A Reason to Convert from Glass to Plastic
 

The finest material for making glass eyes was in short supply during WWII, since it had to be imported from Lauscha, Germany.  Fortunately, the plastics industry had already developed a medical grade acrylic, (as reported by: Berens, C, Rothbard, S.  Synthetic plastic material for implantation following enucleation.  Am J Ophthalmol 1941;24:550).  The time was ripe for its application as a replacement for the glass eye.

It was the Dental Corps, Army of the United States that first reported and published a 'bulletin' (Erpf S. F., Dietz V. H., Wortz M. S., et al.  Prosthesis of the Eye in Synthetic Resin, A Preliminary Report.  The Bulletin of the Army Medical Department, Vol. IV, No 1, July, 1945, 76-86.) on the fabrication of the impression moulded plastic eye.  Needless to say, it was the material of choice when it became available to the public.  The advantages of plastic over glass were numerous.  There was no longer fear of breakage, it would not roughen with wear, and, if it became chipped or scratched, it could easily be repaired and polished.  The curvature and thickness of the impression moulded plastic prosthesis could adapt to the irregular configurations of the orbital tissue, and atonal weaknesses in the eyelids.  It could improve cosmesis when there was orbital volume loss that caused superior sulcus depression of the upper lid.  The moulded prosthesis could also be worn at bedtime, whereas, the glass eye with its smooth concave posterior shape, that allowed tears and secretions to accumulate behind it, had to be removed nightly to give the socket tissues a rest, and to prolong the life of the glass eye.  (The glass eye would roughen and discolor caused by tears and secretions.)