Abstract
Purpose :
To investigate the correlations between retinal vessel calibers and neurodegeneration in patients with type 2 diabetes and no or mild diabetic retinopathy (DR).
Methods :
We included baseline data of 440 patients with type 2 diabetes from a 2-year prospective, interventional, clinical, multicenter trial (EUROCONDOR, NCT01726075). For the study eye, 7-field 30-35° color fundus photos were used to grade for DR, and patients with ETDRS-levels 10-35 were included in the trial. Disc-centered images were analyzed for retinal vessel diameters with semi-automatic software (IVAN). Calibers were summarized into central retinal artery and vein equivalent (CRAE and CRVE). Spectral Domain OCT and multifocal electroretinography (mf-ERG) was used to measure structural and functional neurodegenerative changes, respectively.
Results :
Median age and duration of diabetes was 64 and 10.3 years, and 66.1% were men. ETDRS levels were 10 (42.3%), 20 (37.5%) and 35 (30.2%). Median CRAE and CRVE was 146.7 µm and 215.3 µm. CRAE did not differ according to ETRDS-level (p=0.12), but wider CRVE were found in patients with higher levels of DR (214.5 µm, 213.2 µm and 216.6 µm for ETDRS-levels 10, 20 and 35, respectively, p=0.04). In univariate analyses, CRAE correlated with ganglion cell layer (GCL) thickness (r=0.25, p<0.01) and mean mf-ERG amplitude of ring 1-6 (r=0.10, p=0.03). CRVE correlated with GCL thickness (r=0.19, p<0.01) and retinal nerve fiber layer (RNFL) thickness (r=0.11, p=0.02). Positive correlations between CRAE and mf-ERG amplitudes (ring 2, 3, 5, 6 and mean, p<0.01-0.03) were found in patients with ETDRS-level 20, but not in level 10 or 35. CRVE correlated inversely with mf-ERG implicit time in patients with ETDRS-level 10 (ring 3-6 and mean, p=0.02-0.04), but positively in patients with ETDRS-level 20 (ring 4, 6 and mean, p=0.01-0.02). In an overall multivariable linear regression model, CRAE was associated with GCL thickness (coefficient 0.19 per µm, p<0.01), and CRVE was correlated with RNFL thickness (coefficient 0.13 per µm, p<0.01).
Conclusions :
Retinal vessel calibers were independently associated with structural and functional neurodegeneration. Different correlations were found in patients with no and minimal DR. This suggests a complex neurovascular interaction in the early stages of DR.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.