How Ophthalmologists Can Decarbonize Eye Care

Abstract

Topic:

Understanding approaches to sustainability in cataract surgery and their risks and benefits

Clinical Relevance:

In the United States, healthcare is responsible for approximately 8.5% of greenhouse gas (GHG), and cataract surgery is one of the most commonly performed surgical procedures. Ophthalmologists can contribute to reducing GHG emissions, which lead to a steadily increasing list of health concerns ranging from trauma to food instability.

Methods:

We conducted a literature review to identify the benefits and risks of sustainability interventions. We then organized these interventions into a decision tree for use by individual surgeons.

Results:

Identified sustainability interventions fall into the domains of advocacy and education, pharmaceuticals, process, and supplies and waste. Existing literature shows certain interventions may be safe, cost-effective, and environmentally friendly. These include dispensing medications home to patients after surgery, multi-dosing appropriate medications, training staff to properly sort medical waste, reducing the number of supplies used during surgery, and implementing immediate sequential bilateral cataract surgery where clinically appropriate. The literature was lacking on the benefits or risks for some interventions, such as switching specific single use supplies to reusables or implementing a hub-and-spoke style theatre setup. Many of the advocacy and education interventions have inadequate literature specific to ophthalmology but are likely to have minimal risks.

Conclusions:

Ophthalmologists can engage in a variety of safe and effective approaches to reduce or eliminate dangerous GHG emissions associated with cataract surgery.

Précis

Ophthalmologists have a variety of options for engaging in sustainability at work. Many interventions may also reduce costs while maintaining safety in surgery.

Introduction

Environmental issues are of increasing concern to the general public and to healthcare professionals. Climate change is causing an increase in immediate health threats from drought and fire, flooding and storms, and tick- and mosquito-borne diseases.^1–3 For eye care, climate change will likely increase ocular trauma (from extreme weather events), vector-borne diseases such as trachoma^4–6 and onchocerciasis,^7,8 and diseases affected by exposure to heat, ultraviolet radiation, ozone, and other environmental pollutants.^9–17 Without prompt efforts to address climate change, the severity of these impacts is expected to increase drastically.

Unfortunately, the health care systems charged with maintaining and improving peoples’ health are among the largest contributors to climate changing greenhouse gas emissions. Globally, healthcare emits about 5% of greenhouse gases.¹⁸ The proportion is higher in the United States, where approximately 8.5% of the US’ total greenhouse gas emissions come from the health sector.^19–21 Unintentionally, healthcare is also responsible for other emissions adversely impacting health, including 9% of the US’ toxic air pollutants.²¹

Sustainability efforts within the health care sector have been expanding.²² Hospitals and health systems have been joining organizations like Practice Greenhealth and Health Care Without Harm or, most recently, voluntarily pledging to reduce greenhouse gas (GHG) emissions through the Health Sector Climate Pledge created by the Department of Health and Human Services’ Office of Climate Change and Health Equity (OCCHE).²³ ESG (environmental, social and governance) concerns are now becoming a focus of governing boards and health system leaders as they recognize both the immediate and long term negative consequences of failure to create more resilience in operations and lead efforts toward decarbonization. Medical societies and colleges are also engaging in climate action, through action statements or by joining groups such as the Medical Society Consortium for Climate and Health.^24,25 The American Academy of Ophthalmology (AAO) and American Society of Cataract & Refractive Surgery (ASCRS) joined the Consortium in 2020, giving their members access to educational and advocacy resources.²⁶

Sustainability, Climate, and Eye Health

Though procedures in ophthalmology may use fewer resources and generate less waste than other specialties, the need for eye care is expansive. Cataract surgery, for example, is one of the most commonly performed operations worldwide, and the global need will continue to increase with a growing and aging population. Though there is a dearth of research on the environmental footprint from medical care,²⁷ a small body of literature exists for cataract care and some other eye conditions.^28–37 For high income countries, a majority of emissions originate in the manufacturing and distribution of single use surgical supplies.³⁸ There is substantial variability in waste generation and emissions from cataract surgery in different countries, suggesting improvements are possible.^29,33,39,40 Historically, there has been a tension between reusable and single-use items because of the fear of infection, but the notion that single-use items are safer for patients is not always supported by evidence.^41–43 Advancements in infection control practices such as improved OR ventilation, sterilization methods, surgical technique, and availability of antimicrobial prophylaxis have significantly reduced the risks associated with reusable items.^43–45 Endophthalmitis studies at Aravind Eye Care System raise the possibility that many of the costly and wasteful infection control protocols utilized by operating rooms in the United States could be unnecessary.⁴⁰ A pre-pandemic survey of ophthalmic surgeons and nurses showed overwhelming support for sustainability interventions such as the reuse of supplies and multi-dosing of medications,⁴⁶ with those in Ambulatory Surgical Centers more likely to state that they are already engaged in these practices.^40,47

What Can a Clinician Do?

