Frequency of visual field testing when monitoring patients newly diagnosed with glaucoma: mixed methods and modelling

Abstract

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.

Visual Field Progression in Childhood Glaucoma Versus Open-Angle Glaucoma: A Retrospective Comparative Study

“…Structural assessment with OCT, particularly RNFL thickness, is increasingly used to complement functional testing in glaucoma progression [1][2][3][4]9,10]. In our study, RNFL thickness remained stable in both groups, supporting the notion that structural and functional stability can be achieved with appropriate management [2].…”

“…Several studies emphasize that the frequency and duration of visual field testing are critical for detecting progression, especially in pediatric patients where cooperation and test reliability may vary over time [7,8,10,15]. Recent advances in artificial intelligence and machine learning are beginning to aid in the early detection of rapid progressors, which may further improve outcomes in both pediatric and adult populations [9,14].…”

Visual Field Progression in Childhood Glaucoma Versus Open-Angle Glaucoma: A Retrospective Comparative Study

“…Structural assessment with OCT, particularly RNFL thickness, is increasingly used to complement functional testing in glaucoma progression [1][2][3][4]9,10]. In our study, RNFL thickness remained stable in both groups, supporting the notion that structural and functional stability can be achieved with appropriate management [2].…”

“…Several studies emphasize that the frequency and duration of visual field testing are critical for detecting progression, especially in pediatric patients where cooperation and test reliability may vary over time [7,8,10,15]. Recent advances in artificial intelligence and machine learning are beginning to aid in the early detection of rapid progressors, which may further improve outcomes in both pediatric and adult populations [9,14].…”

Association Between Rate of Ganglion Cell Complex Thinning and Rate of Central Visual Field Loss

“…A key limitation of VF testing is the high test variability, which can make it difficult to detect true change over time . High variability can result in missed or delayed identification of glaucomatous progression, delayed interventions, and worse visual outcomes . In contrast to VF testing, macular OCT has excellent reproducibility and less variability over time .…”

Predicting the Extent of Damage in the Humphrey Field Analyzer 24-2 Visual Fields Using 10-2 Test Results in Patients With Advanced Glaucoma

“… 4 , 5 However, it may be difficult to measure both HFA 10-2 and 24-2 VFs a sufficient number of times in general clinical practice. 6 – 8 Supporting this, in our prior study, a non-negligible proportion (17.3%) of eyes showed further progression of the VF deterioration with the HFA 24-2 test, compared to 26.9% with the HFA 10-2 test. 9 Moreover, significant risk factors for the progression of HFA 24-2 test were identified in our prior study.…”

Visual Field Progression in Childhood Glaucoma Versus Open-Angle Glaucoma: A Retrospective Comparative Study

“…Structural assessment with OCT, particularly RNFL thickness, is increasingly used to complement functional testing in glaucoma progression [1][2][3][4]9,10]. In our study, RNFL thickness remained stable in both groups, supporting the notion that structural and functional stability can be achieved with appropriate management [2].…”

“…Several studies emphasize that the frequency and duration of visual field testing are critical for detecting progression, especially in pediatric patients where cooperation and test reliability may vary over time [7,8,10,15]. Recent advances in artificial intelligence and machine learning are beginning to aid in the early detection of rapid progressors, which may further improve outcomes in both pediatric and adult populations [9,14].…”

Association Between Rate of Ganglion Cell Complex Thinning and Rate of Central Visual Field Loss

“…A key limitation of VF testing is the high test variability, which can make it difficult to detect true change over time . High variability can result in missed or delayed identification of glaucomatous progression, delayed interventions, and worse visual outcomes . In contrast to VF testing, macular OCT has excellent reproducibility and less variability over time .…”

Predicting the Extent of Damage in the Humphrey Field Analyzer 24-2 Visual Fields Using 10-2 Test Results in Patients With Advanced Glaucoma

“… 4 , 5 However, it may be difficult to measure both HFA 10-2 and 24-2 VFs a sufficient number of times in general clinical practice. 6 – 8 Supporting this, in our prior study, a non-negligible proportion (17.3%) of eyes showed further progression of the VF deterioration with the HFA 24-2 test, compared to 26.9% with the HFA 10-2 test. 9 Moreover, significant risk factors for the progression of HFA 24-2 test were identified in our prior study.…”

Visual Field Progression in Childhood Glaucoma Versus Open-Angle Glaucoma: A Retrospective Comparative Study

“…Structural assessment with OCT, particularly RNFL thickness, is increasingly used to complement functional testing in glaucoma progression [1][2][3][4]9,10]. In our study, RNFL thickness remained stable in both groups, supporting the notion that structural and functional stability can be achieved with appropriate management [2].…”

“…Several studies emphasize that the frequency and duration of visual field testing are critical for detecting progression, especially in pediatric patients where cooperation and test reliability may vary over time [7,8,10,15]. Recent advances in artificial intelligence and machine learning are beginning to aid in the early detection of rapid progressors, which may further improve outcomes in both pediatric and adult populations [9,14].…”

Association Between Rate of Ganglion Cell Complex Thinning and Rate of Central Visual Field Loss

“…A key limitation of VF testing is the high test variability, which can make it difficult to detect true change over time . High variability can result in missed or delayed identification of glaucomatous progression, delayed interventions, and worse visual outcomes . In contrast to VF testing, macular OCT has excellent reproducibility and less variability over time .…”

Predicting the Extent of Damage in the Humphrey Field Analyzer 24-2 Visual Fields Using 10-2 Test Results in Patients With Advanced Glaucoma

“… 4 , 5 However, it may be difficult to measure both HFA 10-2 and 24-2 VFs a sufficient number of times in general clinical practice. 6 – 8 Supporting this, in our prior study, a non-negligible proportion (17.3%) of eyes showed further progression of the VF deterioration with the HFA 24-2 test, compared to 26.9% with the HFA 10-2 test. 9 Moreover, significant risk factors for the progression of HFA 24-2 test were identified in our prior study.…”