Purpose To investigate and quantify peripapillary vascular and neuronal changes secondary to diabetic retinopathy, using spectral-domain optical coherence tomography (OCT) and OCT angiography (OCTA).
Design This was a cross-sectional study.
Methods 51 eyes of 51 patients affected by non-proliferative diabetic retinopathy (NPDR) and 19 age-matched healthy control eyes underwent full ophthalmic examination, including OCT and OCTA in the peripapillary area. Vessel area density (VAD), vessel length fraction (VLF) and vessel diameter index (VDI) were quantified in a ring-shaped region of interest of each OCTA image. Capillaries and larger vessels were separately analysed. The thickness of the peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell complex (GCC) was also analysed.
Results VAD and VLF of peripapillary capillaries were significantly reduced in NPDR eyes, along with the progression of NPDR (p<0.05). VDI was significantly reduced in mild (p=0.0093) and moderate (p=0.0190) NPDR eyes, but not in severe NPDR (p=0.0841). Larger peripapillary vessels showed a significant increase of both VAD and VDI in NPDR eyes. pRNFL and GCC thickness decreased in NPDR eyes, reaching statistical significance only for GCC. No statistically significant correlation was found between perfusion parameters and pRNFL and GCC thickness.
Conclusions Retinal capillary remodelling in NPDR involves the peripapillary vascularisation too, as confirmed by OCTA quantitative parameters. The peripapillary macrovasculature and microvasculature need to be separately evaluated. The lack of direct correlation between peripapillary capillaries changes and the loss of retinal nerve fibres suggests that neuronal damage cannot be simply considered secondary to the microvascular one.
- Optic Nerve
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Contributors EM, LF, RP: study conception, design, interpretation of data, drafting and revising; final approval and agreement to be accountable for all aspects of the work. EP, DL: data acquisition/analysis/interpretation, drafting and revising of work, final approval and agreement to be accountable for all aspects of the work.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. The research contribution by the G.B. Bietti Foundation was supported by Fondazione Roma and Ministry of Health.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article.
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