More frequent, more costly? Health economic modelling aspects of monitoring glaucoma patients in England

Systematic methodological review of health state values in glaucoma cost-utility analyses

IMPORTANCE

Describing the characteristics and sources of health state utility values and reporting practice in the literature of cost-utility analyses facilitates an understanding of the level of the transparency, validity, and generalizability of cost-utility analyses. Improving the quality of reporting will support investigators in describing the incremental value of emerging glaucoma interventions.

OBJECTIVE

To describe the state of practice among published glaucoma cost-utility analysis studies, focusing on valuation of health and the quality of reporting.

EVIDENCE REVIEW

We searched several databases including Medline, CINHAL, Embase, Web of Science, Scopus, Biosis previews, the Health Economic Evaluations Database, and the NHS Economic Evaluation Database (NHS EED). We included full-text, English, published cost-utility analyses of glaucoma interventions with quality-adjusted life years (QALYs) as the primary outcome measure to calculate incremental cost-utility ratios. Excluded studies were non-English language, reviews, editorials, protocols, or other types of economic studies (cost-benefit, cost-minimization, cost-effectiveness). Study characteristics, operational definitions of glaucoma health states and health state utilities were extracted. The original source of the health utility was reviewed to determine the scale of measurement and the source of preference weighting. Items from the Systematic Review of Utilities for Cost-Effectiveness (SpRUCE checklist) were used to assess the reporting and quality of health utilities in glaucoma CUA.

FINDINGS

43 CUAs were included, with 11 unique sources of health utilities. A wide range of health utilities for the same Hodapp-Parrish-Anderson glaucoma health states were reported; ocular hypertension (0.84-0.95), mild (0.68-0.94), moderate (0.57-0.92), advanced (0.58-0.88), severe/blind (0.46-0.76), and bilateral blindness (0.26-0.5). Most studies reported the basis for using health utilities (34, 79%) and any assumptions or adjustments applied to the health utilities (22, 51%). Few studies reported a framework for assessing the relevance of health utilities to a decision context (8, 19%). Even fewer (3, 7%) applied a systematic search strategy to identify health utilities and used a structured assessment of quality for inclusion. Overall, reporting has not improved over time.

CONCLUSIONS AND RELEVANCE

This review describes that few CUAs describe important rationale for using health state utility values. Including additional details on the search, appraisal, selection, and inclusion process of health utility values improves transparency, generalizability and supports the assessment of the validity of study conclusions. Future investigations should aim to use health utilities on the same scale of measurement across health states and consider the source and relevance to the decision context/purpose of conducting that cost-utility study.

Feasibility of in-home monitoring for people with glaucoma: the I-TRAC mixed-methods study

Background

Glaucoma is a chronic disease of the optic nerve and a leading cause of severe visual loss in the UK. Once patients have been diagnosed, they need regular monitoring at hospital eye services. Recent advances in technology mean patients with glaucoma can now monitor their disease at home. This could be more convenient for patients and potentially reduce costs and increase capacity for the NHS. However, it is uncertain whether self-monitoring would be acceptable or possible for patients with glaucoma.

Objectives

The objectives were to: identify which patients are most appropriate for home monitoring; understand views of key stakeholders (patients, clinicians, researchers) on whether home glaucoma monitoring is feasible and acceptable; develop a conceptual framework for the economic evaluation of home glaucoma monitoring; and explore the need for and provide evidence on the design of a future study to evaluate the clinical and cost-effectiveness of digital technologies for home monitoring of glaucoma.

Design

In-home Tracking of glaucoma: Reliability, Acceptability, and Cost (I-TRAC) was a multiphase mixed-methods feasibility study with key components informed by theoretical and conceptual frameworks.

Setting

Expert glaucoma specialists in the UK recruited through professional glaucoma societies; study site staff and patient participants recruited through three UK hospital eye services (England, Scotland, Northern Ireland); and UK research teams recruited though existing networks.

Intervention

Home tonometer that measures intraocular pressure and a tablet computer with a visual function application. Patients were asked to use the technology weekly for 12 weeks.

