CHORIOCAPILLARIS VASCULAR PARAMETERS IN NORMAL EYES AND THOSE WITH PACHYCHOROID WITH AND WITHOUT DISEASE

To evaluate the vascular characteristics of the choriocapillaris in eyes with pachychoroid as compared with normal controls.

Eyes with pachychoroid disease were defined as those with a history of central serous chorioretinopathy or peripapillary pachychoroid syndrome. Pachychoroid without disease was defined as eyes with no history of disease with a subfoveal choroidal thickness ≥ the age-adjusted 95th percentile thickness. Frame-averaged optical coherence tomography angiography images of the choriocapillaris obtained with a Zeiss Plex Elite were binarized, skeletonized, and evaluated for vascular branching parameters.

There were 7 normal control subjects, 10 subjects with pachychoroid without disease, and 17 pachychoroid disease subjects. Mean choriocapillaris vessel segment length was 12.19 µm in eyes with pachychoroid disease as compared with 11.48 µm in normal controls and 11.62 µm in pachychoroid without disease (P = 0.003 and P = 0.006, respectively). The branches per square millimeter were fewer in pachychoroid disease (1,215), as compared with normal controls (1,471) or pachychoroid without disease (1,384; P < 0.001, and P = 0.002, respectively). The choriocapillaris vessel diameter was larger, but the fractal dimension was smaller in pachychoroid disease eyes as compared with normal eyes or pachychoroid without disease eyes. There was no statistically significant difference between normal controls and pachychoroid without disease for any measured vascular parameter of the choriocapillaris.

Choriocapillaris vascular parameters suggest that pachychoroid is not necessarily pathologic. It is possible that choroidal thickening is an epiphenomenon, and there are more significant vascular parameters that are related to disease. These concepts may help guide future prospective studies.