Predicting the ideal implant size before enucleation.

PURPOSE: This study of volume replacement in anophthalmic sockets compares the volume replaced by the implant and prosthesis with the volume removed from the socket and evaluates A-scan ultrasonography as a tool to predict an ideal implant size before enucleation. METHODS: In this retrospective study of 59 anophthalmic patients, the volume replaced by the implant and the prosthesis was compared with the volume of the enucleated eye. The volume removed was estimated by calculating the volume of the fellow eye using A-scan ultrasonography. Enophthalmos and superior sulcus deformity were measured and correlated with the percent volume replacement in the anophthalmic sockets. RESULTS: Greater enophthalmos and superior sulcus deformity were found in patients with less than 100% volume replacement compared with those with 100% or more volume replacement. The axial length determined by A-scan ultrasonography of the fellow eye suggested that a larger implant size should have been placed in 76.3% of those patients with less than 100% volume replacement. Sixty-three percent of adult patients could have received an implant more than 22 mm in diameter to fill 80% of the volume removed at enucleation. CONCLUSIONS: A-scan ultrasonography of the fellow eye provides a useful tool for predicting the implant size before surgery for optimal volume replacement.

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.