Tracing the barriers to decarbonising ophthalmology: A review.

As climate change demands increasingly urgent mitigation of greenhouse gas emissions, the health sector needs to do its part to decarbonise. Ophthalmologists share concerns about climate change and seek opportunities to reduce their environmental impact. When measuring the footprint of ophthalmology, major contributions are from patient travel to clinics, and from the large amounts of single-use disposable materials that are consumed during surgeries and sterile procedures. Ophthalmic services in India have already demonstrated systems that consume far fewer of these products through efficient throughput of patients and the safe reuse of many items, while maintaining equivalent safety and quality outcomes. Choosing these low-cost low-emission options would seem obvious, but many ophthalmologists experience barriers that prevent them operating as Indian surgeons do. Understanding these barriers to change is a crucial step in the decarbonisation of ophthalmology and the health sector more broadly.

Associations Between Thinner Retinal Neuronal Layers and Suboptimal Brain Structural Integrity in a Middle-Aged Cohort.

Purpose: The retina has potential as a biomarker of brain health and Alzheimer's disease (AD) because it is the only part of the central nervous system which can be easily imaged and has advantages over brain imaging technologies. Few studies have compared retinal and brain measurements in a middle-aged sample. The objective of our study was to investigate whether retinal neuronal measurements were associated with structural brain measurements in a middle-aged population-based cohort. Participants and Methods: Participants were members of the Dunedin Multidisciplinary Health and Development Study (n=1037; a longitudinal cohort followed from birth and at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, 26, 32, 38, and most recently at age 45, when 94% of the living Study members participated). Retinal nerve fibre layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness were measured by optical coherence tomography (OCT). Brain age gap estimate (brainAGE), cortical surface area, cortical thickness, subcortical grey matter volumes, white matter hyperintensities, were measured by magnetic resonance imaging (MRI). Results: Participants with both MRI and OCT data were included in the analysis (RNFL n=828, female n=413 [49.9%], male n=415 [50.1%]; GC-IPL n=825, female n=413 [50.1%], male n=412 [49.9%]). Thinner retinal neuronal layers were associated with older brain age, smaller cortical surface area, thinner average cortex, smaller subcortical grey matter volumes, and increased volume of white matter hyperintensities. Conclusion: These findings provide evidence that the retinal neuronal layers reflect differences in midlife structural brain integrity consistent with increased risk for later AD, supporting the proposition that the retina may be an early biomarker of brain health.

The prevalence of glaucoma among 45-year-old New Zealanders.

AIM: We aimed to estimate the prevalence of glaucoma in New Zealand using a population-based birth cohort of 45-year-olds. METHODS: Study members of the Dunedin Multidisciplinary Health & Development Study participated (n=938 out of 1037 births (91%)). The data collected included visual acuity, visual field (VF), refraction, central corneal thickness, intraocular pressure (IOP), axial length, spectral domain optical coherence tomography (OCT), and non-mydriatic fundus photographs. Two ophthalmologists reviewed data independently to generate a consensus glaucoma status: "Normal" if no suspicion of glaucoma; "Ocular hypertension" if IOP >21 mmHg; "Glaucoma suspect" if optic disc photograph was suspicious for glaucoma with no more than borderline or non-corresponding VF or OCT abnormalities; and "Glaucoma" if optic disc photograph was suspicious for glaucoma and there were corresponding abnormalities of the OCT or VF. RESULTS: Of 891 participants with sufficient data to assign a glaucoma status, 804 were "Normal" (90.2% [CI 88.3-92.2]), 15 were "Ocular hypertension" (1.68% [95% confidence interval (CI) 0.84-2.5]), 65 were "Glaucoma suspect" (7.30% [95% CI 5.6-9.0]), and 7 were classified as "Glaucoma" (0.79% [95% CI 0.21-1.4]). An additional 73 participants (8.2%, [95% CI 6.3%-10%]) had abnormalities on the OCT scan but were not deemed to be glaucoma suspects. CONCLUSION: The prevalence of glaucoma in New Zealand is between 0.2% and 1.4%, consistent with other population-based studies in the same age group. The study highlights the sensitivity of OCT and the potential for misinterpretation and over-investigation.

