Three-Dimensional Photogrammetric Study on Age-Related Facial Characteristics in Korean Females

Racial and sexual differences of eyebrow and eyelid morphology: three-dimensional analysis in young Caucasian and Chinese populations

Background

With globalization, oculoplastic surgeons must understand the intricate morphological nuances of the periocular region across ethnicities to ensure precise treatment and avoid facial disharmony or dysfunction. Direct comparisons in two-dimensional (2D)-based periocular morphology between studies can be challenging due to the limited number of parameters and complicated variations in equipment, environments, measurement personnel, and methods. Therefore, it is imperative to explore the detailed three-dimensional (3D) periocular morphological disparities between young Caucasian and Chinese populations. This study aimed to establish gender- and ethnicity-specific 3D anthropometric data in periocular soft tissue for young Caucasian and Chinese adults and to determine the inter-racial and inter-gender differences.

Methods

This descriptive, cross-sectional study enrolled 46 Asians and 101 Caucasians aged 18 to 30 years. 3D models were analyzed with 32 landmarks, yielding 21 linear distances, three curvatures, six angles, and three proportions. Comparisons were made across left and right eyes, ethnic groups, and sexes to assess ethnic disparities and sexual dimorphism.

Results

Twenty-nine measurements were compared between the left and right sides revealing significant differences (P<0.002) in two measurements for Caucasian and Chinese females, respectively. However, these differences were submillimeter levels and potentially inconsequential in practical settings with left-right differences of -0.58 and -0.57 mm (P<0.001) for double-eyelid fold-palpebral margin distance (medial) (FPDm) and double-eyelid fold-palpebral margin distance (medial limbus) (FLmD) in Chinese females and -0.38 and -0.52 mm (P<0.001) for palpebral fissure width (PFW) and lower palpebral margin length (LPML) in Caucasian females. Caucasian males displayed significantly larger palpebral fissure height (PFH), iris diameter (ID), LPML, lateral canthal angle (LCA), canthal tilt (CT), palpebral fissure index (PFI), and canthal angular index (CAI), as well as smaller inner intercanthal distance (EnD), outer intercanthal distance (ExD), and canthal index (CI) than Chinese males (P<0.05). In contrast, Caucasian females showed significantly larger PFW, ID, LPML, LCA, CT, and CAI, as well as smaller EnD, ExD, CI, and medial canthal angle (MCA) than Chinese females (P<0.05). Furthermore, Caucasians showed more prominent double-eyelid folds, except at the pupil center in females. In eyebrow measurements, Caucasian males exhibited non-significant differences with Chinese males, while Caucasian females had significantly larger measurements at lateral positions but smaller ones at the endocanthion than Chinese females (P<0.05).

Conclusions

This study established sex- and ethnicity-specific 3D anthropometric data for the periocular region of young Caucasian and Chinese adults. These findings must be considered for periocular disease diagnosis, surgical planning, and outcome evaluation across diverse sexual and ethnic populations.

Objective Assessment of Lower Face and Neck During 1 Year After Rhytidectomy in Asian: When Your Patient Asks You About the Surgical Outcomes

BACKGROUND

The first year after surgery is a period of significant change, during which patients are highly concerned and sensitive about the outcomes.

OBJECTIVE

This study aimed to measure objectively the improvements and changes in the lower face and neck over the course of 1 year after rhytidectomy in Asian.

MATERIALS AND METHODS

This study included a total of 50 patients, comprising 100 hemifaces, who underwent extended deep-plane rhytidectomy using a composite flap from January 2017 to December 2022. The patients' antero-posterior and lateral photographs at pre-surgery, between 2 weeks and 1 month, 3 months, 6 months, and 12 months after surgery were analyzed retrospectively.

RESULTS

Measurements for each period and site are revealed a general trend where the most significant decrease occurred between 2 weeks and 1 month after surgery. This was followed by a slight increase at 3 months, with a subsequent decrease observed at 6 and 12 months after surgery.

