Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Filter by Categories
Guest Editorial
Letter to Editor
Media and News
Original Article
Proceedings of IHOPE Conference
Proceedings of the IHOPE Annual Conference: September 2021
Review Article
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Filter by Categories
Guest Editorial
Letter to Editor
Media and News
Original Article
Proceedings of IHOPE Conference
Proceedings of the IHOPE Annual Conference: September 2021
Review Article
View/Download PDF

Translate this page into:

Original Article
1 (
); 25-31

Eye care and the carbon foot print

Lions Aravind Institute of Community Ophthalmology, Aravind Eye Care System, Madurai, Tamil Nadu, India
Aravind Eye Hospital - Pondicherry, Aravind Eye Care System, Puducherry, India
Facility and Environment, Aravind Eye Care System, Madurai, Tamil Nadu, India
Aurolab, Madurai, Tamil Nadu, India
Corresponding author: Thulasiraj Ravilla, Lions Aravind Institute of Community Ophthalmology, Aravind Eye Care System, Madurai, Tamil Nadu, India.
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

How to cite this article: Ravilla T, Rengaraj V, Balakrishnan N, Ravilla S. Eye care and the carbon foot print. IHOPE J Ophthalmol 2022;1:25-31.



Climate change and its impact on the environment are rapidly becoming a crisis, resulting in extreme climate conditions and directly impacting health. The World Health Organization attributes 13.7 million deaths in 2016 to overall environmental factors. As health-care providers, we seem to be a significant contributor to carbon emissions. Health Care Without Harm, an organization promoting environmental health and justice, estimates that health-care accounts for an equivalent to 4.4% of global net carbon emissions. As a specialty with very high surgical volume, eye care would be contributing a significant portion of these carbon emissions. Thus, there is a need for us to explore ways of mitigating this.

Materials and Methods:

A descriptive case study method has been adopted to study environmentally sustainable practices with published or real-world data. Data from power consumption and energy audits were used in the analysis. The various approaches to reducing carbon emissions in eye care were studied using a broad framework of looking at what resources are deployed and how those resources are used.


Whether it is resources or how they are put to use, there is a great scope for reducing carbon emissions through reducing use, re-use, and recycling. On the energy front just through the use of energy efficient electrical devices, and 8%–10% reduction in power consumption could be achieved immediately. Since green energy is less expensive than grid power, switching to it can generate another 15% in cost savings. It was feasible to switch to green energy for 75% of the power needs in the larger hospitals. Organic water recycling technology could recycle over 90% of the water and re-used it. Lean clinical protocols showed that the carbon emissions could be reduced to 5% of what it is in the west for procedures like phacoemulsification.


While it is inevitable that eye care delivery will generate carbon emissions, it is well within our control to minimize it, per unit of care. This could be achieved essentially by minimizing waste or underutilization, enhancing efficiency, reducing consumption, and reducing patients’ efforts.


These are the early days of trying to figure out, how the eye care sector can change its practices to minimize carbon emissions. A lot more evidence is required, signaling the need for research and publications in this space. As with any activity, for continuous improvement, we need benchmarks and robust monitoring systems. All of these are yet to evolve in clinical care.


Carbon footprint
Eye care


Climate change and its impact on the environment have been taking the center stage in recent years. The recently concluded United Nations Climate Change Conference – COP-26 (Conference of Parties), in Glasgow had the attention of all world leaders and the participation of several Heads of State. Climate change and the threat to our planet are very real and all of us are personally experiencing it with global warming and extreme weather patterns. The World Health Organization attributes 13.7 million deaths in 2016 to overall environmental factors.[1] As health-care providers, we need to be concerned as we are a significant contributor to carbon emissions. Health Care Without Harm and its partners, in their policy paper “Healthcare’s Climate Footprint,” estimate that health care accounts for 4.4% of global net carbon emissions.[2] As members of the eye care sector, we need to be concerned about our contributing role toward the current scenario. An estimated 28 million cataract surgeries are performed annually worldwide.[3]

Assuming that this accounts for 60% of all procedures, the total ocular surgical and other procedures would be around 40 million. This makes eye care a very high-volume surgical specialty within healthcare. While we do not have accurate estimates, we can recognize that such high surgical volumes would make eye care a significant contributor to carbon emissions, within health care. Thus, as eye care providers, we have to hold ourselves accountable for reducing environmental harm. The aim of this article is to present and discuss some of the approaches that can mitigate to a certain extent the impact of eye care on climate change.


