Evaluation of Facial Anthropometry Using Three-Dimensional Photogrammetry and Direct Measuring Techniques

Area of Science:

• Anthropometry
• Medical Imaging
• Biometrics

Background:

• Accurate facial anthropometry is crucial for clinical applications.
• Traditional direct measurements and modern digital imaging techniques are used.
• Assessing the reliability and agreement between these methods is essential.

Purpose of the Study:

• To compare the reliability and agreement of direct caliper measurements versus digital 3D imaging for 14 standard facial distances.
• To identify limitations in anthropometric measurement techniques.
• To provide recommendations for improving facial measurement accuracy.

Main Methods:

• 14 standard facial distances measured on 10 adults using calipers and the 3dMDtrio system.
• Measurements performed by two raters with at least a one-week interval.
• Reliability and agreement assessed using intra-class correlation coefficient (ICC), mean absolute difference (MAD), and Bland-Altman plots with limits of agreement (LOA).

Main Results:

• Average discrepancy (MAD) between digital and direct measurements was 1.6 mm.
• Reliability varied significantly across the 14 anthropometric distances for both methods.
• Only a subset of measurements met stringent criteria (ICC >0.75 and MAD <1 mm) for both intra- and inter-rater assessments.

Conclusions:

• Digital and direct facial measurement methods are generally compatible in reliability and agreement.
• Inconsistent reliability highlights poor landmark identification as a primary limitation.
• Further definition of anthropometric landmarks and evaluator training are recommended to enhance measurement precision.