CONCLUSION

Objective assessment of lower face and neck at each period is considered to be potentially valuable as an evaluation resource for both patients and surgeons.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Facial morphology analysis of Caucasian Brazilian adult women using stereophotogrammetry

This cross-sectional observational study aimed to evaluate and compare facial metrics in women aged 20-65 years using a three-dimensional (3D) stereophotogrammetry system and to establish standardized values for facial metric variations in different age subgroups. This study included 84 Caucasian women divided into two groups based on their age: group 1 (G1) included women aged 20-40 years and group 2 (G2) included women aged 41-65 years. Twenty-one morphometric points on the face were identified, and the facial images were captured using a 3D stereophotogrammetry system, Twenty-three linear measures and 12 angular measures were evaluated, revealing statistically significant differences in 11 linear and 5 angular measures between the groups. In the G2 group, nasal and mouth width, lip philtrum height, Tragus-Nasion and Tragus-Pronasale lengths were increased, along with increased nasofrontal angle, decreased palpebral fissure inclination, and lip vermilion angles. However, palpebral fissure width and height, binocular width, and lip vermilion height were reduced. The aging process in women causes substantial changes in facial features, particularly in the middle and lower thirds of the face. Conversely, no major changes were observed in the upper third of the face. Our study findings provide potential insights for clinicians in developing facial rejuvenation procedures as well as for forensic purposes and surgical planning. The standardized facial metrics values in different age subgroups can guide clinicians in determining appropriate treatment plans for patients seeking facial rejuvenation.

Single-camera photogrammetry using a mobile phone for low-cost documentation of corpses

Photogrammetry is a technique for studying and defining objects' shape, dimension, and position in a three-dimensional space using measurements obtained from two-dimensional photographs. It has gained popularity following the development of computer graphics technologies and has been applied to various branches of medicine. In this study, the authors present a method for low-cost photorealistic documentation of corpses during autopsy using single-camera photogrammetry with a mobile phone. Besides representing the body by demonstrating the injured and non-injured body parts as control, evidencing the body parts on a 3D reconstruction allows easy explanation to nonmedical experts such as lawyers.

Ethnic Considerations When Planning Lip Augmentation

Ideal standards of beauty including preferred lip characteristics vary between ethnicities. Although plump, well-defined lips are globally associated with youth, variation exists with regard to the perceived ideal lip volume and proportions between ethnicities. Proportions that may be assessed when planning lip augmentation include the upper-to-lower lip ratio, philtrum length, upper and lower vermilion heights, the ratio between the philtrum height and that of the upper vermilion, and the lip height-to-lip width ratio.It is important that accurate assessments of patients are made pre- and postaugmentation. However, many aesthetic assessment tools are based on Caucasian models with limited use in other ethnicities. We present a review of the ideal lip characteristics and assessment techniques accounting for ethnicity, with a view to providing practitioners an evidence-based approach to lip assessment and treatment planning for patients of all backgrounds.

Quantifying Dermatochalasis Using 3-Dimensional Photogrammetry

BACKGROUND

Creating an appropriate treatment plan for patients with dermatochalasis requires careful investigation of the periocular region. Utilizing photographic documentation can assist physicians in conducting preoperative analysis and managing expectations regarding surgical outcomes.

OBJECTIVES

This study aimed to quantify the periocular characteristics of dermatochalasis patients using standardized 3D imaging and to compare age and sex-related changes in periocular features.

METHODS

In this cross-sectional study, we recruited 145 Caucasian patients with periocular dermatochalasis, comprising 48 men and 97 women, aged between 35 and 91 years. Standardized three-dimensional facial photographs were taken using the 3D Imaging system VECTRA M3. Linear dimensions, curve length, angle, indices, and sizes were measured and analyzed, including palpebral fissure height (PFH), palpebral fissure width (PFW), upper lid fold-palpebral margin distance (FPD), upper palpebral margin length (UPML), lower palpebral margin length (LPML), canthal tilt (CT), palpebral fissure index (PFI), upper eyelid area, and ocular surface area.

RESULTS

In the female group, the left-side PFH was slightly larger than the right-side PFH (P = 0.023), but the difference was less than 1mm. The corresponding PFI also showed a difference in the female group (P = 0.009). Statistically significant differences were shown in genders for specific parameters, except PFI (P = 0.251) and CT (P = 0.098). Among males, PFW (R = -0.523, p < 0.001) and LPML (R = -0.514, P = 0.264) decreased moderately with age. The correlation between UPML and age was weak (R = -0.367, P = 0.010). Similarly, among females, moderate correlations were found between age and PFW (R = -0.566, P < 0.001) and LPML (R = -0.537, P < 0.001). Additionally, PFH (R = -0.315, P = 0.002), UPML (R = -0.381, P < 0.001), and ocular surface area (R = -0.457, P < 0.001) showed weak correlations with age.

