Evaluation of facial palsy by moiré topography index.

We investigated the usefulness of moiré topography for evaluating facial nerve function in 51 patients with facial palsy and 10 normal volunteers. This method visualizes the shape of objects in three dimensions. We devised three moiré indexes as a simple method of quantifying the severity of facial palsy: the nasolabial groove moiré index, the oral angle moiré index, and the inner canthus moiré index. We compared the results obtained by the moiré indexes with findings obtained using the House-Brackmann grading system and found that they were highly correlated. These three moiré indexes included all the standard factors of the House-Brackmann grading system, allowing us to develop the total moiré index.