Despite increasing knowledge and a growing desire for action, many clinicians are unsure how to begin acting on climate change, especially within the clinical space. Interventions must be carefully selected, as sustainability might conflict with other important concerns, such as: infection control and prevention, excellent clinical outcomes (such as postoperative visual acuity), regulatory and other legal requirements, protocols enforced by accrediting bodies, cost containment, and employee stress and burnout. Here, we describe a variety of potential interventions for cataract surgeries, summarize existing literature on the broader impacts of each intervention, and offer guidance for ophthalmic clinicians on actions they can take to make eye care more sustainable.

Methods

Selecting Interventions

A list of potential interventions to improve environmental sustainability in cataract surgery was generated based on previous literature described above ^{28,39,43,48–51} and field observations. The ‘rethink, reduce, reuse, recycle’ framework was used to develop and organize potential interventions.²² All interventions were sorted into topic domains, including advocacy, education, pharmaceuticals, process changes, supplies, and waste. For this study, our team focused on potential environmental sustainability interventions that could be enacted by clinical personnel such as surgeons, nurses, surgical technicians, and pharmacists. As such, some items were moved into the domain of ‘advocacy’ in anticipation that the clinician could only advocate for those changes rather than directly implementing them (ex: sourcing renewable electricity, encouraging green building design for any new construction or renovations, etc.). For each intervention, the academic literature was reviewed to assess any known impacts to emissions, costs, safety, and outcomes. Gaps in the literature were noted.

Literature Review

A literature search was conducted in the electronic databases PUBMed, SCOPUS, and Cochrane Library to identify articles related to a specific sustainability intervention in the medical space. The article titles and abstracts were screened, and potentially relevant articles were retrieved for evaluation of the full text. The literature for each intervention was summarized and outcomes were compared for effectiveness. In addition to academic databases, we attempted to capture any hospital or health system websites or reports that might specify some of the benefits or challenges associated with adopting a particular intervention.

The study team also qualitatively assessed each intervention in the areas of 1) likely impact on environmental sustainability, specifically greenhouse gas emissions, 2) likely amount of effort for a hospital or health facility to enact, and 3) likely financial impact to the healthcare facility. A simple three-point ranking scale was used to evaluate these effects as either generally positive, neutral, or generally negative.

Decision Chart Development

Focusing specifically on the supply and pharmaceutical interventions, our team developed decision support charts to help navigate the overwhelming array of potential sustainability options for the individual clinician. The charts were developed by assessing the various end points for supply and drug interventions, eg. Reduce, reuse, or recycle, and organizing in a way that optimizes for reduction of supply and drug use first. Reducing supply items typically results in the largest GHG emissions savings.⁵²

Results

Literature about Sustainability Interventions

Table 1 lists the interventions and an assessment of their impact, according to domain type.

Table 1:

Intervention strategies, by topic domain, and their likely impact on environmental footprint, hospital effort, and hospital finances

