Abstract
Purpose :
To estimate the difference in carbon footprint of a novel technology optical coherence topography angiography (OCTA) compared to that of fluorescein angiography (FA), both of which are used in the detection of retinal vascular disease.
Methods :
A component analysis of direct and indirect green-house gas (GHG) emissions calculating activity data attributed to patients attending for FA to the University Hospital of Wales (UHW) was carried out. Data was collected for travel, energy use and procurement and reconciled against the established emissions factor; Publicly Available Specification for measurement of GHG emission for goods and services (PAS2050). This allowed calculation of a single GHG equivalent.
Results :
OCTA can be carried out at the initial outpatient appointment with no additional visits whilst FA is rarely carried out on the same day and usually requires a second visit. This, in combination with the additional staff required, negatively impacts the GHG emission of FA. Therefore, the additional GHG associated with FA compared to OCTA are as follows: building costs; 40.17KgCO2eq, travel-Staff; 33.03KgCO2eq, patient; 4.27KgCO2eq, pharmaceuticals 1.01 KgCO2eq, medical instrumentation 1.41KgCO2eq and waste 1.24KgCO2eq.
This equates to a total GHG emission of 80.51KgCO2eq per patient. Approximately 850 patients attend for FFA on average each year (UHW). Of these, 300 undertake a same day FA, therefore the additional patient transport can be deducted from the GHG value giving 76.24KGCO2eq. This equates to a carbon foot print of 67.15 tonnesCO2eq per year. Studies have shown a good sensitivity and specificity of OCTA in retinal vascular disease when compared to. If we assume a conservative 50% reduction in the number of FA carried out this would lead to a saving of 34 tonnes CO2eq per year in one hospital and if applied nationwide a notable reduction in the carbon footprint of ophthalmology could be made.
Conclusions :
This is the first study to describe the additional GHG emissions associated with FA. Climate change is of upmost global importance and healthcare is responsible for a significant proportion of GHG emissions. Moving from the time consuming and invasive FA to OCTA where possible could produce a notable GHG reduction. This is in addition to the financial cost savings made with fewer hospital appointments and staff costs, and the risk reduction in the avoidance of an invasive procedure.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.