Purpose: To compare the visualization of the choriocapillaris and deeper choroidal vessels in healthy eyes in en face swept-source optical coherence tomography (SS-OCT) versus SS-OCT angiography (SS-OCTA).
Methods: This is a cross-sectional study of consecutive eyes without chorioretinal disease. En face SS-OCT and SS-OCTA images of the choriocapillaris and choroid were assessed for visualization of the vasculature. Choroidal vessel densities (CVD) of the choriocapillaris, inner choroid, midchoroid, and outer choroid were calculated from binarized en face SS-OCT and SS-OCTA images. Paired t-tests and linear regression were used for statistical analysis.
Results: Twenty-seven eyes of 27 patients were included. There was no statistically significant difference between the CVDs of the midchoroid assessed with en face SS-OCT versus SS-OCTA (P = 0.21). However, there were statistically significant differences between the CVDs for the choriocapillaris (P < 0.001), inner choroid (P < 0.001), and outer choroid (P = 0.006). Qualitative analysis revealed incomplete visualization of vessels in the inner choroid and exaggeration of vessel lumens in the outer choroid with SS-OCTA.
Conclusions: Visualization of the choriocapillaris is superior with SS-OCTA, but it has numerous limitations that make visualization of deeper choroidal vessels less reliable when compared with en face SS-OCT. It is important to understand such limitations when using these technologies to study the choroidal vasculature in chorioretinal disease.
Translational relevance: The presented study of optimal imaging techniques for the choroidal vessels of healthy eyes provides an important foundation for future investigations into the role of the choroidal vasculature in chorioretinal diseases.
Keywords: choriocapillaris; choroid; optical coherence tomography angiography; swept source; vessel density.