Friday, November 21, 2008

9.10 Eye popping

Occasionally, patients claim they can do "crazy" things with their eyes. One of them can indeed move her eyes independently, for example. So much for coordinated binocularity. A burning question is: Can the eyes actually pop out of the eye sockets. The video below answers the question in part. It shows voluntary globe luxation, another of those crazy things, which presumably is a painless maneuver. Strictly speaking, it is a form of exophthalmos. Exophthalmos, as we all know, is most commonly seen in Graves disease.

Warning: The following video is a bit on the gruesome side:

(Click on arrow to start the video)

There are all kinds of catastrophic injuries involving the whole eyeglobes. One of them has the eyeball hanging outside of the socket with the eyelids closing behind the eyeball. This is not a pleasant topic; however, from the eyecare point of view, a review is still necessary.

As far as this type of involuntary eye popping, there are two varieties: (1) traumatic avulsion of the globe and (2) traumatic globe luxation. The difference between the two is really the extent of the damages: avulsion involves completely or partially severed extraocular muscles and the optic nerve, whereas in luxation, the muscles and the optic nerve are retained (hence a potentially total recovery after proper care). Luxation can be from a simple act of sneezing - often the patient has shallow eye sockets and weak ligaments.

With globe avulsion, there is very little or in fact zero chance of sight restoration. The 1999 movie, Oliver Stone's Any Given Sunday, has a scene that depicts some hapless football player's eyeball flying across the end-zone when tackled. This is actually probable despite common disbelief. There were indeed incidences of such injuries from through-the-windshield car accidents and blow-to-the-head martial-art competitions.

Perhaps the most disturbing are reports of eyeballs hanging by the threads (i.e., remnants of the optic nerve) in many A-bomb victims in Hiroshima on Aug 6, 1945. The blast force was a "mere" 15 kilo-tons, far less than the warheads in the arsenals of super-powers today, e.g., 300 kT. Destruction on such a scale is beyond imagination/comprehension. Let's not even try.