Treatment of infraorbital/upper and lower eyelids with neuromodulators

Introduction

The appearance of the periorbital region marks the cornerstone of facial attractiveness, an important factor in social and interpersonal interactions. As a “window to the soul,” the eyes can express a variety of emotions and are one of the most compelling facial features.

The use of botulinum toxin (BoNT) in the periocular area has a long history. In fact, the toxin’s cosmetic benefits were first noted in patients treated for strabismus and blepharospasm. It has since been used therapeutically in the eyelid for the treatment of numerous other blepharospastic conditions and systemic diseases affecting the periorbital area, such as facial palsies and lid retraction in thyroid ophthalmopathy. Since then, BoNT has become an important part of the armamentarium for the cosmetic or functional improvement of the periorbital area, alone or in combination with other rejuvenating modalities.

The upper and lower lids contain the thinnest skin of the human body. They also provide functional musculature that is essential for eye protection. As such, BoNT treatment of the periorbital region requires an in-depth understanding of anatomy and the aging process. Appropriate patient selection and careful attention to individualized treatment will further optimize outcomes.

Anatomy of the eye

Complete knowledge of dynamic and age-related volumetric changes in the face is essential for BoNT injectors treating the periorbital region. A further understanding of the function and interaction between various facial muscle groups and the surrounding soft tissue is critical to ensuring successful outcomes. Although global facial anatomy should always be considered in any cosmetic treatment, this chapter will focus solely on the anatomy of the eye relevant to the use of BoNT in the upper and lower eyelids ( Fig. 19.1 ).

The upper periorbital region extends from the eyelid margin to the eyebrow superiorly, with the superior palpebral sulcus (associated with the upper eyelid skin crease) located lengthwise between the medial canthus and the lateral orbital rim. Its location is approximately 7 to 12 mm superior to the eyelid margin and is dependent on ethnic, gender and familial influences. The lower periorbital region extends from the lower eyelid margin to below the inferior orbital rim to join the cheek. In youth, the inferior palpebral sulcus (lower eyelid fold) is located 3 to 5 mm from the lower lid margin.

The orbicularis oculi is the sphincter-like muscle that encompasses the entire periorbital region, extending from above the eyebrow and superior orbital rim, down to the lower cheek inferiorly, through the medial canthus and nasal bridge medially, and beyond the lateral orbital rim, laterally. The function of the orbicularis muscle complex varies depending on the particular segment in question and its denervation. It is a wide, concentric band of muscle comprising the palpebral component, which can be further divided into regional segments of the upper and lower eyelids, and into pretarsal and preseptal portions. The orbicularis oculi is responsible for blinking, gentle eyelid closure, the position of the orbital component, and overall eyelid tone. It is also responsible for forceful lid closure and the production of lateral canthal and lower eyelid rhytids.

Superiorly, the orbicularis oculi interdigitate with other superficial muscles of facial expression, including the frontalis, corrugator, and depressor supercilii muscles. Laterally, it is proximal to the overlying fascia of the temporalis muscles and the muscles of the inferior quadratus labii superioris and zygomaticus complex. Inferiorly, the orbicularis oculi lies flat across the cheek and is considered a part of the superficial musculoaponeurotic system (SMAS), which translates muscle movement into movement of the skin. At the junction of the lower lid with the cheek, the orbicularis oculi muscle forms a direct attachment with the orbital rim at the junction of the palpebral and orbital portions.

Periorbital aging

Aging in the face is most prominent in the midfacial and periorbital regions due to both dynamic and volumetric changes. Bony changes and atrophy of subcutaneous soft tissues lead to a loss of cutaneous support whereby muscles become lax due to reduced support from retaining ligaments. Skin that was once relatively thick, smooth, and youthful becomes thin, rough, and dry with irregular pigmentation and uneven texture. As the skin repositions itself over the changing landscape of the face, wrinkles and fine lines become more static and therefore more prominent. Moreover, youthful soft tissue turgor that once resisted muscular activity is now victim to muscle dominance, leading to a multitude of periorbital changes.

The eyelid skin itself is vulnerable to age-related changes as it is the thinnest skin on the body (<1 mm) and has sparse or nonexistent underlying subcutaneous fat. Over time, the delicate lids are prone to further thinning and stretching by too-vigorous rubbing (habits) or procedures (surgery or fillers) to rejuvenate the area. The lower lid is further subject to fat redistribution, laxity, and weakening of the connective tissue. The normally smooth transition from lower lid to cheek becomes more prominent, with puffiness, dark circles, or dermatochalasis under the eye. Orbital laxity, atrophy, and pseudoherniation give the impression of a sunken eye, and radial wrinkles appear on the lateral aspect of the orbit.

Patient assessment and selection

Successful use of BoNT in the periorbital region demands close attention to anatomic variation and individual goals. A comprehensive assessment of every patient is thus mandatory and must include a thorough medical and cosmetic history, including an ophthalmic history of prior rejuvenation procedures, surgeries, or other ocular conditions that might influence treatment plans, such as dry eye symptoms.

Communication between patient and clinician builds trust and ensures that expectations are not exceeded by realistic outcomes. A pre-treatment consultation should therefore address the transient nature of BoNT injections, the need for frequent touch-ups, common injection-related side effects, and potential complications. Informed consent is essential.

The degree of rhytids in a patient and their potential response to treatment can be assessed via the Glogau photoaging scale ( Table 19.1 ). Skin quality and generalized muscle and ligamentous tone around the eye will also guide treatment. For instance, patients with excessive skin above the eye, prominent fat pads in the lower lid, septal fat herniation, or severe ligamentous laxity and elastosis (identified by a positive snap test), may require additional rejuvenating procedures, such as laser, light-based therapies, or even surgery. All findings, including any sign of ptosis or asymmetry, should be noted and discussed with the patient. Standard digital photographs should be taken both before and after any treatments. Photographs should display the face in repose and at maximal expression to document changes in animation.

Contraindications

Not everyone is a candidate for BoNT therapy in the periorbital region. Aside from general contraindications ( Box 19.1 ), preexisting conditions that could be worsened with BoNT include midfacial paresis, symptomatic dry eyes, stable or progressive muscular dystrophic conditions causing blepharoptosis, and already compromised function of the orbicularis oculi. Caution should prevail in patients with a history of, or complications related to, previous lower eyelid blepharoplasty. BoNT injections should be avoided or dose adjusted in those with significant dry eye syndrome or lower eyelid laxity due to the risk of scleral show.

Indications and techniques

Consensus recommendations have been developed for BoNT dosing and techniques in all areas of the face. However, treatment must be individualized according to each patient’s muscle size, function, and desired outcome.

BoNT reconstituted with preserved saline has been shown to be less painful than reconstitution with nonpreserved saline. Consensus guidelines report a range of dilutions (1 to 4 mL/vial) that rely on the area to be injected and clinician preference. Similarly, the choice of syringe and needle depends on the injector. The authors use a 4 U/0.1 mL dilution or a 2 U/0.1 mL dilution in a single-use 1-cc insulin syringe with a 30- to 32-gauge needle for injections in the periorbital area. Most important, however, is not the exact dilution, but rather the precision of placement and understanding of volumes required to deliver such precise dosing.

In the upper and lower lid, exact placement of injections and conservative doses are crucial for avoiding complications. Topical anesthesia applied for 15 to 20 minutes or use of ice packs prior to treatment of the lower lid can reduce injection-related pain. When treating the lower lid, the needle should be held tangentially to the globe, with the nondominant hand stabilizing the patient’s head ( Video 19.1 ). This will prevent inadvertent or sudden head movement that could lead to direct injury of the eye.