The Environmental Sustainability of Glaucoma

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Article initiated by:

Francesc March de Ribot, MD, PhD

All contributors:

Daniel B. Moore, MD, Francesc March de Ribot, MD, PhD

Assigned editor:

Daniel B. Moore, MD

Review:

Assigned status Up to Date

 by Daniel B. Moore, MD on July 19, 2024.

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Contributing Editors:	add

Introduction

Increased carbon dioxide, amongst other gases in the atmosphere, is warming the planet, causing climate change. Humans and their activities have increased the atmosphere's carbon dioxide levels by greater than 50% in the last 200 years. Continued emissions are leading to increasing warming, with best estimates from global experts suggesting temperatures will reach 1.5°C higher in the near term, with increasing levels of catastrophic consequences the further the temperatures rise. Vulnerable communities locally and globally that have historically contributed the least to climate change are currently the most disproportionately affected.

Globally, the healthcare sector is responsible for 10% of greenhouse gas emissions. The biggest culprit are the operating rooms, which account for 70% of hospital waste and are six times more carbon intensive than the remainder of the hospital. As the healthcare industry expands due to an aging population and improved care, sustainability becomes increasingly important. Ophthalmology, with its high volume of consultations and procedures, has a significant environmental impact, making sustainability efforts crucial.

Glaucoma is a common reason for ophthalmology visits. The global prevalence of glaucoma worldwide was estimated to be 76.0 million in 2020 and 111.8 million in 2040, and affects approximately a 2.51% of the population.

Glaucoma imposes a substantial economic burden. In Spain, the direct costs amounted to 612 euros/patient/year, and productivity losses to 1,946 euros, leading to a total cost of 2,558 euros/patient/year.

Potential Solutions and Future Directions

Diagnosis

The use of disposable tonometer prisms and lenses is related to waste. Within a single eye department in Boston, approximately 61,115 prisms and 800 lenses were purchased yearly, costing $70,282 ($1.15/prism) and $9,040 ($11.30/lens) per year, respectively, resulting in approximately 109.6 kg of plastic waste. However, non-disposable tonometer prisms and lenses could significantly reduce costs to $6,000 ($0.05/prism) and $11,352 ($2.84/lens) for the first year and $3,000 and $2,270 each subsequent year.

Disposable and non-disposable prisms have proved to be equally effective and accurate in measuring IOP92, the use of disposable Tonosafe prisms, which is up to 59% in some UK practices, is probably based on the assumption that they eliminate cross-contamination and the need for disinfection. However, evidence suggests clinical infections transmitted by non-disposable tonometers are low 92, without a strong case for disposable prism use Guidelines on disinfection can encourage a shift away from disposable prisms, reducing cross-contamination risk and cutting costs.

Treatment

Treatment with eyedrops generates continuous plastic waste that usually ends up in landfills or incinerates. In theory, these plastics can be recycled, but in reality, it is less than 8.7%. Each bottle with a 10 mL capacity weighs 6.5 g, but when the same treatment is in an unidose preservative-free single disposable vial, it generates 120 g a month. The use of eyedrops represents a yearly impact of 7 kg CO2 per person. Further, it is estimated that $560 million/year is lost in discarded single-use preoperative eyedrops in the United States, with a single academic medical center estimating it saved $240,000 over 5 years and had a 97% reduction in eyedrop bottle usage when transitioning to multiuser preoperative drops. The use of a drop volume saving adapter such as the Nanodropper in the clinical setting has been found to decrease excess waste and systemic absorption of medication.

Glaucoma surgery impact

Due to high volume, ophthalmologic surgery is one of the biggest sources of waste in the operating room. In the United States alone, there are an estimated 3.8 million cataract surgeries performed every year. Glaucoma surgeries specifically generate significant waste, and are predicted to rise 44% in England and Wales over the next 15 years. The waste results vary significantly in several environments, despite having similar results.

Over 50% of waste from phacoemulsification surgery can potentially be recycled, resulting in 0.139kg of CO2 equivalents less per case. A British study found that a single phacoemulsification procedure generates the same carbon emissions (130kg) as driving a car 500 km (roughly 310 miles). A back of the napkin calculation for the United States suggests the annual carbon emissions for cumulative cataract surgeries would then roughly equal 1.5 billion miles in the car, which is roughly the distance to Saturn and back. The Arivand hospital system, by comparison, wastes only an estimated 6kg of CO2 per case, or the equivalent of driving a car 23 km (14 miles).

More than 90% of ophthalmologists agree that OR waste is excessive and concerning. Ten times as many eye surgeons would prefer reusable versus disposable instruments in the OR, and nearly all are willing to use perioperative medications and intraocular drugs on multiple patients. Most are willing to reuse supplies and products labeled for single use.

A review of existing sustainability strategies for ophthalmologists sound several implementable strategies that are safe, costs effective, and environmentally friendly. These include multi-dosing medications, sending bottles home with patients, training staff to appropriate sort medical waste and recycle when appropriate, decreasing unnecessary supplies during surgery, transitioning to multi-use instruments when possible, and considering immediate sequential bilateral cataract surgery when appropriate.

Conclusions

Glaucoma presents economic and environmental sustainability challenges due to its prevalence and resource consumption. There are multiple clinical and surgical factors to consider, with opportunities to implement change at an individual/institutional level and advocate for broader changes within our organizations and societies.

See also

• Ophthalmology and Climate Change
• Sustainability practices implementation made easy
• The Environmental Sustainability of:
  • Cataract Surgery
  • Dry Eye Disease
  • Intravitreal injections
  • Retina/VR surgery
  • Eye Drops in Surgery