A Greener Today for a More Sustainable Tomorrow: Lowering the Carbon Footprint of Vitreoretinal Practice

In 2019, The Lancet published a report on health and climate change.1 Within the report was this statement: “The life of every child born today will be profoundly affected by climate change. Without accelerated intervention, this new era will come to define the health of people at every stage of their lives.”

Take a moment to let that sink in.

That statement illustrates the undeniable fact that while the world faces numerous threats and challenges, one of (if not the most) critical is that of climate change. Eye health will also be impacted, directly or indirectly, from the extreme weather conditions brought on by the earth’s rising temperature. These include an increased incidence of trachoma infections, vitamin A deficiency eye conditions, cataracts, allergic eye diseases, glaucoma and age-related macular degeneration (AMD).2

Basically, an unhealthy planet leads to an unhealthy everything else — including eyeballs. So, if we want to continue today’s activities tomorrow, we need to act now and implement more sustainable practices.

Ophthalmology and The Climate Crisis

It’s no secret that the medical field, in general, produces a large amount of waste: It’s a major contributor to carbon emissions, with waste production and transport systems being among the highest contributing factors.2

And although ophthalmology might be a smaller specialty compared to say, cardiology, it contributes significantly to healthcare’s carbon footprint. The main culprits driving ophthalmology’s contributions to the climate crisis are high surgical volumes (hello, cataract surgery), single-use products and single-use eye drops, as well as ORs that consume high levels of energy, and repeated office visits by patients who need regular monitoring and treatment.

Clearly the environmental cost of practicing medicine is high — and indeed, sustainability isn’t a concept new to ophthalmology. Studies have found that emissions can be largely reduced by incorporating readily available resource efficiency measures. These include optimizing the use of reusable instruments and supplies, maximizing single-use device reprocessing, promoting minimum waste and recycling practices, using energy-efficient appliances and air-handling systems, and investing in low-carbon energy sources.3

But there are barriers, especially in developed countries that can restrict the ability to be more environmentally friendly. For example, flash autoclaving (or immediate use sterile supplies, IUSS) is a process where instrument trays are sterilized but not allowed to dry and is used in India and other countries. This can lower energy expenditures — however, it’s widely prohibited in the U.S., unless specified by the manufacturer. But does this restriction actually make surgery safer?

“Although these regulatory restrictions are made with the purpose of increasing safety, their effect is theoretical and unproven, and they add energy burdens and expense to the process,” explained Thiel, et al. Although most regulations in developed countries are made with patient safety in mind, greater liability in countries such as the U.S. might drive resource use in operating rooms.3

They continued: “Defensive medicine, not based on scientific evidence of infectious risk, adds to the cost and, therefore, environmental footprint of care.”

Another study compared waste generated from glaucoma surgery in the U.S. versus India.4 The authors stated: “The objective of this pilot study is to call attention to the fact that certain regulations in the U.S. lead to the production of potentially unnecessary waste.”

Of course, there’s a caveat: To even begin addressing this issue in the U.S. and other developed nations, it would require rethinking the process of surgical care delivery and restructuring the laws governing the production of medical waste.

Five Steps to Lower Carbon Emissions in Ophthalmology

So, what can actually be done to help?

The good news is most hospitals and clinics already have some protocols in place to reduce expenses and maximize efficiency while maintaining patient outcomes. And there are also simple things individuals can do to help lower their carbon footprint…

Dr. Redmer van Leeuwen, an ophthalmologist and vitreoretinal surgeon at University Medical Center Utrecht in the Netherlands, spoke with PIE magazine regarding the measures taken to reduce waste at his center. He said that they try to limit the use of disposables in the OR, they ask suppliers for lean custom-packs, and they restrain from using perfluorocarbon liquid (PFCL) and sulfur hexafluoride (SF6) gases as much as possible, “In addition, we shut down air-conditioning when the OR is not in use, and are planning the re-introduction of reusable gowns in the OR,” he shared.

These measures are also recommended by others in the field. In 2021, Dr. Wee Ling Wong and colleagues published Ophthalmology Going Greener: A Narrative Review to explore how ophthalmology can reduce carbon emissions, related costs and overall environmental impact, while maintaining a high standard of patient care.2 This paper reminds us of the 5 R’s of sustainability (reduce, reuse, recycle, rethink and research) and how they can be applied in ophthalmic practice without major disruption — as evidenced by Dr. van Leeuwen.

#1 Reduce waste. Turning off the lights and machines in the operating room when it’s not in use can significantly reduce energy consumption. Or finding sensible solutions to reduce waste — especially plastic packaging — can make a substantial impact, as the majority of surgical equipment is not only wrapped in plastic, it’s often double-wrapped.

