Quadrant asymmetry alteration of deep retinal capillary plexus degeneration in pathological myopia

To measure quadrant asymmetry (QA) alterations of macular retinal microvascular density and determine their effect on pathological myopia. Optical coherence tomography angiography (OCTA) images of 20 control, 42 simple high myopia and 20 pathological myopia eyes were analyzed to quantify the density of the macular retinal microvascular network that included the superficial and deep retinal capillary plexuses (SRCP and DRCP). The definition of QA was calculated by subtracting the minimum value from the maximum value among the four macular respective subfields. The comparison of the QAs of SRCP and DRCP density among the three groups and the effect of QAs on the occurrence of pathological myopia were analyzed. In pathological myopia, densities of the SRCP and DRCP were lower than in simple high myopia and control (P < 0.05). The higher QAs of SRCP and DRCP density occurred in pathological myopia than in simple high myopia and control (P < 0.05). In multivariate binary logistic regression, higher QA of DRCP density was associated significantly with the occurrence of pathological myopia (Odds Ratio = 2.000, P = 0.035) while the QA of SRCP density didn't (P = 0.065). Comparing the intra-quadrant effect on the occurrence of pathological myopia with the analysis of binary multivariate logistic regression, the decreased DRCP density in the macular inferior subfield showed a high risk (Odds Ratio = 0.435, P = 0.030). The occurrence of pathological myopia affected the quadrant asymmetry alterations of macular retinal microvascular density, especially the increased QA of DRCP density with significantly decreased DRCP density in the macular inferior subfield.