The tear trough is the groove extending from the inner corner of the eye, running diagonally downward toward the cheek. This depression separates the thin skin of the lower eyelid from the thicker skin of the upper cheek. A tear trough deformity is a common aesthetic concern, often making a person look perpetually tired or older. This feature results from a complex interplay of inherited facial structure and progressive changes that occur over time.
Understanding the Anatomy of the Tear Trough
The visible tear trough is a shadow created by a change in elevation between different facial fat pads. The underlying bony structure, the orbital rim, provides the foundation for this region. A dense fibrous connection, often called the tear trough ligament, anchors the skin and muscle directly to the bone along the orbital rim.
This ligament creates a fixed boundary, acting like a tether that holds the tissue in place. Above this tether lies the lower eyelid fat; below the ligament is the fat of the upper cheek (malar fat pad). The depression of the tear trough is the visible surface manifestation of this ligamentous attachment point.
The orbital septum is a thin membrane that keeps the orbital fat contained within the eye socket. When orbital fat pushes forward, creating “eye bags,” the tear trough ligament emphasizes the indentation below this bulge. The contrast between the protruding lower eyelid fat and the sunken area at the ligament creates a sharp, shadowed transition.
Inherent Causes: Genetics and Bone Structure
The most stable causes of a prominent tear trough are determined by genetics, which dictate the fundamental structure of the face. Some individuals are born with an inherited facial bone structure that predisposes them to this feature, often noticing it in their teens or early twenties.
A primary structural cause is midface hypoplasia, describing a naturally flatter or recessed bony midface, particularly the cheekbones and the infraorbital rim. When the bony rim supporting the overlying soft tissue is less prominent, it immediately creates a deeper concavity below the eye. This lack of projection exaggerates the shadow effect of the tear trough, regardless of age.
The specific shape and projection of the orbital rim influence where the tear trough ligament attaches. A bony orbit positioned further back, sometimes called a negative vector orbit, provides less support for the soft tissue of the lower eyelid. This anatomical variation makes the ligament’s tethering effect more obvious, resulting in a deeper indentation.
Heredity also plays a role in the thickness of the skin and fat distribution in the lower eyelid area. People with genetically thinner skin under the eyes will have a more visible tear trough because underlying structures, like the orbicularis muscle and blood vessels, are more apparent. This combination contributes to a shadowed appearance that is present even after adequate rest.
Acquired Causes: Volume Loss and Skin Changes
While some tear troughs are present from youth, the majority become significantly more pronounced over time due to progressive changes associated with aging. A significant factor is the loss and downward migration of fat. The superficial cheek fat pads, which once provided a smooth transition between the eyelid and the cheek, begin to shrink and descend due to gravity and volume atrophy.
This loss of volume in the mid-cheek region accentuates the fixed boundary created by the tear trough ligament. As the supportive tissue below the ligament decreases, the attachment point becomes a sharper, deeper valley. Bone remodeling around the eye socket also contributes, as the infraorbital rim gradually recedes and loses density, reducing structural support for the overlying soft tissues.
The tear trough ligament itself may become looser over time, a process known as ligament laxity, which allows tissue to shift and settle, deepening the depression. The skin of the lower eyelid progressively loses elasticity and thickness due to reduced collagen and elastin production. This dermal thinning makes underlying blood vessels and muscle more visible, intensifying the dark, shadowed appearance of the trough.
External Factors That Worsen Appearance
Certain lifestyle and environmental factors do not cause the tear trough but significantly worsen its visual prominence. Chronic sleep deprivation, for instance, leads to vascular congestion, causing blood vessels under the already thin skin to dilate. This increased blood flow makes the area appear darker, exaggerating the shadow cast by the structural hollowing.
Dehydration and a poor diet can negatively affect overall skin volume. When the body lacks sufficient hydration, the skin appears less plump, which can make the bony contours and the tear trough hollow look more sunken. Sun damage is another major contributor, as ultraviolet radiation accelerates the breakdown of collagen and elastin, thinning the delicate lower eyelid skin.
Inflammation caused by allergies or illness also exacerbates the appearance of the trough. Allergic reactions can lead to fluid retention and swelling (edema) in the periorbital tissues. This puffiness pushes the tissue forward and can make the structural indentation of the tear trough look even deeper in contrast.