From Saturday 8 to Sunday 9 September 2018, the Melbourne Convention and Exhibition Centre hosted more than 750 optometrists and optometry students for the seventh Specsavers Clinical Conference (SCC7). With the theme ‘Transforming Eye Health’, the conference program comprised 15 clinical talks delivered over two days by leaders and experts in eye care. Spectrum shares some of the clinical pearls from the event that focussed on two of the most common causes of avoidable blindness – glaucoma and diabetes.
Specsavers Australia & New Zealand Optometry Director Peter Larsen opened the Sunday conference program with a discussion of the early findings from Specsavers’ eye health strategy. To explain the reasoning behind Specsavers Aus / NZ’s focus on outcome-led optometry, he used a sporting analogy, pointing out that data-led performance analysis is something that is cemented into benchmarking and league tables for any competitive event. Peter stressed the importance of data collection to affect decision making and the construction of systematic approaches to solve healthcare problems.
For Specsavers, application of this strategy has involved developing consistent approaches to disease assessment and management in collaboration with RANZCO; rolling out OCT technology across the Australian and New Zealand store network and using this on every patient; measuring improvement of clinical interventions; and benchmarking this against peers and published data. The result of these combined strategies has been a significant and measurable improvement in patient outcomes – in line with Specsavers’ mission to transform eye health across Australia and New Zealand.
Peter introduced the published evidence of measurable improvement within the Specsavers Aus / NZ’s inaugural State of the Nation: Australia & New Zealand Eye Health Report 2018. He explained that the report would be distributed industry-wide, as well as to government and consumers, providing insight on 6.3 million Specsavers patient journeys spanning the previous 18 months.
State of the Nation key findings
In shining a spotlight on some of the key findings from the report, Peter noted that unprecedented store data had been gathered on visual field performance rates. As optometrists are primary healthcare providers, the population seen is largely healthy and disease is the exception. Structural testing in the form of an objective OCT scan, followed by functional testing as indicated, has led to overwhelming data showing an improvement in the detection of these exceptions. Statistically, performance of visual fields has been clinically indicated for at least 10% of patients seen by primary eye care to detect glaucoma at a rate that correlates with well-established population prevalence rates.
Specsavers data presented in the report also shows that use of OCT as part of every standard consultation increases the detection and referral of patients with normal-tension glaucoma across all age groups, with a higher proportion being referred in the younger age groups than has been previously reported.
Moving to diabetes, Peter suggested that increasing accessibility to OCT technology could alleviate the toll on healthcare systems by ensuring early detection of sight-threatening eye conditions, decreasing the prevalence of vision loss and blindness resulting from diabetic retinopathy. Data from the State of the Nation report shows that using OCT on all patients has resulted in almost double the number of diabetic macular oedema cases in diabetic eye referrals. It was also noted that Specsavers recently committed $1 million per year for five years towards the development of KeepSight, an Australian diabetes eye screening program. The national initiative is being developed by Diabetes Australia, Vision 2020 Australia and Oculo, with additional funding being supplied by the Australian Government.
Peter concluded his presentation with a call to action for optometry to continue to use measurable interventions to improve eye care. He determined that by using this approach, Specsavers would continue to have a positive impact on patient care through measurable improvements in patient outcomes.
Combining functional and structural assessment for detection
As a condition that affects approximately 300,000 Australians, 50% of whom have gone undiagnosed, glaucoma is one of the immediate focuses of Specsavers’ ‘Transforming eye health’ mission. Patients suspected of glaucoma and / or at risk of progression need to be correctly identified by all eye care professionals to ensure they receive appropriate, timely and safe clinical care with the finite resources available, as vision loss from glaucoma is irreversible. Appropriate monitoring of patients that are glaucoma suspects or have pre-perimetric glaucoma (in line with the RANZCO Referral Pathway for Glaucoma Management) is equally as important as treatment. For this reason, effective collaborative care is critical to optimal patient outcomes.
Glaucoma was discussed in detail at SCC7 from the perspective of a number of different eye health stakeholders, including from three ophthalmologists and a representative of the patient support group, Glaucoma Australia. Ophthalmologist Dr Tu Tran from Eyes First in Victoria provided a review of the RANZCO Referral Pathway for Glaucoma Management and an overview of how OCT can be used to assist detection and diagnosis, presenting a series of cases as examples. Dr Simon Skalicky, Ophthalmologist at Eye Surgery Associates in Victoria, focussed on how optometry, ophthalmology and Glaucoma Australia could work together for optimal management of glaucoma patients. Both ophthalmologists stressed that to consistently detect glaucoma in optometric practice, functional and structural assessment need to be systematically performed.
