The infraorbital hollow (IOH) refers to the curvilinear or U-shaped depression under the eyes from the nasal bone to the outer corner of the eye and comprises three core elements: the ‘tear trough’ and nasojugal fold medially, and the palpebromalar groove laterally (Fig. 16.1). Although the terms ‘tear trough’ and ‘nasojugal fold’ have historically been used interchangeably, the former – which occurs mildly in all people across all ages – refers to the superior aspect of the latter. A sign of early aging, the deepening of the tear trough leads to a true indentation at the junction of the thin eyelid skin above and thicker skin of the cheek below. Later, the mid-cheek may descend, accentuating a flat or hollow crescent below the eye. The appearance of hollows and dark circles under the eye is the interplay of various factors. Genetics and habits / environmental exposures lead to dyschromias and pigmentation; soft tissue laxity, subcutaneous volume alterations, changes in bony landmarks, and redistribution of superficial fat all lead to shadowed contours and deepening folds. Periorbital volumetric shifting and loss is not an isolated event but part of a global shift in the contours of the aging face.

Figure 16.1 Anatomy of the infraorbital hollow.

There is little to no superficial fat under the lower eyelid. The orbicularis oculi muscle has direct bony attachment for approximately one-third of the orbital rim length, from the nasal bone to the medial limbus. Laterally, orbicularis-retaining ligaments connect the deep surface of the skin to bone. Retaining ligaments weaken, facial bones recede, and volume decreases in the deep fat pads, causing the cheek to descend and superficial fat to accumulate under the eye, all of which combine with genetically predisposed discolorations and bony changes to produce the perception of hollowed and sometimes baggy eyes, deep and shadowed tear troughs, and an aged, fatigued appearance refractory to cosmetic attempts at concealment (Fig. 16.1).

Treatment of the periorbital area with injectable agents allows little room for error and requires careful patient selection, careful choice of filling agent, and precise technique to avoid complications and ensure optimal outcome.

Candidates for augmentation of the infraorbital hollow

Proper patient selection is critical and relies on careful ophthalmologic and medical history and physical assessment. Poor candidates are unlikely to obtain optimal results and may not be satisfied with results and are at higher risk of side effects, such as visibility and irregularity (Table 16.1). Patients with diseases or metabolic conditions that predispose to lower eyelid irregularity or bleeding and infection should be excluded, and all manner of anticoagulant medications and supplements discontinued if medically safe for at least 2 weeks prior to treatment. Some patients have genetically determined pigmentation that may look like a tear trough but without an indentation that can be filled. Pigmented dark lower eyelid circles cannot be improved by fillers and can, in fact, be worsened by treatment. Older patients with thinner, crepe-like, inelastic skin and individuals with pre-existing malar edema – whether metabolic (thyroid disease) or otherwise (i.e. chronic sinus disease, prior surgery, etc.) – may not respond well and also have an increased risk for adverse events and dissatisfaction with these treatments. Patients with orbital fat herniation and significant skin laxity would benefit first from lower lid blepharoplasty or other surgical procedures. Injection works best in patients with thicker and smooth skin and a well-defined tear trough or defined maxillary retrusion / hypoplasia (common in young Asian females), without excessively protruding eyelid fat or excess eyelid skin.

Table 16.1 Identifying candidates for augmentation of the infraorbital hollow

Best candidates	Poor candidates
Young patients with good skin elasticity	Elderly patients with poor skin elasticity
Thick smooth skin	Very thin skin
Good skin tone	Transparent or dyspigmented skin
Minimal laxity	Significant skin laxity
Mild-to-moderate tear troughs	Extremely deep tear troughs

Appropriate filling agents

Thin skin directly overlying bone, allowing any irregularity to be readily visible, propensity for discoloration, and vascularity make the IOH a challenging area to fill. The ideal filler is one with a low extrusion force or density to allow precise and delicate injection through lower gauged needles, and one that is reversible or, at the very least, biodegradable. Because there is a tendency for anything injected into this area to form visible lumps, particularly on animation, permanent fillers should be considered only with great caution.

The use of autologous fat had gained popularity in recent years (also) as a replacement for surgery for the correction of contour defects and has been used for augmentation of the IOH, but results have been generally unpredictable and often associated with considerable side effects such as lumpiness, long-lasting irregularities, volume distortion, and prolonged edema, as well as risks associated with any surgical procedure. More recently, hyaluronic acid (HA) – with its gel consistency, varying concentrations and the possibility of dilution with lidocaine or saline, favorable flow characteristics, fewer side effects, and non-permanence – has emerged as the treatment of choice for augmentation of the lower periorbita by injection. Lumps or irregularities can be avoided with careful and precise injection techniques and can also be reversed through treatment with hyaluronidase, an important consideration when injecting in delicate areas requiring precise placement of filling agent. Surprisingly, HA in the periorbital region yields better than expected longevity. Lambros (and others) have described the persistence of effect, often in excess of 1 year (see Ch. 15). Donath and colleagues used three-dimensional imaging in 20 patients treated in the tear trough with HA and found an average 85% maintenance of effect at the final follow-up visit (average 14.4 months); the patient with the longest duration retained 73% volume augmentation at 23 months without any touch-ups. Side effects with HA can include visibility and nodules, a bluish tint (from the presumed Tyndall effect), along with injection-related bruising and swelling (see Complications).

Calcium hydroxylapatite (CaHA) has yielded positive outcomes in other areas of the face, and Hevia has detailed successful outcomes in the infraorbital region using CaHA diluted by 10–30% with 2% lidocaine. However, CaHA has a history of palpable (and sometimes visible) nodules, particularly in the lips, and Goldman has reported a case of superficial nodularity after injection of CaHA in the IOH. Its major drawback remains the lack of reversibility; despite its biodegradable nature, there is little to do but wait out the occurrence of adverse effects.

