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Indhushree R, Monica R, Coral K, Angayarkanni N, Punitham R, Subburathinam BM, Krishnakumar R, Santanam PP. Visual functions of workers exposed to organic solvents in petrochemical industries. Indian J Occup Environ Med 2017; 20:133-137. [PMID: 28446838 PMCID: PMC5384391 DOI: 10.4103/0019-5278.203138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
AIM The purpose of this study was to evaluate the visual functions of workers exposed to organic solvents in petrochemical industries. MATERIALS AND METHODS Thirty workers from the petroleum refinery and 30 age-matched controls (mean age) were recruited. Visual functions and occupational exposure levels were assessed among both the groups. Visual acuity, contrast sensitivity, color vision, and visual fields were evaluated at the workplace. The biological samples, namely blood and urine, were collected at the workplace and transported to the laboratory for analysis. The urinary excretion of hippuric and methylhippuric acid as well as creatinine was measured by high performance liquid chromatography. RESULTS The mean age of the workers and controls were 39.7 ± 7.6 years and 38.6 ± 8.1, years respectively. The mean years of experience of the workers were 15.6 ± 6.8 years. Visual acuity was >0.01 LogMAR among both the control and case groups. The contrast sensitivity was reduced at 12cpd among workers. Comparison between groups was done using independent sample t-test. The mean difference in color confusion index was 0.11 ± 0.05 (P = 0.037*). The mean difference in visual fields was -0.31 ± 0.36 dB (P = 0.933). The mean difference in urinary hippuric acid level (urinary metabolite of toluene) between the groups was 0.19 ± 0.96 g/g creatinine (P = 0.049FNx01). The mean difference in the excretion of methylhippuric acid (urinary metabolite of xylene) was 0.06 ± 0.04g/g creatinine (P = 0.154). We also found that exposure was a significant risk factor for color vision defect with an odds ratio of 4.43 (95% CI: 1.36-14.4); P = 0.013. CONCLUSION The study results showed that contrast sensitivity and color vision were affected among workers in petrochemical industry.
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Affiliation(s)
- R Indhushree
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India.,Occupational Optometry Service, Sankara Nethralaya, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India
| | - R Monica
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India.,Occupational Optometry Service, Sankara Nethralaya, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India
| | - K Coral
- R S Mehta Jain Department of Biochemistry and Cell Biology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Narayanasamy Angayarkanni
- R S Mehta Jain Department of Biochemistry and Cell Biology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - R Punitham
- Sri Nathella Sampathu Chetty Clinical Laboratory, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India
| | - B M Subburathinam
- Occupational Hygienist, Chennai Petroleum Corporation Limited, Chennai, Tamil Nadu, India
| | - R Krishnakumar
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India.,Occupational Optometry Service, Sankara Nethralaya, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India
| | - P P Santanam
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India.,Occupational Optometry Service, Sankara Nethralaya, Unit of Medical Research Foundation, Chennai, Tamil Nadu, India
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Guyton KZ, Hogan KA, Scott CS, Cooper GS, Bale AS, Kopylev L, Barone S, Makris SL, Glenn B, Subramaniam RP, Gwinn MR, Dzubow RC, Chiu WA. Human health effects of tetrachloroethylene: key findings and scientific issues. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:325-34. [PMID: 24531164 PMCID: PMC3984230 DOI: 10.1289/ehp.1307359] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 02/11/2014] [Indexed: 05/07/2023]
Abstract
BACKGROUND The U.S. Environmental Protection Agency (EPA) completed a toxicological review of tetrachloroethylene (perchloroethylene, PCE) in February 2012 in support of the Integrated Risk Information System (IRIS). OBJECTIVES We reviewed key findings and scientific issues regarding the human health effects of PCE described in the U.S. EPA's Toxicological Review of Tetrachloroethylene (Perchloroethylene). METHODS The updated assessment of PCE synthesized and characterized a substantial database of epidemiological, experimental animal, and mechanistic studies. Key scientific issues were addressed through modeling of PCE toxicokinetics, synthesis of evidence from neurological studies, and analyses of toxicokinetic, mechanistic, and other factors (tumor latency, severity, and background rate) in interpreting experimental animal cancer findings. Considerations in evaluating epidemiological studies included the quality (e.g., specificity) of the exposure assessment methods and other essential design features, and the potential for alternative explanations for observed associations (e.g., bias or confounding). DISCUSSION Toxicokinetic modeling aided in characterizing the complex metabolism and multiple metabolites that contribute to PCE toxicity. The exposure assessment approach-a key evaluation factor for epidemiological studies of bladder cancer, non-Hodgkin lymphoma, and multiple myeloma-provided suggestive evidence of carcinogenicity. Bioassay data provided conclusive evidence of carcinogenicity in experimental animals. Neurotoxicity was identified as a sensitive noncancer health effect, occurring at low exposures: a conclusion supported by multiple studies. Evidence was integrated from human, experimental animal, and mechanistic data sets in assessing adverse health effects of PCE. CONCLUSIONS PCE is likely to be carcinogenic to humans. Neurotoxicity is a sensitive adverse health effect of PCE.