It’s understandable that ophthalmic surgeons might prefer specific equipment for a certain surgical procedure — and as a result, single-packaged disposable surgical equipment, along with gowns and gloves of different sizes, were born into existence. Herein lies another problem: Unused items (whether it’s tools or textiles) in those pre-packaged kits are discarded — which is not only a waste, but a shame as well. The review suggests that doctors could work with industry partners in the “creation of a surgeon-tailored pack with preferred equipment, gloves of their size and disposable gowns, which could reduce the amount of double-packaging of each product.”

Reusable instruments can also greatly reduce waste produced: “Stick to your reusable instruments,” said Dr. van Leeuwen. “Disposables may be attractive in the short-term. But in the end, they are more costly and produce huge amounts of waste.”

Pharmaceutical waste should also be another target to consider to conserve resources and reduce unnecessary waste.

#2 Reuse materials. Reusing materials can be as effective as reducing waste. For example, switching from disposable to reusable surgical gowns in a single hospital led to a waste reduction of 23,000 kg of carbon and saved the hospital $60,000 USD over a 12-month period.2

Clearly, money can be saved by reusing gowns — but there’s always a flip-side. More research is needed on savings, expenditures, as well as potential contamination of reused items. Further, the cost to launder and store these items could render the whole process unsustainable.

#3 Implement recycling programs where possible. Recycling can also be somewhat controversial in medicine, and the ability to segregate waste varies by country. There are also costs associated with recycling to consider. But it can still make a difference: A 2015 study found that recycling did not lead to additional costs — and although the overall impact of recycling and resulting savings were small, it could be magnified if adopted by the national healthcare system.2

This has always been the caveat with recycling: One person dutifully recycling their aluminum cans is unlikely to save the world — but what if 100 million people recycled their cans? This illustrates that really, to make this work — and to make a difference — a big part of the industry would need to embrace a recycling program.

#4 Research best practices. Sustainability in ophthalmology — especially in posterior segment surgery — is an area that needs more research. In particular, data in the following areas would be helpful: the environmental impacts of healthcare activities, life cycle analysis of materials, and cost analysis.

“Innovative design of devices that minimize environmental impact whilst maintaining standard of care would also be useful,” added Dr. Wong and colleagues.

#5 Rethink care for a greener practice. Today, technology can also support a more sustainable practice — especially in vitreoretina, where the chronic and progressive nature of conditions like age-related macular degeneration (AMD) and diabetic retinopathy (DR) require routine monitoring to prevent deteriorating vision and disease progression.

Thus, creating more localized pathways for care — along with developments in artificial intelligence (AI), telehealth platforms and remote monitoring devices — can help monitor and manage these retinal diseases without the need of repeated office visits.

A Greener Today for a More Sustainable Tomorrow: Lowering the Carbon Footprint of Vitreoretinal Practice
What are some ways you can reduce your carbon footprint?

Ophthalmic Gases Increase Emissions

Along with surgical disposables, Dr. van Leeuwen said that general anesthesia with gas, the use of perfluorocarbon liquid (PFCL), and gas tamponade are the main drivers of carbon emissions in vitreoretinal practice.

Fluorinated gases, including sulfur hexafluoride (SF6), hexafluoroethane (C2F6) and octafluoropropane (C3F8), are used in vitreoretinal surgery to repair conditions like retinal breaks, detachments and macular holes. These are among some of the most potent greenhouse gases, with SF6identified by the United Nations Framework Convention on Climate Change (Kyoto Protocol) as one of six gases requiring strict regulation in to reduce global warming.5

“Anesthetic volatile gases (e.g., isoflurane and sevoflurane), fluorinated liquids (PFCL), and ophthalmic gases (SF6, C2F6, C3F8) have an extremely high global warming potential,” said Dr. van Leeuwen. “For instance, global warming potential of SF6 gas is approximately 22,000 times higher when compared to CO2. Moreover, these gases may stay in the atmosphere for more than 20,000 years.”

To circumvent this issue, Dr. van Leeuwen said that vitrectomy would ideally be performed under local anesthesia with air tamponade.

To investigate, a study published in January 2022 compared the potential reduction in carbon CO2 emissions by utilizing air-tamponade (AT) instead of fluorinated gases to manage rhegmatogenous retinal detachment (RRD). The authors included participants from two large tertiary referral vitreoretinal centers where RRDs are exclusively repaired using fluorinated gases (Manchester Royal Eye Hospital (MREH) and Birmingham and Midland Eye Centre (BMEC)) and a tertiary VR center that routinely employs AT in selected RRD cases (University Hospitals Coventry and Warwickshire (UHCW)).

They found that UHCW used AT in 70% of RRD repairs — this enabled the hospital to “greatly reduce the need for the most environmentally damaging SF6 gas, leading to lower CO2 emissions by 47.0% and 41.1% compared to MREH and BMEC, respectively.”

