Measurement of upper eyelid implants curvature by ultrasound

The implantation of eyelid weights in the upper eyelid for treatment of the lagophthalmos in cases of facial paralysis was described for the first time in 1958 by Illig (lid loading). Whereas in the past, only rigid implants made of gold were used, flexible chains made of platinum are now being used frequently to optimize adaptation to the tarsal plate of the upper eyelid. The first step toward assessing the flexibility of the upper eyelid was to determine sonographically the various tarsal diameters of the upper eyelid in healthy eye subjects when the line of vision is changed. In a second step, patients who had received eyelid implants were examined sonographically both pre- and postoperatively to evaluate the curvature response of the upper eyelid after implantation.

The diameter of the upper eyelid tarsal plate in 50 healthy eye subjects was sonographically determined using a 7.5 MHz scanner in a noncontact mode with subjects looking straight ahead and in the abduction position. Rigid gold implants were implanted in 23 patients, and flexible platinum chains were implanted in 24 patients to treat lagophthalmos in facial palsy. The implant diameter was also determined by ultrasound using a 7.5 MHz scanner in a noncontact mode with subjects looking straight ahead and in the abduction position. In addition, the respective upper eyelid tarsal diameters of the patients were sonographically determined preoperatively with subjects looking straight ahead and in the abduction position.

The diameter of the upper eyelid tarsal plate in healthy eye subjects changes to a degree that is statistically significant (P < .001) when the line of vision is changed. The mean value of the diameter of the upper eyelid tarsal plate when looking straight ahead is 19.3 +/- 3.8 mm and in abduction position 30.1 +/- 6.3 mm. In the case of the rigid gold implants, the implant radius does not change postoperatively relative to the line of vision, in accordance with expectations. In contrast, in the case of the platinum chains, a statistically significant change (P < .001) in the implant diameter was found when the line of vision is changed, for a median postoperative follow-up period of 8 months.

Changes in the upper eyelid tarsal plate diameter, which are dependent on the line of vision, and changes in the implant diameter after lid loading can be precisely represented using a 7.5 MHz scanner in the noncontact mode. The flexibility of the upper eyelid when the line of vision is changed also remains intact over an 8 month follow-up when using platinum chains as implant material and thus potentially serves to reduce postoperative complications as well.