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Getz KD, Janulewicz PA, Rowe S, Weinberg JM, Winter MR, Martin BR, Vieira VM, White RF, Aschengrau A. Prenatal and early childhood exposure to tetrachloroethylene and adult vision. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1327-32. [PMID: 22784657 PMCID: PMC3440105 DOI: 10.1289/ehp.1103996] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 06/19/2012] [Indexed: 05/09/2023]
Abstract
BACKGROUND Tetrachloroethylene (PCE; or perchloroethylene) has been implicated in visual impairments among adults with occupational and environmental exposures as well as children born to women with occupational exposure during pregnancy. OBJECTIVES Using a population-based retrospective cohort study, we examined the association between prenatal and early childhood exposure to PCE-contaminated drinking water on Cape Cod, Massachusetts, and deficits in adult color vision and contrast sensitivity. METHODS We estimated the amount of PCE that was delivered to the family residence from participants' gestation through 5 years of age. We administered to this now adult study population vision tests to assess acuity, contrast sensitivity, and color discrimination. RESULTS Participants exposed to higher PCE levels exhibited lower contrast sensitivity at intermediate and high spatial frequencies compared with unexposed participants, although the differences were generally not statistically significant. Exposed participants also exhibited poorer color discrimination than unexposed participants. The difference in mean color confusion indices (CCI) was statistically significant for the Farnsworth test but not Lanthony's D-15d test [Farnsworth CCI mean difference = 0.05, 95% confidence interval (CI): 0.003, 0.10; Lanthony CCI mean difference = 0.07, 95% CI: -0.02, 0.15]. CONCLUSIONS Prenatal and early childhood exposure to PCE-contaminated drinking water may be associated with long-term subclinical visual dysfunction in adulthood, particularly with respect to color discrimination. Further investigation of this association in similarly exposed populations is necessary.
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Affiliation(s)
- Kelly D Getz
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA
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Occupational exposure to different levels of mixed organic solvents and colour vision impairment. Neurotoxicol Teratol 2010; 32:558-62. [DOI: 10.1016/j.ntt.2010.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 05/08/2010] [Accepted: 05/10/2010] [Indexed: 11/19/2022]
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Long JA, Junghans BM. Orienteers with poor colour vision require more than cunning running. Clin Exp Optom 2008; 91:515-23. [PMID: 18637110 DOI: 10.1111/j.1444-0938.2008.00294.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Highly detailed colour coded maps are used in the sport of orienteering to enable competitors to navigate from one check point to another and to provide guidance on the nature of the terrain to be traversed. The colours are defined by the International Orienteering Foundation (IOF) and are said to have been chosen so they will not be confused by competitors who have abnormal colour vision. However, there are anecdotal reports that individuals with colour vision defects do have problems with the colour coding. METHOD A Minolta Spectrophotometer CM-503i was used to measure the CIE x,y chromaticity co-ordinates and the reflectances of the standard colours recommended by the IOF for the colour coding of orienteering maps, as well as the colours on two maps used in orienteering events. RESULTS Four pairs of IOF standard colours are likely to be confused by protan observers and four pairs by deutan observers. There were three pairs of colours likely to be confused by both deutan and protan observers on one of the competition maps and one pair likely to be confused by protan observers on the other map. Some of the colours on the actual competition maps differed noticeably from the standard IOF colours. DISCUSSION Orienteers with more severe forms of abnormal colour vision are likely to be disadvantaged by their inability to differentiate some colours used on orienteering maps. The IOF should choose different colours that are less likely to be confused or should employ a redundant code (such as a pattern or texture). There is need for better quality control of the colours of competition maps to ensure they do conform to the IOF standard colours.
