Comparison of three methods of facial measurement.

The aims of this study were to assess the accuracy of measurements recorded by 3D stereophotogrammetry and to compare three methods of facial measurement: manual anthropometry, 3D stereophotogrammetry and 2D photography. Measurements were taken from 14 landmarks on each of six volunteers and compared. In addition, the variability of the methods was assessed. Three-dimensional measurements were shown to compare well with manual measurements on volunteers as well as test objects for which the mean difference was 0.23 mm (shortest distance) and 0.13 mm (surface). All the three methods of measurement were found to have good levels of repeatability. Two-dimensional measurements were more variable than manual measurements (P=0.021). Three-dimensional stereophotogrammetric measurements were shown to compare well with manual measurements although the values obtained were mostly slightly larger. Stereophotogrammetry allows images to be taken in a Medical Photography Department, facilitating the accurate measurement of facial morphology from digitized data, including changes associated with treatment or growth. There are clear potential benefits of using 3D measurements in the assessment of facial deformity.