Abstract
Purpose :
The ability to measure markers of inflammation and tissue remodeling in periocular tissue would help better understand disease processes and improve clinical decision making. However, quantitative methods to measure these activities are not well established. We hypothesize that spatial frequency domain imaging (SFDI), a noninvasive, quantitative, multispectral imaging technology, can provide periocular tissue’s absorption and scattering characteristics to inform about the tissue composition, hemodynamics, edema, and inflammation.
Methods :
SFDI of periorbital regions were obtained in nine healthy volunteers in compliance with an IRB approved protocol. Imaging is performed at eight center wavelengths (471,526,591,621,659,731,851 nm) and 5 spatial frequencies (0-0.2 mm-1, evenly spaced) over 20cm x 15cm field of view, with typical exposure times of 5-60 ms per image. For each pixel, absorption and reduced scattering coefficients (µa and µ’s, respectively) were determined. Regions of interest (ROI) along the superior/ inferior temporal quadrant, and inferior nasal quadrant are selected for analysis, and compared with adjacent maxillary skin (Figure 1). Tissue optical properties are locoregionally correlated. Paired student’s t-test was used for statistical analysis.
Results :
The periocular region shows several distinct optical property trends. Notably, there is a local increase in the absorption along the inferior temporal quadrant compared to surrounding facial skin (Mean µaITQ/ µaface at 659nm is 1.38, [CI: 1.23, 0.53], p < 0.001). Reduced optical scattering is observed in all three ROIs (19% to 25% reduction in the amplitude of µ’s across the spectra) Deoxyhemoglobin concentration as well as oxygen saturation can be inferred from multispectral data and skin melanin content.
Conclusions :
SFDI provides wide-field assessment of chromophore concentrations of periocular tissue, showing increased absorption by tissue chromophores and decreased scattering. The cutaneous tissue of the periocular region has a thinner epithelium and is devoid of subcutaneous fat, which presents distinct optical properties that optimize SFDI interrogation of inflammatory disease sub-types. Further studies will involve subjects with various etiologies of inflammatory processes in this region using this methodology.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.