Electrical activity of the orbicularis muscles before and after installation of ocular prostheses

This study examined the electrical activity of the superior (SO) and inferior (IO) orbicularis oculi muscles before and after installing ocular prostheses in patients who had undergone unilateral enucleation. Twelve volunteers requiring prostheses were selected. Their electrical activity was monitored at rest and during normal opening and closing of the eyelids, rapid opening and closing of the eyelids, and squeezing. Data were recorded before and 7, 30, and 60 days after the ocular prosthesis was installed. Two-way analysis of variance was performed to verify whether there were any significant differences between the muscles and periods, and means were compared by Tukey-Kramer honestly significant difference (HSD) tests (P < 0.05). Results from the initial period differed significantly from those after prosthesis installation in all clinical situations. The SO had significantly higher electrical activity levels than the IO in all clinical situations but squeezing. The authors observed the same values during the initial period for the condition of rest (SO 8.42/IO 5.93) and the highest values for the condition of squeezing after 60 days (SO 131.50/IO 117.12). Rehabilitative treatment promoted an increase in the electrical activity of the orbicularis oculi muscles, restoring part of the muscle tone and motor function to muscles of the affected area.