Improving the provision of cataract surgery in New Zealand demands disruptive change.

Cataract surgery is a highly cost-effective treatment, but the surgical intervention rate in New Zealand ranks poorly compared with other high-income countries. The combination of a growing and ageing population, lost operating time due to the COVID-19 pandemic, and geographical disparities, is driving up an unmet demand for cataract surgery. We present several evidence-based strategies with overlapping benefits in access, equity, efficiency and sustainability. Key strategies include that Health New Zealand mandate a national prioritisation threshold for surgical access, and that PHARMAC leverage cheaper access to surgical supplies using nationally agreed equipment standards, establishing high-throughput cataract units, offering same day bilateral cataract surgery when appropriate, and rationalising post-operative care.

Doctors' travel in the Anthropocene.

The health sector is uniquely placed as both a significant contributor to greenhouse gas emissions and a first responder to the impacts of climate change. The breadth and complexity of the health sector mean that decarbonisation will be a substantial challenge to current practice. Doctors are leaders in the health system and in their communities, and there are multiple imperatives for doctors to lead on decarbonisation. Here we specifically examine the impact of travel undertaken by hospital-based senior doctors for the purpose of continuing medical education. Where quantified, doctors' travel is a significant source of greenhouse gas emissions for district health boards, although there is significant uncertainty about the estimates. This travel occurs within a system that encourages and enables it through educational, financial, regulatory and cultural mechanisms, and is for many doctors an important component of their job satisfaction. This system needs to be redesigned to optimise education, job satisfaction, collaboration and wellbeing in the decarbonised health sector of the future.

The carbon footprint of cataract surgery in Wellington.

INTRODUCTION: Efforts to improve the sustainability of ophthalmic care require methods to measure its environmental impact and a baseline measurement to compare against in the future. We aimed to measure the carbon footprint of cataract surgery in Wellington. METHODS: We used Eyefficiency, an application using established footprinting methods, to estimate the emissions produced by phacoemulsification surgery in two public and two private hospitals. We measured (1) power consumption, (2) procurement of disposable items and pharmaceuticals, (3) waste disposal emissions and (4) travel (other potential sources were excluded). Where possible we used New Zealand emissions coefficients. RESULTS: We recorded data from 142 cataract surgeries. The average emissions produced by cataract surgery in the region was estimated to be 152kg of carbon dioxide equivalent. This is equivalent to 62L of petrol and would take 45m2 of forest one year to absorb. The great majority of emissions were from procurement, mostly disposable materials, and the second greatest contribution was from travel (driving). CONCLUSION: Estimating the carbon footprint of cataract surgery is becoming easier, but improved methods for measuring the footprint of procured supplies are needed. There are significant opportunities for emissions reduction in the most common surgical procedure in New Zealand.

Loss of Pressure Control Resulting from Tube Bending during Glaucoma Drainage Tube Perforations.

PURPOSE: Tube perforations are a common method of achieving early intraocular pressure control with ligated glaucoma drainage devices (GDDs). Our purpose was to investigate how bending GDD tubes affects the performance of needle perforations. DESIGN: Experimental report. PARTICIPANTS: Twenty silicone GDD tubes attached to 27 G Rycroft cannulae tied with 7-0 Vicryl 10 mm from the cannulae tips. METHODS: Silicone GDD tubing was fitted over a 27 G Rycroft cannula and tied with a 7-0 suture 10 mm from the cannula tip. The tube was perforated 4 mm from the cannula tip with a 25 G needle (tube was kept straight). The tube was secured in a 50-mm water bath. Aqueous food dye was infused through the cannula from an adjustable height. The tube was observed under magnification while the height of the fluid column was adjusted to establish the pressure gradient at which the tube leaked dye (opening pressure) and ceased to leak (closing pressure), while the tube was held straight and bent 90 degrees. Measurements were repeated after a second perforation and a third perforation. Ten tubes were tested this way with 3 sequential slits. The entire experiment was repeated with another 10 tubes, but this time the tube was allowed to bend within the 3.5-mm open prongs of a needle holder during needle perforation. MAIN OUTCOME MEASURES: Opening and closing pressures. RESULTS: For each tube, the opening and closing pressures were similar and highly reproducible, but there was wide variation between tubes. In the tubes kept straight when perforated, the opening/closing pressure ranged from 5 to 25 cmH2O. The opening and closing pressures of slits made in the bent tube were significantly lower, frequently leaking at <1 cmH2O. Bending the tube after perforation could close a slit and prevent leakage at high perfusion pressure. The second and third successive perforations caused lower opening and closing pressures. CONCLUSIONS: Tube perforations behave like pressure-sensitive valves, opening whenever intraluminal pressure increases above a specific value. However, we found a large variation in the performance of fenestrations made with a 25-G hypodermic needle. Allowing the GDD tube to bend during needle perforation increases the risk of very low opening and closing pressures.

