We require that adequate healing take place before fitting. Schedule permitting, we fit the prosthesis at seven to eight weeks after surgery.
Using alginate, we take an impression of the eye socket. Initially, the material has a consistency similar to the white of a hard-boiled egg. With no discomfort to the patient, the alginate sets up in one to two minutes.
After removal from the socket, the impression is encased in dental stone, which is very similar to plaster of paris. The impression material is then removed from the mold and hot wax is poured into the mold and is allowed to cool and harden. What we obtain is a wax piece that constitutes a pattern for the prosthetic eye. The wax allows us to make changes for comfort as well as opening eyelids to match the companion eye.
A iris button, similar to the pupil, iris, and cornea of the front of the eye is chosen and built in the wax pattern. This can be adjusted in order to give the proper direction of gaze. This portion of the proceedings usually takes one to two hours with the patient available for trial fittings so as to give the desired prominence to the artificial eye and create the proper opening and contour of the eyelids.
When satisfied with the wax pattern, we make a final mold of dental stone around it in a brass flask. The pattern is then removed and after placing the iris button back in the mold exactly in the same position, we pack a dough of white plastic into the mold and process it by heated water bath until it has cured. This is the beginning of the final prosthesis.
A thin layer of plastic is ground, filed and sanded from the front surface of the eye. We make a painting shell by placing a clear polyethylene sheet between the artificial eye and a new layer of clear plastic, which then must be cured. The painting lens affords us a way of judging the color of the prosthesis with all optical effects present, while the patient wears the prosthesis. When placed over the surface of the eye, the painting lens will bring the form back to the shape of the original wax pattern.
The coloring of the artificial eye is done with the greatest of care to match the companion eye in current appearance of the living tissue. The patient must be present for this part for this part of the procedure. At intervals, the painted prosthesis can be placed in the socket. We can then judge the color with all illusions present and then alter colors as desired until completely satisfied. Once the eye is completed there can be adjustments of the fit and painting if necessary. The procedure takes 1 day to complete, with difficult socket or swelling sometimes it takes another day longer. This same method is applied to fitting the corneal scleral shells.