A descriptive case study methodology has been adopted to describe the processes followed at a network of eye hospitals in South India, to minimize the carbon footprint in the delivery of eye care, and supported where relevant, with data. Various factors were studied using a broad framework by looking at what resources are deployed and how those resources are used, as shown in [Figure 1]. The environmentally sustainable practices are adapted across all the eye hospitals in the network. The building infrastructure, energy, equipment, water, and consumables are categorized as “resources.” The service design, clinical protocols, procurement, travel of patients and staff, and maintenance protocols are all categorized under “resource utilization.” The resources and their use have all been studied with an environmental sustainability perspective.

Figure 1:: Resources and how they are used.

Monthly power consumption data and studies to make one of the hospitals as a Net Zero Energy Building (nZEB)[4] have been used in this article.


Hospital buildings

These are oriented to minimize solar heat and designed to leverage maximum natural ventilation and lighting [Figure 2], thereby minimizing the need for supplementary lighting and air-conditioning. These have a direct bearing on reducing energy needs.

Figure 2:: Patient arrival or departure waiting area.


With energy, the first strategy would be to minimize energy needs. This is best done by a comprehensive energy audit by competent agencies. This will help establish the annual energy consumption, the pattern of consumption, and the “Energy Performance Index (EPI).” The goal would be to bring the total energy consumption net of green energy (solar or wind) to be 15 KWh or less per sq. meter per year, to be declared as nZEB. In the instance of the Eye Hospital at Pondicherry, the baseline energy consumption, in the year 2020, is shown in [Table 1].

Table 1:: Baseline energy consumption.
Annual energy consumption 1,696,945 kWh
Energy performance index 77 KWh/Sq. Meter/year
Energy performance index goal ≤15 KWh/Sq. Meter/year
Pattern of energy consumption
Lighting and power 44%
Heating, ventilation, and air conditioning 32%
Other equipment 24%

The audit also estimated the energy savings of various interventions, the investments required, and the payback periods for each intervention, as shown in [Table 2]. This helps in making informed decisions on which interventions to prioritize and which ones to defer, based on financial and other considerations like disruption to clinical work.

Table 2:: Investment versus returns analysis.
Measures Energy Savings kWh Annual Cost savings Rs. Cost in Rs. Millions Payback period Years
Wall insulation 50 mm 15,656 161,413 4.8 29.6
Roof insulation 150 mm 48,709 502,190 8.7 17.4
High performance glazing 37,096 382,460 4.5 11.6
Lighting power 162,705 1,677,489 3.1 1.8
Chillers with COP 6.5 73,656 759,393 7.6 10.0
AHUs with ECM Motors 22,663 233,656 3.8 16.3
5-star rated pumps 63,136 650,932 2.6 4.0

COP: Coefficient of performance, AHU: Air handling unit, ECM: Electronically commutated motor (motor that uses electronic controls to vary its speed)

Based on [Table 2], the work has started to replace all existing lights with LED lighting, switch all fans to energy efficient ones as well as replacing motors and chillers for air-conditioners. Due to the pandemic, the pace of work has been hampered and is still a work in progress.

At the eye hospital in Madurai, the energy conservation work was carried out by a company on an arrangement involving sharing of cost savings. They replaced the existing electrical items with LED bulbs for lighting, energy efficient fans, and chillers in air-conditioning plants. [Table 3] shows the power consumption over the years, starting in 2018, the base year before power conservation strategies were implemented. In 2019, when the patient volume was very similar to 2018, which saw a reduction of 8.0% in the power consumption, and this translated to an annual savings of approximately Rs. 2.5 million.

Table 3:: Power consumption and patient load.
Madurai Eye Hospital – Energy Consumption
Year (Jan-Dec) → 2018 2019 2020 2021
Total energy consumption (KWH) 3,876,300 3,565,472 2,361,915 2,752,930
Change % with respect to 2018 –8.0% –39.1% –29.0%
Hospital outpatient visits 875,242 886,818 482,499 753,543
Change % with respect to 2018 1.3% –44.9% –13.9%
Hospital surgeries, lasers, and injections 168,707 165,215 83,690 143,603
Change % with respect to 2018 –2.1% –50.4% –14.9%

Having started work on minimizing energy consumption across all tertiary hospitals in the network, the next strategy was to switch to green energy. That is solar or wind energy. Here again, two options were available – generating own green energy or getting into purchase agreements with third-party producers of green energy. After saturating the option of roof-top solar power panels, we supplemented it by purchasing green power. [Figure 3] shows the transition from grid power to green energy (solar) at the eye hospital in Madurai.

Figure 3:: Trend in shift in energy sources.

The following [Table 4] gives the status of green energy usage in the larger hospitals in the network. With wind energy, which is available round the clock, we were able to substitute the grid power to a greater extent than solar. However, there is a seasonal factor to wind energy and similarly, solar power has the limitation of power generation happening only in the daytime. Since green energy is less expensive than grid power, this too has resulted in savings of about Rs. 6 million per year, for the hospitals in Tamil Nadu.