Results

Forty-two patients were recruited. Retention and completion of follow-up procedures was successful, with 95% (n = 40) completing the 3-month follow-up clinic visits. Adherence to the interventions was generally high [adherence to both devices (i.e. ≥ 80% adherence) was 55%]. Overall, patients and healthcare professionals were cautiously optimistic about the acceptability of digital technologies for home monitoring of patients with glaucoma. While most clinicians were supportive of the potential advantages glaucoma home monitoring could offer, concerns about the technologies (e.g. reliability and potential to miss disease progression) and how they would fit into routine care need to be addressed. Additionally, clarity is required on defining the ideal population for this intervention. Plans for how to evaluate value for money in a future study were also identified. However, the study also highlighted several unknowns relating to core components of a future evaluative study that require addressing before progression to a definitive effectiveness trial.

Limitations

The main limitation relates to our sample and its generalisability, for example, the over-representation of educated persons of white ethnicity who were generally experienced with technology and research motivated.

Conclusions

The In-home Tracking of glaucoma: Reliability, Acceptability, and Cost study has demonstrated 'cautious optimism' when considering patients' and healthcare professionals' views on the acceptability of digital technologies for home monitoring of patients with glaucoma. However, the study also highlighted several unknowns relating to the research question and design of a future evaluative study that require addressing before progression to a randomised controlled trial.

Future work

Further research is required to determine the appropriate population (i.e. low vs. high risk of progression) and further refine the intervention components and delivery for planning of future evaluation studies.

Study registration

This study is registered as Research Registry #6213.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR129248) and is published in full in Health Technology Assessment; Vol. 28, No. 44. See the NIHR Funding and Awards website for further award information.

Glaucoma Home Self-Testing Using VR Visual Fields and Rebound Tonometry Versus In-Clinic Perimetry and Goldmann Applanation Tonometry: A Pilot Study

Purpose

This pilot study aimed to assess the feasibility, accuracy, and repeatability of unsupervised, at-home, multi-day glaucoma testing using the Olleyes VisuALL Virtual Reality Platform (VRP) and the iCare HOME handheld self-tonometer.

Methods

Participants were trained to use two U.S. Food and Drug Administration-registered or approved devices before conducting self-tests at home over 3 consecutive days. The iCare HOME intraocular pressure (IOP) measurements were collected four times daily per eye, and VRP visual field tests were performed once daily. The results were compared with one in-clinic Humphrey Field Analyzer (HFA) visual field test performed on the day of device training, iCare HOME measurements by the trainer, and the last five Goldmann applanation tonometer (GAT) results.

Results

Of 15 enrolled participants, nine of them (60%) completed the study. The six excluded participants could not self-measure using iCare HOME. There was significant correlation between the average mean deviation (MD) values of the at-home VRP tests and in-clinic HFA test (r2 = 0.8793, P < 0.001). Additionally, the average of the sensitivities in five of six Garway-Heath sectors were significantly correlated. VRP test duration was also shorter than in-clinic HFA testing (P < 0.001). Finally, at-home tonometry yielded statistically similar values compared to trainer-obtained iCare HOME values. The mean and range of at-home tonometry were also statistically similar to those for in-clinic GAT, but at-home tonometry demonstrated higher maximum IOP values (P = 0.0429).

Conclusions

Unsupervised, at-home, multi-day glaucoma testing using two devices resulted in the capture of higher maximum IOPs than in the clinic and good MD correlation of VRP with HFA. However, 40% of participants could not self-measure IOP using iCare HOME.

Translational Relevance

The study findings suggest that at-home remote glaucoma monitoring correlates with in-office testing and could provide additional information for glaucoma management, although patients had more difficulty with the iCare HOME than the VRP.

The utilization of artificial intelligence in glaucoma: diagnosis versus screening

With advancements in the implementation of artificial intelligence (AI) in different ophthalmology disciplines, it continues to have a significant impact on glaucoma diagnosis and screening. This article explores the distinct roles of AI in specialized ophthalmology clinics and general practice, highlighting the critical balance between sensitivity and specificity in diagnostic and screening models. Screening models prioritize sensitivity to detect potential glaucoma cases efficiently, while diagnostic models emphasize specificity to confirm disease with high accuracy. AI applications, primarily using machine learning (ML) and deep learning (DL), have been successful in detecting glaucomatous optic neuropathy from colored fundus photographs and other retinal imaging modalities. Diagnostic models integrate data extracted from various forms of modalities (including tests that assess structural optic nerve damage as well as those evaluating functional damage) to provide a more nuanced, accurate and thorough approach to diagnosing glaucoma. As AI continues to evolve, the collaboration between technology and clinical expertise should focus more on improving specificity of glaucoma diagnostic models to assess ophthalmologists to revolutionize glaucoma diagnosis and improve patients care.

