Ophthalmology
Canadian Ophthalmological Society
Canadian Ophthalmological Society CWC Working Group
Last updated: April 2026
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Ocular ancillary testing (e.g., OCT, fundus photos, visual fields) is readily available in many ophthalmology and optometry clinics and utilization is rising. Ancillary testing should be ordered according to history and clinical assessment. There is currently no evidence to support population-level screening using ocular imaging modalities. Importantly, ancillary testing does not adequately replace clinical examination.
Sources:
Baveja L, et al. Overused ophthalmology imaging: More may not be better. [Internet]. 2018 Feb 21 [cited 2025 Nov 18].
Baxter SL. Precision Population-Based Screening for Glaucoma. JAMA Netw Open. 2025 Feb 3;8(2):e2457849. PMID: 39913142.
Ben-Artsi E, et al. Overuse and Underuse of Visual Field Testing Over 15 Years. J Glaucoma. 2019 Jul;28(7):660-665. PMID: 30973423.
College of Optometrists of Ontario. Digital Imaging/fundus photography/retinal imaging in Optometric Practice. [Internet]. 2020 Aug 14 [cited 2025 Nov 18].
Finn AP, et al. Trends in Imaging Utilization Among United States Medicare Beneficiaries and the Impact of the COVID-19 Pandemic. Ophthalmic Surg Lasers Imaging Retina. 2023 Nov;54(11):661-665. Epub 2023 Nov 1. PMID: 37855832.
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Ophthalmology is a high-volume specialty with many patients requiring frequent visits. Travel associated carbon emissions and patient accessibility can be greatly improved by ensuring same-day ancillary testing with examinations, and same-day bilateral procedures or surgeries when appropriate. Where available, teleophthalmology can replace in-person consults for screening and monitoring (e.g. diabetic retinopathy, glaucoma). Canadian teleophthalmology programs have demonstrated reduction of unnecessary referrals and improved follow-up in rural and underserved communities.
Sources:
Canadian Glaucoma Society Teleglaucoma Working Group. Evidence-Informed Approaches to Teleglaucoma in Canada. [Internet] 2021 [cited April 2026].
Grzybowski A, et al. Do we need day-1 postoperative follow-up after cataract surgery? Graefes Arch Clin Exp Ophthalmol. 2019 May;257(5):855-861. Epub 2018 Dec 19. PMID: 30569320.
Power B, et al. Analyzing the Carbon Footprint of an Intravitreal Injection. J Ophthalmic Vis Res. 2021 Jul 29;16(3):367-376. PMID: 34394865.
Spekreijse LS, et al. Equity, access, and carbon cost-effectiveness of bilateral cataract surgery – Authors’ reply. Lancet. 2024 Jan 27;403(10424):354-356. PMID: 38280777.
Spekreijse LS, et al. Safety, effectiveness, and cost-effectiveness of immediate versus delayed sequential bilateral cataract surgery in the Netherlands (BICAT-NL study): a multicentre, non-inferiority, randomised controlled trial. Lancet. 2023 Jun 10;401(10392):1951-1962. Epub 2023 May 15. PMID: 37201546.
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Reusable gowns and ophthalmic instruments undergo standardized sterilization processes that provide equivalent sterility and patient safety while reducing solid waste, water consumption, and greenhouse gas emissions. Life-cycle analyses demonstrate up to a 90–95% reduction in waste and significant reductions in carbon emissions when reusable systems are adopted in cataract surgery. Transitioning to reusable workflows can additionally lower procurement costs without compromising outcomes.
Sources:
McCance E, et al. Comparative carbon footprinting study of reusable vs. disposable instruments in cataract surgery. Eye (Lond). 2025 Jun;39(8):1481-1485. PMID: 39948404.
Morris DS, et al. The carbon footprint of cataract surgery. Eye (Lond). 2013 Apr;27(4):495-501. PMID: 23429413.
Sherry B, et al. How ophthalmologists can decarbonize eye care: a review of existing sustainability strategies and steps ophthalmologists can take. Ophthalmology. 2023 Jul;130(7):702-714. PMID: 36889466.
