Carbon Footprint of Fluorinated Gases Used in Endothelial Keratoplasty

Purpose: The purpose of this study was to examine the direct impact on carbon emissions attributed to the use of fluorinated gases in endothelial keratoplasty (EK) procedures using gas tamponade and to evaluate the respective carbon footprint of different gas delivery systems used in EK procedures. Methods: In this retrospective, single-center environmental impact study, all corneal procedures using fluorinated gases between January 2021 and January 2024 at the Royal Liverpool University Hospital were reviewed and included. The CO2 equivalent emissions were calculated based on the mass of each fluorinated gas used, following the guidelines of the Intergovernmental Panel on Climate Change. Results: Of 357 total procedures (160 Descemet membrane endothelial keratoplasty [44.8%], 118 Descemet stripping automated endothelial keratoplasty [33.1%], and 79 rebubbling [22.1%]), single-use sulfur hexafluoride (SF6) canisters were used in 278 (77.9%) procedures. SF6 canisters used in corneal transplantation emitted nearly 1.5 tons of CO2 over 3 years. The 30-mL canisters emitted twice the CO2 per GBP compared to SF6 15-mL canisters and 4 times that of C2F6 or C3F8 15-mL canisters. Conclusions: Fluorinated gas use in corneal transplantation has a significant environmental impact, which can be reduced by the use of smaller single-use canisters with lower carbon footprint, although manufacturing and disposal concerns remain. Our findings advocate for a more environmentally conscious approach to EK, favoring the use of smaller, more cost-efficient canisters and considering air as an alternative tamponade where possible.