PurposeTo compare intra-retinal layer thickness measurements between eyes with no or mild diabetic retinopathy (DR) and age-matched controls using Spectralis spectral-domain optical coherence tomography (SD-OCT).MethodsCross-sectional observational analysis study. High-resolution macular volume scans (30° * 25°) were obtained for 133 type 2 diabetes mellitus (T2DM) patients with no DR, 42 T2DM patients with mild DR and 115 healthy controls. The mean thickness was measured in all 9 Early Treatment Diabetic Retinopathy Study (ETDRS) sectors for 8 separate layers, inner retinal layer (IRL), outer retinal layer (ORL) and total retina (TR), after automated segmentation. The ETDRS grid consisted of three concentric circles of 1-, 3-, and 6-mm diameter. The superior, inferior, temporal, and nasal sectors of the 3- and 6-mm circles were respectively designated as S3, I3, T3, and N3 and S6, I6, T6, and N6. Linear regression analyses were conducted to evaluate the associations between the intra-retinal layer thicknesses, age, diabetes duration, fasting blood glucose and HbA1c.ResultsThe mean age and duration of T2DM were 61.1 and 13.7 years, respectively. Although no significant differences in the average TR and ORL volumes were observed among the groups, significant differences were found in the volume and sectorial thicknesses of the inner plexiform layer (IPL), outer plexiform layer (OPL) and IRL among the groups. In particular, the thicknesses of the IPL (S3, T3, S6, I6 and T6 sectors) and the IRL (S6 sector) were decreased in the no-DR group compared with the controls (P < 0.05). The thickness of the OPL (S3, N3, S6 and N6 sectors) was thinner in the no-DR group than in mild DR (P < 0.05). The average IPL thickness was significantly negatively correlated with age and the duration of diabetes.ConclusionThe assessment of the intra-retinal layer thickness showed a significant decrease in the IPL and IRL thicknesses in Chinese adults with T2DM, even in the absence of visible microvascular signs of DR.

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Background To (i) evaluate the variations in the foveal avascular zone area (FAZ), vessel density (VD) and foveal ganglion cell layer (GCC) thickness changes in diabetic retinopathy (DR), as demonstrated by OCT angiography (OCTA) and (ii) correlate these variations. Methods This study was a retrospective observational case series of patients with DR. We studied a total of 64 eyes from patients with diabetic mellitus (DM), including 34 eyes with DR (DR group) and 30 eyes with DM without DR (NDR group). Additionally, 20 age-matched normal people were included as the control group. OCTA was performed using an NIDEK RS-3000 Advance device. Retinal capillary VD, FAZ area and GCC thickness were measured in the foveal regions (3*3 mm). Results The FAZ areas in the superficial (SRL) and deep capillary plexus layer (DL) were significantly enlarged in both the NDR and DR groups compared with the control group (p<0.05). In both the NDR and DR groups, the mean VD% in the SRL/DL, the SupGCC and InfGCC thickness were significantly decreased compared with the control group (P<0.05). No significant difference was observed between the NDR and DR groups for these measurements. Multivariable linear regression showed that the AvgGCC thickness was correlated with FAZ area (b=-11.372, p=0.001) and VD% (b=0.752, p=0.007) in the DL. Conclusions The FAZ area, mean VD% and GCC thickness in DR patients were differed compared with healthy controls. The AvgGCC thickness was correlated with FAZ area and VD% in the DL.

Background: To perform a quantitative analysis of retinal microvasculature in patients with early stage diabetic retinopathy (DR) using wide-field swept-source OCTA (SS-OCTA).Methods: 119 eyes of 119 patents (67 eyes with no DR and 52 eyes with mild-moderate NPDR) were enrolled in this observational and cross-sectional cohort study, and an age-matched group consisting of 39 eyes of 39 non-diabetic subjects were set as the control. Each participant underwent a full ophthalmic examination, including wide-field SS-OCTA imaging. On OCTA scans (12mm * 12mm), the mean perfusion area (PA) and vessel density (VD) were independently measured in all 16 Early Treatment Diabetic Retinopathy Study (ETDRS) sectors. Linear regression analyses were conducted to evaluate the influences of PA.Results: In the central ring, there were no significant differences in the average PA and VD among the groups. In the 3 mm radius, the PA and VD of the no DR and mild-moderate NPDR were significant decreased compared with the control group in superior and inferior quadrants. In the wide-field scans (9 and 12mm radius), there was no significant difference in average PA and VD between the groups in each sectors (p>0.05). Regression analysis found that the effect of VD on PA was statistically different (p<0.001).Conclusion: Wide-field SS-OCTA allows for a more thorough assessment of retinal changes in patients with early-stage DR. Decrease in PA and VD was greater in the S3 and I3 sectors, and reductions in PA and VD were uneven in wide-filed sectors (9 and 12mm radius).