Ocular surface and tear film changes in workers exposed to organic solvents used in the dry-cleaning industry

Abstract

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.