Millions of people worldwide wear contact lenses, but a recent pilot study suggests that these lenses may shed microplastics when exposed to sunlight for extended periods. Researchers from the universities of Nanjing and Hohai developed an automated system to determine the amount of microplastics in contact lenses. By taking microscopic images of the lenses, processing them, and quantifying any microplastics present, the team found that lenses exposed to sunlight over time can release tiny fragments of plastic. However, the impact on human health remains unclear.

To conduct their study, the researchers collected six different types of contact lenses from various brands and with different lifespans. They stored the lenses in water, placed them under a lamp that simulated sunlight, and rinsed them with water every 10 hours. After the lenses received the equivalent of 30 or 90 days of sunlight, the researchers analyzed the water in which each lens was stored.

The team discovered that their new automated system provided quicker and more accurate analyses of microplastics compared to manual methods. No microplastics were detected when the lenses were not exposed to simulated sunlight. However, as the contact lenses were exposed to the equivalent of 90 days of sunlight, increasing amounts of shed microplastics were observed. Lenses with shorter lifespans showed the highest levels of microplastic shedding after this exposure.

Based on their data from this small-scale study, the researchers estimate that certain lenses could shed over 90,000 microplastic particles per year if worn for 10 hours a day. Although the direct impact of microplastic exposure on eye health is currently unknown, the researchers emphasize the urgent need for further studies in this area.

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