Topic Domains	Topic Sub-domain	R Category	Intervention Type	GHG (or sustainability) Impact	Effort (from hospital)	Likely Financial Impacts
Advocacy	Health System	Reduce	Encourage sourcing renewable energy (solar, wind, etc.)	high	high	neutral
Advocacy	Health System	Reduce	Encourage sustainability in any capital projects (ex: build new construction or renovations to existing green building standards)	medium	medium	savings
Advocacy	Health System	Rethink	Purchase carbon offsets (for energy emissions from surgery, supply purchases, patient or staff commuting, conference travel, etc.)	high	medium	cost
Advocacy	Health System	Reuse	Contract with a third party single use device reprocessor	high	medium	savings
Advocacy	Manufacturers	Recycle	Inquire or enroll in take-back programs (for expired supplies, etc.)	low	low	savings
Advocacy	Manufacturers	Reduce	Encourage suppliers to reduce/optimize product packaging	medium	low	neutral
Advocacy	Manufacturers	Reduce	Encourage suppliers to switch to virtual Directions for Use (ex: intraocular lens or IOL directions, etc.)	medium	low	neutral
Advocacy	Manufacturers	Reduce	Inquire about the carbon emissions associated with manufacturing their product(s)	high	high	neutral
Advocacy	Manufacturers	Reuse	Ask suppliers about reusable alternatives (ex: reusable IOL loader, etc.)	medium	medium	savings
Advocacy	Manufacturers	Reuse	Encourage suppliers to manufacture single use devices that can be reprocessed	high	low	savings
Education	Patients	Rethink	Educate patients on the dangers of climate change and emissions from medical practice (provides an opportunity to highlight the health system’s accomplishments; can be done passively with posters, etc.)	low	low	neutral
Education	Professional Training	Rethink	Create and/or promote formal educational content on climate and health in medical education, residency training, and ongoing credentialling for ophthalmologists and other health professionals	medium	medium	neutral
Education	Staff	Recycle	Re-educate staff of recycling and other sorting protocols	low	low	savings
Pharmaceuticals	Anesthesia	Reduce	Do not pre-emptively draw up drugs for emergency-use (ex: epinephrine, propofol)	medium	medium	savings
Pharmaceuticals	Dispensing	Reuse	Dispense intra/pre-operative drugs home with patient when appropriate	medium	medium	neutral
Pharmaceuticals	Multi-dosing	Reuse	Multi-dose topical drugs in the pre-operative area (ex: dilating drops)	medium	medium	savings
Pharmaceuticals	Multi-dosing	Reuse	Multi-dose topical drugs in the OR (ex: tropicamide)	medium	medium	savings
Pharmaceuticals	Sizing	Reduce	Reduce/optimize the vial or bottle size of single-use drugs	medium	low	savings
Process	Care Pathway	Reduce	Eliminate pre-operative antibiotics, where clinically indicated, as department policy	medium	medium	savings
Process	Care Pathway	Reduce	Patient uses street clothes (no disposable patient gown)	medium	low	savings
Process	Operations	Rethink	Enact a hub and spoke operating model for high-volume surgeons	low	high	neutral
Process	Operations	Rethink	Enact same-day, sequential bilateral surgeries, where clinically appropriate	medium	medium	neutral
Supplies	Custom Pack	Reduce	Reduce the number of unused items in the custom pack by removing them, and perhaps relocating some things as pick items in individual peel packs (including: gauze, OR towels, single use cups and basins, syringes, pens, bottles, sharps holders, etc.)	medium	low	savings
Supplies	Custom Pack	Rethink	Standardize surgical supplies across surgeons (preference cards, custom packs, and pick items)	low	high	savings
Supplies	Custom Pack	Reuse	Replace single-use plastic basins and cups with reusables (ex: metal or reusable plastic)	medium	medium	savings
Supplies	Draping	Reduce	Face drape only (eliminate full body patient drape)	medium	medium	neutral
Supplies	Draping	Reduce	Eliminate disposable cover on the chair/bed	medium	medium	savings
Supplies	Draping	Reduce	Eliminate draping on other surfaces in the OR (instead clean all surfaces with a sterilizing wipe)	medium	medium	savings
Supplies	Expiration	Reduce	Narrow the expiration window on drugs/supplies in the room (the dates when they would need to be removed)	low	medium	savings
Supplies	Patient	Reuse	Switch to reusable med/surgical supplies (ex: patient restraints, stethoscopes, BP cuffs, etc.)	low	low	savings
Supplies	Preference Card	Reduce	Develop a ‘minimal’ baseline preference card for new employees	medium	low	savings
Supplies	Preference Card	Reduce	Review/optimize all physician preference cards	low	medium	savings
Supplies	Reusable Tray	Reduce	Remove unused instruments from trays and consolidate sets	low	medium	savings
Supplies	Reusable Tray	Reduce	Remove the sterile scope covers	low	high	neutral
Supplies	Reusable Tray	Reuse	Replace all single use plastic bluewrap with reusable hard containers	medium	high	savings
Supplies	Scrub	Reuse	Alternative for disposable, single use BD EZ Scrub	medium	medium	neutral
Supplies	Staff	Reuse	Switch to reusable sterile gowns for surgical team	medium	medium	savings
Supplies	Staff	Reuse	Switch to reusable caps or multiple uses per day	low	low	savings
Supplies	Staff	Reuse	Switch to reusable gowns for non-clinical staff	medium	medium	savings
Waste	Recycling	Recycle	Recycle hard plastic bins and trays	low	medium	neutral
Waste	Recycling	Recycle	Recycle paper packaging (prior to patient entering OR)	low	medium	neutral

