BackgroundVisual field (VF) tests are the benchmark for detecting and monitoring the eye disease glaucoma. Measurements from VF tests are variable, which means that frequent monitoring, perhaps over a long period of time, is required to accurately detect true glaucomatous progression. In 2009, guidelines for the diagnosis and management of glaucoma issued by the National Institute for Health and Care Excellence revealed an absence of research evidence about the clinical effectiveness and cost-effectiveness of using different monitoring intervals to detect disease progression. However, the European Glaucoma Society (EGS) guidelines on patient examination recommend that newly diagnosed glaucoma patients should undergo VF testing three times per year in the first 2 years after initial diagnosis.ObjectivesThe primary objective of this project was to explore the clinical effectiveness and cost-effectiveness of using different monitoring intervals to detect VF progression in newly diagnosed glaucoma patients. Other objectives sought to (1) explore glaucoma patients’ views and experiences of monitoring using focus groups; and (2) establish glaucoma subspecialists’ attitudes regarding frequency of VF testing using a five-item questionnaire.DesignThese questions were investigated using a multicentre audit of current practice and existing NHS data (VF records from almost 90,000 patients). New research knowledge was provided through statistical and health economic modelling of these and additional published data.ResultsThe multicentre audit showed that VF monitoring is, on average, carried out annually. Patient focus groups indicated that, although patients do not like VF testing, they accept it as a critical part of their care. Patients raised concerns regarding distracting testing environments, quality of instructions, explanation of results and excessive waiting times. Questionnaires revealed that clinicians’ attitudes towards the frequency of VF testing varied considerably, and many glaucoma specialists believed that current recommendations are impractical. Statistical modelling suggested that EGS recommendations could be clinically effective as progression can be identified sooner than is possible with annual testing. Health economic modelling suggested that increased VF monitoring may also be cost-effective [incremental cost-effectiveness ratio (ICER) was equal to £21,679].ConclusionsStatistical modelling of VF data suggests there is strong rationale for following EGS recommendations with the primary benefit of providing better information about fast-progressing patients. Our health economic model suggested that increasing VF testingmaybe cost-effective (ICER was equal to £21,679), especially when accounting for gains to society. Nevertheless, many clinicians consider increased VF testing of patients impossible with current resources. In addition, patient focus groups raised concerns about the practicalities of delivery of VF tests.Future workResults from this study could inform the design of a prospective randomised comparative trial of different VF monitoring intervals in glaucoma linked to stratifying patients according to risk factors for progression. The statistical model for VF data can be further developed to be used as a practical tool for optimising individualised follow-up. The views of clinicians and patients indicate that service delivery of VF testing is an important issue and worthy of further investigation. Ensuring the confidence and co-operation of the patient should be at the centre of future research into the most efficient strategies for glaucoma monitoring.FundingThis work was funded by the National Institute for Health Research Health Services and Delivery Research programme.
BackgroundChronic open angle glaucoma (COAG) is an age-related eye disease causing irreversible loss of visual field (VF). Health service delivery for COAG is challenging given the large number of diagnosed patients requiring lifelong periodic monitoring by hospital eye services. Yet frequent examination better determines disease worsening and speed of VF loss under treatment. We examine the cost-effectiveness of increasing frequency of VF examinations during follow-up using a health economic model.MethodsTwo different VF monitoring schemes defined as current practice (annual VF testing) and proposed practice (three VF tests per year in the first 2 years after diagnosis) were examined. A purpose written health economic Markov model is used to test the hypothesis that cost effectiveness improves by implementing proposed practice on groups of patients stratified by age and severity of COAG. Further, a new component of the model, estimating costs of visual impairment, was added. Results were derived from a simulated cohort of 10000 patients with quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) used as main outcome measures.ResultsAn ICER of £21,392 per QALY was derived for proposed practice improving to a value of £11,382 once savings for prevented visual impairment was added to the model. Proposed practice was more cost-effective in younger patients. Proposed practice for patients with advanced disease at diagnosis generated ICERs > £60,000 per QALY; these cases would likely be on the most intensive treatment pathway making clinical information on speed of VF loss redundant. Sensitivity analysis indicated results to be robust in relation to hypothetical willingness to pay threshold identified by national guidelines, although greatest uncertainty was allied to estimates of implementation and visual impairment costs.ConclusionIncreasing VF monitoring at the earliest stages of follow-up for COAG appears to be cost-effective depending on reasonable assumptions about implementation costs. Our health economic model highlights benefits of stratifying patients to more or less monitoring based on age and stage of disease at diagnosis; a prospective study is needed to prove these findings. Further, this works highlights gaps in knowledge about long term costs of visual impairment.
Purpose To examine changes in rates of visual field (VF) progression in patients attending a sample of glaucoma clinics in England between 1999 and 2012. Methods An archive of 473 252 Humphrey VFs recorded across the UK was retrospectively examined. Distribution of rates recorded in the first half of the decade was compared with the second. The relationship between age and severity of MD loss at baseline with rates of loss and frequency of testing was examined. Results VF series from 18 926 eyes were analysed. Median rate of MD loss for the period before and after 2003 was − 0.11 and − 0.06 dB/year, respectively, but the proportion of eyes with medium or fast rates of MD loss remained constant. Median rate of MD loss in older (470 years) eyes was faster than that observed in younger (o60 years) eyes (−0.21 compared with − 0.01 dB/ year). Median rate of loss did not vary with severity of MD loss at baseline. Frequency of testing, typically carried out annually, did not vary by age, rate of loss or disease severity. Conclusions VFs of eyes treated in the first half of the decade deteriorated more rapidly than those in the second half. Several factors might explain these differences but average effects were small and there was no reduction in the proportion of rapidly progressing eyes over the decade. Older age and, to a lesser extent, worse VF damage at diagnosis are indicators for faster VF loss in clinics, but frequency of VF testing was similar for all patients.
Severity of vision loss at the point of glaucoma detection, in those patients diagnosed with a VF defect, is improving over time in England. Nevertheless, the improvement is modest and large numbers of patients still present at glaucoma clinics with significant vision loss in at least one eye. Large scale digital VF data can be used to help monitor and audit health service delivery of glaucoma.
Background/aimsTo determine whether self-reported illness perceptions in newly diagnosed patients with primary open-angle glaucoma (POAG) and ocular hypertension (OHT) are more negative compared with peers who have lived with their diagnosis for more than 2 years.MethodsA cross-sectional study of 58 newly diagnosed patients with POAG and OHT recruited at their first clinic visit. Electronic patient records were used to identify similar patients (n=58, related by age and severity of visual field loss) who had their diagnosis for >2 years. All participants completed the Brief Illness Perception Questionnaire (BIPQ), EQ5D general health measure and Type D Personality Scale (DS14).ResultsAverage BIPQ scores were similar for people newly diagnosed with POAG and POAG diagnosed >2 years and were no different to newly diagnosed OHT and OHT diagnosed >2 years POAG (p=0.46). An analysis correcting for personality type (DS14) and general health (EQ5D) indicated newly diagnosed patients with POAG to have marginally better illness perceptions on individual BIPQ items quantifying impact on life in general, experience of symptoms and ‘understanding’ of their condition (all p<0.01). In contrast, patients with POAG with a diagnosis >2 years understood better their condition to be long-term (p<0.01).ConclusionsSome illness perceptions differed between newly diagnosed people and patients living with their diagnosis for >2 years. Illness perception for people with manifest glaucoma and at risk of glaucoma (OHT) were similar; the latter might benefit from an intervention at diagnosis that highlights the better prognosis for OHT compared with POAG.
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