Ultrasound observational anatomical guideline for retrobulbar hyaluronidase injection

The growing use of injectable cosmetic fillers has been accompanied by an increase in reports of acute vision loss, typically caused by inadvertent intravascular injection and subsequent embolization of the ophthalmic artery, resulting in ocular ischemia. Effective management of this complication remains challenging, as clear clinical guidelines for retrobulbar hyaluronidase injection are lacking. This ultrasound-based observational anatomical guideline provides practical recommendations for retrobulbar administration of hyaluronidase. Real-time ultrasonography allows for direct visualisation of orbital anatomy, enabling the injector to identify the optic nerve sheath complex and surrounding vascular structures. The central retinal artery's entry point into the optic canal is a key anatomical landmark for directing treatment. Based on ultrasound observations, the inferolateral quadrant of the orbit is identified as the safest and most accessible entry site, reducing the risk of damage to extraocular muscles, cranial nerves, and major vessels. The use of ultrasonography enhances both precision and safety, supporting timely and effective management of filler-related ocular complications. Ultrasound observation further confirms that the inferolateral orbital approach offers the most reliable and safe access for retrobulbar hyaluronidase injection. The superior orbital rim and close proximity of the globe restrict needle trajectory from above, increasing the risk of ocular injury. In contrast, the inferior approach provides a wider anatomical corridor, reduces the likelihood of direct contact with the eyeball, and allows safer navigation around critical neurovascular structures. Incorporating real-time ultrasound enhances precision, making the inferior approach the preferred route for managing filler-related ocular complications.