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A. R. Rodrigues, A. M. Bastos, M. I. T. Cortes, E. M. C. B. Lacerda, M. G. Lima, L. C. L. Silveira; Post-Surgery Psychophysical Assessment of Visual Dysfunction of Patients With Intracranial Aneurysms of the Carotid Artery. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1812.
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Psychophysical evaluation of patients which had intracranial aneurysm of the carotid artery (IACA) and were submitted to vascular microsurgery. Achromatic and chromatic spatial vision tests were used.
Patients submitted to vascular microsurgery because of IACA (n=13, 50.2±7.2 yd) were evaluated using psychophysical tests. The luminance spatial contrast sensitivity (SC) and color discrimination capabilities were evaluated. The CS was measured at 11 spatial frequencies by presenting stationary sine-wave gratings. Contrast thresholds were determined via the adjustment method. The color discrimination ability was measured by using a computer version of the Farnsworth-Munsell 100 hue test (FM100). Each target comprised a 1º square patch. The patient’s error score was measured for stimuli with 30% of purity. We used the Mollon-Reffin protocol (MR) (Mollon and Reffin, 1989) to determine patient’s color discrimination thresholds. Five reference chromaticities were used for the surround. Discrimination thresholds were evaluated along 8 chromaticity axes irradiating from the reference points and the results were plotted as MacAdam ellipses.
Patient’s results were compared with those of controls (39-60 yd) (CS, n=28, 50.9±5.5 yd; MR, n=19, 48.3±5.7 yd; FM100, n=35, 48.7±5.6 yd). The t-Student test (p<=0.05) was used for comparison. In general, patients had lower performance than controls in all psychophysical tests. Although there were no statistics differences between patients and controls (p>0.05), the former had a decrease in luminance contrast sensitivity at all spatial frequencies. For the MR test, the patients had color discrimination ellipses with larger area than controls (p<0.05). They had a poorer performance in the FM100 test than controls, making a number of non-oriented errors in the color space and showing higher scores than controls (p<0.05).
Post-surgery patients with IACA display a variable degree of chromatic and achromatic spatial vision deficit. However, the chromatic deficit is much more pronounced. These results support the necessity of performing a follow-up study of these patients, to look for recovery of their visual functions. Additionally, pre-surgery clinical variables as well as post-surgery complications and sequels may have some influence on visual dysfunctions and must be investigated.
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