Table 4:: Six months energy data (October 2020–March 2021): Source and consumption.
Location Total Power consumption Units Green Power Units purchased Green Energy
Wind Solar
Madurai 1,180,956 698,166 59.12%
Coimbatore 709,974 569,122 80.16%
Chennai 673,616 519,617 77.14%
Tirunelveli 504,336 475,299 94.24%
Salem 221,084 187,098 84.63%
Total 3,289,966 662,397 1,786,905 74.45%
20.13% 54.31%


Another important utility is water. The sustainable approach, here, is similar. The first is to minimize water use. Some of the actions toward this are to eliminate leaks and wastage of water, reduce the water flow in faucets to required levels, use of waterless urinals, and so on. Simultaneously, all the used water from all sources including toilets are treated using the organic Decentralized Waste Water Treatment System (DEWATS).[5] In hospitals, where DEWATS is installed, it treats over 90% of the water used and the treated water is reused for toilet flushing and gardens. Overall, across the hospitals, the DEWATS treats over one million liters of water a day. The goal is to have zero water discharge from the hospital and staff accommodations.

Sustainable delivery of eye care

While what is described above relates to infrastructure and utilities like power and water, a lot can be done to reduce the carbon emissions in the delivery of care as shown under “How the resources are used” of the sustainability model, as shown in [Figure 1].

Service design

When we view service design through the sustainability lens, there are several options to reduce the carbon footprint of the caregiving process. The following are some of the strategies that help are:

Closing the care loop

The reality is that the caregiving process involves the travel of patients and hospital staff, the use of equipment, and consumables. This is inevitable and it also results in carbon emissions. Hence, our approach must be to ensure such effort is not wasted on account of inadequate diagnosis, inappropriate treatment advice, or the patient not complying with the advised treatment. Through audits, establishing metrics to monitor the comprehensiveness of diagnosis, treatment advice, and compliance will lead to continuous improvement in the effectiveness of care delivery, minimize wasted effort, and thus minimize the carbon emissions per successfully treated patient.

Minimizing hospital visits

Each visit by the patient also leaves a carbon trail as well the associated effort and costs. Each visit also generates duplicated efforts such as registration, engaging the patient, and taking up a slot of the hospital’s capacity for that day. Thus, completing the entire care cycle as appropriate from diagnosis to treatment, in a single visit, will significantly reduce the effort and associated carbon footprint.

Care at the appropriate level

A combination of outreach and tightly integrated primary, secondary, and tertiary levels of care, enables care to be provided at appropriate levels. At outreach, close to 75% of patients receive a complete eye examination, diagnosis, and a prescription. Those needing glasses are able to get them right at the camp site. Only those who need to go to the hospital for surgery or advanced investigations are referred to the hospital. Similarly, at Vision Centers, over 85% of the patients complete the care cycle locally. Follow-up care or reviewing the outcome of surgery or interventions is all done at the outreach site or the Vision Centers. In a typical year, about 1.2 million outpatient visits are handled between outreach and vision centers and this gives the magnitude of carbon emissions averted.

Equipment maintenance

Routine and preventive maintenance as recommended by the manufacturer, training the clinical team in the proper use and care of equipment, as well as providing the right electrical power and atmospheric environment, all go toward extending the life of the equipment, while also making the equipment available in good working condition for clinical care. Through this process, the purchase of new equipment is either delayed or averted and this too results in the reduction of the carbon footprint associated with the manufacturing and shipment of equipment.


Sharing the annual requirements with the vendors along with the delivery schedule, on the one hand, helps in getting better prices, and allows the vendor also to efficiently plan the supply-chain process. In addition to the transportation of goods, the other major area that can help reduce the carbon footprint is packaging. Bulk packaging, wherever appropriate, reduces packaging materials. When it comes to the purchase of electrical items such as lights, fans, and motors, items that consume less power are purchased – LED lights, fans with BLDC motor (Brushless Direct Current), and high-energy star rated motors. On the clinical and other consumables, there is a high degree of standardization. This goes a long way in reducing inventory and associated reduction waste and obsolescence. All of these help reduce the carbon footprint.

Clinical protocols

This probably is the area, where the most significant reductions in medical waste and associated carbon emissions can be made. In one of our publications, we have described in detail our lean surgical protocol and how the infection rates are no different.[6] In a more recent publication, the medical waste from a phacoemulsification surgery, using our lean clinical protocol, was estimated to be 5.9 kg CO2e, while it was 132.9 Kg CO2e in a UK facility, for the same procedure.[7] During the pandemic, we experimented to see if the operating room protocols mandated in the US resulted in lower post-operative endophthalmitis rates following cataract surgery, when compared to our standard lean protocol. This clinical trial involving 85,552 sequential patients showed that the post-operative endophthalmitis rates were no different.[8]

Travel and transport

This is recognized as an important source of carbon emissions. Eye care as with many other services requires the travel of patients and staff. It also requires the transportation of supplies. While this is inevitable, it is within our scope to minimize travel and transportation. For instance, staff housing on the hospital campus, where feasible, can significantly reduce staff travel. As described earlier, completing the care cycle in a single visit, and providing care at local levels closer to the patient, can all reduce their travel. Optimizing the frequency or replenishment of supplies can potentially reduce the embedded carbon emissions in the supply-chain process.


