Diabetes mellitus tipo 2: estudo morfofuncional com tomografia de coerência óptica e psicofísica visual

Abstract

Introduction: Type 2 diabetes mellitus is an acquired chronic disease related to the imbalance of glucose levels in the body due to lifestyle and environmental factors. Currently, this disorder is a challenge to public health because its complications affect the functionality of organs and tissues, including the eye, hampering the passage of blood and other nutrients to the retina, impairing metabolism and triggering morphological and functional changes in vision which reflect on chromatic and achromatic disorders. Objective: Evaluate the chromatic and achromatic vision in their morphological and functional aspects in people diagnosed with Type 2 Diabetes Mellitus. Methods: It was made a case-control study with a quantitative approach which evaluated 14 participants with type 2 diabetes mellitus with an average age of 57.435 ± 8.69 years old and compared to the control group evaluation results with an average age of 51, 66 ± 7.29. All participants underwent ophthalmic clinical evaluation consisting of refraction, assessment of intraocular pressure, retinography and optical coherence tomography (OCT). For comparison it was used 251.2 to 172.8 as normal range for the foveal thickness and 120.71 to 82.3 for the thickness of the optic nerve. Then the participants were submitted to a psychophysical evaluation through Lanthony D15 desaturated, Farnsworth-Munsell FM-100and the spatial luminance contrast sensitivity function-CSF. The results were tabulated in Microsoft Office Excel 2007 program and statistically analyzed by BioEstat 5.3 and D15 Analysis for MATLAB programs. The study was approved by the Research Ethics Committee of the Federal University of Amapá under the FR-278871/09 protocol. Results: The pre-clinical evaluation showed that participants had normal visual response in the Ishihara test. The ophthalmological evaluation showed that all participants had a visual acuity within the established parameters of 20/40 or better. No participant had intraocular pressure greater than 21mmHg. In the retinography no participant had a diagnosis of diabetic retinopathy and the OCT showed that the foveal thickness and the layer of optic nerve fibers presented changes of values and there were significant statistical correlation with glycated hemoglobin and blood glucose. The psychophysical evaluation showed that the visual performance of the group with T2DM was worse than the control group performance because there were statistical variations in Lanthony D15 desaturated related to the color confusion index, C-Index and S-Index. In the FM-100 test the spatial error exhibited statistical variance inthe control group. In the CSF test low and media frequencies showed greater variance in the control group as well. Conclusion: The findings show that changes in optical coherence tomography examinations were associated in at least one of the three psychophysical tests used in this study, so it is possible to conclude that morphological damage tends to impair functional. We also emphasize the presence of functional losses, even if we did not detect morphological alterations. In this way, we reinforced the importance of psychophysical tests in the monitoring of the functional capacity of the visual system, before the lesions were installed