The periorbital complex typically shows signs of aging in the mid-30s with skin color and consistency changes. A quantitative analysis of periorbital aging with 3-D surface imaging reveals a paradoxical finding that total eyebrow volume remains constant with age but there is a change in the relative ratio of fat to muscle content. There is a decrease in the soft tissue/muscle volume but an increase in the fat content as revealed in 3-D reconstruction analysis using CT scans of the face. In the younger individual, the major component of eyebrow volume is soft tissue and muscle, with only 18% of the volume consisting of fat. In the more mature patient, there is a significant increase in the galeal fat pad (including the ROOF), which now represents 81% of brow volume.
There is a predictable resorption of facial bone with aging that includes expansion of the superomedial and inferolateral aspects of the orbital rim. This increase in orbital volume coupled with a relative decrease in intraorbital fat leads to a shift in the peak of the upper lid from medial to lateral, and the formation of an A-frame or infrabrow hollow in Caucasians, and a pan-upper eyelid volume loss in people of color. Associated aging skin changes and actinic damage (lines/creases/dyschromias/atrophy), volume loss at the soft tissue/muscle layer and bony remodeling create the appearance of progressive deflation of the entire region. The eyebrow loses its fullness, appears flattened and lacks contour, making the supraorbital rim appear more prominent. The frontal bone is progressively remodeling with age, and shows increased curvature of the upper forehead with flattening of the lower forehead and glabella in the mature individual. The loss of structure and support is evidenced by head of eyebrow deflation, which contributes to dermatochalasia of the infrabrow medial canthal region.
Aging therefore results in a change in location and contour of the eyebrow. Whereas gradual descent of the eyebrow with intendant dermatochalsia has been thought to be the exclusive pattern, it has become apparent that eyebrows can actually go up with age due to the interplay of frontalis muscle static dominance and bony orbital expansion. The deteriorated tissue of the region is more susceptible to the vectors of pull of the underlying muscles (dynamic discord), resulting in the variable positions of the entire eyebrow as seen in the elderly.
If the eyes are commonly referred to as the windows of the soul, then the eyebrow is the frame of humanity, emotion, personality, and empathy. With prolonged habit plus genetics, the frowning negative expressions of the stress of life become present even at rest, but more obvious with animation, giving the angry – worried – upset – annoyed – stressed appearance that often has very little to do with the actual demeanor of the patient. For over 25 years, neuromodulators have been used to obliterate glabellar lines in an attempt to soften the patient’s severe look. In the early years of neuromodulators, most aesthetic injectors did not taken advantage of the anatomical studies of the glabellar complex and the variable contribution of these muscles to the position of the medial head of the brow – the aim was to eliminate the frown zones with no attention to what the eyebrows were doing or what they looked like after treatment. The “Spock brow” became the new norm. In the late 1990’s, injection specialists began elevating the eyebrows with neuromodulators to create what was called the “Botox® Brow Lift” by relaxing the eyebrow depressors so the static contribution of the frontalis muscle to eyebrow position was dominant. Starting in 2003, the authors began “shaping” the eyebrows with precise injections of BoNT and then adding HA fillers to underpin and help shape the brows, incorporating cannulas in 2010 and by design – by choice – re-creating the peak of the feminine eyebrow pre-determined by the Golden Mean phi calipers.
With ageing, exposure to both ultraviolet and infrared radiation, habitual smoking, and contact with pollution result in the facial skin deteriorating at a faster rate than the diminishing strength of the underlying mimetic muscles. The repetitive movements of blinking, squinting and facial expressions further compound the facial envelope’s waning structure leading to both a static and dynamic discord of eyebrow position and movement. As for other areas of the face, the artistic use of filler and neuromodulator can restore the proportion, harmony and balance of youth to the eyebrow region. Feminizing the eyebrow in the female patient is one of the more rewarding restoration projects, both for the syringe therapist and the patient. This is usually a serendipitous experience for patients as they are often unaware of the gradual negative changes in eyebrow position and shape. Even in those faces that have won the genetic DNA lottery, eyebrow shaping further enhances facial harmony, balance and proportion. No longer the focus of isolated toxin therapy, non-surgical eyebrow shaping can best be accomplished by the synergy of neuromodulator and filler.