Advocacy & Education

Recognizing the limits of an individual in tackling a problem as large as climate change, the categories of advocacy and education are meant to illustrate ways in which clinicians can leverage their authority and respected position to achieve climate action reach. According to an annual Gallup poll, the American public typically ranks clinicians (doctors and nurses) as the most trusted professions.⁵³ Doctors often hold substantial power at their medical facilities when it comes to decision-making and planning, and this can apply to cataract surgery as well as many other procedures and specialties.

Within their institution, clinicians can engage in educational activities, such as grand rounds or training sessions with their peers and colleagues, to discuss sustainability, climate change, and proper waste sorting. Though virtually no academic literature exists studying the impact of inter-collegial discussions in the medical space, climate communication is seen as an essential step in addressing the crisis.^54–57 Clinicians can also advocate to add formal coursework on climate and health to medical and nursing school curriculums and continuing education programs, to better prepare clinicians for their future work. A few studies have monitored changes to medical education, but it may be too early to determine whether approaches are effective for preparing these students for the climatic changes they will experience in their practices.^58–66

Waste training in medicine has a larger literature base. Recycling is an important component of dealing with operating room waste. Proper waste sorting and recycling in operating rooms can have a positive environmental and financial impact, but several barriers to operating room recycling exist. Operating room staff should be trained on proper waste sorting and recycling protocols, and clinicians can both advocate and educate on this topic. A survey of clinicians at Mayo Clinic found that 57% of respondents were unclear on which items in operating room are recyclable. After the implementation of a recycling education program, cost savings of 10.3% were achieved in sharps waste disposal.⁶⁷ Another study created a 409% increase in recycling participation following distribution of an informational email, posting of recyclable materials guides in each room, and convenient placement of recycling receptacles.⁶⁸ A recycling improvement program, consisting of staff training sessions and educational materials, could have a substantial impact on environmental emissions.

Clinicians might also leverage their relative local influence by advocating for changes such as investing in renewable energy sources, green building design, and carbon offsets. These are all well-tested methods of reducing GHGs and other emissions; however, they often require consensus-building from many stakeholders. Carbon offsetting, the practice of paying a third party to “absorb” GHG emissions, is a common but debatable practice.^69,70 Some approaches can provide combined community benefit, and monetizing GHG emissions provides some financial incentives for their reduction. However, offset programs should be carefully vetted. In general, it is better to prevent emissions than to rely on these absorption schemes.^71,72 That said, many health systems and other businesses rely on carbon offsetting to reach their carbon reduction or elimination goals, and use carbon offsetting while they explore options for direct GHG reductions.⁷³

This advocacy could extend beyond health system practices and policies, to local and federal governments. Groups such as the Medical Society Consortium for Climate and Health support clinicians in writing editorials and contacting legislators.⁷⁴ Manufacturers will also respond to the clinician voice. Clinicians can use their individual and collective power to talk to suppliers, manufacturers, drug developers, and product representatives about developing more sustainable products. Sustainability for manufacturers could take the form of new product design using more sustainable materials and decreased packaging, products that create less waste, or optimizing aspects of manufacturing, such as energy and water use or distribution routes.^75,76 Because the production and manufacturing of medical products results in at least 15% of the industry’s GHGs, this is an important group to engage and mobilize.

Pharmaceuticals

While new drug formulations and packaging decisions have a role in clinical sustainability, ophthalmologists have direct control over the use and waste of pharmaceuticals in cataract surgery. With 3.8 million cataract procedures performed every year in the United States, medications potentially totaling $560 million are needlessly discarded.^77,78 Single dose eye drops in preoperative and postoperative settings have been found to create substantial physical and financial waste and environmental pollution.³¹ There is a consensus within ophthalmology that excessive surgical drug waste unnecessarily increases the carbon footprint and costs of cataract surgery.⁷⁷ An obvious approach, relatively unstudied in ophthalmology,⁷⁹ would be to resize single-dose vials to volumes more appropriate for a single surgery. Unfortunately, this intervention may not always be cost effective.

