Stephenson:Neal:Quicksilver:857:blowout fracture (Henry Pollock)
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Stephensonia
...was noted, with professional interest, by the tavernkeeper, who didn't look directly at it... he'd endured a blowout fracture of the left eye-socket.
Following a blow to the orbital rim by an object too large to enter the orbit, it is relatively common to see the eye itself become sunken and restricted in its motion. The fellow eye moves normally but the eye in question stops at some point. This is likely to cause double vision in the mind of the affected and a question as to the direction of gaze in the mind of the observer. This pattern was recognized early.
Byron Smith is credited with explaining the mechanism (Smith B, Regan WF. (1957) Blow out fracture of the orbit. Mechanism and correction of internal orbital fracture. American Journal of Ophthalmology 44, 733-739) by which hydraulic forces push the intraorbital contents through the weakest part of the orbit, usually the floor, and frequently result in entrapment of tissue within the maxillary sinus. This entrapment mechanically restricts rotation of the eye. Treatment at present consists of elevating the structures back into the orbit and bridging the gap in the orbital floor with a form of plastic. This was unavailable in 1688 and an appearance like "a clay effigy" was a likely result.