The Environmental Sustainability of Cataract Surgery
Introduction to Cataract Surgery and its Challenges
Climate change is a health issue described as “the greatest threat to global health in the 21st century” by the World Health Organization. The effects of climate change are already harming health around the world, and impacts will only intensify in the coming years. Heat waves and rainstorms are becoming more deadly, disease outbreaks last longer and are seen in new regions, wildfire smoke from tinder-dry forests reduces air quality, and food and water security are threatened by extreme weather. There is an imperative for quick action on many fronts to recognize and respond to climate threats, to support “greener” systems throughout the economy, and to communicate effectively about these issues for the sake of safeguarding human health. Additionally, climate change will disproportionately affect areas with weak health infrastructure, mostly developing countries. Healthcare is responsible for roughly 10% of the US’s carbon emissions, and roughly 70% of this waste can be attributed to the carbon footprint of operating rooms. This waste has a financial burden as well since 12% of Medicare’s budget (almost 3.5 billion annually) is spent on cataract surgery alone. Inevitably, the burden of the cost of cataract surgery will increase given the projected increase in our global aging population.
Cataract is the leading cause of blindness and severe visual impairment worldwide. It is therefore not surprising that cataract surgery is one of the oldest and most commonly performed procedures. In 2019, 29 million cataract surgeries were performed globally, a figure that is projected to increase to 50 million in 2050. Due to the sheer volume of cases, the environmental burden from this single surgical indication has been well-documented. Recently, global efforts to engage and educate the ophthalmic community about more sustainable practices have been established and unique recommendations have been made. It is becoming increasingly necessary to evaluate well-intentioned but questionable practices based on data regarding cataract surgery outcomes.
The environmental challenge of running an operating room is a systems-level issue. Notable complexities include overhead lighting and ventilation, sterilization of supplies, single-use disposable materials, electricity, and contracts. However, there are environmental challenges unique to running an ophthalmic surgical hospital with a large cataract surgery volume. Due to the nature of ophthalmology’s high procedural volume, ophthalmologists are in a unique position to empower institutions and to lead efforts to make healthcare more economically and environmentally stable.
Potential Solutions and Future Directives
Surgical Hand Antisepsis
The waterless alcohol-based surgical scrub is strongly recommended for prevention against surgical antisepsis. Despite this recommendation by leading health organizations, water-based scrub techniques remain the mainstay of scrubbing procedures. One leading academic ophthalmology center calculated a savings of 61,631 L of water per operating room (OR) per year using an alcohol-based scrub. Using calculations based on the direct purchase costs of scrubbing materials, water company invoices, and the flow rate of scrub sinks at this single institution, an estimated $280,000 - $348,000 could be saved per OR per year by switching to waterless scrub techniques. The economic and environmental impact is a strong justification for conserving water and for shifting to nonaqueous surgical scrubs.
Medical Waste Management
The life cycle assessment (LCA) is a tool used to quantify emissions (to land, air, and water) at each stage in a product’s life cycle. This tool accounts for processes such as the extraction of raw materials as well as the energy used to produce and manufacture the product. It also includes transportation, sterilization, and disposal costs. This methodology allows for the calculation of the carbon footprint of cataract surgery. A recent study by Morris et. al calculated the carbon footprint of a single cataract surgery at a British academic institution.Over 50% of the energy used was estimated to come from the greenhouse gas emissions associated with the production, consumption, and disposal of the products consumed in cataract surgery. The remaining carbon admissions of a single cataract surgery were from either energy use of the building and allotted operating room space, or the mode of travel for each patient during their initial assessment, actual surgery, and follow-up appointments. Therefore, efforts to reduce carbon emissions in the surgical cataract pathway that target the procurement and usage of surgical equipment would have the greatest impact on achieving this goal, as compared to focusing on travel emissions or building energy emissions alone.