CONCLUSIONS

The study found that dermatochalasis usually affects both eyes simultaneously, and age is a significant factor in the morphological changes of certain periocular features regardless of sex. The PFI is not influenced by age or sex. These findings may provide useful information for surgical planning and understanding age-related changes in the periocular area.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An Anthropometric Study of the Morphologic Facial Index of Tibetan Youth in Tibet

The purpose of this study was to understand sex differences and variations in facial indices among Tibetans and to create and evaluate anthropometric data on facial morphology. The study population consisted of 476 native Tibetans (241 males and 235 females) aged 18 to 24 years. The means and SD facial width was 133.53±7.31 mm for males and 133.95±8.10 mm for females; the difference between the sexes was not statistically significant. The means and SD facial height was 107.68±5.76 mm for males and 111.95±14.28 mm for females; the difference between the sexes was statistically significant (u=-8.394, P=0.000). The morphologic facial index was 80.86±5.82 (means±SD) for males and 83.91±11.90 (means±SD) for females; the difference between the sexes was statistically significant (u=-6.581, P=0.000). The proportion of the Tibetan male facial shape was hypereuryprosopic (45.6%) > euryprosopic (31.1%) > mesoprosopic (18.7%) > leptoprosopic (3.3%) > hyperleptoprosopic (1.2%). The proportion of the Tibetan female facial shape was hypereuryprosopic (25.5%) > mesoprosopic (22.6%) > euryprosopic (21.7%) > leptoprosopic (17.4%) > hyperleptoprosopic (12.8%). Facial width was positively correlated with height (male r=0.306, P=0.000; female r=0.144, P=0.027), weight (r=0.470, P=0.000 for males; r=0.337, P=0.000 for females), and BMI (r=0.378, P=0.000 for males; r=0.291, P=0.000 for females). Facial height was positively correlated with height (r=0.329, P=0.000 for males; r=0.137, P=0.035 for females) and weight (r=0.391, P=0.000 for males; r=0.170, P=0.009 for females). Facial height was positively correlated with BMI in Tibetan males (r=0.293, P=0.000), but no significant correlation was found in Tibetan females. The morphologic facial index of Tibetans was positively correlated with age (r=0.183, P=0.004 for males; r=0.171, P=0.009 for females). The results indicated that Tibetan youth in Tibet have a predominantly hypereuryprosopic facial shape and that facial features are related to age, height, and weight. Some common facial morphology features exist among the Tibet Tibetans, northeastern Indians, and Nepalese in the 3 different regions of the Sino-Tibetan language family. The data from this study provide basic information for the study of Tibetans in the fields of physical anthropology, forensic medicine, maxillofacial surgery, and plastic surgery.

Differences in Nasal Shapes and the Degree of Changes Over a Decade or More: A Paired Analysis

OBJECTIVES

This study investigated age-related differences in nasal morphometry and the degree of changes within an individual over at least a 10-year period by pairing previous and recent three-dimensional reconstructed computed tomography (CT) images.

METHODS

Forty-eight adult Korean patients who underwent at least two CT scans of the nasal region with an interval of at least 10 years were selected. Patients were categorized into six subgroups according to sex and age (20-39 years, 40-49 years, and ≥50 years) at the time of initial imaging. Eight nasal parameters were measured on the initial and recent images, and paired comparisons between the two images were performed based on the data. The differences in the degree of change by age were also analyzed.

RESULTS

Over an average image interval of 12 years, men exhibited an increase in the nasofrontal angle (3.2°±5.4°, P=0.041), profile nasal length (1.7±1.7 mm, P=0.002), and nasal bridge height (1.2±1.6 mm, P=0.002). Conversely, they showed a decrease in the nasofacial angle (-2.3°±2.9°, P=0.010). Women also demonstrated an increase in the nasofrontal angle (2.5°±5.2°, P=0.010), profile nasal length (1.4±1.9 mm, P<0.001), and nasal bridge height (1.3±1.6 mm, P<0.001). However, they exhibited a decrease in the nasofacial angle (-2.0°±2.1°, P<0.001), glabella angle (-9.1°±9.8°, P<0.001), and pyriform angle (-8.5°±10.1°, P<0.001). With the exception of the nasal bridge height (P=0.036) and pyriform angle (P=0.022), the degree of changes in most parameters did not show significant differences across age groups.

CONCLUSION

Our findings indicate that the aging nose exhibits a greater nasal length with inferior angulation of the nasal tip, with an increase in the nasofrontal angle, profile nasal length, and nasal bridge height, along with a decrease in the nasofacial angle. The degree of most nasal morphologic changes demonstrated no significant differences by specific age group.

A novel standardized approach for the 3D evaluation of upper eyelid area and volume

Background

Three-dimensional (3D) surface imaging and morphometrics are becoming the preferred craniofacial surface imaging modality. However, as a unique advantage of 3D imaging, areal and volumetric measurements have been rarely conducted and validated for evaluating soft tissue change in the periocular region, especially the upper eyelids. Therefore, based on an existing periocular landmark identification strategy, we proposed a novel modified method to define a standardized upper eyelid region for areal and volumetric measurements and validate its reliability for future clinical application.

