| Objective:To investigate variations in macular blood flow density and morphological structural in early age-related macular degeneration by using optical coherence tomography angiography,and to explore the blood flow density of choroidal capillary layer is correlated with the blood flow density of the superficial and deep retina in the macular area.Methods:The retrospective review included 35 patients(35 eyes)which were diagnosed with wet age-related macular degeneration in one eye and the fellow eye with early ARMD in our hospital at February 2018.All the patients with early ARMD eyes were imaged by OCTA at two points:baseline and 2years later.To obeserve the change of the range of 3mm×3mm macular blood flow density of superficial retinal layer,deep retinal layer and choroidal capillaries layer,foveal avascular zone area,perimeter and acircularity index,and the macular thickness of the full layer,inner layer,outer layer retina,ISOS-BRM and subfoveal choroid thickness.A total of 35 healthy eyes with matched age and sex were enrolled in the control group.Results:This study included 35 eyes of 35 patients which were diagnosed with wet age-related macular degeneration in one eye and the fellow eye with early ARMD.There were 20 males and 15 females,aged 53-72(mean64.2±8.34)years old.There were 35 cases in the blank control group consisting of healthy persons,including 19 males and 16 females,aged 52-75(mean63.6±7.04)years old.(1)Comparison between the initial diagnosis group and the healthy control group:At the first diagnosis group,The range of 3mm×3mm macular blood flow density of superficial retinal layer,deep retinal layer and choroidal capillaries layer was measured to be 40.72±3.89%,45.21±2.46%and 0.57±0.04%,respectively,which were all reduced and the difference was statistically significant(t=2.25 p=0.03;t=2.53 p=0.018;t=3.02 p=0.006)compared with healthy,the macular thickness of the full layer,inner layer and the subfoveal choroid were 237.28±13.06μm,42.5±4.1μm and 253.64±50.78μm,respectively,which were all lower than healthy controls and the difference was statistically significant(t=2.29 p=0.03;t=2.38 p=0.02;t=-2.05 p=0.03),while the ISOS-BRM thickness in the macular area is 205.18±10.31μm,which is not statistically different than healthy controls but has a tendency to increase(t=-1.13 p=0.37).The area and perimeter of FAZ in the macular area,AI and outer retina thickness were 0.28±0.09mm2,2.21±0.37μm,1.18±0.13 and61.78±2.37μm,respectively,and there was no significant change compared with healthy controls(t=0.58 p=0.72;t=-0.13 p=0.89;t=-1.1 p=0.28;t=0.49p=0.68).(2)Comparison between the initial diagnosis group and the after 2 years group:Two years later,The range of 3mm×3mm macular blood flow density of deep retinal layer and choroidal capillaries layer was measured to be43.47±1.47%and 0.52±0.05%,respectively,which were further lower than the initial diagnosis and the difference was statistically significant(t=2.27 p=0.03;t=2.76 p=0.01),the superficial retinal capillaries density is 39.62±3.64%and the subfoveal choroid thickness is 246.35±42.97μm,which is compared with the initial diagnosis,There was no statistical difference but also showed a decreasing trend(t=0.8 p=0.43;t=0.76 p=0.5).The thickness of the outer retinal layer was 64.35±1.29μm,which increased compared with the initial diagnosis and the difference was statistically significant(t=2.48 p=0.02),the full retinal thickness and inner retinal thickness were 235.37±15.47μm and 41.3±2.56μm,respectively,and there was no significant change from the initial diagnosis(t=-0.82 p=0.56;t=0.74 p=0.52),The thickness of ISOS-BRM is207.32±9.39μm.Compared with the initial diagnosis,there is no statistical difference,but there is an increasing trend(t=-1.21 p=0.18).The FAZ area,circumference and AI are 0.3±0.02 mm~2,2.23±0.59 and 1.19±0.27,no significant changes compared with the initial diagnosis(t=0.46 p=0.64;t=-0.18p=0.9;t=-0.84 p=0.46).(3)the blood flow density of the choroidal capillary layer in early ARMD patients was positively correlated with the blood flow density in superficial retinal layer and deep retinal layer at baseline and two years after frist definite diagnosis.Conclusion:1.The range of 3mm×3mm macular blood flow density of superficial retinal layer,deep retinal layer and choroidal capillaries and inner retinal thickness were all reduced,In addition to the outer retina and choroid,The blood flow density and nerve structural are also affected to a certain extent.With the progress of the disease,The range of 3mm×3mm macular blood flow density of deep retinal layer and choroidal capillaries in the early ARMD are further reduced,and the thickness of the outer retina is increased.2.There were no significant differences in the area,circumference,and AI of the FAZ in the early ARMD patients,whether compared with healthy controls or 2 years after the initial diagnosis.However,as the disease progresses,the area of the FAZ and the AI showed an increasing trend,which indicates that the observation indexes of the foveal avascular area have certain significance for the monitoring of disease development,but are not specific to the occurrence of the disease.3.The blood flow density of the choroidal capillary layer in early ARMD patients is positively correlated with the blood flow density of the superficial and deep retina in the macular area.As the disease progresses,the blood flow density of the choroidal capillary layer is correlated with the blood flow density of the superficial and deep retina increase.4.The measurement of blood flow density and morphological structure of the macula based on OCTA is of great significance for further clarifying diagnosis,monitoring and studying the pathogenesis. |
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