Online Circular Contrast Perimetry via a Web-Application: Establishing a Normative Database for Central 10-Degree Perimetry

Purpose

To establish a normative database using a central 10-degree grid pattern for the online circular contrast perimetry (OCCP) application.

Participants

Fifty participants with mean age 65 ± 13 years were selected for this study. One eye from each participant that met inclusion criteria was randomly included in the cohort.

Methods

The web-application delivered online 52-loci perimetry in a central 10-degree pattern using circular flickering targets. These targets consist of concentric sinusoidal alternating contrast rings. Users were guided by the application to the correct viewing distance and head position using in-built blind spot localization and webcam monitoring. A spinning golden star was used as the fixation target and patients performed the test in a darkened room following standard automated perimetry (SAP).

Results

The reliability rates and global indices for OCCP were similar to SAP. OCCP mean sensitivity reduced with age at a similar rate to SAP. Mean sensitivity per loci of 10-degree OCCP was greater than SAP by 1.24 log units (95% CI 1.23 to 1.26) and obeyed a physiological hill of vision. Small differences existed in mean sensitivities between OCCP and SAP which increased with increasing spot eccentricity. Mean deviation (MD) displayed good agreement between the two tests.

Conclusion

Central 10-degree online circular contrast perimetry via a computer-based application has comparable perimetric results to standard automated perimetry in a normal cohort.

Burden of Glaucoma in the United Kingdom: A Multicenter Analysis of United Kingdom Glaucoma Services

OBJECTIVE

To determine the spectrum of glaucoma-associated health care resource utilization among outpatients attending National Health Service (NHS) hospital glaucoma clinics and the costs of managing glaucoma in this setting.

DESIGN

Retrospective observational cohort study using electronic medical record data.

SUBJECTS

Patients aged ≥ 18 years attending 5 NHS glaucoma clinics in the United Kingdom (2013‒2018) with ≥ 12 months of continuous electronic medical record data.

METHODS

Deidentified Medisoft Ophthalmology electronic medical record data (January 2013‒December 2018) from 43 742 eligible patients were categorized by year of clinic visit. Extracted information included patient demographics, glaucoma diagnoses, topical glaucoma medication prescription start/stop dates, types/numbers of glaucoma clinic visits, glaucoma investigations (visual acuity, intraocular pressure, visual field, and OCT), and glaucoma procedures received over 12 months after the first ("index") visit of the specified year. Direct glaucoma-related health care costs (clinic visits, investigations, procedures, and ongoing glaucoma medication initiated in the clinic) were estimated from event volumes and unit costs (UK national tariffs) and expressed from the direct-payer perspective.

MAIN OUTCOME MEASURES

Glaucoma diagnoses and topical glaucoma medication use at the index clinic visit; numbers of glaucoma clinic visits, investigations and procedures; and glaucoma-related health care costs over 12 months postindex.

RESULTS

For the 2016 cohort (n = 21 719), the estimated average total cost of NHS-provided glaucoma care over 12 months was £405 per patient (medical staff services £209, glaucoma investigations £126, glaucoma medication £40, glaucoma procedures £26). Among this cohort, 40.8% had ocular hypertension/suspected glaucoma, 70% had 0-to-mild visual field impairment, and 14% had undergone a glaucoma procedure. Over 12 months, patients received (mean) 2.0 glaucoma clinic visits and 1.5 visual field tests, and 7% underwent glaucoma procedure(s). Results were similar for the other years examined.

CONCLUSIONS

Cost estimates for managing patients with glaucoma in the UK are required for effective service planning. Appreciable proportions of patients managed in NHS glaucoma clinics may be considered at low risk of blindness (glaucoma suspects and those with ocular hypertension with mild visual field loss) and may be more appropriately managed with alternative, more affordable models of care.

Effect of Testing Frequency on the Time to Detect Glaucoma Progression With Optical Coherence Tomography (OCT) and OCT Angiography

PURPOSE

To determine how the frequency of testing affects the time required to detect statistically significant glaucoma progression for circumpapillary retinal nerve fiber layer (cpRNFL) with optical coherence tomography (OCT) and circumpapillary capillary density (cpCD) with OCT angiography (OCTA).

DESIGN

Retrospective, observational cohort study.

METHODS

In this longitudinal study, 156 eyes of 98 patients with glaucoma followed up over an average of 3.5 years were enrolled. Participants with 4 or more OCT and OCTA tests were included to measure the longitudinal rates of cpRNFL thickness and cpCD change over time using linear regression. Estimates of variability were then used to re-create real-world cpRNFL and cpCD data by computer simulation to evaluate the time required to detect progression for various loss rates and different testing frequencies.

