Diagnostic capability of perimetry and optical coherence tomography based retinal thickness measurements in diabetic patients with no or mild retinopathy.

Purpose

This study aimed to compare and evaluate the diagnostic potential of visual field parameters and different retinal layers thicknesses among diabetic patients with and without diabetic retinopathy and non-diabetic controls.

Methods

A total of 174 participants were enrolled and divided equally into three groups of 58 subjects: (1) healthy controls, (2) diabetic patients without diabetic retinopathy (NoDR), and (3) diabetic patients with mild non-proliferative diabetic retinopathy (NPDR). Retinal layer thicknesses (eight layers × five macular sectors) and visual field (mean deviation, MD; pattern standard deviation, PSD) were compared using one-way ANOVA with Tukey post-hoc testing. Pearson correlations between MD/PSD and retinal layer thickness were computed to test structure-function association.

Results

Temporal NFL thickness was markedly greater in NPDR (25.14 ± 8.62 µm) than in NoDR (19.43 ± 4.17 µm) or controls (19.34 ± 5.15 µm; P < 0.001), and this difference persisted after age adjustment (P < 0.001). MD showed good diagnostic performance for NoDR vs control (AUC 0.766) and NPDR vs control (AUC 0.876), outperforming PSD (AUC 0.646 and 0.719, respectively); the NoDR-vs-control MD difference remained significant after age adjustment (P = 0.011) but was substantially attenuated, and the PSD group difference was fully explained by age (age-adjusted P = 0.80). No meaningful correlation was found between MD/PSD and any retinal layer thickness (all |r| < 0.21).

Conclusion

Temporal NFL thickening in NPDR and reduced visual field MD represent the most robust structural and functional abnormalities in this study.