A computer-based method of measuring facial asymmetry. Results from an assessment of the repair of cleft lip deformities.

The appearance of the nose, mouth and nostrils was analysed in two series of unilateral, complete cleft lip patients. A programme was written for use on a BBC microcomputer to measure the symmetry of facial features traced from photographs. Symmetry was measured using one of two methods: determining the area of non-overlap when one side was reflected on the other (area method) or calculating the distance from regularly spaced points on the outline of one side to the nearest point on the reflection of the opposite side (curve method). The rankings of the photographs based on these results were compared with the subjective rankings given by a lay panel. The results based on the curve method agreed well with the subjective rankings (P for Spearman Rank Correlation Coefficients = less than 0.02). The technique provides a cheap, simple and quick method of comparing symmetry in groups of patients.