Reducing carbon footprint in cataract services: A cross-sectional study of sustainable eye hospital models advancing circular economy principles.

Abstract

Introduction: Global warming is one of the biggest threats of the 21^st century. Health care facilities are also one of the main contributors to carbon emission leading to global warming.

Materials and methods: A retrospective observational study analyzed data of 5 years from 2019 to 2023 at our institute. Carbon footprint was quantified using the greenhouse gas (GHG) Protocol (scopes 1-3), with outcome variables including total emissions (kg CO₂e/patient), single-use waste (kg/patient) undergoing cataract extraction were included; exclusions applied for combined procedures. Sustainability measures encompassed reusable instruments, solar energy adoption and waste segregation. Data were analyzed descriptively with ANOVA for initiative impacts.

Results: Each case of small incision cataract surgery (SICS) from the surgical procedure till discharge generated a waste of 310 g on average, resulting in a total of 3.20 kg CO₂ equivalent. The cumulative effect of operating 32073 SICS cases of community patients accounted for a total of 113.13 tonnes of CO₂ which was overcome by absorption of 133.22 tonnes of CO₂ by the green cover present in our campus which covers approximately four acres (174240 sq. feet) in area. Solar panels generate 125 kW of power, saving approximately 1.5 Lakhs (668 Omani Rial) worth of energy bills every month. Sixty-five cows produce between 120 l and 200 l of milk daily, which is used for the canteen and distributed to community patients. The cow dung is fed into the biogas plant (the dome), where it's converted into 2.5 commercial cylinders of gas. Leaves from the trees are collected and converted into compost, which is used to fertilize 2.5 acres (108900 sq. feet) of land. Wastewater is treated in a sewage treatment plant, and the purified water is then used to irrigate the 2.5 acres (108900 sq. feet) of land and water the campus gardens.

Conclusion: Eye hospitals should prioritize routine carbon audits using GHG Protocol scopes, Miyawaki-type of gardening in limited areas, and solar integration to achieve net-zero emissions without compromising outcomes. Adopting these scalable practices positions providers as leaders in planetary health.