Allowing patients to use topical medications after discharge, rather than discarding the unused medication can address some drug waste issues.⁸⁰ A recent position paper endorsed by ASCRS, AAO, AGS (American Glaucoma Society), and OOSS (Outpatient Ophthalmic Surgery Society) supports sending drugs home with patients that must be continued postoperatively, stating that “It is wasteful and unnecessarily burdensome to discard the newly opened multi-use bottle and instead require the patient to purchase the same medication through an outpatient pharmacy.”⁷⁷ Despite this, there is wide regional variation in pharmaceutical dispensing regulations. Recent legislative efforts at the state level have been successful in reducing regulatory obstacles to allow medication to be sent home with patients. In 2021, legislation in Illinois was signed into law stipulating that topical medications ordered at least 24 hours preoperatively and used in the OR must be properly labeled before the unused portion can be given to patients for post-discharge care.

Another approach to combatting drug waste in cataract surgery is multi-dosing bottles. Single use eye drops have been associated with increased cost, up to three times as much, compared with multi-dose bottles.⁸¹ A 2022 study found multi-dose preoperative and pre-injection eyedrop protocols saved approximately $240,000 per institution over a 5 year period and led to a 97% reduction in the number of bottles disposed.⁸² On a per mL basis, Rahemtulla et al. (2021) found that single use dilating eye drops are four times more expensive than multi-dose bottles.⁸¹ Other studies have reported similar cost reductions, one of them focusing specifically on topical anesthetics and fluorescein dye.^81,83,84 The negative environmental impact is attributed to the waste accumulation from extra packaging and unused drug.⁸¹ Additionally, minimally used bottles are often disposed with regular trash, and the chemicals may contaminate drinking water. In 2013, the AAO published recommendations supporting the use of multi-dose eye drops to minimize waste, cost, and environmental impact.³⁵ In 2015, ASCRS announced their position supporting the use of multi-dose eye drops on multiple patients as long as proper protocols are followed.⁸⁵

The primary concern with multi-dose eye drops is risk of infection.⁸⁶ Some multi-dose bottles contain preservatives, but these only inhibit the growth of bacteria and do not prevent contamination. Multiple studies have assessed microbial contamination of multi-dose eye drop containers, finding bacteria or other microbes in 0.7% to 40% of bottles or bottle tips, depending on the type of drug, the length of use, and use setting (e.g. inpatient, outpatient, or surgical).^80,87–89 Improper use appears to be the main cause of contamination, with increased risks when the application time period is increased, untrained staff handle the drops, and the eye drops are used on a larger number of patients.⁸⁶ One study found a contamination rate of 2.5%, which would result in a 1:400 risk of cross-contamination with coagulase-negative staphylococcus if the bottle was reused once and 1:80 if reused 6 times.⁹⁰ This study suggested that reducing this particular infectious risk to zero costs the UK National Health Service between £2.75–4.6 million per year and generates over 6.85 tons of paper waste and 12.69 tons of plastic waste.⁹⁰

Contamination of the dropper and, furthermore, contamination of the solution is the biggest concern in extended use of multi-dose eye drops. A variety of guidelines governing pharmacies and organizations exist to ensure quality of eye drops and reduced risk of contamination and infection. The US Pharmacopeia 797 provides guidelines for the use of sterile preparations and multi-dose vials to ensure patient safety and quality of care.⁹¹ Policies and procedures for the successful use of multi-dose eye drops include guidelines for handling the dropper bottle, expiration dating, training of the medical staff who administer eye drops, and clearly identifying when dropper bottles should be discarded due to contamination.⁹² To handle the dropper, staff should wash their hands before and after administering eye drops to patients, the tamper-proof seal should be unopened before using the dropper and completely removed before using, and when the cap is removed to use the medication, it should be placed inside up on a clean surface to avoid contamination. After use, the cap should be placed in a sterile manner and screwed down tightly to avoid leaking and contamination.⁹² According to these guidelines, if a multi-dose vial has been opened or accessed, the vial should be dated and discarded within 28 days unless otherwise specified by the manufacturer. However, each center can set their own criteria; some discard bottles after 24 hours³⁵ and some after 28 days.⁹² A 28 day expiration date, once opened, is based on a flawed 2015 CMS Surveyor Infection Control Working Group checklist. In June, 2022, CMS clarified that only injectable vials are subject to this expiration date, unless otherwise noted by the manufacturer, and that eyedrops can be used multidose on multiple patients with aseptic application techniques, proper storage, and manufacturer multi-dose labeling.⁹³ Surveyors nationally were educated about this change. Regular training of new and existing staff on handling and administration policies is vital for patient safety and quality of care.