RESULTS

The time required to detect a statistically significant negative cpRNFL and cpCD slope decreased as the testing frequency increased, albeit not proportionally. cpCD detected progression slightly earlier than cpRNFL. Eighty percent of eyes with a cpCD loss of -1%/y were detected after 6.0, 4.2, and 4 years when testing was performed 1, 2, and 3 times per year, respectively. Progression in 80% of eyes with a cpRNFL loss of -1 µm/y was detected after 6.3, 5.0, and 4.2 years, respectively.

CONCLUSIONS

cpRNFL and cpCD are comparable in detecting progression. As there were only small changes in the time to detect progression when testing increased from 2 to 3 times per year, testing twice per year may provide sufficient information for detecting progression with either OCT or OCTA in clinical settings.

Impact of Smoking on Visual Field Progression in a Long-term Clinical Follow-up

PURPOSE

To investigate the effect of smoking on rates of progressive visual field (VF) damage over time in glaucoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Five hundred eleven eyes of 354 patients with glaucoma followed up from multicenter glaucoma registries.

METHODS

In this longitudinal study, 354 patients with primary open-angle glaucoma with a minimum of 3 years of follow-up and 5 VF tests were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Univariate and multivariate linear mixed models were used to investigate the effects of smoking on rates of 24-2 VF mean deviation loss. Visual field progression was defined using pointwise linear and significant negative VF mean deviation loss. Logistic regression was used to identify baseline factors and whether different levels of smoking intensity were associated with VF progression. Kaplan-Meier survival analysis and the log-rank test were used to compare the cumulative risk ratio of progression between smoker and never smoker groups.

MAIN OUTCOME MEASURES

Visual field progression.

RESULTS

Five hundred eleven eyes of 354 patients were included over the median follow-up of 12.5 years. Median baseline age was 64.8 years. Of the 354 patients, 124 (35%) were Black, and 149 (42.1%) and 168 (59.8%) had reported a history of smoking or alcohol consumption, respectively. In a multivariate model, higher smoking intensity was associated with faster VF loss (coefficient, -0.05 decibels (dB)/year per 10 pack-years; 95% confidence interval [CI], -0.08 to -0.01 dB/year per 10 pack-years; P = 0.010). Developing VF progression in eyes of heavy smokers (≥ 20 pack-years) was 2.2 times more than in eyes of patients without smoking history (odds ratio, 2.21; 95% CI, 1.02-4.76; P = 0.044). Statistically significant differences were found between heavy smokers (≥ 20 pack-years) and never smokers by Kaplan-Meier analysis (P = 0.011, log-rank test).

CONCLUSIONS

Heavy smokers are more likely to sustain VF loss in eyes with glaucoma. The prospective longitudinal design of this study supports the hypothesis that levels of smoking may be a significant predictor for glaucoma progression. Additionally, this information can be used for clinically relevant tobacco prevention and intervention messages.

Patients' Views of Visual Field Testing and Priorities for Research Development and Translation into Practice

PURPOSE

Information regarding the views of patients, on visual field testing is limited, and no information exists regarding their preferences for test developments. This study aimed to increase knowledge of patients' experiences of visual field assessment and to explore their opinions and priorities regarding current areas of research and development.

DESIGN

Online questionnaire with purposive sampling design.

PARTICIPANTS

Adults who regularly undergo visual field tests in Australia who report having glaucoma or being at glaucomatous risk.

METHODS

An anonymous survey, implemented using the Qualtrics webtool, with both closed- and-open ended questions designed to explore opinions regarding visual field testing, visit attendance for perimetry, as well as priorities for developments.

MAIN OUTCOME MEASURES

The survey assessed 3 domains: (1) opinions regarding test duration and visit frequency, (2) subjective experience, and (3) perspectives on future developments.

RESULTS

One hundred fifty-two complete survey responses were obtained. The median age of participants was 66 years (interquartile range [IQR], 60-72 years). Most participants (70%) had experience of undergoing more than 11 visual field tests. Participants recalled that they completed visual field tests in median of 6 minutes (IQR, 5-8 minutes) and were willing to accept additional time (median, 5 minutes; IQR, 3-6 minutes) to obtain more information. Participants were prepared to increase both the number of visual field tests per eye and the frequency of visual field tests (median, 3 visits per year; IQR, 2-4 visits per year) to gain more information about their visual status. Regarding future developments, the most preferred option was "similar test times but an increase in the level of information about my visual field," which ranked significantly higher than all other options, including "shorter test times that maintain the currently available level of information about my visual field."

