PURPOSE: To determine and compare the amount of daily disposable (DD) contact lenses (CL) it takes to reach the equivalent amount of material in commonly used plastic items.
METHODS: A leading DD lens was dehydrated using an isotemp vacuum oven at 56˚C for 19 hours, and the dry weight was measured on a Metler Toledo scale. Commonly used items such as a water bottle, CL case, CL solution bottle and credit cards were also measured for comparison purposes and the equivalent weights calculated.
RESULTS: The calculated weight of a year supply of dehydrated DD lenses (730) weighed 11.36g or 0.40oz. This is equivalent to the average weight of 2.30 credit cards. The average weight of a multipurpose solution (MPS) CL case is the equivalent of over a 4 year supply of lenses, while a peroxide case has a weight equal to more than 8 years worth of lenses in it. It takes over a 2.5 year supply of DD lenses to equal the average weight of the material in one bottle of either MPS or peroxide CL solution. A 20oz bottle of water has the equivalent weight of 1,586 dehydrated CLs or a 2.17 year supply.
CONCLUSIONS: If patients are concerned about throwing a lens away every day, doctors can reassure them it's not the lenses that have a large impact, but the solution bottles and cases needed to store reusable lenses. Doctors can also use real world examples to compare how many lenses are equivalent to common items such as water bottles and credit cards. Although there is more packaging waste associated with DD CLs, it is possible to recycle some of that material (plastic and cardboard only) by following the specific guidelines of one's city recycling program and seeking further information on how to recycle #5 polypropylene plastic in one's area.