Microplastic contamination in artificial tears in South Korea: Potential for direct ocular exposure

Yun-Hee Choi; Nayoon Park; Juyang Kim; Seul-Ah Park; Jaehak Jung; Jong Suk Song; Yoon-Hyeong Choi; Dong Hyun Kim

doi:10.1016/j.clae.2024.102325

Microplastic contamination in artificial tears in South Korea: Potential for direct ocular exposure

Cont Lens Anterior Eye. 2024 Nov 11:102325. doi: 10.1016/j.clae.2024.102325. Online ahead of print.

Authors

Yun-Hee Choi¹, Nayoon Park², Juyang Kim³, Seul-Ah Park³, Jaehak Jung³, Jong Suk Song², Yoon-Hyeong Choi⁴, Dong Hyun Kim⁵

Affiliations

¹ Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea; School of Health and Environmental Science, Korea University, Seoul, South Korea.
² Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
³ Korea Institute of Analytical Science and Technology, Seoul, South Korea.
⁴ School of Health and Environmental Science, Korea University, Seoul, South Korea. Electronic address: yoonchoi@korea.ac.kr.
⁵ Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. Electronic address: amidfree@gmail.com.

PMID: 39532599
DOI: 10.1016/j.clae.2024.102325

Abstract

Purpose: To investigate microplastics (MP) contamination in artificial tear (AT) products.

Method: Five hyaluronic acid ATs (two multi-use and three disposable ATs) were used to gauge MP levels in three scenarios: 1) initial drop and remaining liquid after opening the lid upward; 2) remaining liquid after opening the lid downward and discarding two drops; and 3) remaining liquid after opening the lid downward and discarding half of it. Raman spectroscopy was used to identify the quantity, morphological characteristics, and composition of MPs. Scanning electron microscopy/energy dispersive spectroscopy was used to examine the surface traits and elements of MPs and ATs.

Results: MPs were detected in 4 out of 5 ATs in the initial drops, containing 0.50 ± 0.65 particles/30 mL, whereas the remaining solution had 0.75 ± 0.72 particles/30 mL. After discarding two drops, 0.14 ± 0.35 particles/30 mL were present in the remaining solution. No MPs were detected after discarding half drops. Most MPs were transparent (95 %), irregular fragments (55 %) sized 10-20 μm (35 %), and made of polyethylene (95 %). If patients use the first drops of ATs four times a day for a year, individuals can be exposed to 730.0 particles. This exposure can be reduced to 204.4 particles by discarding the first two drops before use.

Conclusion: MPs are observed in commercially available ATs, and human eyes may be directly exposed to MPs through the use of ATs.

Keywords: Artificial tears; Microplastics; Raman spectroscopy; SEM/EDS; Surface characterization.