CONCLUSIONS

Our study confirms, in a different population and health care system, previous research reporting patient perspectives on visual field assessment. We further revealed that health care consumers show a strong preference for accurate information about their vision and report being prepared to undergo longer visual field tests or more visual field tests to achieve that outcome.

The Effect of Transitioning from SITA Standard to SITA Faster on Visual Field Performance

PURPOSE

To determine the effect of transitioning from Swedish Interactive Thresholding Algorithm (SITA) Standard to SITA Faster on visual field (VF) performance in glaucomatous eyes with a broad spectrum of disease severity undergoing longitudinal VF testing in a real-world clinical setting.

DESIGN

Retrospective, longitudinal study.

PARTICIPANTS

A total of 421 patients (766 eyes) with manifest or suspect glaucoma followed at a single institution.

METHODS

Each included eye received the following sequence of VF examinations during routine clinical care: (1) SITA Standard, (2) SITA Standard, and (3) SITA Faster (mean time between tests = 13.9 months). Intra-eye comparisons were made between the first 2 VFs (Standard-Standard sequence) and the last 2 VFs (Standard-Faster sequence). The primary dependent variable was the difference in mean deviation (MD) between the second and first VF of the sequence (ΔMD, calculated as MDVF2 - MDVF1). The primary independent variable was the VF sequence (Standard-Standard or Standard-Faster). Linear mixed-effects models were used to study the effect of testing sequence on ΔMD, adjusting for confounders including time between VFs and change in false-positive (FP) errors. Results were stratified to understand the effect of glaucoma severity on the relationship between testing sequence and ΔMD.

MAIN OUTCOME MEASURES

The difference in ΔMD between Standard-Standard and Standard-Faster sequence by mild, moderate, and advanced disease severity.

RESULTS

In eyes with mild or suspect glaucoma, there was no significant difference in ΔMD between Standard-Faster and Standard-Standard sequences (-0.23 decibels [dB]; 95% confidence interval [CI], -0.60 to 0.15 dB). However, the Standard-Faster sequence was associated with a 0.87 dB (95% CI, 0.18-1.57 dB) improvement in ΔMD compared with the Standard-Standard sequence in eyes with moderate glaucoma and a 1.49 dB (95% CI, 0.79-2.19 dB) improvement in ΔMD in eyes with advanced glaucoma.

CONCLUSIONS

Converting to SITA Faster in eyes that were previously followed with SITA Standard led to similar VF performance in mild glaucoma but resulted in higher MD values in moderate and advanced glaucoma. For patients with moderate or severe glaucoma, this may conceal disease progression when transitioning testing strategies.

Acceptability of a home-based visual field test (Eyecatcher) for glaucoma home monitoring: a qualitative study of patients' views and experiences

OBJECTIVES

To explore the acceptability of home visual field (VF) testing using Eyecatcher among people with glaucoma participating in a 6-month home monitoring pilot study.

DESIGN

Qualitative study using face-to-face semistructured interviews. Transcripts were analysed using thematic analysis.

SETTING

Participants were recruited in the UK through an advertisement in the International Glaucoma Association (now Glaucoma UK) newsletter.

PARTICIPANTS

Twenty adults (10 women; median age: 71 years) with a diagnosis of glaucoma were recruited (including open angle and normal tension glaucoma; mean deviation=2.5 to -29.9 dB).

RESULTS

All participants could successfully perform VF testing at home. Interview data were coded into four overarching themes regarding experiences of undertaking VF home monitoring and attitudes towards its wider implementation in healthcare: (1) comparisons between Eyecatcher and Humphrey Field Analyser (HFA); (2) capability using Eyecatcher; (3) practicalities for effective wider scale implementation; (4) motivations for home monitoring.

CONCLUSIONS

Participants identified a broad range of benefits to VF home monitoring and discussed areas for service improvement. Eyecatcher was compared positively with conventional VF testing using HFA. Home monitoring may be acceptable to at least a subset of people with glaucoma.

Glaucoma Home Monitoring Using a Tablet-Based Visual Field Test (Eyecatcher): An Assessment of Accuracy and Adherence Over 6 Months

Purpose

To assess accuracy and adherence of visual field (VF) home monitoring in a pilot sample of patients with glaucoma.