Despite the evidence, many practices continue to require single-dose eye drops for cataract surgery because of fear of cross-contamination between subjects. Most studies that encourage single dose eye drops over multi-dose eye drops do not mention the training of technicians administering and handling the drops.⁸⁶ Wu et al. (2021) showed through video recordings and bacterial cultures the efficacy and safety of multi-dose preoperative eye drops administered by properly trained ophthalmic technicians.^35,86 At the end of each day, they sent all used bottles to the microbiology laboratory and cultured samples obtained from bottle tips. None of the bottle tips revealed positive bacterial cultures.³⁵ Virani et al (2016) collected multi-dose eyedrops used long term (37 days to 54 days) and the eye drop solution was cultured for assessment of microbial contamination.⁹⁴ They showed that none of the eye drop solutions had any growth on any culture media after 14 days. Based in their results they stated that the contamination of drops is not a rule, even after a month of being open. Several authors emphasized that the protocol and training of personal for multi-dose drops instillation is vital to avoid contamination.^35,94,95

The presence, type, and concentration of preservatives has been shown to affect the incidence of contamination.⁹⁵ It’s been reported that most of the medications contaminated had thimerosal or benzalkonium chloride as preservatives.⁹⁶ It’s also been suggested that the role of preservatives is not sufficient to ensure the sterility of multi-dose eye drops.⁹⁶ Aside from the risk of infection, bacterial contamination alters the solution’s pH and reduces the efficacy of the medication.⁹⁶

Tsegaw et al (2017) reported a contamination rate of 11%, all of it being from the dropper’s tip and none from the residual solution of the dropper.⁹⁶ The prevalence of contamination of single use drops was 3.2% and of multi-dose eyedrops was 24.3% and contamination levels increased in both as the duration of used increased from 1 week to greater than 1 week. However, this literature comes from other international settings and may not be representative of a US case.

Jensen et al. (2014) created a protocol that states a multi-dose dropper is contaminated when: the tip is touched by any structure or surface of the eye; the tip is touched by the administering staff member; a seal-open dropper has no expiration date; a seal-open dropper has an expiration date greater than 28 days; and/or there is an open, uncapped bottle, regardless of expiration date.⁹² Following each of the variations in process identified, they demonstrated that the postoperative infection rates in patients undergoing cataract surgery were similar using single-dose or multi-dose eye drops. As such, while the various processes do not follow current FDA guidelines, one could view the study outcome as a risk assessment to provide justification for use within an accredited facility. Cost advantages to using multi-dose eye drops were significant for both the patient and the healthcare facility preoperatively, intraoperatively, and postoperatively.⁹²

Anesthesia is another aspect of care that can generate unnecessary waste and environmental emissions. We were unable to find literature specifically focused on environmental emissions associated with ophthalmic anesthesia, but generically, there are guidelines for “greening” anesthetic practice which should be utilized.^50,97 Importantly, lower-impact anesthesia options should be prioritized, and in the case of ophthalmology, general anesthesia is used infrequently and anesthetic gases such as desflurane and sevoflurane are potent greenhouse gases whose emissions should be avoided if possible.^98–100

In summary, the evidence shows that limited durations of use, proper handling of multi-dose droppers, and regular training of administering staff can minimize the risk of contamination, decrease waste, and decrease environmental and financial costs before, during, and after cataract surgery.^35,81,92 However, this practice should be implemented with rigorous policies and staff training, and may not be appropriate for every ophthalmic setting.

