# Radial peripapillary capillary changes and retinal nerve fiber layer alterations in diabetic foot ulcers with mild-to-moderate nonproliferative diabetic retinopathy: an OCTA study

## TL;DR

This study finds that diabetic foot ulcers are linked to retinal blood vessel and nerve changes in patients with mild-to-moderate diabetic retinopathy.

## Contribution

The study is the first to link diabetic foot ulcers with radial peripapillary capillary and retinal nerve fiber layer changes in nonproliferative diabetic retinopathy.

## Key findings

- DFU patients had significantly lower radial peripapillary capillary density compared to controls and NPDR-only patients.
- RNFL thickness was increased in DFU patients, especially in the inferior-hemi and temporal-inferior quadrants.
- Optic disc area was larger in DFU patients, possibly influencing RNFL measurements.

## Abstract

This study aimed to evaluate the impact of diabetic foot ulcers (DFUs) on retinal microvascular changes, specifically the radial peripapillary capillary (RPC) vessel density and retinal nerve fiber layer (RNFL) thickness in patients with mild-to-moderate nonproliferative diabetic retinopathy (NPDR).

Ninety participants were enrolled and divided into three groups: 30 patients with DFUs and mild-to-moderate NPDR, 30 patients with NPDR but without DFUs, and 30 healthy controls. RPC density and RNFL thickness were evaluated using optical coherence tomography angiography (OCTA), a noninvasive imaging method. Comparisons between groups were made with statistical adjustments, including optic disc area.

Patients with DFUs exhibited significantly lower RPC vascular density across multiple quadrants than those without DFUs and healthy controls (p < 0.001). Furthermore, RNFL thickness was significantly increased in the DFU group, particularly in the inferior-hemi (p < 0.001) and temporal-inferior (p < 0.001) quadrants. The optic disc area was significantly larger in the DFU group (p = 0.017), which may have influenced the RNFL measurements.

The study underscores notable alterations in RPC density and RNFL thickness among patients with DFUs and mild-to-moderate NPDR. These alterations may reflect systemic microvascular impairment, potentially exacerbated by systemic inflammation, or changes suggestive of reactive gliosis, though further validation is needed. These findings underscore the need for early ophthalmological evaluation and a comprehensive approach to managing both peripheral and ocular diabetic complications. Future studies incorporating systemic inflammatory biomarkers and functional visual assessments are needed to explore the mechanisms underlying these retinal changes.