Glaucoma was characterised as the accelerated apoptosis of retinal ganglion cells leading to the death of ganglion cells and loss of axons. Retinal nerve fibre layer (RNFL) thinning and cupping of the optic disc occurs, becoming progressively obvious at a structural level. However, at this stage, the patient could be asymptomatic and visual fields may be normal. By the time a corresponding visual field defect is detected on standard automated perimetry (Table 1), 25-50% retinal ganglion cells could already have been lost.
Pre-perimetric glaucoma is diagnosed when a patient presents with matching disc and OCT defects, but has normal visual fields. Dr Tran explained that 10-2 fields might highlight losses in early stages when 24-2 fields appear normal. She advised that pre-perimetric glaucoma patients should be considered for referral to ophthalmology, to develop a close co-management or collaborative care plan.
Drs Tran and Skalicky agreed that OCT was able to detect structural changes earlier than potential correlating visual field changes, underscoring the technology’s value in primary eye care. Dr Tran also pointed out that while underlying causes of glaucoma are multi-factorial, all current treatments are directed at IOP control – the only known modifiable risk factor. As such, the ophthalmologists recommended that assessment of the optic nerve head should include fundoscopy and / or OCT, IOP measurement, and threshold visual fields.
Care provided in this manner is supported through utilisation of the 10940 Medicare visual fields item number. This may be used where there are clinical indicators, and billing is not dependent on the outcome of the visual field test – only on the clinical need. Importantly, performance of visual fields at the time of comprehensive assessment reduces the risk of losing patients in the follow-up process.
Elaborating on the importance of the correlation of structural and functional loss in diagnosing glaucoma, Dr Skalicky explained that glaucoma is asymmetric by nature. As such, in OCT, ganglion cell complex asymmetry respecting the horizontal midline is considered suspicious, and a diagnosis is certain when accompanied by correlating visual field defects. He added that evidence of a Drance haemorrhage indicates active disease progression, and the co-existence of high IOPs and damaged discs should prompt further investigation.
Dr Tran’s advice for optometrists when making a diagnosis was to consider all information available to them to reach a logical conclusion (Figure 1). This includes structure and function, presence of disc haemorrhage, reliable monitoring of IOP, family history, patient age, and other risk factors associated with the patient’s health and history.
When assessing visual field defect progression, she said a reduction of >1dB / year can be significant and outside of normal ageing. When using OCT to assist in assessing if RNFL thinning is outside normal ageing, a loss of >4µm / year is significant. Much like visual fields, OCT scans need to be reliable and reproducible between visits for accurate conclusions to be drawn.
Considerations for routine use of OCT
Reinforcing Dr Tran’s recommendation for using all information available to reach a diagnosis, Dr Jesse Gale, Consultant Ophthalmologist at Wellington Hospital in New Zealand, cautioned that OCT was not intended to be used in isolation to detect or diagnose multi-factorial diseases such as glaucoma.
In his presentation on identifying glaucoma amongst “countless imperfect OCT scans”, Dr Gale said using OCT as part of routine practice is a new approach in the diagnosis of glaucoma and is expected to lead to significant learnings regarding the impact eye health providers can have on reducing the rate of undiagnosed disease. However, while OCT is a useful tool in imaging and analysing ocular structures in great detail, it must be used in conjunction with other complementary tests and clinical judgement. It is the correlation of all structural and functional information obtained through a thorough assessment that enhances detection of glaucoma, Dr Gale stated.
When using OCT on every patient, Dr Gale said there are a few considerations optometrists need to be aware of, including ‘red disease’ and ‘green disease’. ‘Red disease’ describes an OCT scan that shows abnormalities in a patient that does not have any definite pathology. Essentially, their ocular structures, while lying outside the normative 95% confidence interval, are ‘normal’ for them. Dr Gale said it was important for optometrists to identify these patients to reduce unnecessary costs and minimise patient anxiety.
He referenced a study that found that in 2,300 Spectralis SD-OCT scans from the Massachusetts Eye & Ear Infirmary, 46% had at least one image artefact4. The top 10 causes of OCT image artefacts on RNFL scans were as follows:
- De-centration (28% of scans)
- Error associated with posterior vitreous detachment (14%)
- Posterior RNFL misidentification (8%)
- Poor signal (5%)
- Anterior RNFL misidentification (3%)
- Missing parts (2%)
- Peripapillary atrophy (PPA) associated error (1%)
- Incomplete segmentation (1%)
- Motion artefact (<1%)
- Cut-edge (<1%).
It is important for clinicians to be able to recognise when the above artefacts occur.
