It’s not easy to estimate the carbon footprint of optometry. Contact lens (CL) products alone, including packaging, represent 0.5% of total environmental waste (Morgan et al, 2003). 

But disposable CLs are far from the only source of single-use plastics in eye care. A study at Boston Medical Center in the US found that the hospital produced 109.6kg of plastic waste yearly from disposable tonometer prisms and gonioscopy lenses that could be avoided by switching to reusables (Park and LaMattina, 2020). 

In the UK, it’s likely more than 30 tonnes of dummy spectacle lenses were discarded in 2019, according to calculations by John Keep of DKO Independent Opticians in Somerton, Somerset. He looked at total spectacle lenses sold, multiplied by 3g per discarded dummy lens, minus an assumed reglaze rate. “As an industry we all share the responsibility to be as clean and green as possible,” he says.