Health Economic Analysis in Glaucoma.

The pressure on glaucoma services is ever-growing, and policymakers seek robust cost-effectiveness arguments in their decisions around resource allocation. The benefits of glaucoma are in preventing or delaying a future loss of vision and associated quality of life, and this expectation is quantified using a metric called utility which can be compared against other disease states. In recent clinical trials lasting up to 3 years, it has been difficult to show a difference in utility between glaucoma treatments in this limited period of time. When it comes to cost, the direct medical costs are only part of the broad range of costs that glaucoma brings to patients and communities, and the estimation of these costs can be difficult and imprecise. While the cost-effectiveness of glaucoma care, in general, is not in dispute, especially over longer time frames, the inability to measure changes in utility in shorter time frames impedes the uptake of innovations around the world. A number of approaches to improve the sensitivity and specificity of utility measurements are under investigation.

Visual Outcomes in the Management of Diabetic Maculopathy in Central Australia.

PURPOSE: In major urban centres and high-resource settings, treatment of diabetic maculopathy with anti-Vascular Endothelial Growth Factor (VEGF) injections has largely displaced laser treatment. However, intravitreal therapy alone requires frequent follow-up, a barrier to adherence in remote Australia. We report vision outcomes of phased diabetic maculopathy treatment in remote Central Australia for maculopathy using laser and, in a subset, supplementary injection treatment. METHODS: We audited clinical records of patients undergoing laser treatment for diabetic maculopathy between 2001 and 2013 at an ophthalmology service based at Alice Springs Hospital, a regional hub in remote Australia. All patients receiving macular laser treatment were included, and some required supplementary injection(s). The primary outcome measure was change in best-corrected visual acuity [BCVA] from baseline treatment. RESULTS: Of 338 maculopathy-treated patients, 88% were indigenous and 39% were male. Of 554 maculopathy laser-treated eyes, 118 (21%) received supplementary injection/s. In the laser treatment phase, median BCVA was 78 letters at baseline (interquartile range 62-80) and decreased by a median of two letters at final visit. In the subset who underwent subsequentinjection treatment, BCVA was 60 letters at first injection, with a median five-letter increase by final visit. Overall outcomes were similar in Indigenous and non-Indigenous Australians. Predictors of reduction in BCVA in the macular laser treatment phase were better baseline BCVA, older age, and PRP treatment (all p < .005). CONCLUSION: Laser treatment for diabetic maculopathy preserved vision in Central Australia, where barriers to follow-up can preclude regular injections. Supplementary injections stabilized vision in the laser-resistant subset.

New Zealand ophthalmologists' opinions and behaviours on climate, carbon and sustainability.

