There is growing evidence of an increase in microplastic pollution of the aquatic environment, and wider environmental concerns regarding use and disposal of materials. This study examines the annualised waste produced by two representative contact lens modalities and the end of life disposal of contact lenses and packaging.
Using a representative daily disposable system (somofilcon A) versus a reusable monthly replacement system (somofilcon A with multipurpose solution); packaging and contents were sorted by material and weighed. Annualised figures were calculated assuming compliant, full-time use, with lenses worn in both eyes. Calculations for reusable lenses included all lens care products; 12 solution bottles and 12 lens cases. Once categorised, materials that would enter household waste or recycling during normal use were identified.
Four categories of material were identified: liquid; paper and cardboard; metal; plastics (high-density polyethylene, polypropylene and hydrogel plastic). The reusable system generated 0.8kg of material solid waste (MSW) over a year, the daily disposable system 1.1kg. Plastics accounted for the most significant proportion of MSW by mass for both systems. The annualised mass of somofilcon A was 0.3g and 10g for reusable and daily disposable lenses, respectively. Curbside recycling schemes vary across the United States. To avoid curbside contamination, conservative figures are that households can recycle 20% of waste from daily disposable lenses, rising to 88% with a reusable system. These figures are based on acceptance of cardboard packaging and multipurpose solution bottles. Upto 100% of MSW generated by contact lens use can be recycled using partnership schemes.
In the United States, waste generated per person is approximately 2kg per day. Contact lens use accounts for only a small percentage of waste, 0.12-0.15% by mass, and a significant proportion of this can be recycled. Contact lens wearers should be aware of local recycling schemes or initiatives and encouraged to dispose of worn lenses in a waste receptacle, rather than a sink or lavatory to avoid microplastic contamination of the marine environment.