Process

Interventions to the process for ophthalmic surgery include optimizing a standard preference card, having the patient wear street clothes, changing to a hub and spoke model of surgery, and conducting same-day, simultaneous bilateral cataract surgeries. Optimizing surgical preference cards to a standard minimum represents a particularly attractive intervention in terms of financial savings and environmental impact. A universal preference card in other surgical specialties has been shown to reduce costs drastically, especially if it reduces unused supplies.^101–103 In studies where it has succeeded, preference card standardization relies on surgeon buy-in and engagement, through open communication and incentive. Additionally, major US health systems such as Banner Health and University of Missouri Health Care have reported cost savings due to preference card standardization.^103,104 While the financial benefit of preference card standardization has been clearly demonstrated, the environmental impact remains more nebulous. Studies on the sterilization of tools, amount of requested supplies a la carte, and operating room time would clarify how standardizing preference cards improves the footprint of cataract surgery.

While the conventional viewpoint that patient gowning reduces unnecessary contamination merits consideration,¹⁰⁵ there has been a lack of evidence demonstrating that patient gowning results in a significant decrease in adverse ophthalmic outcomes. Patients at Aravind Eye Hospital wear their own clothes for cataract surgery with no significant difference in rates of endophthalmitis,¹⁰⁶ and the lack of gowning is practiced already in some US facilities.⁴⁷ Additionally, wearing gowns has been shown to increase stress and anxiety for patients due to exposing their bodies.¹⁰⁷ Ophthalmic surgery seems to present a unique opportunity for this intervention, since these operations typically only need to access the eye. Nevertheless, a study involving the different practical considerations of gowns, including contamination, access for intravenous lines, comfort, warmth, and soiling is needed.

For surgeons in higher volume settings, a hub and spoke model of surgery could improve operational efficiency and reduce emissions associated with energy consumption. In this model, the surgeon is the hub that does the operation while the midlevel ophthalmic personnel are the spokes that do the preoperative and postoperative preparations. Aravind has patients within the same operating room on two separate tables but regulations in the United States would require multiple operating rooms for different patients.¹⁰⁶ One of the main benefits of improved efficiency lies in reduced energy usage of the operating room. While this would still apply, the benefit might be mitigated by the ratio of operating rooms to patients, and number of operating room personnel, staying the same. Additionally, efficiency alone is not always a financial benefit as Roberts et. al. found in their evaluation of a hub and spokes model for femtosecond laser-assisted cataract surgery compared to traditional phacoemulsification surgery.¹⁰⁸ Although financial and environmental considerations can have mutual goals, a life cycle assessment (LCA) of a surgical hub and spokes model would identify the different variables affected by a model change.

Immediate sequential bilateral cataract surgery (ISBCS) involves performing phacoemulsification with intraocular lens placement in both eyes of the patient on the same visit in the same operative setting. Though this practice has been widely debated, literature increasingly supports the use of ISBCS for its benefits in providing faster patient rehabilitation, and cost and time savings.¹⁰⁹ Environmental emissions are reduced from limiting the duplication of pre- and post-operative visits and travel time for the patient. According to data from the Bureau of Labor Statistics’ American Time Use Survey, the average time spent traveling to access healthcare services is 34 minutes, so reducing the number of visits required could significantly reduce travel related environmental emissions.¹¹⁰ However, there is typically limited reduction in supplies used as, in the US, both surgeries are treated as separate cases for infection control purposes. The infection risks of ISBCS are now recognized to be low with the advent of intracameral antibiotics. Numerous studies have proven ISBCS to be more cost-effective and efficient.^109,111,112

ISBCS also offers the ability to improve OR efficiency in terms of reduced patient transfer and preparation times, which could allow more surgeries to be performed within a given time. O’Bart et al. (2020) demonstrated that with ISBCS it is possible to achieve an average 16% reduction in the time taken to perform two cataract surgeries.¹¹³ Additionally, there is potential room to reduce waste by optimizing staff schedules to align with case schedules.

Supplies & Waste

Unused surgical supplies are routinely discarded in operating rooms, which significantly contributes to waste and the overall carbon footprint. Consistently unused items should be removed from surgical custom packs and surgeon preference cards wherever possible, to save on costs, waste generation, and embodied emissions. Some single-use items could be replaced with a smaller product. For example, in the US many ophthalmic facilities use a full-body drape during eye surgeries where a smaller face drape may be sufficient. Additionally, many single-use items could be substituted with reusable alternatives without compromising clinical outcomes.

