Nonselective loss of contrast sensitivity in visual system testing in early type I diabetes
| Autor: | Aldo V. Greco, Salvatore Caputo, Vittorio Porciatti, Angelo Maria Minnella, Giovanni Ghirlanda, Benedetto Falsini, M. A. S. Di Leo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1992 |
| Předmět: |
Adult
Male medicine.medical_specialty Endocrinology Diabetes and Metabolism media_common.quotation_subject Audiology Visual system Retinal ganglion Contrast Sensitivity psychophysical test Reference Values Foveal Internal Medicine medicine Psychophysics Humans Contrast (vision) Fluorescein Angiography media_common Glycated Hemoglobin Advanced and Specialized Nursing diabetes Diabetic Retinopathy business.industry Settore MED/30 - MALATTIE APPARATO VISIVO medicine.disease Surgery Diabetes Mellitus Type 1 Optic nerve Female Spatial frequency business Retinopathy |
| Popis: | Objective Psychophysical methods in patients with diabetes mellitus reveal deficits of central or foveal vision. Our aim was to evaluate the contrast-sensitivity thresholds in 24 insulin-dependent (type I) diabetic patients with a short disease duration and without retinopathy, taking into account metabolic control. Research Design and Methods The control group consisted of age-matched nondiabetic subjects. None had visual or systemic symptoms. Contrast sensitivity measured at eight different spatial frequencies to sinusoidal bar patterns of 0.6–12.2 cycles/deg can detect functional defects in the spatially sensitive retinal ganglion cells or in higher visual pathways. We performed two different temporal types of contrast-sensitivity testing, dynamic (8 Hz) and static (0 Hz). Results Significant losses with dynamic contrast-sensitivity test at all but the highest spatial frequencies (i.e., 12.2 cycles/deg) were shown, whereas there was significant attenuation of contrast sensitivity at five spatial frequencies (1.0, 1.4, 2.2, 7.1, and 9.6 cycles/deg) in the static mode. Grating losses ( Conclusions Our results suggest an early, generally nonselective neuronal damage of visual pathways that occurs before the onset of clinically detectable retinopathy. The visual deficit may be related directly to the effects of diabetes; repetitive minor hypoglycemic insults may contribute more than a marked hyperglycemic condition to the mechanisms underlying physiological changes along the optic nerve. |
| Databáze: | OpenAIRE |
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