Methods

Forty-four healthy adult volunteers were enrolled in this cross-sectional study. Three-dimensional facial images were taken with a 3D imaging system. Subsequently, the upper eyelid region selection and areal and volumetric measurements were conducted using a modified landmarks localization strategy to evaluate their intrarater, interrater, and intramethod reliability.

Results

Areal measurement of the upper eyelid revealed highly reliable outcomes for intraclass correlation coefficient (ICC), mean absolute difference (MAD), relative error measurement (REM), technical error of measurement (TEM), and relative technical error of measurement (%TEM) of 0.982, 0.1620 cm2, 2.9%, 0.1510 cm2, and 2.7% for intrarater reliability, respectively; 0.969, 0.2076 cm2, 3.7%, 0.1930 cm2, and 3.5% for interrater reliability, respectively; and 0.917, 0.3636 cm2, 6.5%, 0.3354 cm2, and 6.0% for intramethod reliability, respectively. Unsatisfactory results were found for the volumetric measurement of the upper eyelid: the ICC, MAD, REM, TEM, and %TEM estimates for intrarater reliability were 0.992, 0.2299 mL, 10.3%, 0.2414 mL, and 10.8%, respectively; for interrater reliability, these values were 0.985, 0.2749 mL, 12.3%, 0.3253 mL, and 14.6%, respectively; and for intramethod reliability, these values were 0.433, 1.6716 mL, 77.9%, 2.0615 mL, and 96.1%, respectively.

Conclusions

This is the first study to propose a standardized upper eyelid region selection strategy and simultaneously validate its reliability for 3D areal and volumetric measurements. This study confirmed the high-level reliability of areal measurement and poor reliability of volumetric measurement based on direct measurements using a single image, which may provide better results when this method is combined with the image overlapping and registration procedure. However, this is subject to further validation. Nonetheless, this method could provide quantitative areal and volumetric data on the upper eyelids and might have widespread application potential in the future.

Accuracy of RGB-D camera-based and stereophotogrammetric facial scanners: a comparative study

OBJECTIVES

This study aimed to evaluate and compare the accuracy and inter-operator reliability of a low-cost red-green-blue-depth (RGB-D) camera-based facial scanner (Bellus3D Arc7) with a stereophotogrammetry facial scanner (3dMD) and to explore the possibility of the former as a clinical substitute for the latter.

METHODS

A mannequin head was selected as the research object. In the RGB-D camera-based facial scanner group, the head was continuously scanned five times using an RGB-D camera-based facial scanner (Bellus3D Arc7), and the outcome data of each scan was then imported into CAD software (MeshLab) to reconstruct three-dimensional (3D) facial photographs. In the stereophotogrammetry facial scanner group, the mannequin head was scanned with a stereophotogrammetry facial scanner (3dMD). Selected parameters were directly measured on the reconstructed 3D virtual faces using a CAD software. The same parameters were then measured directly on the mannequin head using the direct anthropometry (DA) method as the gold standard for later comparison. The accuracy of the facial scanners was evaluated in terms of trueness and precision. Trueness was evaluated by comparing the measurement results of the two groups with each other and with that of DA using equivalence tests and average absolute deviations, while precision and inter-operator reliability were assessed using the intraclass correlation coefficient (ICC). A 3D facial mesh deviation between the two groups was also calculated for further reference using a 3D metrology software (GOM inspect pro).

RESULTS

In terms of trueness, the average absolute deviations between RGB-D camera-based and stereophotogrammetry facial scanners, between RGB-D camera-based facial scanner and DA, and between stereophotogrammetry facial scanner and DA were statistically equivalent at 0.50±0.27 mm, 0.61±0.42 mm, and 0.28±0.14 mm, respectively. Equivalence test results confirmed that their equivalence was within clinical requirements (<1 mm). The ICC for each parameter was approximately 0.999 in terms of precision and inter-operator reliability. A 3D facial mesh analysis suggested that the deviation between the two groups was 0.37±0.01 mm.

CONCLUSIONS

For facial scanners, an accuracy of <1 mm is commonly considered clinically acceptable. Both the RGB-D camera-based and stereophotogrammetry facial scanners in this study showed acceptable trueness, high precision, and inter-operator reliability. A low-cost RGB-D camera-based facial scanner could be an eligible clinical substitute for traditional stereophotogrammetry.

CLINICAL SIGNIFICANCE

The low-cost RGB-D camera-based facial scanner showed clinically acceptable trueness, high precision, and inter-operator reliability; thus, it could be an eligible clinical substitute for traditional stereophotogrammetry.