Study of diffuse scattering on facial surface using ray tracing approach.

Summary

Validated ray-tracing shows that the subvisible microtexture width-to-height ratio predominantly governs skin diffuse scattering: finer microtexture increases diffuse reflection and soft-focus, enhancing perceived radiance. The model also quantifies increased transversal light exit with finer SMT, offering a quantitative framework for cosmetic formulation and dermatologic imaging.

Key Findings

• Subvisible microtexture width-to-height ratio is the dominant determinant of diffuse scattering and soft-focus.
• Finer SMT (smaller ratio) increases diffuse reflection and perceived radiance.
• Macrotexture affects scattering but to a lesser extent than SMT.
• Finer SMT increases transversal light exit from within the skin, quantified by the model.

Clinical Implications

While not directly clinical, the model can inform dermatologic imaging protocols and objective assessment of skin quality, aiding evaluation of cosmetic interventions and guiding noninvasive treatment endpoints.

Limitations

• Simulation-based findings with limited direct in vivo validation reported
• 2D SMT modeling may not capture full 3D skin complexity and biological variability

Future Directions

Integrate 3D microtopography from in vivo imaging, validate against clinical photography and goniophotometric data, and couple with formulation variables to predict product-induced changes.