Design

Prospective longitudinal feasibility and reliability study.

Methods

Twenty adults (median 71 years) with an established diagnosis of glaucoma were issued a tablet perimeter (Eyecatcher) and were asked to perform 1 VF home assessment per eye, per month, for 6 months (12 tests total). Before and after home monitoring, 2 VF assessments were performed in clinic using standard automated perimetry (4 tests total, per eye).

Results

All 20 participants could perform monthly home monitoring, though 1 participant stopped after 4 months (adherence: 98% of tests). There was good concordance between VFs measured at home and in the clinic (r = 0.94, P < .001). In 21 of 236 tests (9%), mean deviation deviated by more than ±3 dB from the median. Many of these anomalous tests could be identified by applying machine learning techniques to recordings from the tablets' front-facing camera (area under the receiver operating characteristic curve = 0.78). Adding home-monitoring data to 2 standard automated perimetry tests made 6 months apart reduced measurement error (between-test measurement variability) in 97% of eyes, with mean absolute error more than halving in 90% of eyes. Median test duration was 4.5 minutes (quartiles: 3.9-5.2 minutes). Substantial variations in ambient illumination had no observable effect on VF measurements (r = 0.07, P = .320).

Conclusions

Home monitoring of VFs is viable for some patients and may provide clinically useful data.

Functional assessment of glaucoma: Uncovering progression

Clinicians who manage glaucoma patients carefully monitor the visual field to determine if treatments are effective or interventions are needed. Visual field tests may reflect disease progression or variability among examinations. We describe the approaches and perimetric tests used to evaluate glaucomatous visual field progression and factors that are important for identifying progression. These include stimulus size, which area of the visual field to assess (central versus peripheral), and the testing frequency, evaluating which is important to detect change early while minimizing patient testing burden. We also review the different statistical methods developed to identify change. These include trend- and event-based analyses, parametric and nonparametric tests, population-based versus individualized approaches, as well as pointwise and global analyses. We hope this information will prove useful and important to enhance the management of glaucoma patients. Overall, analysis procedures based on series of at least 5 to 6 examinations that require confirmation and persistence of changes, that are guided by the pattern and shape of the glaucomatous visual field deficits, and that are consistent with structural defects provide the best clinical performance.

Selective laser trabeculoplasty versus drops for newly diagnosed ocular hypertension and glaucoma: the LiGHT RCT

BACKGROUND

Newly diagnosed open-angle glaucoma (OAG) and ocular hypertension (OHT) are habitually treated with intraocular pressure (IOP)-lowering eyedrops. Selective laser trabeculoplasty (SLT) is a safe alternative to drops and is rarely used as first-line treatment.

OBJECTIVES

To compare health-related quality of life (HRQoL) in newly diagnosed, treatment-naive patients with OAG or OHT, treated with two treatment pathways: topical IOP-lowering medication from the outset (Medicine-1st) or primary SLT followed by topical medications as required (Laser-1st). We also compared the clinical effectiveness and cost-effectiveness of the two pathways.

DESIGN

A 36-month pragmatic, unmasked, multicentre randomised controlled trial.

SETTINGS

Six collaborating specialist glaucoma clinics across the UK.

PARTICIPANTS

Newly diagnosed patients with OAG or OHT in one or both eyes who were aged ≥ 18 years and able to provide informed consent and read and understand English. Patients needed to qualify for treatment, be able to perform a reliable visual field (VF) test and have visual acuity of at least 6 out of 36 in the study eye. Patients with VF loss mean deviation worse than -12 dB in the better eye or -15 dB in the worse eye were excluded. Patients were also excluded if they had congenital, early childhood or secondary glaucoma or ocular comorbidities; if they had any previous ocular surgery except phacoemulsification, at least 1 year prior to recruitment or any active treatment for ophthalmic conditions; if they were pregnant; or if they were unable to use topical medical therapy or had contraindications to SLT.

INTERVENTIONS

SLT according to a predefined protocol compared with IOP-lowering eyedrops, as per national guidelines.

MAIN OUTCOME MEASURES

The primary outcome was HRQoL at 3 years [as measured using the EuroQol-5 Dimensions, five-level version (EQ-5D-5L) questionnaire]. Secondary outcomes were cost and cost-effectiveness, disease-specific HRQoL, clinical effectiveness and safety.