Any activity involving the movement of people, transportation of and consumption of materials as well as waste, will generate carbon emissions. Thus, it is inevitable that eye care delivery too, will. Our goal, thus, is to see how this can be minimized, per unit of care. This is where innovative approaches and practices can be brought in. Bringing down the carbon emissions per unit of care is essentially driven by minimizing waste or underutilization, enhancing efficiency, reducing consumption, and reducing patients’ effort. All of these by design will also reduce the unit cost of providing care as well the cost of accessing care by the patient. Thus, this would also be a win-win, for the provider and the patient.

Given the global urgency, a working group was formed in 2017, under the International Agency for the Prevention of Blindness (IAPB). This followed the global recognition that climate change is everyone’s problem and as a significant contributor to climate change, health care is morally obliged to take lead. IAPB’s climate action working group, following several rounds of deliberations, came up with a ten-point call to action statement [Box 1] for influencing eye care providers and associated stakeholders, to consciously implement initiatives to address climate change, within their organizations and programs.[9] IAPB Climate Action Working Group also brought out a more detailed companion guide, describing in detail, sustainable practices in eye care.[10]


These are very early days in the movement to address the adverse impact due to climate change. We need more evidence to catch the attention of providers and policymakers to generate the importance that this urgently requires. Recently, a survey was conducted on cataract surgeons and nurses to assess their attitudes toward operating room waste and their willingness to shift to reusable supplies.[11] Of the more than 1300 ophthalmologists and nurses interviewed, 78% believed that more supplies should be reused and 90% were concerned about global warming. More such studies are required to shift policies. We need to develop metrics and tools that will allow us to quantify and monitor the carbon emissions caused by eye care services. We also need to establish benchmarks so as to know, where we stand in this. It is important that we leave our planet as a better place for future generations. We have this responsibility and we need to act now based on what we already know and gather evidence to design newer approaches.

Declaration of the patient consent

Patient’s consent not required as there are no patients in this study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


  1. , , , , , , et al. The environmental footprint of health care: A global assessment. Lancet Planet Health. 2020;4:e271-9.
    [CrossRef] [Google Scholar]
  2. . Health care's Climate Footprint: How the Health Sector Contributes to the Global Climate Crisis and Opportunities for Action. . Health Care without Harm. Available from: [Last accessed on 2022 Mar 03]
    [Google Scholar]
  3. . Future of Cataract Surgery Seems Promising by Richard L Lindstrom, MD. Available from:,are%20performed%20every%20day%20globally [Last accessed on 2022 Apr 07]
    [Google Scholar]
  4. . Available from: [Last accessed on 2022 Mar 03]
  5. Decentralized Wastewater Treatment System at Aravind Eye Hospital, Pondicherry. Available from: [Last accessed on 2022 Mar 03]
    [Google Scholar]
  6. , , , , , . Incidence of post-cataract endophthalmitis at Aravind eye hospital: Outcomes of more than 42,000 consecutive cases using standardized sterilization and prophylaxis protocols. J Cataract Refract Surg. 2009;35:629-36.
    [CrossRef] [PubMed] [Google Scholar]
  7. , , , , , , et al. Cataract surgery and environmental sustainability: Waste and lifecycle assessment of phacoemulsification at a private healthcare facility. J Cataract Refract Surg. 2017;43:1391-8.
    [CrossRef] [PubMed] [Google Scholar]
  8. , , , , . Changing operating room practices: the effect on postoperative endophthalmitis rates following cataract surgery. Br J Ophthalmol. 2022;2021:320506.
    [CrossRef] [PubMed] [Google Scholar]
  9. . The International Agency for the Prevention of Blindness. Available from: [Last accessed on 2022 Mar 03]
    [Google Scholar]
  10. . Guide for Environmentally Sustainable Practices in the Eye Health Sector. Available from: [Last accessed on 2022 Mar 03]
    [Google Scholar]
  11. , . Ophthalmic instrument cleaning and sterilization task force. Survey of cataract surgeons' and nurses' attitudes toward operating room waste. J Cataract Refract Surg. 2020;46:933-40.
    [CrossRef] [PubMed] [Google Scholar]
Show Sections