REDUCING THE CARBON FOOTPRINT OF CATARACT SURGERY: A SYSTEMATIC REVIEW

The healthcare sector, including the National Health Service (NHS), is a significant contributor to carbon emissions, accounting for approximately 4% of the UK's total emissions. To address this, the NHS has set ambitious targets to achieve net-zero emissions by 2040 (direct) and 2045 (indirect), respectively. Ophthalmology is a high-volume specialty within the NHS, contributing to 8.1% of all hospital outpatient visits in 2018-19. Cataract surgery is one of the most commonly performed surgical procedures worldwide, with over 500,000 cases performed annually in the UK alone. While essential for visual health, each cataract surgery has an estimated carbon footprint of 150-180 kg CO2 equivalent, influenced by factors such as surgical techniques, equipment usage, energy consumption, and waste generation. This review aims to explore innovative approaches to cataract surgery that can reduce its environmental impact.

Secondary study - systematic review.

A literature search was conducted using the databases EMBASE, MEDLINE, and Cochrane Library. Keywords such as "cataract surgery," "sustainability," and "carbon footprint" were used to identify relevant studies. Two independent reviewers underwent title, abstract and full text screening. The selected studies were further analysed and categorised into three domains: pre-operative, intra-operative, and post-operative approaches to reduce the carbon footprint of cataract surgery. Each study was assigned to one or more of these domains based on its primary focus.

Pre-operatively, 9 studies highlighted the "Green Theatre Checklist". Sustainable practices included minimising drug waste (7 studies), using reusable textiles (theatre hats, gowns, trolley covers – 4 studies each, 0.5-1.5kg CO2 equivalent per case), and topical anaesthesia over sub-Tenon's injections (3 studies – 1.1-1.3 kg CO2 equivalent per case). Intraoperatively, 7 studies supported short-cycle instrument processing and safe reuse of phaco tips for cost and waste reduction. Post-operatively, 10 studies found telemedicine and home devices reduce patient travel emissions.

Given that cataract surgery is the most commonly performed surgical procedure globally, reducing the carbon footprint of each operation can significantly contribute to sustainability and the NHS's net-zero goals. While initiatives like the "Green Theatre Checklist" are being increasingly adopted, other approaches, such as telemedicine for cataract follow-ups, are still in their early stages and require further development and implementation. To encourage widespread adoption of sustainable practices in ophthalmology, additional research and trials are necessary to validate the effectiveness and feasibility of these approaches. By prioritising sustainability, ophthalmologists can play a crucial role in reducing the environmental impact of their practice.