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CLINICAL RELEVANCE: Pupil size evaluation using clinical examination may be important for detecting and monitoring individuals at risk of neurotoxic effects from chemical exposure, as it may enable early intervention and the implementation of preventive measures. BACKGROUND: This work aimed to investigate the association between pesticide exposure and pupil size. Pupil size is regulated by muscarinic and nicotinic receptors, and it is well-established that common pesticide chemicals disrupt this regulation. METHODS: Twenty agricultural workers exposed to pesticides, and twenty participants not exposed, underwent visual screening, and pupil size evaluation under mesopic and photopic conditions. Additionally, signs of neurotoxicity and pesticide exposure in both groups were evaluated using the modified version of the neurotoxic symptoms questionnaire (Q16) and measuring cholinesterase (AChE) levels in blood, respectively. RESULTS: Agricultural workers exposed to pesticides had a score indicating medium-high level of neurotoxicity (49.85 (SD ± 8.94)) which was significantly higher (t (36) = 7.659, p ≤ 0.0001) than non-exposed participants who had low levels of neurotoxicity (27.25 SD ± 8.86). There was a significant difference in pupil size (mm) under mesopic (t (19) 4.42 p = 0.003) and scotopic (t (19) 4.63, p = 0.0002) conditions between the two groups. Additionally, there was a significant difference in AChE blood levels (t (19) 2.94 p = 0.008) between exposed and non-exposed participants, indicating that exposed workers had low levels of this enzyme (average exposed group 3381 U/L (SD ± 1306)) compared to the non-exposed group (average non-exposed group 4765 U/L (SD ± 1300)). A significant negative correlation between AChE levels, years of exposure, and pupil size was found. The latter finding importantly showed that smaller pupils are associated with the accumulation of acetylcholine or a decrease in the activity of the enzyme AChE. CONCLUSION: Pupil size of agricultural workers exposed to pesticides can be abnormal and is associated with neurotoxicity as indicated by symptomatology and cholinesterase levels. Evaluation of pupil size may be useful for clinically detecting neurotoxicity.
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Workers in the dry-cleaning industry are exposed to organic solvents that may cause eye irritation and tear film changes. Objective To quantify changes in the ocular surface and tear film in dry cleaners exposed to organic solvents and associate these changes with ocular irritation as reported in a symptom questionnaire for dry eye diagnosis. Methods This was a case and control study in which the characteristics and eye-irritation symptoms were compared between two groups of 62 participants that were either exposed or not exposed to organic solvents. A general optometric examination and the following test were performed: lipid interferometry, Lissamine Green Stain, tear breakup time, Schirmer I, conjunctival impression cytology and the Donate dry eye symptoms questionnaire. Results Sixty-five percent of exposed workers obtained a higher score than 13 on the Donate dry eye symptoms questionnaire which indicated the presence of more irritation symptoms than those in the non- exposed group. A Chi-square analysis indicated the exposed group reported significantly higher incidences (P <0.005) for eye irritation symptoms of sandy sensation; tearing eyes sensation; foreign body sensation; tearing; dry eye; dryness; eyestrain and heavy eyelids. A Mann Whitney-U indicated greater severity only for symptoms relating to dry eye; sandy sensation; foreign body sensation, tearing; tearing eyes and dryness. There was a statistically significant difference (P <0.05) for Schirmer I; tear break up time; and the ocular surface assessed with Lissamine green staining and conjunctival impression cytology between groups. A reduction in the thickness of the lipid layer in the exposed group compared to the non-exposed group was observed. Surprisingly, clinical test outcomes were not significantly correlated with dry eye symptoms nor years of exposure. Conclusion Workers in the dry-cleaning industry exposed to organic solvents are associated with changes in ocular surface and tear film generating irritation symptoms commonly present in evaporative dry eye.
