Corneal Surgery’s Contribution to Climate Change

The fight against climate change involves ophthalmology as much as, or more than, other medical specialties. The effect of fluorinated gases used in keratoplasty procedures may have a greater impact than many might suspect, according to Matteo Airaldi MD.

“We know that healthcare contributes significantly to greenhouse gas emissions. In particular, in the UK, 5.5% of the country’s emissions are attributed to the national healthcare system,” said Dr Airaldi, presenting on behalf of Alfredo Borgia MD.

“In ophthalmology, fluorinated gases used during surgery are the main contributors to greenhouse gases. These include sulphur hexafluoride (SF₆), hexafluoroethane (C₂F₆), and octafluoropropane (C₃F₈).”

Describing these gases as having a “high global warming potential,” he said they are used in routine procedures, including vitreoretinal surgery and endothelial keratoplasty. To understand their full impact on the environment, Drs Borgia and Airaldi evaluated the carbon emissions originating from the latter procedure.

Their research was organised as a retrospective single-centre study at the Royal Liverpool University Hospital between 2022 and 2024 and involved 357 endothelial keratoplasty cases. These included Descemet membrane endothelial keratoplasty (DMEK), ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK), and rebubbling.

In total, 160 DMEK procedures (44.8%) were performed, 118 (33.1%) UT-DSAEK, and 79 (22.1%) rebubbling.

Equivalent CO₂ was calculated according to data provided by the Intergovernmental Panel on Climate Change (IPCC), and both 15 mL and 30 mL canisters of fluorinated gases were used. SF₆ gas at a concentration of 20% was used during the DMEK and UT-DSAEK procedures; however, the rebubbling procedures used a combination, including air.

The study found that the total number of procedures in the study emitted 1.5 tonnes of CO₂ over three years, equivalent to approximately “14,000 kilometres driven by an average car.” SF₆ 30 mL emitted 4.93 kg of CO₂ per canister over the same period, equivalent to four times that of C₂F₆ or C₃F₈ 15-mL canisters, whereas 15-mL canisters of SF₆ emitted 2.46 kg of CO₂.

“SF₆ has a significant carbon footprint despite its clinical benefits; it’s responsible for four times as many emissions as other fluorinated gases we considered. The smaller, 15-mL canisters are more efficient, especially C₂F₆ and C₃F₈,” Dr Airaldi said.

“Using an air tamponade for rebubbling may be sustainable in low-risk cases. Reusing canisters that have undergone filtration could be considered, where safe and permitted.”

The researchers concluded with a call to action to ophthalmic surgeons to consider how they can integrate eco-conscious choices in corneal surgery without compromising patient care. They highlighted the current policy of utilising disposable, single-use canisters as being particularly problematic, as alluded to in their study’s findings.

“We can reduce the environmental impact of corneal surgery by preferring smaller canisters, choosing alternative gases or air, and by advocating for more sustainable packaging. We might also have the possibility of reusing gases from larger cylinders,” Dr Airaldi said.

Dr Airaldi presented on behalf of Dr Borgia at the 2025 EuCornea conference in Prague.

Matteo Airaldi MD is a doctoral candidate at the University of Brescia, Italy. matteo.airaldi@unibs.it

Alfredo Borgia MD, FEBO is a cornea consultant at the “Mons. Dimiccoli” Teaching Hospital, Barletta, Italy. alfredo.borgia@aslbat.it