A Contact Lens’ Journey to the Ocean
Updated: Feb 24
Contact lenses are designed to correct your vision for a temporary duration of time. Before you head to bed, you remove your contact lenses from your eyes to throw them out… but what is the next step? Where do your contact lenses go once you dispose of them? Rolf Halden, Ph. D., who has worn glasses and contact lenses for much of his adult life, set out to find the answer to this question.
Image: Contact lens fragments from sewage sludge
According to Halden’s research, approximately 15-20% of contact lens users in America throw away their contacts either by flushing them down the sink or toilet. This improper disposal method leads to a series of complications, starting with the lens’ destination: wastewater treatment plants. Believe it or not, around 6-10 metric tons of plastic ends up in these wastewater plants per year in America alone. Once the contacts reach the wastewater plants, they go through a slightly different process than traditional plastics. Contacts are composed of softer plastic, which helps oxygen pass through it to ensure that the eyes have access to an oxygen supply. This difference in material led Halden and his team to an interesting discovery regarding the structure of contact lens plastic. In their study, they exposed different plastic polymers found in contact lenses to various wastewater microorganisms. These microbes were found to weaken the polymer bonds, allowing the plastic to break down into smaller pieces known as microplastics.
Microplastics are a huge threat towards marine life, as they kill nearly 100 million marine animals annually (including fish and birds). Oftentimes, many animals mistaken plastic for food, and as the indigestible plastic creates a blockage in their digestive systems, they unfortunately get tricked into starvation.
Raising awareness for proper contact lens disposal is crucial! By flushing contacts down the drain, they will inevitably have a lasting impact on the environment, contributing to plastic pollution. In general, it is best for contact lenses to be thrown into the garbage, where they can degrade in landfills rather than the ocean. There are alternative options for correcting your vision such as prescription glasses, which do not have to be changed as often, or laser surgery, which is effective, but more expensive and less accessible to everyone. In the future, Halden’s team hopes to save aquatic life and reduce plastic pollution by encouraging contact lens companies to include labels for proper disposal instructions.