Dr Gale noted, however, that glaucoma can co-exist in patients with red disease. An example of this is a highly myopic patient with tilted discs, large crescents of PPA and axial elongation. High myopia is a clear risk factor for glaucoma, and Dr Gale said the above presentation would almost certainly give rise to a ‘red’ OCT scan. He stressed that visual field assessment is imperative to determine if a functional defect is an enlarged blind spot from PPA, or an asymmetrical mid-peripheral nasal step requiring further assessment.
Dr Gale explained that ‘green disease’ describes a patient that exhibits a normal OCT scan but displays other signs leading to diagnosis of a disease. An example is a patient who presents with normal IOPs but experiences IOP spikes. Another example is focal rim loss that is small, and hence appears ‘green’ and may be missed when averages are calculated, leading to a false ‘normal’ result.
Both situations highlight the risks of relying solely on OCT to diagnose glaucoma in primary eye care. Dr Gale referred to the RANZCO Referral Pathway for Glaucoma Management, which clearly recommends holistic assessment of presenting risk factors, family history, IOPs, disc and RNFL assessment (including OCT / imaging), and visual fields to come to an initial diagnosis and classification of risk.
Supporting glaucoma patients
Once a diagnosis has been made, the focus for eye health professionals shifts to management and treatment. Dr Tran said the RANZCO referral guidelines would support optometrists in their management of glaucoma patients, from early through to advanced stages. Dr Skalicky went into patient management in more detail in his presentation, emphasising that treatment and management of glaucoma needs to be patient-centric with the aim of maintaining visual function and quality of life.
Dr Skalicky discussed MIGS (minimally invasive glaucoma surgery) as one type of glaucoma treatment, stating that he believed it had revolutionised management of glaucoma. Outlining some of the other treatment options available, he added that SLT (selective laser trabeculoplasty) is well accepted as first-line therapy in conjunction with, or as an alternative to, topical treatment, and can be used across all stages of the glaucoma continuum. Benefits include a reduction in ocular surface symptoms and a reduction in the need for compliance with ‘drops’, supporting IOP outcomes and long-term cost effectiveness. Compared with ALT (argon laser trabeculoplasty), less energy is used over a wider field, so there is less trabecular meshwork damage. In addition, SLT has efficacy rates of 70-75%, blunts the steroid response, can be repeated, lowers IOPs, and reduces IOP fluctuations. Treatment options and rationale should be discussed with the patient, and target pressures set, with a reduction of IOP by 20-30% recommended.
Dr Skalicky said engagement with the treating ophthalmologist for the purposes of collaboration and / or co-management of the glaucoma patient alongside other health professionals would assist with compliance and reduce the risk of avoidable blindness. Communication needs to be a ‘tight-cast web’ that includes the optometrist, ophthalmologist, GP, pharmacist, family and patient support services such as Glaucoma Australia, he said. It was noted that the electronic referral platform Oculo was ideal for supporting this communication network, with Dr Skalicky adding that taking this collaborative approach encouraged patients to practise self-care.
Glaucoma Australia CEO Annie Gibbins provided more information about the patient support services available to glaucoma patients. Glaucoma Australia supports both diagnosed glaucoma patients as well as glaucoma suspects through all stages of their journey – from preliminary diagnosis or suspicion of glaucoma to treatment adherence and living with glaucoma.
Glaucoma Australia recommends optometrists refer patients at the beginning of their journey, when they are a glaucoma suspect. Currently, Glaucoma Australia’s services are primarily accessed only when patients have severe, visually impacting, end-stage glaucoma. Annie stated that intervening when vision loss is at 2% is significantly more impactful than when loss is at 50%, and added that regular support from Glaucoma Australia in between optometry / ophthalmology appointments to provide information can assist with compliance.
Many patients who are suspects or have early glaucoma still have trouble with their understanding of the condition and stress, as well as their adherence to appointment attendance, monitoring, and treatments. Annie said an example of the kind of support provided by Glaucoma Australia is reiterating to the patient that glaucoma, if detected, is largely manageable and treatable. She added that information already provided by optometrists can also be re-emphasised, including the correct use of topical therapy, dosage, correct methods of instillation and side effects.
Recent data collected by Glaucoma Australia shows that health professionals are best placed to inform patients of their service. For optometrists, Annie suggested the easiest and most convenient way of referring patients to Glaucoma Australia was through Oculo when finalising an initial ophthalmology referral.
Prevalence and classification
Another eye disease that was widely discussed at SCC7 was diabetic retinopathy. Guidelines for the detection and management of diabetic eye disease was the subject of the presentation delivered by Dr Erwin Groeneveld, a Brisbane-based ophthalmologist who has served as Director of Ophthalmology at the Princess Alexandra Hospital in Queensland.