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Túnica Conjuntiva/efeitos dos fármacos , Síndromes do Olho Seco/diagnóstico , Compostos Orgânicos/toxicidade , Solventes/química , Lágrimas/efeitos dos fármacos , Adolescente , Adulto , Astenopia/etiologia , Estudos de Casos e Controles , Túnica Conjuntiva/patologia , Túnica Conjuntiva/fisiologia , Síndromes do Olho Seco/etiologia , Pálpebras/efeitos dos fármacos , Pálpebras/fisiopatologia , Feminino , Humanos , Lavanderia , Lipídeos/química , Masculino , Exposição Ocupacional , Compostos Orgânicos/química , Lágrimas/química , Lágrimas/fisiologia , Adulto JovemRESUMO
PURPOSE: To investigate whether exposure to occupational levels of organic solvents in the dry cleaning industry is associated with neurotoxic symptoms and visual deficits in the perception of basic visual features such as luminance contrast and colour, higher level processing of global motion and form (Experiment 1), and cognitive function as measured in a visual search task (Experiment 2). METHODS: The Q16 neurotoxic questionnaire, a commonly used measure of neurotoxicity (by the World Health Organization), was administered to assess the neurotoxic status of a group of 33 dry cleaners exposed to occupational levels of organic solvents (OS) and 35 age-matched non dry-cleaners who had never worked in the dry cleaning industry. In Experiment 1, to assess visual function, contrast sensitivity, colour/hue discrimination (Munsell Hue 100 test), global motion and form thresholds were assessed using computerised psychophysical tests. Sensitivity to global motion or form structure was quantified by varying the pattern coherence of global dot motion (GDM) and Glass pattern (oriented dot pairs) respectively (i.e., the percentage of dots/dot pairs that contribute to the perception of global structure). In Experiment 2, a letter visual-search task was used to measure reaction times (as a function of the number of elements: 4, 8, 16, 32, 64 and 100) in both parallel and serial search conditions. RESULTS: Dry cleaners exposed to organic solvents had significantly higher scores on the Q16 compared to non dry-cleaners indicating that dry cleaners experienced more neurotoxic symptoms on average. The contrast sensitivity function for dry cleaners was significantly lower at all spatial frequencies relative to non dry-cleaners, which is consistent with previous studies. Poorer colour discrimination performance was also noted in dry cleaners than non dry-cleaners, particularly along the blue/yellow axis. In a new finding, we report that global form and motion thresholds for dry cleaners were also significantly higher and almost double than that obtained from non dry-cleaners. However, reaction time performance on both parallel and serial visual search was not different between dry cleaners and non dry-cleaners. CONCLUSIONS: Exposure to occupational levels of organic solvents is associated with neurotoxicity which is in turn associated with both low level deficits (such as the perception of contrast and discrimination of colour) and high level visual deficits such as the perception of global form and motion, but not visual search performance. The latter finding indicates that the deficits in visual function are unlikely to be due to changes in general cognitive performance.
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Lavanderia , Exposição Ocupacional/análise , Compostos Orgânicos/toxicidade , Solventes/toxicidade , Visão Ocular/efeitos dos fármacos , Adulto , Sensibilidades de Contraste/efeitos dos fármacos , Humanos , Neurotoxinas/toxicidade , Estimulação Luminosa , Tempo de Reação/efeitos dos fármacos , Limiar Sensorial/efeitos dos fármacosRESUMO
Los trabajadores de limpieza en seco están expuestos a los disolventes orgánicos como el percloroetileno(perc). Este puede afectar el Sistema Nervioso Central (snc), provocar neurotoxicidad y asociarse con alteraciones visuales-neurológicas relacionadas con la función visual de sensibilidadal contraste (fsc) y la pérdida de la visión del color. Objetivo: determinar los déficits de sensibilidad al contraste (sc) por frecuencia espacial en un grupo de trabajadores de lavandería expuestos a niveles ocupacionales de perc y su relación con síntomas neurotóxicos. Materiales y métodos: estudio de casos y controles en 40 trabajadores de lavandería y en 35 personas normalesno expuestas a perc en Bogotá, Colombia. La fsc se evaluó utilizando métodos psicofísicos; las frecuencias espaciales estudiadas fueron 0,5, 1,0, 2,0, 4,0, 8,0 y 16,0 cpd. La neurotoxicidad se evaluó mediante el cuestionario modificado Q16. Resultados: se observaron diferencias significativas en sc por encima de 1,0 cpd (p < 0,05). La correlación de Spearman mostró una relación negativa significativa entre la puntuación del cuestionario Q16 versión modificada y las frecuencias espaciales 2,0, 4,0 y 8 de cpd (Rho de Spearman p < 0,05) en los casos. La prueba de U de MannWhitney mostró diferencias significativas entre casos y controles para el cuestionario Q16 modificado(p <0,05). Conclusión: la fsc fue significativamente menor en los expuestos a perc para las frecuencias espaciales superiores a 1,0 cpd. La presencia de síntomas neurotóxicos en trabajadores de lavado en seco se asocia con pérdidas en las fsc en las frecuencias espaciales medias y altas.
