Detection Of Retinal Vascular Density And Related Factors In Myopia By Optical Coherence Tomography Angiography (OCTA)

Objective: To study the changes of retinal vascular density in myopia and the related factors affecting the changes of retinal vascular density by optical coherence tomography angiography(OCTA).Methods: A total of 45 cases and 90 eyes aged between 20 and 40 years were included in the study..Among them,15 cases(30 eyes)were in low myopia group(-0.50~-3.00D),15 cases(30 eyes)were in moderate myopia group(-3.25~-6.00D)and 15 cases(30 eyes)were in high myopia group(>-6.00D).Microvessel density of macular area and optic disc area was collected by OCTA,and superficial and deep layers of macular area and peripapillary capillary network(RPC)layers were obtained automatically.Density calculation was carried out by using self-contained software.Variance and linear regression were used to analyze the effect between equivalent spherical mirror,ocular axis and retinal vascular density..Result:Among myopic people aged 20~40 years,the differences between the three groups of total vascular densities in the superficial and deep macular area in the retinal vascular layer were statistically significant(P<0.001,P=0.011).Among them,compared with the other two groups,the vascular density in the superficial and deep parafovea of the macular area was significantly reduced in patients with high myopia(P<0.001,P=0.022),while there was no statistical difference between the three groups(P=0.395,P=0.489)in fovea.Compared with the other two groups,the vascular density of RPC full-layer and peripapilary area in patients with high myopia was significantly decreased(P=0.029,P=0.032),but the vascular density in inside disc was increased instead(P=0.006).Among them,patients with low and moderate myopia had significantly higher vascular density in the nasal side(superior and inferior)of the RPC peripapilary area(P<0.001,P=0.006).There was a significant negative correlation between the total vascular density in the superficial and deep macular area and the ocular axis(r=-0.53,P<0.05).R =-0.229,P <0.05),with no significant correlation with the equivalent spherical mirror(P=0.209,P=0.656).There was no significant correlation between the vascular density in the optic disc and peripapilary of the RPC layer and the equivalent spherical mirror and eye axis(P=0.063,P=0.794).P=0.380,P=0.298).Conclusion: In young and middle-aged myopic people,with the increase of eye axis,the vascular density in the macular area decreases gradually.In patients with simple high myopia,the whole retinal vascular density decreased in both macular area and optic disc area before pathological changes in fundus.