Neurovisual abnormalities preceding the retinopathy in patients with long-term type 1 diabetes mellitus

• Published in: Graefe's archive for clinical and experimental ophthalmology 2001-09, Vol.239 (9), p.643-648
• Main Authors: MENDONCA LOPES DE FARIA, Jacqueline, KATSUMI, Osamu, CAGLIERO, Enrico, NATHAN, David, HIROSE, Tatsuo
• Format: Article
• Language: English
• Subjects: Adult; Area Under Curve; Associated diseases and complications; Biological and medical sciences; Case-Control Studies; Contrast Sensitivity - physiology; Diabetes Mellitus, Type 1 - diagnosis; Diabetes Mellitus, Type 1 - physiopathology; Diabetes. Impaired glucose tolerance; Diabetic Retinopathy - diagnosis; Diabetic Retinopathy - physiopathology; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Evoked Potentials, Visual - physiology; Female; Humans; Male; Medical sciences; Middle Aged; Ophthalmology; Retina - physiopathology; Vision Disorders - diagnosis; Vision Disorders - physiopathology; Visual Acuity - physiology; Visual Pathways - pathology
• ISSN: 0721-832X; 1435-702X
• DOI: 10.1007/s004170100268

Changes in the retina caused by diabetes may lead to visual impairment in dim light, even with good visual acuity and visual fields. To evaluate the visual abnormalities preceding the retinopathy in patients with type 1 diabetes mellitus (DM), we applied electrophysiological methods. The visual evoked responses were recorded with sinusoidally modulated vertical gratings at 10 spatial frequencies presented sequentially on a high-resolution monitor in patients with type 1 DM and in normal volunteers. Similarly, the contrast visual evoked responses of 10 contrast levels were recorded at five spatial frequencies. Both amplitudes at the second harmonic were calculated by discrete Fourier transform. The visual acuity and contrast thresholds were determined objectively. There was dissociation between the Snellen and the estimated visual evoked response acuity measurements in patients with diabetes (r2=0.077, P=0.44). The saturation phenomena were observed at lower levels of contrast stimuli than in normal individuals at. 1.0, 2.0, 4.0 and 8.0 cycles per degree (P=0.0001). The contrast sensitivity function was deeply abnormal in all tested patients despite the metabolic control. The values of the area under the curve of the visual evoked response amplitude-contrast level function at five spatial frequencies were smaller in patients with DM than in the control group (P