The prevailing notion for not reusing tools in the operating room comes from well-intended regulations to decrease infection complications and decrease liability. However, current data suggests that this concern may no longer be valid. Haripriya et. al. report low post-operative endophthalmitis rates after 600,000 phacoemulsification and MICS cases in their retrospective trials. These studies occurred at Aravind Eye hospital, a low-resource hospital in Tamil Nadu, India, that reuses phacoemulsification tips, capsulotomy cystotomes, and irrigation tubing. Although there are limitations of the retrospective study, it suggests that by modeling institutions that have achieved this high rate of success, reuse of surgical tools can be done with a low risk of complications. One chief concern in such cases is the risk of infection, or endophthalmitis. The authors were able to achieve a 3.5-fold reduction in rate of endophthalmitis with the use of intracameral moxifloxacin. Notably, an injected bolus of intracameral moxifloxacin, though commonly performed off-label in the United States for prevention of postoperative endophthalmitis, has yet to be validated with prospective randomized trials and level 1 evidence. This is in contrast to the notable five-fold reduction of endophthalmitis rates documented with the use of intracameral cefuroxime as seen in the landmark European Society of Cataract and Refractive Surgeons endophthalmitis study. As such, no FDA-approved, commercially available moxifloxacin for intracameral injection has been available to surgeons.
Regarding phacoemulsification, the durability and structural changes to a phaco tip during surgery can affect the emulsification ability of the tip. It is therefore significant when porcine animal studies simulating phacoemulsification surgeries reveal no significant microscopic wear. Tsaousis reports that that there are no ultrastructural differences in eight different types of phacoemulsification tips after five uses in porcine models. Each tip, whether labeled for single-use or multiple-uses, was used in five cataract surgeries with varying density porcine lenses and at an extreme setting of 100% phaco power. These tips were then immediately compared using characterization techniques such as scanning electron microscopy (SEM). There was no significant evidence of microscopic damage, breakage, fissures, or failure. Aravind Eye Hospitals have also implemented other efforts to reduce the environmental emissions of cataract surgeries, for example by installing solar panels to reduce the burden of diesel generators and by installing a wastewater treatment center that repurposes water for gardening and toilets.
Drug Waste Management
Drug waste significantly increases the environmental burden and carbon footprint of cataract surgery. Tauber et. al. examined four U.S. surgical facilities that, on average, discarded $148 worth of medications per cataract case. Assuming approximately 3.8 million cataract cases per year in the U.S., a total of $560 million in medications are discarded annually. The potential carbon footprint from unused pharmaceuticals was calculated using greenhouse gas emissions, air pollutant emissions, and water-pollutant emissions from each institution. Per cataract surgery, the discarded drugs amounted to approximately 30 kg of CO2 emissions, which could amount to 105,000 metric tons of CO2 emissions in the U.S. for all cases per year – the equivalence of “driving a car from Anchorage, Alaska to Miami, Florida [up] to 51,400 times every year.”
In 2019, the Illinois Society of Eye Physicians and Surgeons (ISEPS) surveyed 73 ophthalmologists regarding current OR practices of discarding topical medications. The survey revealed that only 40% of OR medications can be taken home by the patient if the medication was ordered from an on-site pharmacy, and only 30% of OR medications can be taken home if the medication was ordered be an external pharmacy. The main reasons cited for this included the logistical concern regarding counseling patients on taking the medications, the state and facility protocols prohibiting hospital dispensation of inpatient drugs, and inability of the pharmacy to attach patient instruction labels required for a patient to leave with a medication. Mydriatic drops were the most frequently discarded topical OR medication, followed by antibiotic drops/ointments and anti-inflammatory drops. Forty-two percent of ophthalmologists indicated that at least one patient experienced an adverse outcome due to medications not being offered and patients subsequently facing financial and insurance barriers to obtaining necessary medications. Among those outcomes were postoperative inflammation (66%) and infection (21%), suggesting that quality of care is negatively impacted by patients not being able to receive medications directly from the OR.
