Clinical Study On The Changes Of Retinal Blood Flow Density In Patients With Different Severity Of OSAHS

Objective:The aim of the study is to measure the vascular density in the inner retina of patients with obstructive sleep apnea by optical coherence tomography angiography,and to analyze the correlation between the blood flow density in the inner retina and the severity of OSAHS.Methods:42 patients with sleep snoring in the sleep medical center of the second hospital of Shanxi Medical University were selected by collecting basic information and completing overnight polysomnography,from August 2020 to March 2021.According to the sleep apnea hypopnea index,the patients were divided into mild to moderate group（AHI≤30times/h）,severe group（30times/h≤AHI≤60 times/h）,very severe group（AHI≥60times/h）.Optical coherence tomography（OCT）was used to observe the fundus and measure the macular fovea thickness.The retinal vessels within 3×3 centimetre were quickly scanned with the optic disc and the center of the macula as the center in the angiography mode.The images were saved and collected.Using the special stratification function of the instrument,it can be divided into superficial vascular complex plexus（SVC）and deep vascular complex plexus（DVC）,according to the blood flow.SVC layer can be divided into nerve fiber layer vascular plexus（RFLVP）and superficial vascular plexus（SVP）.DVC layer can be divided into middle vascular network plexus（ICP）and deep vascular network plexus（DCP）.After image processing,the vascular density of each layer can be calculated automatically,and the vascular density of inner retinal layer and macular center of different layers of blood in optic disc area and macular area are compared among groups.Finally,we compared the relationship between the clinical characteristics and PSG monitoring indicators,including the retinal inner layer vascular density and macular fovea thickness at different levels of optic disc and macular blood.SPSS 25.0 software was used to analyze the data.Results:1 Basic data analysis:there were no significant differences in gender,age,neck circumference,body mass index（BMI）,controllable hypertension and diabetics among the groups（P<0.05）;2 Analysis of PSG monitoring indexes and blood flow density of different vascular layers in optic disc area and macular area measured by OCTA in each group.Results:there were significant differences in AHI,SpO₂min and Tmax among each group（P<0.05）,There was no significant difference in SpO₂mean among the groups;there was significant difference in macular SCV layer,RFLVP layer,SVP layer between mild to moderate group and severe group（P<0.05）;there was significant difference in macular DCV layer,ICP layer between severe group and very severe group and mild to moderate group（P<0.05）,but there was no significant difference between severe group and very severe group（P>0.05）There were no significant differences in other layers of macular area,blood flow density of each layer of optic disc area and fovea between the groups（P>0.05）;3 Pearson correlation analysis between SCV layer,RFLVP layer,SVP layer,DVC layer,ICP layer and PSG monitoring indicators:there was a significant egative correlation between blood flow density,blood flow density and Tmax in SVC layer,SVP layer（r=-0.145,-0.462,P<0.05）,and there was a significant positive correlation between blood flow density,blood flow density and SpO₂min _in SVP layer,DVC layer（r=-0.320,0.314,P<0.05）;4 Multiple linear regression analysis was performed between SCV layer,RFLVP layer,SVP layer,DVC layer,ICP layer and risk factors of OSAHS:SCV layer,SVP layer were correlated with age（b=0.002,P=0.021<0.05）.Conclusion:1 OSAHS can affect the blood flow perfusion in the macular area of the inner layer of the retina.The blood flow density of the deep and shallow layers of the retina decreased,and no change in the blood flow density of the optic disc was found;2 Tmax and SpO₂min at night may be the main reasons for the decrease of retinal blood flow density in OSAHS patients;3 OCTA can provide reference value for the evaluation of OSAHS and the follow-up of treatment effect.