# Clinical Significance of Conjunctival Microvascular Density in Diabetic Retinopathy: A Multimodal Correlation Study Based on Swept‐Source Optical Coherence Tomography Angiography

## TL;DR

This study explores using conjunctival blood vessel density as a potential indicator for diabetic retinopathy severity when retinal imaging is hindered.

## Contribution

The study introduces conjunctival microvascular assessment via SS-OCTA as a novel indicator for retinal damage in diabetic retinopathy.

## Key findings

- Conjunctival vessel density decreases with increasing diabetic retinopathy severity, especially in the temporal region.
- Lower conjunctival vessel density correlates with reduced retinal blood flow and thinner nerve layers.
- Conjunctival vessel density is not significantly different in diabetic patients without retinopathy compared to controls.

## Abstract

Diabetic retinopathy (DR) with media opacity presents a diagnostic challenge for retinal evaluation. This study investigated whether conjunctival microvascular assessment using swept‐source optical coherence tomography angiography (SS‐OCTA) can serve as a potential indicator of retinal pathology. We conducted a comparative study of 163 patients with diabetes (110 with DR, subdivided into 55 nonproliferative and 55 proliferative cases) and 49 age‐matched healthy controls. All participants underwent SS‐OCTA for conjunctival vessel density (VD) measurement and standard retinal OCTA for retinal VD and ganglion cell complex (GCC) analysis. Statistical correlations were performed to evaluate the relationship between the conjunctival and retinal parameters. Conjunctival VD showed a progressive reduction in DR severity, most prominently in the temporal region (70.7% in controls vs. 55.6% in patients with proliferative diabetic retinopathy [PDR]). Temporal conjunctival VD correlated well with retinal damage, and lower conjunctival density was linked to reduced retinal blood flow (r = 0.21–0.26) and thinner nerve layers (r = 0.22). No significant differences in VD were found between controls and patients with diabetes without DR, suggesting a specificity for retinopathic changes. SS‐OCTA assessment of conjunctival VD may provide clinically useful information regarding the retinal status in patients with DR with compromised fundus visualization. This approach is a practical alternative when traditional retinal imaging is obstructed by media opacities.