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Where available, multidose eye drops should be used over single-use minims. Single-use drops generate up to eight times more plastic and nine times more energy use than multidose bottles. Multidose drops should be utilized until their labelled expiry date with correct storage and handling. Up to 72% of multidose bottles are thrown out prematurely, contributing to unnecessary pharmaceutical waste, higher cost, and increased environmental burden.
Sources:
Chang DF, et al. Guidelines for the cleaning and sterilization of intraocular surgical instruments. J Cataract Refract Surg 2018; 44(6): 765-73.
Daughton CG, et al. Lower-dose prescribing: minimizing “side effects” of pharmaceuticals on society and the environment. Sci Total Environ. 2013 Jan 15;443:324-337. PMID: 23201698.
Latham SG, et al. Achieving net-zero in the dry eye disease care pathway. Eye (Lond). 2024 Apr;38(5):829-840. Epub 2023 Nov 13. PMID: 37957294.
Tan JM, et al. Ophthalmic Drop Waste Due to Self-imposed Use Cessation Dates. Ophthalmology. 2024 Nov;131(11):1345-1347. PMID: 38960336.
Tauber J, et al. Quantification of the cost and potential environmental effects of unused pharmaceutical products in cataract surgery. JAMA Ophthalmol. 2019 Oct 1;137(10):1156-1163. PMID: 31369052.
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Lean streamlined packs common to all surgeons containing essential high use items only are recommended, with other items and instruments available separately on demand. Large custom surgical packs often contain low-use items that are discarded unopened, or reusable items that must be re-sterilized, once a pack is opened. Removing unused components reduces waste, avoids unnecessary wear and tear shortening the life of reusable instruments, decreases cost, and does not affect surgical workflow or patient outcomes. Optimization projects have shown annual savings of $27,000–$32,000 CAD along with major reductions in plastic waste. Regular review of pack composition ensures supplies match clinical needs.
Sources:
Canadian Ophthalmological Society. Marysville Surgical Centre internal audit (data cited in COS Toolkit). [Internet] 2026 [cited 2026]. Website coming soon.
Canadian Ophthalmological Society. Canadian Ophthalmological Society Sustainability Toolkit: Operating Room – Custom Packs Optimization. [Internet] 2026 [cited 2026]. Website coming soon.
Malcolm J, et al. Reducing the carbon footprint of cataract surgery: co-creating solutions with a departmental Delphi process. Eye (Lond). 2024 May;38(7):1349-1354. Epub 2023 Dec 28. PMID: 38155328.
McCance E et al. Comparative carbon footprinting study of reusable vs. disposable instruments in cataract surgery. Eye (Lond). 2025 Jun;39(8):1481-1485. PMID: 39948404.
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Sterility measures should be re-evaluated for every patient and procedure. Many sterility measures are non-evidence based, guided by habit or opinion. However, their use contributes to increased costs and waste. Recent evidence supports that procedures like intravitreal injections can be safely performed without sterile drapes or sterile gloves, while a face drape only may suffice for cataract surgery instead of a full body drape. Drapes and covers can represent more than half of cataract procedural pack mass. Downsizing these alone can significantly reduce greenhouse gas emissions.
Sources:
Bhavsar AR, et al. Risk of Endophthalmitis After Intravitreal Drug Injection When Topical Antibiotics Are Not Required: The Diabetic Retinopathy Clinical Research Network Laser-Ranibizumab-Triamcinolone Clinical Trials. Arch Ophthalmol. 2009;127(12):1581–1583. PMID: 20008710.
Morris DS, et al. The carbon footprint of cataract surgery. Eye (Lond). 2013 Apr;27(4):495-501. Epub 2013 Feb 22. PMID: 23429413.
Ophthalmic Instrument Cleaning and Sterilization Task Force. Reducing Topical Drug Waste in Ophthalmic Surgery. American Academy of Ophthalmology. [Internet] 2022 [cited 2026].
Sherry B, et al. How ophthalmologists can decarbonize eye care: a review of existing sustainability strategies. Ophthalmology. 2023 Jul;130(7):702-714. PMID: 36889466.