The Carbon Footprint of Intravitreal Injections

Outside of surgical procedures that require gases, intravitreal injections are a very common treatment in posterior segment practice — and they generate a lot of waste. To analyze where emissions may be reduced, Power et al., researched the carbon footprint of a single intravitreal injection (IVT) at Mater Misericordiae University Hospital Dublin in regard to materials procurement, patient travel and building energy use.6

They found that a single IVT (excluding the anti-VEGF agent) was associated with carbon emissions of 13.68 kg CO2eq. The authors shared that this equates to 82,100 kg CO2eq annually for their service. Leading the pollution train in carbon emissions was patient travel (77%), followed by procurement (19%) and finally, building energy use (4%). However, they noted that once an anti-VEGF agent is included, the environmental cost of procurement rises and varies widely at 20, 320 and 423 kg CO2eq per injection for bevacizumab, ranibizumab and aflibercept, respectively.

Harking back to unused items in injection packs: If items considered dispensable by surgeons were omitted, it would cut an estimated 0.56 kg per injection (3,360 kg CO2eq annually). While this speaks to the researchers’ service alone, if extrapolated to the U.K. as a whole, it could save 450,000 kg CO2eq. This is major — and if you’re not quite sure how major — the authors provide this context: A single one-way economy transatlantic flight produces 480 kg CO2eq per person.

Additionally, the authors said that unnecessary single-use plastics from routine procedure packs should also be reduced: “Three of the four dispensable items in our packs are hard plastic … the annual weight of the dispensable plastic in the packs used by our service is over 240 kg.”

What this study shows is that “the far larger contribution of the production, distribution and consumption elements of procurement, compared with the waste disposal element, highlights the need to target emission generation at source.”

Indeed, if the item doesn’t exist — it’s carbon footprint doesn’t either: “The omission of unnecessary items eliminates all of the emissions embedded in the procurement process of an item,” said the authors.

“If sustainability is a goal of the wider ophthalmology community, intravitreal injections, due to their exponential increases in volume, should be a prime target for such efforts,” the authors continued, adding that procurement should be a main focus of such efforts. The authors also point to innovation in drugs and devices — such as long-acting agents to reduce the number of IVTs needed — could create more sustainable treatment regimens.

“Clinicians should recognize that they can make simple changes that can have an immediate positive impact on carbon emissions. We must lead by example and address the harmful effects of mindless wastefulness in our daily practice. We strongly advocate bottom-up interventions to drive an overall reduction in carbon emissions in ophthalmology and healthcare as a whole,” the authors concluded.

And these bottom-up initiatives are not only simple, they can be implemented now to lower carbon emissions. But of course, the first step is recognizing that we have a problem.

“Climate change — or better yet, the climate crisis — is a much bigger threat to humankind than COVID. It has been predicted a long time ago and we notice its effects today, but the long-term consequences will be disastrous,” said Dr. van Leeuwen. “All individuals have to change their behavior, both professionally and privately, in order to avert an uninhabitable earth.”


  1. Watts N, Amann M, Arnell N, et al. The 2019 report of The Lancet Countdown on health and climate change: ensuring that the health of a child born today is not defined by a changing climate. Lancet. 2019;394(10211):1836-1878.
  2. Wong, Y.L., Noor, M., James, K.L. et al. Ophthalmology Going Greener: A Narrative Review. Ophthalmol Ther. 2021;10: 845-857.
  3. Thiel CL, Schehlein E, Ravilla T, et al. Cataract surgery and environmental sustainability: Waste and lifecycle assessment of phacoemulsification at a private healthcare facility. J Cataract Refract Surg. 2017;43(11): 1391-1398.
  4. Namburar S, Pillai M, Varghese G, Thiel C, Robin AL. Waste generated during glaucoma surgery: A comparison of two global facilities. Am J Ophthalmol Case Rep. 2018;12:87-90.
  5. Moussa G, Andreatta W, Ch’ng SW, et al. Environmental effect of air versus gas tamponade in the management of rhegmatogenous retinal detachment VR surgery: A multicentre study of 3,239 patients. PLoS One. 2022;17(1):e0263009. 
  6. Power B, Brady R, Connell P. Analyzing the Carbon Footprint of an Intravitreal Injection. J Ophthalmic Vis Res. 2021;16(3): 367-376.

Editor’s Note: A version of this article was first published as the Cover Story of PIE Issue 21.

Foto 1 Redmer 2021_resized

Dr. Redmer van Leeuwen is a medical retina consultant and vitreoretinal surgeon at the University Medical Center Utrecht, the Netherlands. Next to his clinical and research activities, he is committed to sustainability in healthcare. Together with Sjoerd Elferink, he founded the Dutch Taskforce on Sustainable Ophthalmology. This taskforce develops guidelines for safe and sustainable procedures in ophthalmology and has an advisory role to the board of the Dutch Ophthalmic Society. [Email:]

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