Application Of Optical Coherence Tomography Angiography In Observing Microvascular Change In Macular Area Of Patients With Early Diabetic Retinopathy

Object: To observe the changes of microvascular in macular area of patients with early stages of diabetic retinopathy by optical coherence tomography angiography,and analyze the clinical significance of OCTA in early DR screening,monitoring,diagnosis and treatment.Methods: Retrospective analysis of 27 diabetic patients(52 eyes)treated in the ophthalmology clinic of The First Affiliated Hospital Of China Medical University from May 2019 to October 2019,those patients were examined by the same experienced ophthalmologist.According to the international clinical staging standard of diabetic retinopathy established in 2002,the patients were divided into 12 cases(24 eyes)of the non-DR group(NoDR group)and 15 cases(28 eyes)of the mild nonproliferative diabetic retinopathy group(mild NPDR group).In addition,18 cases(30 healthy eyes)matched by age and gender were selected as the normal control group.The general information and ophthalmic examination data of each group were collected.The general information included age and gender.In addition,diabetes patients included the course of diabetes,glycosylated hemoglobin(HbA1c)value and serum creatinine value.Ophthalmic examination data included naked eye sight,corrected visual acuity,optometry,intraocular pressure,slit lamp examination,fundus examination after mydriasis,fundus color photography,and OCTA examination.The area and average blood vessel density of the foveal avascular zone(FAZ)in the superficial retinal capillary plexus(SCP)and deep rentinal capillary plexus(DCP)were quantitatively analyzed by scanning the macular area with the range of 6mm×6mm using the Angio Retina mode in Heidelberg OCTA instrument,it is also compared with HbA1 c and serum creatinine.At the same time,qualitative analysis of SCP and DCP blood flow images in the macular area of microvascular morphological abnormalities,such as microaneurysms,abnormal arch ring morphology,capillary non-perfusion areas and vascular tortuosity.Results: The FAZ area of SCP in the normal control group,NoDR group and the mild NPDR group are 0.45±0.12mm~2?0.59±0.13mm~2?0.62±0.15mm~2;the FAZ area of DCP are 0.31±0.07 mm~2?0.43±0.15mm~2?0.45±0.11mm~2;the blood vessel density ofSCP are 29.91±4.82%?25.07±3.81%?23.96±6.52%;the blood vessel density of DCP are 26.14±5.66%?22.12±6.13%?17.54±5.66%.Compared with the normal control group,the FAZ area of SCP and DCP increased in the NoDR group,and the blood vessel density decreased in the NoDR group.The differences were statistically significant(all P<0.05).Compared with the normal control group,the FAZ area of SCP and DCP increased in the mild NPDR group,and the blood vessel density decreased in the mild NPDR group.The differences were statistically significant(all P<0.05).Compared with the NoDR group,the blood vessel density of DCP decreased in the mild NPDR group,and the difference was statistically significant(P<0.05).The FAZ area and blood vessel density of the SCP and the FAZ area of the DCP weren't significantly different form those of the NoDR group(all P>0.05).The FAZ area of SCP and DCP in the DM patients included in the study was not correlated with HbA1c(all P>0.05).The vessel density of SCP and DCP was not correlated with HbA1c(all P>0.05).The FAZ area of SCP and DCP in DM patients was not correlated with the serum creatinine(all P>0.05).The vessel density of SCP and DCP was not correlated with creatinine(all P>0.05).In 24 eyes of the NoDR group,3 eyes with microaneurysms,accounting for 12.5%;5 eyes with abnormal arch ring morphology,accounting for 20.8%;6 eyes with the non-perfusion area of capillary,accounting for 25%;2 eyes with vascular tortuosity,accounting for 8.3%.In 28 eyes of the mild NPDR group,13 eyes with microaneurysms,accounting for 46.4%;14 eyes with abnormal arch ring morphology,accounting for 50%;14 eyes with the non-perfusion area of capillary,accounting for50%;9 eyes with vascular tortuosity,accounting for 32.1%.In 52 eyes of DM patients,microaneurysms were found in 16 eyes.Among them,there were 3 eyes of microaneurysms in SCP and DCP layers,2 eyes in SCP layer and 11 eyes in DCP layer.The number of SCP and DCP microaneurysms was 1.33±0.52 and 2.33±0.97 respectively,and the number of microaneurysms in DCP layer was more than that in SCP layer,the difference was statistically significant(P<0.05).Conclusion: 1.Before the early lesions of DR were found in the fundus examination after mydriasis under slit limp,OCTA could detect the damage of retinal microcirculation in the macular area,including the increase of FAZ area and the decrease of vessel density in SCP and DCP layer,and the abnormal morphological changes of macular microvessels;2.With the development of DR lesions,the vessel density in DCP layer decreased;3.The number of microaneurysms in DCP layer in early DR was more than that in SCP layer.4.FAZ area and vessel density of SCP and DCP layer were not correlated with HbA1 c and serum creatinine of patients with DM.