The neuro-ophthalmological effects related to long-term occupational exposure to organic solvents in painters

Low-level occupational exposure to BTEX and dyschromatopsia: a systematic review and meta-analysis

Objectives. The present study aimed to assess whether occupational exposure to low concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) is associated with color vision impairment. Methods. We queried PubMed, Scopus, Embase, Web of Science and ProQuest as the main databases, as well as gray literature such as Google Scholar. A random-effects model was used to assess relative risk. A funnel plot was created to assess publication bias. Meta-regression analysis was applied to identify variables that explain the between-study variation in the reported risk estimate. Results. An overall standardized mean difference of 0.529 (95% confidence interval [0.269, 0.788]; p < 0.0001) was obtained in the random-effects model, which corresponded to a medium-size effect. Duration and the levels of exposure to benzene, toluene and xylene were the significant predictors of the magnitude of the combined risk estimate. Chronic exposure to low levels of BTEX was associated with dyschromatopsia determined by the color confusion index. Conclusions. The impairments can occur even at exposures lower than the occupational exposure limits of BTEX. However, there are several flaws in the determination of workers' exposure, which did not allow to establish how low a level of these chemicals can cause color vision impairment.

Patient barriers and facilitators for making environmental and behavioral modifications for dry eye in the United States

BACKGROUND

Managing dry eye disease (DED) is expensive. Often, prescribed treatments improve clinical signs but not patient-reported symptoms. In large surveys, clinicians and patients ranked environmental and behavioral modifications among the most important DED-related research priorities. Our purpose was to investigate the barriers to and facilitators of use of these modifications by patients with DED in the United States and how their use may be impacted by socioeconomic status (SES).

METHODS

Using Qualtrics, we conducted an anonymous online survey of adults with DED living in the United States in August to September 2022. Patients were identified through the Dry Eye Foundation, Sjögren's Foundation, and a DED clinic in Colorado. We used an established index for classifying respondent SES based on education, household income, and employment. Outcomes included use of environmental and behavioral modifications and barriers to and facilitators of their use.

RESULTS

We included 754 respondents (SES: 382 low, 275 high, and 97 unclear). Most were aged 18 to 49 years (67%), female (68%), and White (76%) and reported dealing with DED for ≤5 years (67%). The most frequent modifications were taking breaks to rest eyes (68%), increasing water intake (68%), and using hot/cold compresses (52%). For these three, the biggest facilitators were as follows: belief that the modification works (27 to 37%), being recommended it (24 to 26%), and ease of use/performance (21 to 32%). Across modifications, the biggest barriers were difficulty of use (55%), lack of family/employer/social/community support (33%), and lack of awareness (32%). The data do not suggest discernible patterns of differences in barriers or facilitators by SES.

CONCLUSIONS

Greater emphasis should be placed on explaining to patients how environmental and behavioral modifications might mitigate DED. Employers and members of patients' support systems should be guided regarding how best to support patients in managing DED symptoms.

Risk assessment of chemical mixtures by benchmark dose-principle component analysis approach in occupational exposure

Mixtures of organic solvents are widely used in industrial processes. Risk assessment for chemical co-exposure has always been a challenge in past years. The present study aims to employ principle component analysis (PCA) to produce an entry for benchmark dose approximation in shoemakers based on the color vision effect. A total of 134 subjects consisting of 67 shoemakers and 67 staff workers were employed for Benchmark Dose (BMD) evaluation. Occupational exposure to benzene, toluene, xylene, and n-hexane was evaluated using NIOSH 1501 and OSHA ID-07 methods. The color vision effect was quantified using Lanthony D-15 desaturated test (D-15d). PCA was run for cumulative exposure dose (CED) of the solvents by MATLAB 2018. Finally, the lowest 95% confidence limit of the benchmark dose (BMDL) was determined using US EPA benchmark dose software (BMDS) version 3.2.1. The color confusion index (CCI) level in shoemakers increased from 1 to 1.15 by a median of 1.07. There was a significant difference in the CCI level (p value<0.0001) between exposed and control subjects. The first score of PCA was used as intake dose level (IDL) in solvents co-exposure. Using BMD analysis, the log-logistics model was fitted with a p-value> 0.1 and the lowest BMDL level. BMDL level was evaluated at 1.63, 10.25, 2.21, and 3.35 ppm for benzene, toluene, xylene, and n-hexane, respectively. The results showed a risk of color vision effect with co-exposure to solvents at different levels in the occupational exposure standards. In conclusion BMDL-PCA approach has been suggested for the risk assessment of chemical co-exposure.

Occupational exposure evaluation of Brazil university community to the volatile organic compounds

Occupational exposure to volatile organic compounds (VOC) might generate serious worker health damages. Therefore, biological monitoring is essential to evaluate exposure biomarkers from highly toxic chemicals, ensuring better attention to the worker health. In this study was developed and validated a bioanalytical method based on high-performance liquid chromatography coupled to photodiode array (HPLC-PDA) for the quantification of VOC biomarkers in urine samples from Federal University of Goias (UFG) workers. Samples were collected from 30 occupationally exposed subjects after application of a questionnaire survey. The following biomarkers hippuric acid, methyl-hippuric acid, mandelic acid, phenylglyoxylic acid and phenol were quantified, representing exposition to toluene, xylene, styrene, ethylbenzene, benzene and phenol solvents, respectively. Hippuric acid levels were found close to or above the reference values, although a subject had levels higher than preconized by Biological Limit Values (BLV) guideline of 4.0 mg/g creatinine. Five subjects had 3 and 4-methylhippuric acid ranging from 0.1 to 1.0 mg/g creatinine. These results indicate a moderate to high VOC exposure from UFG workers. Multivariate analysis generated four clusters and indicated that histotechnicians and graphic workers need especial attention on occupational VOC exposure. The results from this study reinforce the need for reliable methods able to the biological monitoring as an important tool for assessing occupational exposure.