By Michael T. Yen, MD
This study reports on the use of hyaluronic acid for orbital volume enhancement in both sighted orbits and anophthalmic orbits in five patients who had enophthalmic appearance. The study's author, who performed all of the procedures, injected Restylane Sub-Q (Q-Med, Uppsala, Sweden), which is longer lasting and thicker than other nonanimal stabilized hyaluronic acid (NASHA) products, into the patients' orbits. Good correction of orbital volume was achieved, with enophthalmos reduction measured at 2 mm per 2-mL injection following initial treatment in all patients. The magnitude of the effects of repeated injections was smaller.
Complications due to the injections occurred in two patients and included discomfort and vasovagal symptoms. In subsequent patients, a peribulbar injection of a local anesthetic was administered before the hyaluronic acid injection to minimize potential oculocardiac reflex symptoms. In one patient, hyaluronic gel migrated into the lower eyelid postoperatively, necessitating treatment with hyaluronidase to eliminate the migrated gel. Reduction of enophthalmos was approximately 50% of the initial reduction eight to 12 months following hyaluronic acid treatment.
Treatment of enophthalmos and especially the anophthalmic socket can be very challenging. Traditionally, placement of an orbital implant has been the only technique available to provide additional orbital volume augmentation. This is an extensive surgical procedure, usually requiring general anesthesia and a large incision to accommodate the relatively hefty size of the implant. The advantages of being able to inject material into the orbit for volume enhancement are that the procedure is minimally invasive and usually performed in the office.
In the past, glass beads, hydrogel pellets, hydroxyapatite granules, and other materials have been injected into the orbit. However, postinjection migration and extrusion have remained concerns. The use of hyaluronic acid is of significant interest since it is a well-tolerated naturally occurring material that causes minimal complications, even when postinjection migration occurs. In cases where migration is undesirable, the migrated hyaluronic acid can be removed through hyaluronidase injections.
Restylane Sub-Q is not currently available in the United States, and there are no plans to introduce it. However, Restylane and Perlane (also NASHAs made by Q-Med) are similar products that are currently available in the United States. These products are not quite as thick as Sub-Q. Therefore, if they are used to augment orbital volume, they may not provide the same level of longevity reported with Sub-Q in this study. Nonetheless, hyaluronic acid should be considered for short to medium duration orbital volume enhancement in sighted and anophthalmic sockets.