INTRODUCTION
For dermatologists, periocular “dark circles†fall among the most difficult complaints to address. In most cases, we have little information regarding etiology and no gold-standard treatment option. For patients, periocular hyperpigmentation can be stigmatizing, portraying a tired, stressed, aged, or hungover appearance. The extent of the problem is reflected in the sheer number of products advertised to either lighten or cover the pigmentation. A search for “dark circles†on Amazon.com identified 302 products, while Sephora.com had 141, and Bizrate.com had more than 500. The upper limit of the price range was $520 for a 4-oz topical (Table 1). On YouTube.com, there are 120,000 videos devoted to the subject. A recent article in the New York Times reported that sales of products designed to get rid of dark circles was in excess of $1 billion in 2006.1 Given the extent of public interest and paucity of information, the goal of this article is to present dermatologists with a complete review of the literature with regard to anatomy, definition, etiology, and treatment of periocular hyperpigmentation.
Anatomy
Evaluation and treatment of “dark circles†requires a thorough understanding of periocular anatomy, especially with respect to the tear trough, also known as the nasojugal groove, a natural depression that extends inferolaterally from the medial canthus to the midpupillary line. In most individuals, it is no longer than 3 cm. The continuation of the tear trough is the lid–cheek junction, also known as the palpebromalar groove, which begins at the midpupillary line and runs parallel to the orbital rim.2,3
In a study of cadaveric lower lid and midface dissections, it was demonstrated that the tear trough and lid–cheek junction correspond to the junction between the palpebral and orbital portions of the orbicularis oculi muscle. The skin overlying the palpebral orbicularis (lower eyelid skin) was thin and had no subcutaneous fat, while the skin over the orbital orbicularis (cheek skin) was thicker and was separated from the underlying muscle by the malar fat pad.2
Definition
Thinning of the skin, atrophy of malar fat with age, and enlargement of the orbital bony space result in an increasingly hyperpigmented concavity at the medial border of the eyelid and cheek known as the tear trough deformity. Clinically, the severity of the tear trough deformity can be categorized into 3 classes based on the length of the defect. In class I patients, the hollowing is limited to the medial one-third of the orbit. Class II patients have a defect that extends to the midpupillary line, while class III patients have a full depression that continues circumferentially along the orbital rim. Severity of the tear trough deformity parallels malar fat atrophy. Therefore, as the midface becomes flatter, dark circles appear more prominent.3
Causes
Various causes can lead to the appearance of dark circles around the eyes, including postinflammatory hyperpigmentation secondary to atopic dermatitis or allergic contact dermatitis, periorbital edema, increases melanin and hemosiderin deposition, increased visibility of blood vessels, and aging with increased skin laxity (Table 2).
Postinflammatory Hyperpigmentation
Atopic dermatitis and allergic contact dermatitis are frequent causes of chronic rubbing around the eyes. Chronic rubbing will
