A recent study found that 15 to 20 percent of people in the US who wear contact lenses flick their fiddly lenses down the drain via the bathroom sink or toilet. Considering that around 45 million people wear contacts in the US, that’s a lot of unneeded plastic winding up in our waterways. The authors of the study say that lenses should be recycled where this is possible but if not they should be disposed of by putting them in with other solid, non-recyclable waste.