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In first presentations of uveitis, systemic investigations should be guided by clinical history and exam rather than via a ‘catch-all’ approach. The ULISSE multicentre randomized trial showed a standardized, minimal-first-line strategy was non-inferior for etiologic yield and significantly lower cost than an open strategy. The Canadian National Uveitis Survey likewise recommended against nonselective testing as more costly, inefficient and more likely to confound accurate uveitis diagnosis through false positive results, than optimized selective testing only as necessary.
Sources:
de Parisot A, et al. Randomized Controlled Trial Evaluating a Standardized Strategy for Uveitis Etiologic Diagnosis (ULISSE). Am J Ophthalmol. 2017 Jun;178:176-185. Epub 2017 Mar 31. PMID: 28366648.
Forooghian F, et al. Anterior uveitis investigation by Canadian ophthalmologists: insights from the Canadian National Uveitis Survey. Can J Ophthalmol. 2006 Oct;41(5):576-83. PMID: 17016528.
Hwang DK, et al. Step-wise diagnostic approach for patients with uveitis – Experts consensus in Taiwan. J Microbiol Immunol Infect. 2022 Aug;55(4):573-580. Epub 2022 Mar 18. PMID: 35361552.
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The Canadian Ophthalmological Society (COS) created its Choosing Wisely Canada (CWC) list of recommendations by establishing a national sustainability in ophthalmology working group comprised of experienced ophthalmologists, fellows, residents and medical students from multiple faculties across Canada. The working group completed an extensive review of the relevant worldwide literature to create a detailed and comprehensive sustainability in ophthalmology toolkit, integrated with multiple real life examples and Canadian case studies, in addition to “vignettes” illustrating current Canadian ophthalmologists’ approaches drawn from polling COS members. A subgroup dedicated to drafting the CWC guidelines for COS then reviewed the sustainability toolkit to identify the most salient evidence supported recommendations exemplifying CWC principles. These key points are highlighted in the CWC list of recommendations and will be presented at the 2026 CWC National Meeting.
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Choosing Wisely Canada’s climate-conscious recommendations are developed by clinician societies to improve planetary health without compromising patient care. These recommendations highlight everyday practices we can reduce or eliminate to minimize environmental harm. Visit our climate page to explore all the recommendations and learn more.
Sources:
Baveja L, et al. Overused ophthalmology imaging: More may not be better. [Internet]. 2018 Feb 21 [cited 2025 Nov 18].
Baxter SL. Precision Population-Based Screening for Glaucoma. JAMA Netw Open. 2025 Feb 3;8(2):e2457849. PMID: 39913142.
Ben-Artsi E, et al. Overuse and Underuse of Visual Field Testing Over 15 Years. J Glaucoma. 2019 Jul;28(7):660-665. PMID: 30973423.
College of Optometrists of Ontario. Digital Imaging/fundus photography/retinal imaging in Optometric Practice. [Internet]. 2020 Aug 14 [cited 2025 Nov 18].
Finn AP, et al. Trends in Imaging Utilization Among United States Medicare Beneficiaries and the Impact of the COVID-19 Pandemic. Ophthalmic Surg Lasers Imaging Retina. 2023 Nov;54(11):661-665. Epub 2023 Nov 1. PMID: 37855832.
Canadian Glaucoma Society Teleglaucoma Working Group. Evidence-Informed Approaches to Teleglaucoma in Canada. [Internet] 2021 [cited April 2026].
Grzybowski A, et al. Do we need day-1 postoperative follow-up after cataract surgery? Graefes Arch Clin Exp Ophthalmol. 2019 May;257(5):855-861. Epub 2018 Dec 19. PMID: 30569320.
Power B, et al. Analyzing the Carbon Footprint of an Intravitreal Injection. J Ophthalmic Vis Res. 2021 Jul 29;16(3):367-376. PMID: 34394865.
Spekreijse LS, et al. Equity, access, and carbon cost-effectiveness of bilateral cataract surgery – Authors’ reply. Lancet. 2024 Jan 27;403(10424):354-356. PMID: 38280777.
Spekreijse LS, et al. Safety, effectiveness, and cost-effectiveness of immediate versus delayed sequential bilateral cataract surgery in the Netherlands (BICAT-NL study): a multicentre, non-inferiority, randomised controlled trial. Lancet. 2023 Jun 10;401(10392):1951-1962. Epub 2023 May 15. PMID: 37201546.