To set the scene, Dr Groeneveld provided several statistics in relation to the prevalence and impact of diabetes. He stated that more than one million Australians currently have diagnosed diabetes, and approximately 87% of these people have type 2 diabetes, with the rest made up of type 1 and gestational diabetes. He explained that the cost impact on the health system primarily relates to management of the complications caused by diabetes, with diabetic retinopathy being the most common microvascular complication of diabetes. Peripheral neuropathy carries a 30-50% lifetime risk and diabetic nephropathy occurs in 50% of people with diabetes at some point. Management of these conditions makes up 80% of costs relating to diabetes.
Severe non-proliferative diabetes, proliferative diabetes and diabetic macular oedema were cited as the main causes of disabling vision loss in people with diabetes. Dr Groeneveld said optometrists play an intrinsic role as primary eye care providers to work collaboratively with GPs to screen for diabetic eye disease, manage and advise on modifiable risk factors, and effectively reinforce compliance with review schedules, treatment and advice.
One in five people with type 2 diabetes have diabetic retinopathy at the time of diagnosis and most are likely to be asymptomatic to any vision problems. This means that a comprehensive diabetic eye health screening, including dilation, should be conducted at the time of diagnosis. Dr Groeneveld pointed out that this was a recommendation reflected in the RANZCO Referral Pathway for Diabetic Retinopathy, which he described as a useful guide for optometrists on timely assessment, indications for dilated fundus examinations, and referrals to ophthalmology. It should be noted that according to the Medicare guidelines, it is most appropriate for optometrists to bill 10915 for this type of comprehensive eye examination.
The role optometrists have in performing timely dilated fundus examinations was explored further by Dr Xavier Fagan, Ophthalmologist for Ringwood Eye Specialists and Northern Eye Consultants in Victoria. In his presentation on ophthalmic signs of systemic disease and working collaboratively with medicine, Dr Fagan outlined the current evidence that fundus examination outside of the ETDRS 7 standard fields changes the level of retinopathy reported in 10% of cases, and the presence of diabetic retinopathy gives a 3.5 times increased chance of progression, which in turn, influences the review schedule and management plan for these patients (Figure 2).
Dr Groeneveld said diabetic macular oedema is the major cause of blindness in type 2 diabetes. He explained that as leakage at the macula can occur before visual acuity is affected, OCT is a very useful and important tool in diagnosing diabetic macular oedema and is highly effective in detecting ‘sub-clinical’ macular oedema. This is a key consideration for screening of patients with diabetes as the clinical information provided by OCT aids with pre-empting progression of diabetic retinopathy earlier than other forms of clinical testing.
Dr Fagan shared Dr Groeneveld’s view that OCT enhances the ability to detect and diagnose diabetic retinopathy. He said it is particularly useful for distinguishing lipid deposits within the retinal layers, sub-retinal fluid in diabetic macular oedema and micro aneurysms, and described how this could be used to aid in the classification of diabetic retinopathy and to direct timely referrals to ophthalmology.
Collaborating to limit diabetic retinopathy progression
Dr Groeneveld noted that patients with pre-proliferative diabetic retinopathy should be assessed regularly for monitoring of visual acuity, imaging of the macula, and to ensure a dilated fundus examination is performed at least every two years. He warned that once diabetic retinopathy occurs, the risk of progression to develop vision-threatening retinopathy increases at an accelerated pace as the retinopathy advances.
He added that optometrists should have a robust understanding of the relative risk profile for the development of diabetic retinopathy, and use appropriate questioning and investigation to tailor management plans and recall schedules based on the risk of development or progression of diabetic retinopathy.
Key risk factors for the progression of diabetic retinopathy in patients with type 2 diabetes were outlined as follows:
- Duration of diabetes
- Elevated HbA1c (most important modifiable risk factor – 1% reduction can lead to significant reduction in risk for peripheral neuropathy, microvascular disease and cardiovascular complications)
- Indigenous or Polynesian origin.
Dr Groeneveld highlighted cross-collaboration involving communication with GPs as essential in supporting effective control of HbA1c levels, hypertension and dyslipidemia, which are the key modifiable risk factors for development of diabetic retinopathy. He spoke specifically about fenofibrate, a common therapeutic agent prescribed by GPs that is indicated in the control of dyslipidemia for people with type 2 diabetes as an adjunct to diet control. It has been shown to reduce the progression of diabetic retinopathy in patients with type 2 diabetes who have existing diabetic retinopathy.
