High-Intensity Focused Ultrasound for the Treatment of Infraorbital Fat Protrusion: A Preliminary Case Series.

Infraorbital fat (IOF) protrusion is a common feature of periorbital aging and is commonly managed with lower blepharoplasty. Although surgical approaches can provide predictable aesthetic outcomes, there remains interest in minimally invasive treatment options for appropriately selected patients. This preliminary case series evaluated the feasibility, short-term tolerability, and clinical outcomes of high-intensity focused ultrasound (HIFU) for the treatment of IOF protrusion. Three Korean patients (two female and one male; mean age, 48 years) underwent HIFU treatment using LinearZ device at focal depths of 4.5 and 9.0 mm following pre-treatment ultrasonography. Each treatment session delivered 0.6 J per shot in DOT mode under local anesthesia. Clinical photographs, patient satisfaction, and Global Aesthetic Improvement Scale (GAIS) scores were assessed three months after the final treatment session. All three patients showed clinically observable improvement in infraorbital bulging and lid-cheek contour, with high patient satisfaction. GAIS scores were 4, 5, and 4, respectively. Treatment was well tolerated, with transient erythema and edema reported and no major adverse events observed during follow-up. Given the very small sample size, absence of a control group, subjective and non-blinded outcome assessment, lack of systematic post-treatment imaging or quantitative fat measurements, and short follow-up, these findings should be considered preliminary and hypothesis-generating. Larger controlled studies incorporating objective outcome measures are warranted to establish efficacy, durability, and optimal treatment parameters of HIFU for IOF protrusion.