RESULTS

Of the 718 patients enrolled, 356 were randomised to Laser-1st (initial SLT followed by routine medical treatment) and 362 to Medicine-1st (routine medical treatment only). A total of 652 (91%) patients returned the primary outcome questionnaire at 36 months. The EQ-5D-5L score was not significantly different between the two arms [adjusted mean difference (Laser-1st - Medicine-1st) 0.01, 95% confidence interval (CI) -0.01 to 0.03; p = 0.23] at 36 months. Over 36 months, the proportion of visits at which IOP was within the target range was higher in the Laser-1st arm (93.0%, 95% CI 91.9% to 94.0%) than in the Medicine-1st arm (91.3%, 95% CI 89.9% to 92.5%), with IOP-lowering glaucoma surgery required in 0 and 11 patients, respectively. There was a 97% probability of Laser-1st being more cost-effective than Medicine-1st for the NHS, at a willingness to pay for a quality-adjusted life-year of £20,000, with a reduction in ophthalmology costs of £458 per patient (95% of bootstrap iterations between -£585 and -£345).

LIMITATION

An unmasked design, although a limitation, was essential to capture any treatment effects on patients' perception. The EQ-5D-5L questionnaire is a generic tool used in multiple settings and may not have been the most sensitive tool to investigate HRQoL.

CONCLUSIONS

Compared with medication, SLT provided a stable, drop-free IOP control to 74.2% of patients for at least 3 years, with a reduced need for surgery, lower cost and comparable HRQoL. Based on the evidence, SLT seems to be the most cost-effective first-line treatment option for OAG and OHT, also providing better clinical outcomes.

FUTURE WORK

Longitudinal research into the clinical efficacy of SLT as a first-line treatment will specify the long-term differences of disease progression, treatment intensity and ocular surgery rates between the two pathways.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN32038223.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 31. See the NIHR Journals Library website for further project information.

Systematic Review of Economic Evaluations in Primary Open-Angle Glaucoma: Decision Analytic Modeling Insights

OBJECTIVE

Our objective was to review, compare and gain insight into economic evaluations in primary open-angle glaucoma (POAG) with a focus on existing decision analytic models.

METHODS

A literature review was performed using clinical and specialized databases following best practices. Relevant inclusion criteria included the development of a decision analytic model, the assessment of POAG interventions, and a full economic evaluation in terms of costs and health-related outcomes. Model inputs and settings were extracted, compared and analyzed. Main study incremental outcomes were also reported.

RESULTS

The literature review identified 22 full articles in alignment with the eligibility criteria for a total of 15 countries and a wide range of years from 1983 to 2018. Interventions included as competing alternatives in the eligible studies were topical medications (33%), screening or diagnosis (33%), surgical interventions (10%), laser trabeculoplasty (10%) and minimally invasive surgeries (3%). Markov models using transition states were the most common type of modeling approach. Cost-utility models using a mid- to long-term time horizon with a national payer perspective were the most frequent type of economic evaluation identified. Model states commonly included disease severity levels, as defined by glaucoma staging systems, and other relevant events such as blindness and death. Authors did not sufficiently justify key modeling assumptions, inputs or the robustness of their findings.

CONCLUSIONS

Decision analytic models in POAG can reasonably guide future modeling research by revealing common practices, inputs and assumptions. Furthermore, this review revealed evidence gaps in terms of unexplored interventions and treatment sequences.

Patient-reported Outcomes, Functional Assessment, and Utility Values in Glaucoma

In clinical glaucoma research, the measurement of patient reported outcomes, functional assessment of disability, and health economic impact is critical. However, valid, time-efficient and comprehensive tools are not available and several current instruments lack in the appropriate precision for measuring the various dimensions of glaucoma-related quality of life (QoL), including functioning and mobility. Furthermore, statistical methods are inconsistently and sometimes incorrectly used in otherwise sound clinical studies. Standardizing and improving methods of patient-centered data collection and analysis in glaucoma studies are imperative. This paper outlines recommendations and provides a discussion of some of the pertinent issues relating to the optimization of patient-reported outcomes research in glaucoma.

Clinical Evaluation of Swedish Interactive Thresholding Algorithm-Faster Compared With Swedish Interactive Thresholding Algorithm-Standard in Normal Subjects, Glaucoma Suspects, and Patients With Glaucoma

PURPOSE

To compare the visual fields results obtained using the Swedish interactive thresholding algorithm-Standard (SS) and the Swedish interactive thresholding algorithm-Faster (SFR) in normal subjects, glaucoma suspects, and patients with glaucoma and to quantify potential time-saving benefits of the SFR algorithm.