Augmentation techniques

Techniques for augmentation under the eye vary. Replacing periorbital volume entails not only focusing on specific regions in the IOH requiring augmentation – the tear trough, the central and lateral aspect of the orbital rim, the palpebromalar groove – but other areas that influence the appearance of the lower eye. A deflated medial cheek, for example, will look unnatural without concurrent augmentation, particularly on animation. In fact, correction of the cheek will often improve the appearance of the IOH, necessitating smaller amounts of filling agent to achieve optimal results. Ideally, periorbital volume augmentation should be performed in conjunction with rejuvenation of the mid-face and sometimes to the entire face to preserve harmony and restore aesthetic proportion.

Skin preparation, anesthetic, and syringes

Patients are treated sitting in an upright position. Photographs should be taken with controlled lighting, which can illuminate rather than disguise the appearance of rhytides, tear trough deformity, and lower lid fat prolapse. After all makeup has been removed and skin thoroughly cleaned with alcohol, the patient is asked to look upward to accentuate and delineate the borders of the tear trough, and all areas of injection can be marked using a fine-tipped marker, including adjacent areas requiring augmentation (Fig. 16.2).

Figure 16.2 Patient (A) before and (B) after treatment.

The choice of anesthetic will depend on the area to be treated, needle size, number of injection sites, and patient tolerance. Usually a combination of topical anesthetic (or ice), the use of HA agents containing lidocaine, or dilution of filling agent with lidocaine with epinephrine provides adequate pain relief. Direct infiltration of local anesthetic can be used to numb the malar area and lateral orbit; infraorbital nerve block is administered with a small volume of 0.5–0.1% lidocaine with epinephrine. Only minimal volumes of the anesthetic solution are used so that the volume status of the mid-face and tear trough is not distorted. Sometimes topical anesthetic cream or gel applied to the area to be treated and left in place a minimum of 20 minutes may be all that is necessary for pain relief.

Type and size of syringe in the IOH range from a 30-gauge blunt-tipped cannula to 27- to 32-gauge needles, depending on injector preference, treatment area, and technique used. Blunt cannulas may eliminate the risk of inadvertent intravascular injection; however, some injectors believe needles allow more precise placement of filler material in the periorbital region and these adverse events can almost always be avoided with careful injection technique.

General techniques

With thin skin overlying bone and little to no subcutaneous fat, the IOH is an unforgiving region and challenging to treat. Injections often produce discoloration or bruising, and any irregularity is readily visible. Anatomical areas of concern include the prominent infratrochlear vessels adjacent to the nasal bone, and the infraorbital nerve, more often located approximately 14 mm below the bony orbital margin in the mid-pupillary line.

Pearl 1

Anatomical areas of concern in the infraorbital hollow include the infratrochlear vessels and infraorbital nerve.

Small amounts of filler – generally no more than 1 mL in total for both sides – under low pressure will avoid complications such as a ‘sausage roll’ appearance under the eye and retrograde embolus into the periorbital vasculature as the filler inadvertently slips behind the orbital septum. If 0.2–0.4 mL of HA does not lead to a noticeable improvement, it is possible – or even likely – the filler has been misplaced. The attempt here is to place a confluent deposit of filler material along the orbital rim, beneath the apparent ‘hollow’ without complete volume filling of the agent and allowing the additional physical properties of these filling agents (including hydrophilicity) to augment the overlying soft tissues to reduce the appearance of the ‘trough’.

Injections are deep in the suborbicularis plane at or below the orbital rim at the supraperiosteal level except in the medial aspect of the orbicularis oculi, which attaches to bone and requires direct injection. Superficial injections in the periorbital region increase the risk of visibility and skin discoloration secondary to the Tyndall effect (see Complications), although some researchers (such as Hirmand) have described the occasional need for very superficial subdermal injection using a 32-gauge needle for spot application over a 1–2 mm surface area to ‘lift’ the overlying skin.

Use of the smallest possible gauge but longer needles (i.e. a 1-inch [12 mm] 30-gauge needle) and reducing the number of injection sites can minimize post-injection bruising caused by trauma to blood vessels as the needle passes through the skin and the underlying orbicularis oculi muscle. When using multiple passes and layered techniques, it is best to withdraw the needle just enough to reposition it without exiting back through the muscle.

Augmentation of the infraorbital hollow

Linear threading (the fanning technique) (Fig. 16.3) and serial puncture (Fig. 16.4) are the most commonly used techniques in the IOH. Goldberg & Fiaschetti describe deep injection using multiple needle passes to layer and feather the filler in a three-dimensional pattern in the IOH and cheek. Morley & Malhotra used the serial puncture technique with three to eight injections along the inferior IOH, depositing small aliquots of filling agent. Hirsch and colleagues detail the use of 1-inch needles and two or three injection sites just above the periosteum to augment the lateral to medial IOH, using the push-ahead technique, in which the submuscular layer is dissected by the forward movement of the filling agent rather than the tip of the needle. Small aliquots of 0.1–0.2 mL are deposited along the length of the groove, using digital manipulation instead of frank injection in the medial portion to avoid inadvertent injection of the infratrochlear vessels and infraorbital nerve. Hirmand describes a similar technique of discontinuous deposition using a blunt cannula, three to five injections of 0.01–0.5 mL deep in the supraperiosteal plane in the medial aspect of the tear trough, with gentle digital massage to disperse the filler into the intended location. The vertical supraperiosteal depot technique, pioneered by Sattler (see Ch. 25), involves the vertical deposition of small aliquots of filling agent (0.02–0.5 mL) at the supraperiosteal level using a 90° angle, with injections placed 2–3 mm apart.