Abstract
Given the importance of the periorbital area in facial expression and as an indicator of age, facial rejuvenation often needs to address infraorbital hollowing. Hyaluronic acid (HA) has become a treatment of choice in attenuating infraorbital grooves and smoothening the eyelid-cheek junction. This article (1) presents the definition and origin of infraorbital age-related landmarks, namely the midface, tear trough and palpebromalar groove, (2) reviews the anatomical characteristics and the course of neurovascular structures to delineate the treatment area, and (3) emphasizes the importance of choosing the right injection techniques and products for safe, effective, and natural-looking rejuvenation of the infraorbital area. Patient selection should rely on defined criteria, weighing the procedure's benefit vs the risk of implant irregularities or visibilities. To achieve natural-looking results, it is recommended to first address volume loss in the midface. If the outcomes are not satisfactory, direct treatment of infraorbital hollow can be performed using a maximum filler volume of 0.5 mL per eye, administered at the supraperiosteal level, through either a serial puncture injection or linear threading technique with a needle, or by using retrograde or anterograde linear threading or deposition of microboluses with a cannula. The choice of the HA filler should be based on its ability to adapt during facial movement; the filler should therefore be smooth, malleable, and present limited hygroscopicity. Level of Evidence: 5 (Therapeutic).