Environmental Impact of Eye Care Procedures and Visual Healthcare Services: A Systematic Review and Meta-Analysis.

Topic: To quantify the environmental impact of eye care procedures (carbon footprint, waste, and energy use) and assess the effectiveness of sustainability strategies.

Clinical relevance: Eye care procedures, including cataract surgery, one of the most common globally, generate considerable carbon emissions and waste. Because healthcare accounts for 4.4% of global greenhouse gas emissions, assessing the environmental footprint of ophthalmology is increasingly important. Current practices favor single-use devices and energy-intensive systems, with limited recycling, posing notable sustainability challenges.

Methods: A systematic search, registered in PROSPERO (CRD420251036827), was conducted in PubMed, Web of Science, Scopus, and the Cochrane Library without restrictions on publication date or language and completed on April 20, 2025. Eligible studies reported quantitative environmental indicators associated with visual healthcare activities. Data were extracted independently by 2 reviewers following Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines and assessed for methodological quality using the Methodological Index for Non-Randomized Studies tool. Continuous variables such as kilograms of carbon dioxide equivalent (CO₂e) per procedure and waste generation were descriptively summarized, without pooled quantitative synthesis, to highlight interstudy variability. Publication bias was evaluated using funnel plots.

Results: From 14 955 initial records, 26 studies met inclusion criteria, with 15 eligible for meta-analysis. Reported carbon footprints varied widely across procedures and settings, with substantial heterogeneity (I² = 100%) precluding the calculation of a meaningful pooled estimate. Cataract surgery exhibited the highest reported footprint (up to 322 kg CO₂e), followed by trabeculectomies (99-126 kg CO₂e) and intravitreal injections (13.7-277 kg CO₂e). Waste generation ranged from 0.05 kg to 3.1 kg per procedure, with a large proportion classified as theoretically recyclable but infrequently recycled because of biosafety restrictions. Consumption per cataract surgery varied between 17.8 and 35.09 kWh, strongly influenced by the source of electricity. Sustainability interventions such as reusable surgical instruments, eco-designed surgical packs, and the reduction in patient visits demonstrated significant reductions in environmental impact, with reusable sets achieving a 96% reduction in emissions after 19 cycles of use. The overall certainty of evidence was judged to be low to very low according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessments.

Conclusions: Eye care procedures contribute significantly to healthcare's environmental burden. Targeted sustainability interventions, supported by systemic institutional reforms, offer promising pathways to reduce emissions and promote environmentally responsible visual healthcare. However, conclusions should be interpreted with caution, given the low to very low certainty of the available evidence.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.