Geometric Morphometrics and the Design And Fit of Personal Protective Equipment

The effectiveness of personal protective equipment, such as respirators, helmets, etc., is dependent upon their capacity to accommodate or conform to morphometric variation amongst users. In many cases, standard approaches for doing this involve the use of multiple, linear distance measures subjected to a Principal Components Analysis (PCA) to reduce the dimensionality of the data to a tractable number, e.g., two. The resulting scatterplot is then partitioned into blocks and sampling minima for each block established to provide what is believed to be an adequate coverage of the targeted population. Geometric morphometrics (GM) is an approach to the analysis of shape variation that focuses mostly, though not exclusively, on two- and three-dimensional coordinates of anatomical landmarks. Unlike traditional approaches, GM automatically preserves all of the geometric relationships between the landmarks identified for analysis and provides a more comprehensive and powerful analysis of shape (size-free geometry) or form (size+shape) variation. As such, GM offers considerable potential for improving the design and fitting of personal protective equipment.