The Injection for the Lower Eyelid Retraction: A Mechanical Analysis of the Lifting Effect of the Hyaluronic Acid.

[BACKGROUND] It has been reported that the injection of the hyaluronic acid (HA) into the lower lid area could improve lower eyelid retraction. However, the published studies offered few insights into the mechanism of this treatment. When the underlying mechanism is not clear, many surgeons will not trust the method enough to apply it in their clinical practice. The purpose of this article was to propose a possible explanation for the underlying mechanism of the treatment and further verify the method by a series of cases.

[METHODS] The authors performed a mechanical analysis on the physical impact of HA on the lower eyelid. In the clinical cases, we injected the fillers under the orbicularis muscle to correct lower lid retraction. The results were evaluated by the standardized marginal reflex distance 2 (MRD2) immediately and 9 months later.

[RESULTS] From October 2013 to October 2015, the injections were carried out in 27 cases (14 post-blepharoplasty and 13 involuntary). In 26 cases (96.3%), the retraction was completely corrected and did not recur through the last follow-up. The average improvement of the standardized MRD2 was 0.84 mm immediately after the injection and 1.19 mm 9 months later. Complications were not reported.

[CONCLUSION] Lower eyelid retraction could be treated by the injection of HA under the orbicularis muscle. The filler in this situation acted as a lifter because the filler changed the balance of force of the lower lid, forcing it to shift upward to gain the new balance. The 'lifter' mechanism could be applicable to other facial injections that generate elevating effects.

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