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Discussion: quantitative evaluation of volume augmentation in the tear trough with a hyaluronic acid-based filler: a three-dimensional analysis.

T is no part of the face that conveys as much negative perceptual information in such a small area as the tear trough. Its presence can make one appear tired, dissipated, haggard, unhealthy, and worse. The tear trough is usually described as the medial part of the hollow between the lower lid and cheek. It may extend down the face as the nasojugal crease and also continue laterally, where it circles the lower lid, rising to the level of the bony orbital rim by the lateral canthus. This latter border is inconsistently named but is sometimes called the orbitcheek, or orbitomalar crease. As a depression that separates the lid from the cheek, it also fares well with injection, although that was not studied here. A few sets of factors create the tear trough: one is the difference in skin texture, thickness, and color present where the thin lid skin joins the thicker cheek. Sometimes, this light-dark, textural border alone appears like a tear trough but without an indentation that can be filled. Injections do not improve this group. Another factor is the shadow formed by the indentation of the tear trough itself and the overlying expansion of lower lid fat. This latter group will be improved by injecting the hollow, filling the indentation, and leveling the lid-cheek junction. Patients need to be told that color and texture differences will persist. As the tear tough and orbitomalar crease become more prominent with age, they appear to descend; however, longitudinal observation of faces shows that they are remarkably constant in position.1 Because hyaluronic fillers are mainly (and unimaginatively) used in the lips and nasolabial folds, clinicians have assumed that the duration of the products in these locations is a constant defined by their chemistry. Experience across the face shows that duration of hyaluronic products varies widely, depending on their site of placement.2,3 Although in the lips and nasolabial folds, duration varies from months to 1 year, visible effects of up to 3 years in the tear trough, temples, brow, and nasal tip have been documented. It seems reasonable to ascribe this difference in longevity to animation and motion; at least there is an association. We have not seen duration past 3 years, which may represent the biological longevity of this particular product. This study, though conducted with a small number of patients, corroborates these findings numerically, with use of the three-dimensional camera. These are remarkable instruments, here showing resolution of a few tenths of a cubic centimeter of volume difference in the face over time. The authors demonstrate the slow decay rate and persistence of product, in this case Restylane (Medicis Aesthetics, Scottsdale, Ariz.), to the end of the study period, along with continued clinical improvement. They make a number of other pertinent observations that will be familiar to clinicians performing injections in this area. I find that injecting product onto the periosteum is probably the technique of choice, at least in the medial tear trough. Duration and effect of volume with hyaluronic acids seem to be less lasting in men. It would be interesting to see what the three-dimensional camera shows in this population. Everyone who deals with the face and perceptions of it knows that patients forget how they used to appear, sometimes with shocking rapidity, leading some to think the effect has worn off before it actually has. As the authors observe, photographing the tear trough is sometimes difficult. By moving remote lights around or by bouncing the light of an on-camera flash from