Association of neuroretinal parameters with diabetic neuropathy and nephropathy

To evaluate OCT based associations of retinal neuropathy with nephropathy and peripheral neuropathy in a cohort of 100 diabetic patients utilizing eGFR, nerve conduction velocity (NCV) and ganglion cell layer (GCL) and retinal nerve fibre layer (RNFL) thickness as potential neuroretinal biomarkers of diabetic microvascular damage.

TOPCON: 3D OCT-1 Maestro version 8.3 X; Glaucoma analysis in the macula, 3D: macula V mode was used for obtaining mean layer thickness of 7mm x 7mm area surrounding the fovea after automated segmentation of SD-OCT images. eGFR and NCV were recorded.

Statistical analysis: -SPSS 20 statistical software package was utilized for analysis. Bivariate correlation analysis was done for determining relationship between nerve conduction velocities of sensory and motor nerves, eGFR and mean RNFL and GCL thickness. Regression analysis and Chi-square test was done to evaluate the extent of these associations.

There was strong interrelationship between all variables except triglycerides which had a minimal effect on age and duration of diabetes. Regression analysis showed significant association between eGFR and RNFL or GCL thickness (F=14.40; F=10.18) but not between nerve conduction velocity and the same (F=1.76;F=2.62) but Chi-square revealed significant relationship between grades of nephropathy (x² =25.87; p<0.001 for RNFL, x²=12.943;p<0.005 for GCL) neuropathy (x²=12.94;p=0.44 for RNFL, x²=25.65;p=0.002 for GCL) with RNFL and GCL thickness.

The study provides evidence of the concept that such a classification is possible but larger population based studies are needed for framing a dependable and flawless corroboration.