Comparison of the accuracy of two-dimensional and three-dimensional photography in the facial measurement of patients with unilateral cleft lip

To compare the measurement accuracy of two-dimensional (2D) photography and three-dimensional (3D) photography in the analysis of the asymmetric appearance of children with cleft lip and palate and the influence of the severity of asymmetric deformity on the accuracy of facial measurement to guide clinical measurement work.

Children with unilateral cleft lip were enrolled in this prospective study. Seven parameters--the deviation of the pronasale, subnasale, and labrale superius, as well as the cleft/noncleft ratio of the width of nostrils, length and height of lateral lips and height of columella-were measured with Vernier calipers as the gold standard. Traditional 2D photography and 3D stereophotogrammetry photos were taken and measured. The extent of cleft malformation is indicated by the ratio of the cleft side to the noncleft side. The error size is represented by the ratio difference between two-dimensional photography or stereophotogrammetry with the ratio of the gold standard.

Thirteen patients were eventually recruited. The measurement results of the ratio of lateral lip height by 2D photography tended to be larger (P = 0.019), and the measurement results of the ratio of columella height tended to be smaller (P = 0.008). The measurement results of the deviation of the subnasale by stereophotogrammetry tended to be smaller (P = 0.003). The pronasale deviation (P = 0.022) with two-dimensional photography, the deviation of the labrale superius (P = 0.025) and the ratio of lateral lip length (P = 0.036) with stereophotogrammetry had a significant negative correlation with the extent of cleft malformation.

Both two-dimensional photography and stereophotogrammetry have errors and biases that underexaggerate or overexaggerate the extent of cleft malformation, and some errors may increase with the decrease in the extent of cleft malformation. When applying two-dimensional and three-dimensional photography to analyze cleft lip and palate deformities, these biases should be considered to evaluate the face more objectively.