Unused Pharmaceutical Products in Cataract Surgery Raise Costs and Carbon Footprint

MedicalResearch.com Interview with:

Dr. Thiel

Cassandra L. Thiel, PhD
Assistant Professor
NYU Langone School of Medicine
Department of Population Health
NYU Wagner Graduate School of Public Service
NYU Tandon School of Engineering

MedicalResearch.com: What is the background for this study?

Response: Most healthcare professionals and researchers are aware that the healthcare sector makes up about 18% of the US Gross Domestic Product. What many do not realize is that all of that economic activity results in sizable resource consumption and environmental emissions. The healthcare industry is responsible for 10% of the US’s greenhouse gas (GHG) emissions and 9% of air pollutants.1 Sustainability in healthcare is a developing field of research and practice, and my lab offers data and information by quantifying resource use and emissions of healthcare delivery. We started looking at cataract surgery a few years ago, in part because operating rooms (ORs) typically represent the largest portion of spending and garbage generation in a hospital.2,3 Cataract surgeries are interesting because they are one of the most common surgeries performed in the world. In the US, we spend $6.8 billion on them each year. Any changes we can make to individual cases would have much larger, global impacts.

I studied cataract surgeries at a world-renowned, high-volume eye surgery center in India and helped validate that clinical care could be designed in a way that was effective, cost-efficient, and resource efficient. Compared to the same procedure in the UK, this surgery center generates only 5% of the carbon emissions (with the same outcomes).2 This site’s standard policy is to multi-dose their eye drops, or use them on multiple patients until the bottle was empty. As such, the site generated very little waste.

Returning to the US, I observed cataract cases and heard the complaints of OR staff that they had to throw out many partially used or unused pharmaceuticals. In reviewing the literature, we could not find a study that quantified how much we were throwing away and what it cost us to do so. We, therefore, set up a study to look at this particular issue.

MedicalResearch.com: What are the main findings? 

Response: We observed cataract surgeries in four different surgical centers in the northeastern US and weighed any remaining portions of pharmaceuticals left after the each case. Across the four centers, there were 116 unique drugs surveyed. Conservatively assuming that any drugs we could not measure were completely used, we found that a mean of 83,070 mL of 183,304 mL (45%) of drugs were unused and disposed each month (all four sites combined). Allocating the total cost of the drug procurement to the unused portion, we found each site (individually) spends $41 to $217 per case on unused drugs. Per month, the sites are throwing out anywhere from $36,900 to $195,200 worth of drugs from cataract surgeries each month. The manufacturing and delivery of these drugs has an impact on our environment. We calculated that the GHG emissions from producing these unused drugs ranged from 418 kg CO2-equivalents per month at our lowest site to 2,498 kg CO2-e at our highest. These emissions are comparable to driving a regular passenger vehicle 1,025 to 6,120 miles.

Taking our worst-case hospital and extrapolating to all the cataract surgeries in the US, GHGs from producing unused and wasted cataract drugs could be as high as 105,000 metric tons of CO2-e. That is like driving a car between Anchorage, AK and Miami, FL 51,400 times every year. 

MedicalResearch.com: What should readers take away from your report?

Response: The US healthcare system is costly and has a large environmental footprint. The system of care – from the policies, regulations, and practices followed daily in medical facilities, to the way supplies are manufactured and packaged – can be modified to improve the value of care. Our study quantifies one small issue – the waste of partially or completely unused drugs in cataract surgery. But given the number of cataract surgeries done in the US and the other medical procedures which face similar challenges in efficient drug delivery, tackling this small issue could result in substantial financial and environmental savings for the US healthcare system. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work? 

Response: Through conversations with OR staff, we identified a few of the issues that seem to contribute to drug waste, for example: size of packaging for single-dose drugs, policies that prohibit sending topical drugs home with patients from the OR, and policies that prohibit multi-dose drugs in the OR. We do not know if this is a comprehensive list of challenges nor which obstacles would represent the largest opportunity for reducing the cost and footprint of care while maintaining safe and effective surgeries. This definitely needs to be studied further. We would also like to pilot and test intervention strategies in order to identify best practices for reducing drug and supply waste in cataract (and other) surgeries.

MedicalResearch.com: Is there anything else you would like to add? 

Response: There are many interesting groups trying to tackle environmental sustainability and resource efficiency in medical care. For eye health professionals, we recommend checking out the work and forums of the International Agency for Prevention of Blindness (IAPB) Environmental Sustainability Work Group, the Royal College of Ophthalmologist Sustainability Work Group, and the Centre for Sustainable Healthcare. 

Any disclosures?

Unrelated to this paper, I am a sustainability consultant with Stryker Corporation.


  1. Eckelman MJ, Sherman J. Environmental Impacts of the U.S. Health Care System and Effects on Public Health. PLoS ONE. 2016;11(6):e0157014.
  2. 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.
  3. Venkatesh R, van Landingham SW, Khodifad AM, et al. Carbon footprint and cost–effectiveness of cataract surgery. Curr Opin Ophthalmol. 2016;27(1):82-88.
  4. Tauber J, Chinwuba I, Kleyn D, Rothschild M, Kahn J, Thiel CL. Quantification of the Cost and Potential Environmental Effects of Unused Pharmaceutical Products in Cataract Surgery. JAMA Ophthalmol. Published online August 01, 2019. doi:10.1001/jamaophthalmol.2019.2901


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Last Updated on August 2, 2019 by Marie Benz MD FAAD