This study spurred the Illinois Senate Bill 0579 to allow partially used topical drops from the OR and ER for post-discharge patient use, and delegates responsibility to the physician (not pharmacist) for medication counseling. Following this bill, the American Medical Association unanimously adopted a resolution to include the safe use of multidose medications for multiple patients. The resolution also advocates for the involvement of stakeholders, such as ophthalmology state organizations, sponsors, and hospital associations, in achieving these goals. These positions regarding safety of multidose eyedrop use have since been endorsed by the American Academy of Ophthalmology (AAO), the American Society of Cataract and Refractive Surgery (ASCRS), and the American Society of Ophthalmic Registered Nurses ASORN.At the institutional and national level, a collaboration must occur between OR administration, staff, and regulators, with ophthalmology societies and sponsors, to create drug waste policies that mitigate OR waste, allow post-discharge use by the patient, permit multidosing for multiple patients, and improve quality of care.
The operating room logistics of low-resource and low-staffed eye hospitals such as the Aravind Eye Hospital in India can provide an effective model in optimization of available personnel and equipment. Prior to the COVID-19 pandemic, Aravind was using two patient beds in one operating room. While the surgeon is operating on one patient, the other bed is being prepped for the next surgery. Therefore, the turnover between cases is effectively reduced. With this methodology, these surgeons each perform about 60 cases per day. Even though this assembly-line model may not be easily adapted globally, it is a remarkable approach for its optimization of their surgical staff. With good clinical outcomes and low post-operative endophthalmitis rates, the assembly-line model and reusable instruments policy of Aravind serves as a strong justification for optimizing the operating room for “greener” cataract surgeries.
Cataract surgeon expertise impact
Cataract surgeon expertise impacts the production of waste material and time consumption. Trainees produced 58.7% (0.267kg) more waste per phacoemulsification than their seniors, with a double mean operating time (42 minutes for trainees versus 20 minutes for seniors).
32.2%, of general waste generated during cataract surgery comprises packaging materials for intraocular lenses (IOL) and viscoelastic. A notable contributor to this waste is the presence of information leaflets in multiple languages, which are redundant because they are rarely used and could be easily replaced by a link to a website or QR code.
To illustrate, in the Cardiff cataract pathway in the UK, the IOL itself weighs less than 1g, while its packaging weighs a substantial 64g, including a 70-page booklet translated into 11 different languages.
Surprisingly, over 60 countries currently do not accept electronic instructions for medical devices. This list comprises not only smaller low- to middle-income countries but also larger nations like China, Russia, and South Africa.
Surgical Team Education and Awareness
Many studies regarding preventing ophthalmology device-associated infections have been published to consolidate the differences between surgeon opinions and evidence-based medicine. An online survey distributed to the surgical staff of cataract surgeries yielded over 1100 responses, 91% of which expressed concern about climate change, and 93% felt that actionable steps should be taken now to reduce the environmental burden of cataract surgeries. This survey further highlights what the driving factors were for waste in the opinions of the surgeons (77% of respondents) and nurses/administrators (18% of respondents). Interestingly, a surgeon’s preference in tools and equipment was not rated high, but manufacturers’ and regulatory agencies’ opinions were felt to be strong driving factors contributing to waste. In fact, 79% of respondent surgeons preferred reusable over disposable tools if the performance and functionality was equivalent. If the survey responses demonstrate a true willingness from surgical staff to participate in reducing waste, then a standard list of equipment for cataract surgery that contains the least number of materials can be encouraged at individual institutions.
Cataract surgeries continue to pose a major environmental and economic challenge in developing and developed countries. Unique to cataract surgery is its globally high volume of procedures annually, thus generating an unsustainable amount of unnecessary operating room waste. The cataract surgical pathway presents enormous costs in the procurement, consumption, disposal, and transportation of necessary materials. The lack of sustainability of cataract surgery is a largely a systems-level issue, and therefore continued efforts through multinational initiatives and ophthalmology societies are needed. There are many ophthalmology societies already advocating for more sustainable practices. With regards to local/institutional efforts, training cataract surgeons on greener surgical practices is necessary, and lessons can be adapted from low resource hospitals. It is our responsibility as healthcare professionals to reduce greenhouse gas emissions, especially in the procurement and consumption process of OR materials. Since cataract surgery is prevalent globally, it should be a core focus of the campaign for greener operative practices.
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