Retinal vasculature–function correlation in non-proliferative diabetic retinopathy
To compare and correlate retinal microcirculation and function in patients with non-proliferative diabetic retinopathy (NPDR).
Thirty-three healthy controls (33 eyes), 36 diabetic patients with no clinically detectable retinopathy (NDR, 36 eyes) and 101 patients (101 eyes) with NPDR (35 mild NPDR, 34 moderate NPDR, 32 severe NPDR) were involved in the study. We used optical coherence tomography angiography (OCTA) to quantify the macular vessel density (VD) of superficial capillary plexus (SCP), deep capillary plexus (DCP) and foveal density in a 300 μm region around foveal avascular zone. Retinal function was assessed by a mydriasis-free, full-field flicker electroretinogram (FERG) recording device, and the amplitudes and implicit time were recorded. The association between microvascular parameters and FERG results was analyzed with stepwise multiple linear regression model.
Decreased amplitudes and delayed implicit time, as well as lower parafoveal/perifoveal VD in both SCP and DCP, were found in NDR group and NPDR groups compared with the control group (all p < 0.05). Specifically, the FERG parameters and microvascular indices were comparable between NDR group and mild NPDR group (all p > 0.05). However, compared to mild NPDR, the reduction in FERG amplitude was more pronounced than the reduction in parafoveal VD (both SCP and DCP) in severe NPDR. Stepwise multiple linear regression analyses showed that delayed implicit time was significantly correlated with increased age and decreased VD of parafoveal region in both SCP and DCP in patients with NPDR. Meanwhile, decreased amplitude was significantly associated with decreased VD of parafoveal region in both SCP and DCP in patients with NPDR.
Macular VD in both superficial and deep capillary plexus correlated with ERG implicit time and amplitude in mild-to-severe NPDR. OCTA and FERG may both be useful in detection of preclinical DR and early DR, but once the disease deteriorates, FERG may be more sensitive to discern progression of DR.
KeywordsDiabetic retinopathy Retinal imaging Electroretinogram Macular
This study was supported by Grant 81800829 from National Natural Science Foundation of China to Cheng Yang and Grant 81870663 from National Natural Science Foundation of China to Honghua Yu. The sponsors or funding organizations had no role in the design or conduct of this research.
Compliance with ethical standards
Statement of human rights
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Statement on the welfare of animals
No animals were used in this study.
Informed consent was obtained from all individual participants included in the study.
Conflict of interest
The authors declare that they have no conflict of interest.
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