[Impaired visual pathway functions in patients with type 1 diabetes]

The study was undertaken to examine visual pathway function by psycho- and electrophysiological studies in patients with type 1 diabetes. Sixty-three patients (age 25±2.3 years) with moderate type 1 diabetes in a subcompensated state (mean HbA1c 7.4±0.2%), including 32 patients without diabetic retinopathy (DR) and 31 patients with nonproliferative diabetic retinopathy were examined. A control group consisted of 30 healthy individuals. The complex of diagnosis included critical flicker frequency test, retinal light and contrast sensitivity threshold tests, electroretmography (ERG), and studies of optic nerve lability and visual evoked potentials (VEP). A comprehensive study established functional visual pathway abnormalities that were undetectable on routine ophthalmologlcal examination. Lower ERG "a" wave amplitudes, higher latency, and reductions in the amplitude of VEP P100 peak and in spatial contrast sensitivity for low frequencies were of the greatest value in the diagnosis of diabetic abnormalities of the visual pathway. Visual pathway lesions are detectable in patients with type 1 diabetes without DR. In the latter, these lesions are more pronounced.