Peripapillary microvasculature in patients with diabetes mellitus: An optical coherence tomography angiography study

Abstract

To evaluate changes in peripapillary microvascular parameters in diabetes mellitus (DM) patients using optical coherence tomography angiography (OCTA). Seventy-one diabetic patients (40 in the no diabetic retinopathy [DR] group and 31 in the non-proliferative DR [NPDR] group) and 50 control subjects. OCTA (Zeiss HD-OCT 5000 with AngioPlex) 6 × 6 mm scans centered on the optic disc were analyzed. Peripapillary vessel density (VD), perfusion density (PD) in superficial capillary plexus (SCP) were automatically calculated. The average macular ganglion cell-inner plexiform layer (mGC-IPL) and peripapillary retinal nerve fiber layer (pRNFL) thicknesses of the no DR and NPDR groups were significantly thinner than those of the control group. The no DR and NPDR groups showed lower peripapillary VD and PD in SCP compared with the control group. Using univariate regression analyses, the average mGC-IPL thickness, the pRNFL thickness, the no DR group and NPDR group were significant factors that affected the peripapillary VD and PD in SCP. Multivariate regression analyses showed that the grade of DR was a significant factor affecting the peripapillary VD and PD in SCP. OCTA revealed that peripapillary microvascular parameters in the no DR and NPDR groups were lower than those of normal controls. The peripapillary VD and PD in SCP were correlated with the mGC-IPL thickness, the pRNFL thickness, and the no DR and NPDR groups. Changes in peripapillary OCTA parameters may help with understanding the pathophysiology of DM and evaluating a potentially valuable biomarker for patients with subclinical DR.

Figure 1

The tendency of average peripapillary area vessel density and perfusion density among groups. Boxes are 25% to 75% (lower to upper) quartiles, lines in boxes are medians, and whiskers indicate variability (minimum and maximum values). The Jonckheere–Terpstra test showed significant negative trends in the order of the control, no DR, and NPDR groups of the peripapillary area (A) vessel density and (B) perfusion density (Jonckheere-Terpstra [J-T] statistic = −5.737, p < 0.001; J-T statistic = −5.318, p < 0.001, respectively).

Figure 2

Scatter plots of association with peripapillary retinal nerve fiber layer (pRNFL) thickness in diabetic patients. The duration of diabetes, average macular ganglion cell-inner plexiform layer (mGC-IPL) thickness, peripapillary area vessel density (VD) and perfusion density (PD) in superficial capillary plexus were significantly correlated with pRNFL thicknesses. Correlation coefficients (r) and p-values are shown.

Figure 3

Optical coherence tomography angiography 6 × 6 mm scan image centered on the optic disc. The en face image of the superficial layer overlaid with the Early Treatment of Diabetic Retinopathy Study grid. The diameters of the three concentric circles are 1, 3, and 6 mm. The measurement tool (AngioPlex software, version 10.0; Carl Zeiss Meditec) provided (A) peripapillary vessel density and (B) perfusion density measurements in individual subfields. The bold box shows the automatic quantitative measurements for an average of the inner ring and outer ring. Area marked in pink shows the peripapillary area we defined.