Avaliação psicofísica da visão espacial cromática e acromática de pacientes pós-operatórios de microcirurgia vascular para aneurismas intracranianos do sistema carotídeo

Abstract

The intracranial saccular aneurysms constitute the main cause of spontaneous meningeal or subarachnoid hemorrhage. The complications derived from the sprouting of such aneurysms hemorrhage, classified as sensorial (acuity and visual field), motor (motility of extra-ocular muscle), and perceptual, are considered as well studied by neurosurgery due to relative similarity between cases. However, little is known about possible postoperative perceptual and cognitive alterations. In the present study, the visual sensitivity of patients in postoperative condition of intracranial aneurysm of the carotid system to achromatic and chromatic spatial stimuli was evaluated. The contrast sensitivity to luminance spatial gratings was measured in eleven spatial frequencies (0,2, 0,5, 0,8, 1, 2, 4, 8, 10, 15, 20, and 30 cycles/degree). The color discrimination ability was measured by a version of the Farnsworth- Munsell test with 85 hues, divided in four series of stimuli presented sequentially, being one serie with 22 stimuli and three series with 24 stimuli. For the measure of color discrimination thresholds, 5 MacAdam’s ellipses were determined and, for each one of them, discrimination thresholds had been measured in 20 directions of the CIE 1976 color space, through the test of Mollon-Reffin. The studied variables were compared with the statistical norms of agematched control subjects. The results show that, individually, there are not significant losses of spatial contrast sensitivity. However, individual losses in color discrimination ability and individual alterations in color discrimination thresholds in all color confusion axis (protanopic, deuteranopic and tritanopic) were detected. Thus, it can be concluded that color vision have sensorial parameters which measurement can be useful in the evaluation of patients postoperative of intracranial aneurysm of the carotid system.