Deep Retinal Capillary Plexus Decreasing Correlated With the Outer Retinal Layer Alteration and Visual Acuity Impairment in Pathological Myopia

The purpose of this study was to measure alterations of inner retinal microvascular density and outer retinal sublayer thicknesses in pathological myopia, and to correlate the measured parameters with best corrected visual acuity (BCVA).Optical coherence tomography (OCT) and OCT angiography (OCTA) images of 21 control, 48 simple high myopia, and 22 pathological myopia eyes were analyzed to quantify the thicknesses of the outer retinal sublayers and the density of the inner retinal microvascular network that includes the superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP). Retinal sublayer thicknesses and microvascular densities were compared among the three groups, and correlations of sublayer thicknesses and microvascular densities with BCVA were determined.In pathological myopia, density of the DRCP, thicknesses of myoid and ellipsoid zone (MEZ), interdigitation zone and retinal pigment epithelium/Bruch complex (IZ + RPE), and choroid were lower than in simple high myopia (P < 0.05). The decreased DRCP density was correlated with thinner MEZ and IZ+RPE in pathological myopia (P < 0.05), but not in simple high myopia (P > 0.05). Simple linear regression showed that axial length, female, thicknesses of outer plexiform layer (OPL), MEZ, IZ + RPE, choroid, and density of the SRCP and DRCP were correlated with BCVA. In multiple regression analysis, worse BCVA was associated only with thinner MEZ, thinner choroid, and decreased DRCP (P < 0.05).Alteration of inner retinal microvascular density and outer retinal sublayer thicknesses occurred in pathological myopia, especially decreased DRCP and thinner MEZ, which were significantly associated with worse BCVA.