A Reason to Convert from Empirical to Impression Fitting

The initial transition from glass eyes to plastic ocular prostheses had now taken place.  The inevitable was yet to happen, the manner in which a custom prosthetic eye was to be fitted.  This meant conversion from the glass eye makers empirical (less time consuming) trial and error fitting method, to the more exacting impression moulding technique.  At the onset of this plastic era, there were few adherents for the Army Dental Corps method of impression taking.  However, those ocular prosthetists who did use the more time consuming flush fitting technique were discovering (as well as their referring ophthalmologists) that former glass eye wearers, had fewer complaints about excessive tearing and secretions.  The reason for this occurrence, was that fluids could no longer pool behind its flush fitting posterior surface (which was a cause for irritation and infections of the nonconforming prostheses).  The positive aspect of this conversion to impression fitting began to pay dividends for the wearer.  It was no longer necessary to remove and clean the prosthesis three or more times during the day, nor was it necessary to remove it at bedtime.  Despite this less attentive care, the conjunctival tissue in the cavity remained white and quiet (no sign of chronic irritation), and for some patients, they were experiencing wearing comfort for the first time.

In additional to less tearing, secretions and more wearing comfort, there was a degree of movement of the prosthesis from the underlying tissues and the (orbital volume augmented) ball implant.  Of course, the extent of motility was limited, since there was no direct attachment of the eye muscles to the sphere, and in many cases the implant had migrated out of the muscle cone. This usually restricted movement to two quadrants (depending on the migration of the ball).

The next link in the chain of events was to obligate the use of impression moulded fitting procedures for all plastic ocular prostheses, by introducing the dual purpose implant for "orbit volume augmentation" and "motility."