Background Soft tissue filler is commonly used for facial contouring. However, incorrect use can lead to severe ocular complications. Even though filler injections are quite different from fat grafts, they are considered similar procedures. However, to date, there are no proven preventive measures or treatments for blindness secondary to soft tissue filler injections. Objectives This literature review aimed to investigate visual compromise secondary to soft tissue filler injection and discuss the related vascular anatomy, pathophysiology, and prevention of ocular complications of soft tissue filler injections. Methods A literature search until July 2018 was performed for reports on visual compromise after filler injections. We evaluated the previous literature and eliminated cases using fat grafts and unknown fillers. Results A total of 50 reports of filler‐induced visual compromise were identified. Analysis of these cases showed that the procedure with greatest risk was nasal augmentation, followed by glabellar wrinkle treatment. Within the last 3 years searched, 35% of reported cases involved treatment of the nose. There were no reports of blindness from injections into the temple or chin and relatively few case reports involving forehead injections. Conclusion The most common injection site associated with blindness in a previous report was the glabella; however, the most common site currently associated with blindness due to filler injections was the nose. Extreme caution is necessary when performing nasal augmentation or glabellar wrinkle correction using soft tissue fillers to avoid the branches of the internal carotid artery.

BACKGROUND Hyaluronic acid (HA) fillers are the most commonly used fillers for soft-tissue augmentation. The face is a dynamic structure. Facial rejuvenation by filler products depends on mechanical forces on the region of the face. The successful use of injectable HA fillers requires an understanding of the options available. OBJECTIVE The purpose of this study is to measure the rheological properties of HA fillers and to clarify how to select these fillers considering their rheological properties. MATERIALS AND METHODS Rheological characterization was performed on 41 fillers. Physical parameters directly linked to product performance were measured. RESULTS The properties of the HA fillers varied. These findings provide a basis for selection guideline regarding rheological properties in facial rejuvenation. CONCLUSION The authors' report is the largest study to determine the rheological properties of HA fillers to date. Understanding the fillers' properties can help physicians select the appropriate fillers for more predictable and sustainable results.

High-intensity focused ultrasound (HIFU) can be applied noninvasively to create focused zones of tissue coagulation on various skin layers. We performed a comparative study of HIFU, evaluating patterns of focused tissue coagulation and ablation upon application thereof. A tissue-mimicking (TM) phantom was prepared with bovine serum albumin and polyacrylamide hydrogel to evaluate the geometric patterns of HIFU-induced thermal injury zones (TIZs) for five different HIFU devices. Additionally, for each device, we investigated histologic patterns of HIFU-induced coagulation and ablation in serial sections of cadaveric skin of the face and neck. All HIFU devices generated remarkable TIZs in the TM phantom, with different geometric values of coagulation for each device. Most of the TIZs seemed to be separated into two or more tiny parts. In cadaveric skin, characteristic patterns of HIFU-induced ablation and coagulation were noted along the mid to lower dermis at the focal penetration depth of 3 mm and along subcutaneous fat to the superficial musculoaponeurotic system or the platysma muscle of the neck at 4.5 mm. Additionally, remarkable pre-focal areas of tissue coagulation were observed in the upper and mid dermis at the focal penetration depth of 3 mm and mid to lower dermis at 4.5 mm. For five HIFU devices, we outlined various patterns of HIFU-induced TIZ formation along pre-focal, focal, and post-focal areas of TM phantom and cadaveric skin of the face and neck.

Background: Soft-tissue necrosis caused by vascular compromise is a frequent and troublesome complication of hyaluronic acid filler injection. Hyaluronidase has been proposed as a treatment for this condition. This study aimed to determine the effective dose and administration interval of hyaluronidase injection in a skin necrosis animal model. Methods: New Zealand rabbits were used to simulate the hyaluronic acid–associated vascular occlusion model. Hyaluronic acid filler (0.1 ml) was injected into the central auricular artery to create an occlusion. Three rabbit auricular flaps were injected with 500 IU of hyaluronidase once (group A) and three flaps each were injected at 15-minute intervals with 250 IU of hyaluronidase twice (group B), 125 IU of hyaluronidase four times (group C), 100 IU of hyaluronidase five times (group D), and 75 IU of hyaluronidase seven times (group E), all at 24 hours after occlusion. No intervention was administered after occlusion in the control group. Flap fluorescence angiography was performed immediately after hyaluronidase injection and on postoperative days 2, 4, and 7. Flap necrotic areas were analyzed. Results: All control and experimental flaps demonstrated total occlusion after hyaluronic acid injection. The average total survival rate (positive area/total area ×100 percent) of control flaps was 37.61 percent. For experimental groups, the average total survival rates were 74.83 percent, 81.49 percent, 88.26 percent, 56.48 percent, and 60.69 percent in groups A through E, respectively. Conclusion: A better prognosis can be obtained by administering repeated doses rather than a single high dose of hyaluronidase.