Assessing Human Exposure to Pollutant Emissions from Brick Kilns on Ocular and Neuronal Health: A pilot study in the Refugio Brickmaking Region

Paula Karolina Pedroza Carrillo¹Anuar Salazar Gomez¹Ana Mariela Jimenez Alcala²Daniela del Rocío Nilo Olmos¹Blanca Perez Perez¹Valeria Guadalupe Rocha Villa¹Ana Laura Martínez Rodriguez²Stéphanie C. Thébault³Luis Fernando Hernandez Zimbron^1,2*

• ¹Laboratorio de investigación interdisciplinaria - Area Optometría, Escuela Nacional de Estudios Superiores, Unidad León, UNAM, León, Guanajuato, Mexico
• ²Escuela Nacional de Estudios superiores, Unidad León, UNAM, León, Mexico
• ³Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Queretaro, Mexico

León, Guanajuato, Mexico, faces significant air pollution due to emissions from artisanal brick kilns. Prolonged exposure to these pollutants has been associated with neurotoxicity symptoms and potential risks of neurodegenerative diseases. However, their effects on ocular health, including visual symptoms and neurotoxic manifestations, remain poorly understood.The aim was to evaluate visual health and retinal function, alongside the prevalence of neurotoxicity symptoms and the identification of neurodegenerative markers in the ocular surface among residents near the Refugio Brickmaking Region, León, Guanajuato, Mexico, and to correlate pollutant exposure with ocular health status, neurotoxicity symptoms, and neurodegenerative markers.A cross-sectional study was conducted with 13 participants exposed to brick kiln emissions and 13 non-exposed controls. Clinical evaluations included vital signs, visual acuity tests, refraction, the Q16 neurotoxicity questionnaire, and the OSDI questionnaire. Statistical analyses were performed using Mann-Whitney U tests for neurotoxicity scores and Chisquare tests for correlations between pollutant exposure and ocular and neurotoxic symptoms. The exposed group had an average age of 44.64 years compared to 52.38 years in controls, with diabetes prevalence at 21.43% versus 53.85%. Six ocular symptoms were prevalent among the exposed group: foreign body sensation, blurred vision, itchy eyes, watery eyes, photophobia, and decreased visual acuity. Exposed participants had worse binocular uncorrected distance visual acuity (UDVA ≥ 0.3 logMAR), a higher prevalence of myopia, and slightly increased dry eye prevalence. Neurotoxicity scores indicated a Medium-Low level (36.08 ± 14.9) in the exposed group versus Low (28.62 ± 7.78) in controls. Anxiety or depression was reported by 61.5% of exposed participants compared to 15.4% of controls.The study demonstrated a strong association between environmental exposure to brick kiln emissions and ocular health deterioration, along with an increased prevalence of neurotoxicity symptoms such as anxiety and depression. These findings emphasize the need for stricter regulations to protect workers and residents in high-risk areas. Public health policies and protective equipment are critical to mitigate these health risks.