Disposable custom procedure packs minimize surgical preparation time and reduce touch-points on products, leading to lower risk of contamination. However, custom packs often contain items that are infrequently used, contributing to unnecessary expense and waste. Once a custom pack is opened, every item in the pack must be discarded, even if it has not been used. Clinicians often add items to the packs yet find it difficult to remove unnecessary items. In terms of both environmental impact and financial savings, optimizing custom procedure packs can be significantly beneficial, and several facilities have reported positive results. By streamlining their packs to remove infrequently used items, Marysville Surgical Center has saved $32,000 annually without increasing room turnover times.¹¹⁴ Items should be made available as needed (sometimes called ‘pick items’) to avoid unnecessarily opening a custom pack or kit to access a single item. Despite the potential for reducing cost and waste, there are few studies available on the topic.

While a single-use, disposable drape covering the face is necessary for cataract surgery, some facilities instead use a large, full body drape. We were unable to find literature identifying pros and cons of either approach, but are aware of eye surgery centers using both approaches.⁴⁷

Studies have found that the use of reusable surgical gowns reduces GHG emissions and solid waste generation while also providing superior protection and durability compared to single-use gowns.¹¹⁵ Vozzola, et al. (2018) compared the environmental impacts of market-representative reusable and disposable gowns using standard lifecycle assessment procedures. Compared to the disposable gown system, the reusable gown system showed a 28% reduction in energy consumption, a 30% reduction in greenhouse gas emissions, a 41% reduction in blue water consumption, and a 93% reduction in solid waste generation.¹¹⁶ Aravind Eye Hospital uses reusable surgical gowns and other linens along with numerous other sustainable practices with surgical outcomes that are equivalent to Western countries.⁴⁷ However, there is a lack of prospective, randomized studies comparing the clinical impact of reusable vs single-use surgical gowns. There are also limited studies on the impacts of reusable draping on infections.^117–121

Manufacturers may have some solutions to reducing supply waste, though a clinician may need to advocate for their health facility to participate. Examples include vendors that can assist with single-stream recycling (such as Stericycle),¹²² or single-use device reprocessors who have US Food and Drug Administration approval to clean, sterilize, and resell single use medical and surgical products.^123,124 Such initiatives can increase the circularity of medical products and materials, leading to a reduction in resource extraction from producing items new each time.⁴⁴

Decision Tree for Prioritizing Sustainability Strategies in Ophthalmology

The multitude of options available to an individual can be overwhelming. Though there are many frameworks to decide what activities might be most fulfilling for an individual or most impactful in reducing GHGs, we have put together a decision tree to aid in making changes to clinical practice, focusing specifically on supplies (Figure 1) and pharmaceuticals (Figure 2).

Figure 1:

Decision Flow Chart for Selecting Sustainability Interventions related to Supplies in Cataract Surgery (in the US)

Figure 2:

Decision Flow Chart for Selecting Sustainability Interventions related to Pharmaceuticals in Cataract Surgery (in the US)

Considerations for Clinics and Other Healthcare Spaces

Though we focus primarily on an operating room setting, other spaces for healthcare delivery can substantial environmental impacts as well. Some of the strategies here can be applied to other clinical spaces and other surgical disciplines, but there may be strategies unique to these areas. For example, outpatient departments screening patients may use other types of disposable supplies and have other, unique forms of waste (ex: energy use, travel needs of patients, etc.).¹²⁵

Conclusions

There are many ways to improve the efficiency and sustainability of cataract surgery and eye care. Not every intervention has been well studied; for example, there are likely contextual factors that will determine whether reusable supplies or multi-dosing of drugs is appropriate for a specific facility. Which interventions will work best must be determined by the individual stakeholders at each hospital or health system. Despite the limitations of existing literature, there is sufficient evidence that reducing environmental emissions in the operating room is achievable and cost efficient.

Though addressing the climate crisis may still feel overwhelming for the individual clinician, research suggests that climate action and activism builds resilience, helping to stave off climate-related anxiety and depression.^126–128 We hope this article provides clinicians with some guidance and literary tools to support climate action within their professional institutions, and we recommend clinicians peruse https://eyesustain.org/ for updated information on sustainability, climate, and health for ophthalmology.