The Determination of Type 2 Diabetes Mellitus’s Impact on the Density of Retinal Blood Vessels and the Choriocapillaris: Optical Coherence Tomography Angiography Study

Abstract

Optical coherence tomography angiography (OCTA) was used to analyze the alterations in the density of retinal blood vessels and the choriocapillaris (VD) in patients suffering from type 2 diabetes mellitus (T2DM). One hundred sixty-six eyes of 83 patients (43 of whom were men and 40 women, with a mean age of 58.59 ± 14.04) with T2DM and without diabetic retinopathy were examined for the purpose of conducting the observational prospective study. The control group (CG) consisted of 66 eyes in 33 healthy subjects (15 male and 18 female, with a mean age of 55.12 ± 12.70). The measurement regions of vessel density (VD) included the deep capillary plexus (DCP), the superficial capillary plexus (SCP), and the choriocapillaris. The results indicate considerable differences in the VD of the DCP and SCP when comparing the control group with the study groups ( p < 0.001 ). In comparison with the control group ( p < 0.001 ), there was a statistically significant reduction in the VD of the choriocapillaris in the study group. Furthermore, patients with T2DM showed a significantly decreased VD concerning the control in different macular regions. Thickness in several macular regions in the study group significantly decreased compared to the ones in the control group. OCTA was used to gather relevant information about the vascular changes which occurred in T2DM patients, assessed through the quantitative analysis of the blood flow in the retina and choriocapillaris.

Reduced macular thickness and vascular density in abnormal glucose metabolism patients: A meta-analysis of optical coherence tomography (OCT) and OCT angiography studies

“…The basic characteristics of the included studies are summarized in Table 1, which comprised 13,773 participants and 15,416 eyes from 23 countries worldwide. In all the studies, there were participants with T2D ( n = 49), [2–6,9,19,21,26–29,32,38–73] T1D ( n = 27), [1,17,18,20,24,30–32,36,37,46,55,56,70,71,74–85] T1D/T2D mixed ( n = 9), [22,25,33,86–91] prediabetes ( n = 5) [9,10,42,92,93] and unclear ( n = 4). [16,94–96]…”

“…Then, the source of heterogeneity was explored by eliminating the literature individually. The three reports [ 47 , 49 , 94 ] were the main sources of heterogeneity for OCT-related outcomes, while the other four studies [ 36 – 38 , 57 ] produced substantial heterogeneity among the variables detected by OCTA [Table 3 ]. Similarly, after excluding studies with greater heterogeneity, the conclusions about the three variables above were also reversed [Table 3 ].…”

Choroidal changes in patients with diabetic retinopathy

“…The relationship between the choriocapillaris and retinal vascular plexus is another issue that is not well understood. Reviewing previous reports, most of them included patients with DR of all severities and reported that both retinal capillary plexus density and choriocapillaris density decreased along with more severe DR [9,10,[28][29][30]. According to the report of Lupidi et al [11], choriocapillaris vascular perfusion density (VPD) was negatively correlated with deep capillary plexus VPD of the retina in low-grade DR.…”

“…Choriocapillaris ow was found to be decreased in DR patients [9,10]. However, there are limited data on the relationship between choriocapillaris ow and other parameters, such as retinal vascular density and CTh.…”

“…Several previous studies have reported that choroidal changes in diabetic patients might have an important role in the development of DR. [1][2][3][4] With the advancements in optical coherence tomography (OCT) technology, previous studies have demonstrated several choroidal changes associated with DR. These choroidal changes included choroidal thickness (CTh) [5][6][7][8], choroidal vascular index (CVI) [9][10][11][12] and choriocapillaris ow. Unfortunately, there were con icting results on diabetic choroidal changes according to previous studies.…”