Prevalence of occupational ocular accidents caused by chemical products in the casuistry of the Toxicological Information Center of Rio Grande do Sul, Brazil

Introduction
The effects of toxic substances on visual organs have been recognized as an important problem of occupational health. International studies show ocular accidents represent around 12% of every working accident reported in Finland, 3% in the United States. In Brazil, 2.5 million of people are estimated to suffer these disturbances annually. Approximately 60.000 of these injuries are associated to severe sight loss.

Methods
Analysis on the prevalence of occupational ophthalmologic accidents caused by chemical products reported to the Toxicological Information Center of Rio Grande do Sul, Brazil, within 2005 and 2009 about the main chemical substances associated. It also aims at relating the sector of occupational activity to ocular accidents. A relation on occupational ophthalmologic accidents and the records opened due chemical products was elaborated, retrospectively. Occupational activity was correlated to the accident through two case studies. 

Results
Accidents caused by industrial chemical products were the most prevalent (39%), followed by household cleaning ones (30%). Alkalis were predominant among industrial chemical accidents (27%), mainly calcium hydroxide (74%), present in civil engineering. Then, lesions caused by acids (12%), especially sulphuric acid (47%), used in fertilizer, mining and petrochemical industries. Acids cause less severe lesions than bases because they promote precipitation of ocular proteins, which form a barrier against acid penetration. Accidents caused by household products do not show significant difference to the ones caused by industrial chemical products.

Discussion
Alkalis are the most prevalent chemical products in occupational ocular accidents, mainly in civil engineering. There is no significant difference between accidents caused by household products and the ones by industrial chemical products, which represent serious public health problem because they are of customary and daily usage. It is important to improve notification of these accidents, adopting preventive measures in order to inform that the quick treatment with water and saline solution avoids sequelae.