| Research backgroundDiabetic retinopathy(DR)is one of the most common complications of diabetes,which has attracted more and more attention with the increasing prevalence of diabetes.Diabetic retinopathy is a microvascular change caused by diabetes,and the choroid is a highly vascularized structure,which is responsible for the supply of blood and nutrition in the outer layer of the retina,and participates in the composition of the blood-retinal outer barrier.The change of its structure can affect the function of the retina.At present,it is not clear whether diabetic choroidopathy occurs before diabetic retinopathy,and the relationship between them has not been determined.With the emergence and development of enhanced Depth Imaging Spectral Domain Optical Coherence Tomography(EDI SD-OCT),a method for in vivo non-invasive quantitative evaluation of choroidal structure is provided,and the measurement of choroidal volume(CV)and choroidal vascular index(CVI)is realized.In this study,CV and CVI were introduced as evaluation indexes,and EDI-OCT was used to explore the changes of choroidal structure in diabetic patients without retinopathy,so as to provide monitoring indicators for early detection of diabetic retinopathy,and provide inspiration and basis for further study of the relationship between diabetic retinopathy and diabetic choroidopathy.Objective:To observe the changes of choroidal volume and choroidal vascular index in type 2 diabetic patients without diabetic retinopathy by using EDI SD-OCT.Methods:42 diabetic patients(65 eyes)without diabetic retinopathy were included in this project as diabetic group,and 34 volunteers without diabetes mellitus(65 eyes)constituted the control group.To measure choroidal volume and choroidal vascular index,all subjects were accepted EDI-OCT examination,and their choroidal images were collected.In addition,the general data and relevant eye data of the research subjects were collected.The difference of choroidal volume and choroidal vascular index between the two groups was analyzed.In addition,the correlation between the parameters and choroidal volume or choroidal vascular index was analyzed,as well as the correlation between choroidal vascular index and choroidal volume.Results:There was no significant differences in age,gender composition,ocular axis,intraocular pressure and diopter between the diabetes group and the control group.The total choroidal volume and the corresponding volume of nine regions in the diabetic group were lower than those in the control group,and there were significant differences in total choroidal volume and the corresponding volume of nine regions between the two groups.The CVI of the control group and the diabetic group were(0.66±0.04)and(0.64 ±0.05)respectively.Compared with the control group,the average values of TCA,LA and CVI in the diabetes group were lower and the average value of SA was higher than that of the control group.Except for CVI and LA,there was no significant difference in TCA and SA between the two groups.The correlation analysis showed that there was a negative correlation between the choroidal vascular index and the course of diabetes.The total choroidal volume and the volume of the central ring of the choroid were positively correlated with CVI.There was no statistical difference in the other correlation analysis.Conclusion:The choroidal volume and choroidal vascular index in patients with non-diabetic retinopathy are smaller than those in normal subjects,suggesting that there had been changed in choroidal structure before the occurrence of retinopathy in the macular area.Choroidal vascular index decreases as prolonging of the course of diabetes.Choroidal volume and choroidal vascular index can be quantitatively observed by EDI-OCT in patients with type 2 diabetes mellitus,which can provide evidence for the early diagnosis of diabetic retinopathy. |
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