Published online Jul 26, 2020. doi: 10.12998/wjcc.v8.i14.3000
Peer-review started: February 25, 2019
First decision: April 8, 2020
Revised: May 12, 2020
Accepted: June 20, 2020
Article in press: June 20, 2020
Published online: July 26, 2020
Functional epiphora is a clinical condition which is not due to an anatomic defect. Most studies agree that it involves the action of the orbicularis oculi muscle, particularly its deeper segment (Horner’s muscle), but the exact mechanism is not clear.
To evaluate the orbicularis oculi muscle in functional epiphora patients using electromyography (EMG).
A total of 8 Chinese patients (16 eyes) with functional epiphora were enrolled in this study, and ten volunteers (10 eyes) were included as normal controls. Five epiphora patients (five eyes) with facial palsy served as positive controls. Quantitative EMG was performed in the deeper segment of orbicularis oculi muscle. The average duration of each EMG waveform was measured.
The average duration of EMG waveforms in the normal control group, the functional epiphora group, and the facial palsy group were 6.39 ± 0.73 ms, 9.39 ± 1.32 ms and 11.2 ± 1.42 ms, respectively. The duration of EMG waveforms was significantly longer in the functional epiphora group than in the normal control group (P < 0.05), and shorter than that in the facial palsy group (P < 0.05).
These data indicate the presence of neurogenic orbicularis oculi muscle damage in epiphora patients, which may be the cause of functional epiphora. The etiology of neurogenic damage in the orbicularis oculi muscle requires further investigation.
Core tip: Functional epiphora is a clinical condition which is not due to an anatomic defect, and the cause of functional epiphora is not very clear. In this study, we used electromyography as a valuable tool to evaluate the orbicularis oculi muscle, and the results suggest neurogenic muscle motor neuron disease in functional epiphora patients. This study reveals a possible new approach for the treatment of functional epiphora.