Full text
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| Author(s): |
Thiago Leiros Costa
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Psicologia (IP/SBD) |
| Defense date: | 2010-12-13 |
| Examining board members: |
Dora Selma Fix Ventura;
Paulo Roney Kilpp Goulart;
Mirella Gualtieri
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| Advisor: | Dora Selma Fix Ventura |
| Abstract | |
Purpose: To evaluate the outcome of chronic occupational exposure to a mixture of solvents on the visual system of a group of gas station workers. Methods: 25 gas station workers (20 male; M=36,4 years old, SD=8,9) and 25 controls (10 male; M=33,8 years old, DP=8,8) with no history of chronic exposure to solvents were tested for hue discrimination and arrangement, spatial contrast sensitivity, visual field and multifocal VEPs. Urinary concentrations of toluene (M=0,3g/g of creatinine; Sd=0,16) and xylene metabolites (M=0,1 g/g creatinine; SD=0), along with the time of work (M=9,6 years; SD=6,2) were used as indicators of the exposure. The participants were submitted to an ophthalmologic examination and corrected the visual acuity to 20/20 whenever needed. All measurements were monocular (eye randomly chosen) and only one eye was tested, except for Multifocal Visual Evoked Potential (mfVEP) and the automated perimetry. Color was evaluated with the Lanthony D15d and Cambridge Colour Test 2.0. Automatic static perimetry used the white-on-white 24-2 protocol of the Humphrey Field Analyzer II-750i. Visual field was also evaluated with the mfVEP system Veris Science 5.2.4. Contrast sensitivity was measured with Metropsis software, using sine wave gratings of 0,2; 0,5; 1,0; 2,0; 5,0; 10,0 and 20,0 cpd. Results: The results for the two groups were compared using the Mann-Whitney U test. In the color discrimination test, the groups were significantly different for the thresholds in the three confusion axis tested (p<0,05), area of the ellipse (p<0,01) and ellipticity (p<0,05). In the color arrangement test, the two groups were significantly different (p<0,01). The automated perimetry results were also significantly different between groups for the 90, 150 e 210 eccentricity rings (p<0,05) and the MD and PSD values (p<0,05). Only three of the workers were tested with the mfVEP so far. All three had at least 30 sectors in the visual field 10 with significant loss of amplitude in the response (p<0,05, when compared to normative data). This result was not observed in the control group. The Spearman correlation coefficient was used to look for significant correlations between time of work and visual performance. For color vision, we found significant positive correlation between time of work and indexes of the Lanthony D15d (p=0,52; p<0,05) and deutan axis thresholds (p=0,59; p<0,05) for the CCT test. The analysis of sensitivity in eccentricity rings of perimetry data showed significant negative correlation with the time of work for the Fovea (p=-051; p<0,05) and rings of 30 (p=-0,46; p<0,05), 90 (p=-0,46; p<0,05) e 150 (p=-0,46; p<0,05). The contrast sensitivity data was not significantly correlated with time of work. Conclusions: The results presented here suggest that chronic occupational exposure to organic solvents leads to changes in the visual system function even when the exposure is within occupational safety limits. The results also suggest that the visual changes are extensive and diffuse (AU) | |
| FAPESP's process: | 09/07089-1 - Visual repercussions of the occupational exposure to solvents |
| Grantee: | Thiago Leiros Costa |
| Support Opportunities: | Scholarships in Brazil - Master |