# Utility of 3D Imaging in the Objective Evaluation of Glabellar Lines Following Botulinum Toxin Treatment

## TL;DR

This study shows that 3D imaging can objectively measure improvements in glabellar lines after botulinum toxin treatment, offering a more accurate alternative to traditional methods.

## Contribution

The study introduces laser-based 3D imaging as a novel, objective method for evaluating glabellar line treatment outcomes.

## Key findings

- 3D imaging showed high precision with errors ≤2% for area, perimeter, and volume, and ≤0.5 mm for depth.
- Significant reductions in wrinkle depth were observed after botulinum toxin treatment.
- 3D measurements correlated with patient satisfaction and Global Rating of Outcome scores.

## Abstract

Background/Objectives: Objective and reproducible evaluation of glabellar lines remains challenging, as current clinical assessments rely largely on subjective rating scales and two-dimensional photography, which lack depth information. This study aimed to assess the clinical utility of a laser-based three-dimensional (3D) imaging approach for objective quantitative evaluation of glabellar lines in adults undergoing botulinum toxin treatment. Methods: A laser-based 3D imaging system was used to quantitatively measure glabellar line morphology. System accuracy for area, perimeter, volume, and depth was evaluated using standardized physical models. In a prospective observational study, 31 adults with moderate-to-severe glabellar lines undergoing routine botulinum toxin treatment were assessed at baseline, day 7, and week 4. Quantitative 3D measurements were compared with clinician- and participant-reported severity scores, as well as patient satisfaction and Global Rating of Outcome (GRO) scores. Results: The 3D imaging measurements demonstrated high geometric measurement precision, with errors ≤2% for area, perimeter, and volume, and ≤0.5 mm for depth. Significant reductions in wrinkle depth were observed after treatment. Quantitative 3D measurements showed moderate correlations with clinician-reported scores (r = 0.53–0.54) and participant-reported scores (r = 0.59–0.66). Improvement rates derived from 3D measurements were positively correlated with patient satisfaction and GRO scores. Conclusions: Laser-based 3D imaging provides an objective and quantitative approach for evaluating glabellar lines and treatment response to botulinum toxin. This method may complement conventional clinical assessments and support further validation in larger clinical studies.