3D Speckle tracking photogrammetry that measures the strain placed on facial soft tissues during movements may help researchers better understand how the face ages.
The new findings appear in Plastic and Reconstructive Surgery—Global Open.
“The technology of three-dimensional optical imaging can be used to advance our understanding of facial soft-tissue dynamics and the effects of animation on facial strain over time,” the study authors write.
To arrive at their findings, researchers sprayed a “speckle” pattern onto 13 subjects’ faces. After a digital image was made in a “neutral” facial expression, the study participants were photographed making different facial expressions, such as smiling, laughing, and grimacing; surprised and angry expressions; and whistling (pursed lips).
The Heat Is On
Using the speckle pattern, the imaging system software was able to demonstrate and quantify the strain on facial soft tissues caused by these facial movements.
The 3D imaging technique—used by engineers to measure strain on various materials—has recently been applied to measuring the mechanical properties of biological organs and tissues. The system generates a “heat map” color scale, with red indicating the area of greatest strain and blue showing areas of lesser strain.
For all six expressions, the heat map showed the areas of greatest strain were located in the midface and lower face. For subjects older than 40, strain was greater in the perioral region: about 58%, compared to 34% for those younger than 40.
The age-related increase in strain with lip-pursing was even greater in the nasolabial folds. Older subjects also showed greater asymmetry of strain in the nasolabial fold, the researchers report.
Overall stretch in the lower face during lip-pursing was greater in women than men. For smiling and other facial expressions, measurements of strain were similar for older and younger subjects.
The pilot study confirms that movement of the perioral tissues is an important contributor to facial aging.
“We hope these data will serve as a first step for improving our ability to understand and develop more effective treatments for the lower face and beyond,” study authors write. The new soft tissue strain analysis could also have “broad and functional implications” for various types of reconstructive surgery procedures, such as abdominal wall reconstruction, facial reanimation surgery, and facial reconstruction after trauma.