Dry cleaning workers are exposed to organic solvents like perchlorethylene (perc). This can affectthe Central Nervous System (cns), provoke neurotoxicity and associate to neuro-visual alterations related to the visual contrast sensitivity function (csf) and the loss of color vision. Objective: To determine the deficits of contrast sensitivity (csf) by spatial frequency in a group of dry cleaning workers exposed to occupational levels of perc and its relation to the neurotoxic symptoms. Materials and methods: A case and control study in 40 dry cleaning workers and in 35 regular people withno exposure to perc was done in Bogota, Colombia. The csf was evaluated using psychophysical methods; the spatial frequencies studied were 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 cpd. Neurotoxicity was evaluated with the modified questionnaire Q16. Results: Significant differences were observedin cs above 1.0cpd (p < 0.05). The Spearman correlation showed a significant negative relation between the punctuation of the modified version of the Q16 questionnaire and the spatial frequencies 2.0, 4.0 and 8 cpd (Spearmanp Rho < 0.05) in the cases. The Mann Whitney U test showedsignificant differences between cases and controls for the modified Q16 questionnaire (p <0.05).Conclusion: the csf was significantly lower in those exposed to perc for the spatial frequencies above 1.0 cpd. The presence of neurotoxic symptoms in dry cleaning workers is associated with losses in csf in medium and high spatial frequencies.
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Humanos , Sensibilidades de Contraste , Síndromes NeurotóxicasRESUMO
Objetivo: modificar el cuestionario de síntomas neurotóxicos (Q16) y evaluar su repetibilidad y comparabilidad. Metodología: un grupo de cien participantes entre los dieciocho y los cuarenta años con un nivel educativo equivalente a bachillerato o formación técnica, aproximadamente similar al nivel de educación de los trabajadores de lavandería de Bogotá, fue empleado para validar el cuestionario en Sídney, Australia. Tres cuestionarios y uno sobre información demográfica fueron aplicados a los participantes. El cuestionario Q16 modificado fue aplicado dos veces para evaluar su repetibilidad. Resultados: sesenta hombres y cuarenta mujeres participaron en el estudio.Para analizar la confiabilidad del cuestionario Q16 modificado fue aplicado el Alfa de Cronbach, obteniéndose un coeficiente de consistencia interna alfa de 0,887. Para evaluar la repetibilidad se aplicó el test de t pareada, obteniéndose diferencias significativas en dos preguntas con valores p = 0,027 y p = 0,020, respectivamente. Comparando los resultados de la escala de Likert con el original se observaron relaciones directas entre los mismos. Conclusiones: el cuestionario modificado Q16 brinda más opciones de respuesta con mayor acercamiento a la realidad, consistencia interna y repetibilidad. El cuestionario modificado Q16 puede ser una mejor opción para evaluarlos síntomas neurotóxicos.
Objective: To modify the neurotoxic symptoms questionnaire (Q16) and assess its repeatability and comparability. Materials and Methods: A group of 100 participants ranging from the ages of 18 to 40, with an education level equivalent to high school or technical college, similar to the education level of dry-cleaners in Bogotá was used to validate the questionnaire in Sydney, Australia. Three test questionnaires and a demographic information questionnaire were presented to participants.The modified Q16 was applied twice in order to evaluate repeatability. Results: Sixty males and forty females participated in the study. Cronbachs Alpha was applied in order to analyze the reliability of the Q16 modified with a Likert scale, getting an internal consistency of 0.887. The paired t test was applied in order to evaluate repeatability, obtaining significant differences in two questions with p=0.027 and p=0.020 values, respectively. Comparing the results of the Likert scale scores with the original, a direct link was observed between them. Conclusions: The modifiedQ16 provides more answer choices, closer to reality, internal consistency and repeatability. The modified Q16 may be a better option to assess neurological symptoms.