IMPORTANCE: Ophthalmology faces imperatives to improve sustainability, but there is uncertainty about how to respond. BACKGROUND: We sought New Zealand ophthalmologists' opinions on climate change, sustainability and the role of ophthalmologists in responding to these issues, as well as information on the extent that ophthalmology practices are acting on sustainability. DESIGN: Anonymous online survey of New Zealand fellows and trainees (178) of the Royal Australian and New Zealand College of Ophthalmologists (RANZCO) was conducted. PARTICIPANTS: Forty-seven respondents (response rate 26%) were included in the study. METHODS: Respondents were asked their level of agreement with statements on climate, health and sustainability and invited to comment. Current sustainability activities were collected from clinical leaders and directors of hospital departments and private practices. MAIN OUTCOME MEASURE: Distribution of agreement scores was the main outcome measure. RESULTS: Agreement with mainstream positions on climate change was as expected. A minority of up to 19% expressed the opinion that climate change was not due to human activity, and did not require mitigation. Younger ophthalmologists tended to have greater agreement with the need for broad-based political action on climate mitigation than those aged over 50 years. Most practices had room to improve on reducing waste, travel and carbon footprints. CONCLUSIONS AND RELEVANCE: The majority of New Zealand ophthalmologists are concerned about anthropogenic climate change. Currently, sustainability is not a performance indicator for New Zealand district health boards, so there is limited incentive to drive improvements. These data form a reference point to compare future opinions and ophthalmology carbon footprinting.

Optic Nerve Head Drusen: An Update.

Optic nerve head drusen are benign acellular calcium concretions that usually form early in life, just anterior to the lamina cribrosa. Improving imaging using optical coherence tomography suggests they are common and may be present in many clinically normal discs. These drusen may change in appearance in early life, but are generally stable in adulthood, and may be associated with visual field defects, anterior ischaemic optic neuropathy, or rarer complications. Based on long-term clinical data and optical coherence tomography, we propose a refined hypothesis as to the cause of optic disc drusen. Here we summarise recent findings and suggest future studies to better understand the forces involved.

Factors predicting the success of trabeculectomy bleb enhancement with needling.

BACKGROUND: Bleb needling is widely used to restore flow and lower intraocular pressure (IOP) in a failing trabeculectomy. We aimed to measure the safety and efficacy of needling in a large cohort and identify factors that were associated with success and failure. METHODS: This retrospective audit included all patients who underwent needling at Addenbrooke's Hospital, Cambridge over a 10-year period. Data were available on 91 patients (98% of patients identified), including 191 needlings on 96 eyes. Success was defined as IOP below 21 mm Hg or 16 mm Hg or 13 mm Hg consistently, without reoperation or glaucoma medication. Risk factors for failure were assessed by Cox proportional hazard regression and Kaplan-Meier curves. RESULTS: Success defined as IOP <16 mm Hg was 66.6% at 12 months and 53% at 3 years and success defined as IOP <21 mm Hg was 77.1% at 12 months and 73.1% at 3 years. Failure after needling was most common in the first 6 months. Factors that predicted failure were flat or fibrotic blebs (non-functional) and no longer injected, while success was predicted by achieving a low IOP immediately after needling. No significant complications were identified. CONCLUSION: Needling was most successful soon after trabeculectomy, but resuscitation of a long-failed trabeculectomy had lower likelihood of success. The safety and efficacy compare favourably with alternative treatment approaches.

Analysis combining correlated glaucoma traits identifies five new risk loci for open-angle glaucoma.

Open-angle glaucoma (OAG) is a major cause of blindness worldwide. To identify new risk loci for OAG, we performed a genome-wide association study in 3,071 OAG cases and 6,750 unscreened controls, and meta-analysed the results with GWAS data for intraocular pressure (IOP) and optic disc parameters (the overall meta-analysis sample size varying between 32,000 to 48,000 participants), which are glaucoma-related traits. We identified and independently validated four novel genome-wide significant associations within or near MYOF and CYP26A1, LINC02052 and CRYGS, LMX1B, and LMO7 using single variant tests, one additional locus (C9) using gene-based tests, and two genetic pathways - "response to fluid shear stress" and "abnormal retina morphology" - in pathway-based tests. Interestingly, some of the new risk loci contribute to risk of other genetically-correlated eye diseases including myopia and age-related macular degeneration. To our knowledge, this study is the first integrative study to combine genetic data from OAG and its correlated traits to identify new risk variants and genetic pathways, highlighting the future potential of combining genetic data from genetically-correlated eye traits for the purpose of gene discovery and mapping.