Purpose: To evaluate the accuracy and interobserver variability of three-dimensional (3D) stereophotogrammetric imaging for volumetric assessment in the periorbital region and to propose a protocol for measurement. Methods: A cross-sectional study was performed. Fifty-eight normal adult subjects had photographs taken using the VECTRA M3 imaging system on two separate occasions at a single center teaching hospital. The primary study outcome measurement was mean volume change in the periorbital region, using different methods of image analysis with the following variables: registration method, eyes open or closed, eyelids measured separately or together, extension of area measured to include mid-face. Accuracy was defined as the agreement between paired images with no measured change in volume (0 mL). The agreement between two independent observers was assessed using Bland-Altman plots. Results: There was a statistically significant difference (P < .0001) between the different methods of measurement, with registration of images having the most effect (partial eta squared 0.229). A mean change in volume of 0.11 ± 0.13 mL was reported for the most accurate method. Agreement between observers was confirmed (highest Intraclass Correlation Coefficient 0.63). Conclusions: Assessment of volumetric change in the periorbital region using 3D image reconstruction is accurate with good interobserver repeatability and is suitable for clinical use. A protocol for data acquisition using the VECTRA M3 is proposed. 3D image reconstruction holds promise to enable diagnosis, treatment monitoring, and surgical outcome evaluation in ocular adnexal disease.
Keywords: 3D imaging; 3D stereo photogrammetry; Orbital soft tissue; Vectra; Volume.