A study found that microplastics were detected in disposable artificial tears on the market, and that the caps should be removed while holding the product upside down to reduce the amount entering the eyes.
Caution is advised when using artificial tears immediately after opening, as microplastics can enter the eye. For this reason, the Ministry of Food and Drug Safety recommends discarding the first one or two drops before using them. However, the evidence regarding the amount of microplastics contained in the first one or two drops remains unclear.
Accordingly, a joint research team including Professor Kim Dong-hyun of the Department of Ophthalmology at Korea University Anam Hospital and Director Jeong Jae-hak of the Korea Institute of Analytical Sciences conducted a study on five hyaluronic acid-based artificial tears currently on the market to determine how much microplastics are contained in artificial tears.
The research team used artificial tears
▲Remove the cap while holding it upright, discard the first drop, and discard the remaining solution.
▲Remove the cap while holding it upside down, drop two drops and discard the remaining solution.
▲After removing the lid while holding the tube upside down, about half of the solution was discarded, and the remaining solution was divided and analyzed for microplastic content. Raman spectroscopy and scanning electron microscopy were used for the analysis.
The analysis results showed that microplastics were not detected only in the remaining solution after discarding about half of it. The first drop, which was dropped after removing the cap while holding the artificial tear solution upright, contained 0.50 ± 0.65 microplastic particles per 30 mL. The remaining solution contained 0.75 ± 0.72 particles per 30 mL. After discarding two drops while holding the solution upside down, the remaining solution contained 0.14 ± 0.35 particles per 30 mL. Results were similar for both single-use and reusable containers.
In summary, to reduce microplastic exposure, hold the artificial tear bottle upside down, remove the cap, and discard about half of the solution before use. Professor Kim Dong-hyun explained, "Most of the microplastics in artificial tears are released when the cap is removed. Holding the tear bottle upside down and removing the cap prevents the microplastics from falling into the solution thanks to gravity."
He also said, “If you discard about half of the solution before use, it seems that the small amount of microplastics generated inside the container are also removed,” and “Since the Ministry of Food and Drug Safety also recommends that artificial tears be used only once, it seems like it would be a good idea to discard about half of the solution before use.”
According to the research team, if an individual uses the first drop of artificial tears four times a day for a year, they could be exposed to a total of 730.0 microplastic particles. Discarding the first two drops before use would reduce this to 204.4.