suggestive of basilar skull fracture, with a positive predictive value of 85%. Most often associated with fractures of the anterior cranial fossa. 
^Herbella, FA; Mudo M, Delmonti C, Braga FM, Del Grande JC (December 2001). "'Raccoon eyes' (periorbital haematoma) as a sign of skull base fracture". Injury32 (10): 745–7. doi:10.1016/S0020-1383(01)00144-9. PMID11754879.Cite uses deprecated parameters (help)