McCance E, et al. Comparative carbon footprinting study of reusable vs. disposable instruments in cataract surgery. Eye (Lond). 2025 Jun;39(8):1481-1485. PMID: 39948404.
Morris DS, et al. The carbon footprint of cataract surgery. Eye (Lond). 2013 Apr;27(4):495-501. PMID: 23429413.
Sherry B, et al. How ophthalmologists can decarbonize eye care: a review of existing sustainability strategies and steps ophthalmologists can take. Ophthalmology. 2023 Jul;130(7):702-714. PMID: 36889466.
Chang DF, et al. Guidelines for the cleaning and sterilization of intraocular surgical instruments. J Cataract Refract Surg 2018; 44(6): 765-73.
Daughton CG, et al. Lower-dose prescribing: minimizing “side effects” of pharmaceuticals on society and the environment. Sci Total Environ. 2013 Jan 15;443:324-337. PMID: 23201698.
Latham SG, et al. Achieving net-zero in the dry eye disease care pathway. Eye (Lond). 2024 Apr;38(5):829-840. Epub 2023 Nov 13. PMID: 37957294.
Tan JM, et al. Ophthalmic Drop Waste Due to Self-imposed Use Cessation Dates. Ophthalmology. 2024 Nov;131(11):1345-1347. PMID: 38960336.
Tauber J, et al. Quantification of the cost and potential environmental effects of unused pharmaceutical products in cataract surgery. JAMA Ophthalmol. 2019 Oct 1;137(10):1156-1163. PMID: 31369052.
Canadian Ophthalmological Society. Marysville Surgical Centre internal audit (data cited in COS Toolkit). [Internet] 2026 [cited 2026]. Website coming soon.
Canadian Ophthalmological Society. Canadian Ophthalmological Society Sustainability Toolkit: Operating Room – Custom Packs Optimization. [Internet] 2026 [cited 2026]. Website coming soon.
Malcolm J, et al. Reducing the carbon footprint of cataract surgery: co-creating solutions with a departmental Delphi process. Eye (Lond). 2024 May;38(7):1349-1354. Epub 2023 Dec 28. PMID: 38155328.
McCance E et al. Comparative carbon footprinting study of reusable vs. disposable instruments in cataract surgery. Eye (Lond). 2025 Jun;39(8):1481-1485. PMID: 39948404.
Bhavsar AR, et al. Risk of Endophthalmitis After Intravitreal Drug Injection When Topical Antibiotics Are Not Required: The Diabetic Retinopathy Clinical Research Network Laser-Ranibizumab-Triamcinolone Clinical Trials. Arch Ophthalmol. 2009;127(12):1581–1583. PMID: 20008710.
Morris DS, et al. The carbon footprint of cataract surgery. Eye (Lond). 2013 Apr;27(4):495-501. Epub 2013 Feb 22. PMID: 23429413.
Ophthalmic Instrument Cleaning and Sterilization Task Force. Reducing Topical Drug Waste in Ophthalmic Surgery. American Academy of Ophthalmology. [Internet] 2022 [cited 2026].
Sherry B, et al. How ophthalmologists can decarbonize eye care: a review of existing sustainability strategies. Ophthalmology. 2023 Jul;130(7):702-714. PMID: 36889466.
de Parisot A, et al. Randomized Controlled Trial Evaluating a Standardized Strategy for Uveitis Etiologic Diagnosis (ULISSE). Am J Ophthalmol. 2017 Jun;178:176-185. Epub 2017 Mar 31. PMID: 28366648.
Forooghian F, et al. Anterior uveitis investigation by Canadian ophthalmologists: insights from the Canadian National Uveitis Survey. Can J Ophthalmol. 2006 Oct;41(5):576-83. PMID: 17016528.
Hwang DK, et al. Step-wise diagnostic approach for patients with uveitis – Experts consensus in Taiwan. J Microbiol Immunol Infect. 2022 Aug;55(4):573-580. Epub 2022 Mar 18. PMID: 35361552.
About Choosing Wisely Canada
Choosing Wisely Canada is the national voice for reducing unnecessary tests and treatments in health care. One of its important functions is to help clinicians and patients engage in conversations that lead to smart and effective care choices.
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