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Affiliation(s)
- Jennifer A Long
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Abstract
Based on toxicology, metabolism, animal studies, and human studies, occupational exposure to chlorinated aliphatic solvents (methanes, ethanes, and ethenes) has been associated with numerous adverse health effects, including central nervous system, reproductive, liver, and kidney toxicity, and carcinogenicity. However, many of these solvents remain in active, large-volume use. This article reviews the recent occupational epidemiology literature on the most widely used solvents, methylene chloride, chloroform, trichloroethylene, and tetrachloroethylene, and discusses other chlorinated aliphatics. The impact of studies to date has been lessened because of small study size, inability to control for confounding factors, particularly smoking and mixed occupational exposures, and the lack of evidence for a solid pathway from occupational exposure to biological evidence of exposure, to precursors of health effects, and to health effects. International differences in exposure limits may provide a "natural experiment" in the coming years if countries that have lowered exposure limits subsequently experience decreased adverse health effects among exposed workers. Such decreases could provide some evidence that higher levels of adverse health effects were associated with higher levels of solvent exposure. The definitive studies, which should be prospective biomarker studies incorporating body burden of solvents as well as markers of effect, remain to be done.
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Affiliation(s)
- Avima M Ruder
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH 45226, USA.
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Tannock R, Banaschewski T, Gold D. Color naming deficits and attention-deficit/hyperactivity disorder: a retinal dopaminergic hypothesis. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2006; 2:4. [PMID: 16441891 PMCID: PMC1403787 DOI: 10.1186/1744-9081-2-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Accepted: 01/27/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND Individuals with Attention-Deficit/Hyperactive Disorder (ADHD) have unexplained difficulties on tasks requiring speeded processing of colored stimuli. Color vision mechanisms, particularly short-wavelength (blue-yellow) pathways, are highly sensitive to various diseases, toxins and drugs that alter dopaminergic neurotransmission. Thus, slow color processing might reflect subtle impairments in the perceptual encoding stage of stimulus color, which arise from hypodopaminergic functioning. PRESENTATION OF HYPOTHESES 1) Color perception of blue-yellow (but not red-green) stimuli is impaired in ADHD as a result of deficient retinal dopamine; 2) Impairments in the blue-yellow color mechanism in ADHD contribute to poor performance on speeded color naming tasks that include a substantial proportion of blue-yellow stimuli; and 3) Methylphenidate increases central dopamine and is also believed to increase retinal dopamine, thereby normalizing blue-yellow color perception, which in turn improves performance on the speeded color naming tasks. TESTING THE HYPOTHESIS Requires three approaches, including:1) direct assessment of color perception in individuals with ADHD to determine whether blue-yellow color perception is selectively impaired; 2) determination of relationship between performance on neuropsychological tasks requiring speeded color processing and color perception; and 3) randomized, controlled pharmacological intervention with stimulant medication to examine the effects of enhancing central dopamine on color perception and task performance IMPLICATIONS OF HYPOTHESIS If substantiated, the findings of color perception problems would necessitate a re-consideration of current neuropsychological models of attention-deficit/hyperactivity disorder, guide psycho-education, academic instruction, and require consideration of stimulus color in many of the widely used neuropsychological tests.
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Affiliation(s)
- Rosemary Tannock
- The University of Toronto, Toronto, Canada: Brain and Behaviour Research Program, The Hospital for Sick Children, Toronto, Canada
- Centre for Advanced Study at the Norwegian Academy of Science and Letters 2004–2005, Norway
| | - Tobias Banaschewski
- Child and Adolescent Psychiatry, University of Göttingen, Germany
- Centre for Advanced Study at the Norwegian Academy of Science and Letters 2004–2005, Norway
| | - David Gold
- The University of Western Ontario, London, Canada
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