Background
To evaluate visual function in patients with early type 2 Diabetes Mellitus (DM2) without diabetic retinopathy and good metabolic control, and to analyze the role of chronic systemic ischaemia in neurretina of these patients.
Methods
Sixty eyes of 60 patients with DM2 and without any signs of diabetic retinopathy, and 60 eyes of 60 healthy controls underwent visual acuity (VA), contrast sensitivity vision (CSV; using the Pelli Robson chart and CSV 1000E test), color vision (using the Farnsworth and LÂŽAnthony desaturated D15 color tests) and visual field (Easyfield perimeter) evaluation to measure visual dysfunction. A comparison between patients with different disease duration time and presence/absence of systemic vascular complications was performed.
Results
The group of patients showed worse VA at 2.50% (p=0.002) and 1.25% contrast (p=0.007), worse CSV at high spatial frequencies (12 cpd, P=0.007; 18 cpd, p=0.011), and worse color vision (Farnsworth test, p=0.006; Lanthony test, p<0.001), compared to healthy controls. Visual field parameters were similar in both groups. Patients with longer disease duration had lower results in the ETDRS test, and those patients with chronic systemic vascular complications presented worse CSV at 18 cpd (p=0.024) and color indexes in Lanthony color test (p=0.014).
Conclusions
Patients with non-severe, early, type 2 DM without diabetic retinopathy and good metabolic control present visual dysfunction compatible with retinal neurodegeneration. Subclinical ischaemia might be a contributory factor to further neuronal damage in this pathology.