Assessment of Human Health Risks from Exposure to Lubricating Eye Drops Used in the Treatment of Dry Eye Disease

Dry eye disease is a common condition in which tear production or quality is insufficient to lubricate the eyes properly. Standard treatment usually involves lubricating eye drops. In this study, we assessed the human health risks, including both non-carcinogenic and carcinogenic effects, associated with long-term exposure to the chemical elements arsenic (As), cadmium (Cd), cobalt (Co), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) in eye drops used in Brazil. The results indicated that the Co concentration (1.1048 mg/kg) in the eye drops sample 5 exceeded the limit established by the ICH Q3D (R2) guideline for parenteral products (0.5000 mg/kg). Additionally, As levels in eye drop samples 2, 8–10, 12, 13, and 16, as well as Cd levels in samples 2, 3, 8–10, and 12, exceeded the limits established by the Brazilian Pharmacopoeia for parenteral administration (0.0500–0.0532 mg/kg). The main health risk appears to come from oral exposure, as the drug can drain into the nasal cavity via the nasolacrimal duct and then be absorbed through the gastrointestinal tract. While none of the tested eye drops posed non-carcinogenic risks, carcinogenic risks from oral exposure to As and Cd were identified, with overall risk levels exceeding acceptable thresholds. These findings emphasize the need for strict regulation and continuous monitoring of these products to reduce health risks and prevent long-term damage.