NFL thickness was associated with age, but not with AMD or DR, whereas DR was independently associated with reduced NFLP VD, which also significantly correlated with DR severity.
Key Findings
Results
Age was independently associated with both NFL thickness and NFLP vessel density in multivariate analyses.
Study included 74 healthy controls, 101 patients with AMD, and 117 patients with DR
Imaging was performed using a Solix OCTA device centered on the optic disc
In healthy controls, age was significantly correlated with NFL thickness (Spearman's ρ = -0.26, P = 0.026)
In healthy controls, age was significantly correlated with NFLP VD (ρ = -0.32, P = 0.006)
Age associations were confirmed in both multivariate and age-matched analyses
Results
AMD was not independently associated with either NFL thickness or NFLP vessel density.
Multivariate analyses demonstrated no significant association between AMD and NFL thickness
Multivariate analyses demonstrated no significant association between AMD and NFLP VD
The lack of association with AMD was confirmed in age-matched analyses comparing AMD patients to healthy controls
One eye per participant was analyzed to avoid inter-eye correlation bias
Results
Diabetic retinopathy was independently associated with reduced NFLP vessel density but not with NFL thickness.
DR was associated with NFLP VD but not NFL thickness in multivariate analyses
This finding was confirmed in age-matched comparisons between DR patients and healthy controls
117 patients with DR were included in the study
The association was independent of age, which was also a significant covariate
Results
NFLP vessel density decreased significantly with increasing diabetic retinopathy severity.
The correlation between NFLP VD and DR severity was statistically significant (P < 0.001)
This suggests NFLP VD may serve as a marker that tracks disease progression in DR
The severity-dependent reduction was observed across DR severity groups
The findings support further investigation of NFLP VD in relation to DR while accounting for age
Methods
The study used optical coherence tomography angiography (OCTA) to measure both structural and microvascular parameters of the nerve fiber layer.
Imaging was performed with a Solix OCTA device
The device was centered on the optic disc to capture NFL thickness and NFLP vessel density
Both structural (NFL thickness) and angiographic (NFLP VD) parameters were assessed
Analyses included multivariate models and age-matched comparisons to account for confounding by age
What This Means
This research suggests that the tiny blood vessels supplying the nerve fiber layer of the eye — a thin layer of nerve tissue near the retina — are specifically affected in diabetic retinopathy (DR), and that this damage becomes worse as the disease progresses. Using a specialized imaging technique called optical coherence tomography angiography (OCTA), researchers measured both the thickness of the nerve fiber layer and the density of its blood vessels in nearly 300 participants, including healthy individuals and patients with either age-related macular degeneration (AMD) or diabetic retinopathy.
The study found that while normal aging reduces both nerve fiber layer thickness and blood vessel density over time, only diabetic retinopathy — not AMD — was additionally linked to reduced blood vessel density in the nerve fiber layer. Importantly, this reduction in blood vessel density tracked with how severe the diabetic retinopathy was, suggesting it could potentially reflect disease burden. In contrast, the physical thickness of the nerve fiber layer did not appear to be specifically affected by either AMD or DR beyond what aging alone would cause.
This research suggests that measuring blood vessel density in the nerve fiber layer using OCTA imaging may be a useful tool for understanding and monitoring diabetic retinopathy, and that future studies should account for patients' age when interpreting these measurements. The findings highlight a distinction between structural and vascular changes in the eye, pointing to microvascular damage as a potentially important feature of diabetic retinopathy that merits further investigation.
Hua X, Hormel T, Wang J, Flaxel C, Bailey S, Hwang T, et al.. (2026). Structural and Angiographic Assessment of the Nerve Fiber Layer in Age-Related Macular Degeneration and Diabetic Retinopathy.. Investigative ophthalmology & visual science. https://doi.org/10.1167/iovs.67.11.17