Retinal diabetic neuropathy causes visual impairment through the degeneration of neurons in the retina. Combining evidence from patients and mouse models, Researchers demonstrate that retinal diabetic neuropathy causes progressive neuronal damage before signs of vascular abnormalities appear.
Using an imaging technique called optical coherence tomography, the authors found that the nerve fiber layer and ganglion cell/inner plexiform layer became progressively thinner over a 4-year period in 45 patients with type 1 diabetes. The retinal tissue layers were also thinner in six donor eyes from deceased diabetic individuals, compared with nondiabetic controls, even though retinal capillary density was not different between the two groups.
Similarly, mouse models of type 1 and type 2 diabetes showed significant, progressive thinning of the two tissue layers, but no vascular abnormalities, compared with nondiabetic control mice. Taken together, the results suggest that retinal diabetic neuropathy is a progressive condition that precedes diabetes-induced vascular changes.
According to the authors, the findings could aid the development of treatment options for retinal diabetic neuropathy and potentially other forms of diabetic eye disease.