Empirical impression technique for artificial eye fitting.
Using an impression of the anophthalmic socket to facilitate the design of an artificial eye is common practice today. The Modified Impression technique was described in the American Journal of Ophthalmology, February 1969, by Lee Allen and Howard E. Webster. It is a highly successful method that involves taking an impression of the socket using an impression tray, then making a wax casting of the impression, and final modifications to the anterior aspect of the wax model. A different technique has been in use in our office and elsewhere for more than 15 years, also with a high degree of success. We've dubbed it the "Empirical/Impression" method. It involves similar steps to the Modified Impression system, but in different order: first a wax model of the anterior aspect of the eye is designed and modified; second, an impression is made of the socket, using this wax model as an impression tray. The primary advantage of this method is efficiency. It involves one less laboratory procedure, hence making a "one-day custom eye" a reality. Although this process can be used in almost any case, the Modified Impression technique may work better for certain highly irregular sockets where "reading" the fornices by empirical means may be difficult. Either method requires a highly skilled and experienced fitter to make appropriate modifications to the anterior aspect of the prosthesis.