He said it was also the responsibility of optometrists to work with GPs to reinforce advice on diet, exercise and other associated risk factors such as smoking. Monitoring and reiterating the importance of compliance with prescribed medications is something that optometrists should include as part of their routine care of patients with diabetes, he stated. Routine eye reports to GPs, endocrinologists, and other related health professionals are also vitally important and influential in enhancing the outcome for patients with diabetes.
Predicting risk in diabetes
Outlining the numerous mechanisms of vision loss in diabetic retinopathy, Dr Groeneveld explained that the mechanisms primarily relate to sequelae of retinal ischemia and macular oedema (primary or secondary to cataract surgery). Other causes were also discussed, including vitreous hemorrhages, epiretinal membranes, retinal detachment and neovascular glaucoma (less common in diabetes compared to CRVO), cataract, and peripheral vision loss caused by laser treatment. Laser treatment can also increase the risk of rhegmatogenous retinal detachments.
Dr Groeneveld said the mainstay treatment for proliferative diabetic retinopathy is laser therapy, anti-VEGF treatment through intraocular injections and less commonly, vitrectomy. For diabetic macular oedema, treatment options consist of corticosteroids, laser treatment and anti-VEGF intraocular injections. This is particularly important for phakic patients as treatment with corticosteroids is contraindicated due to the risk of development of lens opacities. However, Dr Groeneveld noted that no treatment method is without risk, and explained that the reported risk of infection for intraocular injections is approximately one in 4,000 to one in 5,000 patients.
Professor Jonathan Shaw, Deputy Director at Melbourne’s Baker Heart and Diabetes Institute, articulated the need to find better ways of predicting risk of complications for people living with diabetes. He stated that as a leading cause of vision loss in working-age people, diabetic retinopathy imposes a great burden on individuals affected and the healthcare system.
Delegates were given an overview of PREDICT, the major new study Prof Shaw is currently undertaking which aims to find ways of predicting and identifying those who will develop complications associated with diabetes. The study will look at new mechanisms of predicting risk to inform new treatments.
Prof Shaw explained that a multifaceted approach was required to link and understand biological, behavioural and psychological factors, as well as the clinical risk factors Dr Groeneveld had discussed in detail. The study is currently seeking 2,500 participants with diabetes in metropolitan Melbourne who will undergo comprehensive diabetic assessments, including blood and urine tests, heart scans, comprehensive eye examination including OCT, tests of memory and mental agility, and tests of physical function.
Challenges in patient engagement
Taryn Black, Director of Policy and Programs for Diabetes Australia, brought to life the challenges that exist regarding patient engagement in eye care in her presentation on the importance of regular eye screening and early detection, and the treatment of diabetes-related eye disease. She noted that an estimated 50% of people with diabetes are not getting the recommended eye tests, and shared the alarming finding from a national survey conducted in 2018 that 64% of people with diabetes are not aware that diabetes can affect the eyes.
Accessibility, lack of understanding, confusion about the process, fear and mental illness were listed as factors contributing to a lack of engagement and compliance for patients living with diabetes. Taryn added that this could be perpetuated by ineffective communication between optometrists and GPs. She alluded to frequent use of fear-based messaging and overuse of technical terminology as alienating the general population.
During her presentation, Taryn’s colleague spoke powerfully from the perspective of a person living with diabetes. She said that providing clear explanations of clinical tests and using simple terminology were effective techniques to ensure patients developed trust in optometrists and took away with them the important information about their condition and the things they could do to prevent vision loss. She added that empowering patients to self-manage through positive reinforcement was more effective for promoting compliance than blaming or shaming them. She also reiterated the importance of communicating a clear management plan and involving GPs and other healthcare professionals for better patient outcomes.
- Hodapp, E., Parrish, R., & Anderson, D. (1993). Clinical decisions in glaucoma. St. Louis (Mo.): Mosby.
- World Health Organization. International Classification of Diseases: http://www.who.int/classifications/icd/en/
- Tran, T. (2018). Glaucoma: Review of referral pathway, case reviews, OCT overview. Presentation, 7th Specsavers Clinical Conference.
- Liu, Y., Simavli, H., Que, C., Rizzo, J., Tsikata, E., Maurer, R., & Chen, T. (2015). Patient Characteristics Associated With Artifacts in Spectralis Optical Coherence Tomography Imaging of the Retinal Nerve Fiber Layer in Glaucoma. American Journal Of Ophthalmology, 159(3), 565-576.e2. doi: 10.1016/j.ajo.2014.12.006
- Groeneveld, E. (2018). Guidelines for detection and management of diabetic eye disease. Presentation, 7th Specsavers Clinical Conference.