Choroidal blood flow velocity and resistance in inferior posterior staphyloma using a novel superpixel technique in laser speckle flowgraphy

This study examined choroidal circulation in inferior posterior staphyloma (IPS) eyes using mean blur rate (MBR) and beat strength over MBR (BOM) from laser speckle flowgraphy. Eighteen eyes from 12 patients with treatment-naïve IPS were studied, including 9 eyes with subretinal fluid (SRF). The thinnest part of the choroid was identified via optical coherence tomography, and rubber bands were placed at bordering across the superior and inferior regions. MBR and BOM, indices of blood flow velocity and resistance, were measured and analyzed. The MBR ratio and the BOM ratio, both arbitrarily prepared markers to show greater circulatory characteristics of IPS in smaller values, were compared between eyes with and without SRF. On average, the inferior region had a lower MBR and a higher BOM than the superior region. Both the MBR and BOM ratios were smaller in IPS eyes with SRF than in IPS eyes without SRF (all: P < 0.05). The inferior region had lower choroidal blood flow velocity and higher resistance than the superior region in IPS. Greater circulatory characteristics of IPS were observed in eyes with SRF, suggesting that SRF was driven by the unbalanced distribution of choroidal blood flow.