Comparison of choriocapillaris perfusion between swept-source optical coherence tomography angiography and spectral-domain optical coherence tomography angiography in five different choriocapillaris slabs in patients with intermediate age-related macular degeneration.

Purpose: To analyze choriocapillaris (CC) perfusion using swept-source optical coherence tomography angiography (SS-OCTA) and spectral-domain optical coherence tomography angiography (SD-OCTA) in five CC slabs in patients with intermediate age-related macular degeneration (iAMD).

Methods: This is a cross-sectional study of 23 eyes of 20 patients who underwent three 3 × 3 mm OCTA, one with SS-OCTA and two with SD-OCTA, a non-averaged scan (V1) and a four-scan volume (V4). Percentage of flow deficits (FD%), average size of FD (µm2), total area of FD (mm2) and number of FD were calculated in different CC slabs (automatic, 11-21 μm, 21-31 μm, 31-41 μm, 16-31 μm).

Results: There was a statistically significant difference in all parameters and all slabs analyzed, when comparing SS-OCTA versus SD-OCTA V1 and SD-OCTA V1 versus SD-OCTA V4. Nevertheless, when comparing SS-OCTA versus SD-OCTA V4, significant differences were only found for the automatic and the 31-41 μm slab. When comparing the FD% between different slabs on the same device, significant differences were also found.

Conclusion: Quantification of CC FD% is impacted by the CC slab, the type of OCTA used, and volume averaging in SD-OCTA. Given the significant impact on quantitative results, comparisons between studies and instruments and/or with/without averaging are difficult, even at the same slab depth.