DESIGN

Prospective, cross-sectional study.

METHODS

One randomly selected eye from 364 patients (77 normal subjects, 178 glaucoma suspects, and 109 patients with glaucoma) seen in a single institution underwent testing using both SS and SFR on the Humphrey Field Analyzer. Cumulative test time using each algorithm was compared after accounting for different rates of test reliability. Pointwise and cluster analysis was performed to determine whether there were systematic differences between algorithms.

RESULTS

Using SFR had a greater rate of unreliable results (29.3%) compared with SS (7.7%, P < .0001). This was mainly because of high false positive rates and seeding point errors. However, modeled test times showed that using SFR could obtain a greater number of reliable results within a shorter period of time. SFR resulted in higher sensitivity values (on average 0.5 dB for patients with glaucoma) that was greater under conditions of field loss (<19 dB). Cluster analysis showed no systematic patterns of sensitivity differences between algorithms.

CONCLUSIONS

After accounting for different rates of test reliability, SFR can result in significant time savings compared with SS. Clinicians should be cognizant of false positive rates and seeding point errors as common sources of error for SFR. Results between algorithms are not directly interchangeable, especially if there is a visual field deficit <19 dB.

Taking the strain? Impact of glaucoma on patients' informal caregivers

PURPOSE

To estimate informal caregiver (ICG) strain in people from a glaucoma clinic.

METHODS

Patients with glaucoma were consecutively identified from a single clinic in England for a cross-sectional postal survey. The sample was deliberately enriched with a number of patients designated as having advanced glaucoma (visual field [VF] mean deviation worse than -12 dB in both eyes). Patients were asked to identify an ICG who recorded a Modified Caregiver Strain Index (MCSI), a validated 13 item instrument scored on a scale of 0-26. Previous research has indicated mean MCSI to be >10 in multiple sclerosis and Parkinson's disease. All participants gave a self-reported measure of general health (EQ5D).

RESULTS

Responses from 105 patients (43% of those invited) were analysed; only 38 of the 105 named an ICG. Mean (95% confidence interval [CI]) MCSI was 2.4 (1.3, 3.6) and only three ICGs recorded a MCSI > 7. The percentage of patients with an ICG was much higher in patients with advanced VF loss (82%; 9/11) when compared with those with non-advanced VF loss (31%; 29/94; p = 0.001). Mean (standard deviation) MCSI was considerably inflated in the advanced patients (5.6 [4.9] vs 1.5 [2.2] for non-advanced; p = 0.040). Worsening VF and poorer self-reported general health (EQ5D) of the patient were associated with worsening MCSI.

CONCLUSION

ICG strain, as measured by MCSI, for patients with non-advanced glaucoma is negligible, compared with other chronic disease. ICG strain increases moderately with worsening VFs but this could be partly explained by worse general health in our sample of patients.

Care pathways for glaucoma detection and monitoring in the UK

Glaucoma presents considerable challenges in providing clinically and cost-effective care pathways. While UK population screening is not seen as justifiable, arrangements for case finding have historically been considered relatively ineffective. Detection challenges include an undetected disease burden, whether from populations failing to access services or difficulties in delivering effective case-finding strategies, and a high false positive rate from referrals via traditional case finding pathways. The enhanced General Ophthalmic Service (GOS) in Scotland and locally commissioned glaucoma referral filtering services (GRFS) elsewhere have undoubtedly reduced false positive referrals, and there is emerging evidence of effectiveness of these pathways. At the same time, it is recognised that implementing GRFS does not intrinsically reduce the burden of undetected glaucoma and late presentation, and obvious challenges remain. In terms of diagnosis and monitoring, considerable growth in capacity remains essential, and non-medical health care professional (HCP) co-management and virtual clinics continue to be important solutions in offering requisite capacity. National guidelines, commissioning recommendations, and the Common Clinical Competency Framework have clarified requirements for such services, including recommendations on training and accreditation of HCPs. At the same time, the nature of consultant-delivered care and expectations on the glaucoma specialist's role has evolved alongside these developments. Despite progress in recent decades, given projected capacity requirements, further care pathways innovations appear mandated. While the timeline for implementing potential artificial intelligence innovations in streamlining care pathways is far from established, the glaucoma burden presents an expectation that such developments will need to be at the vanguard of future developments.

Evaluating the Impact of Uveitis on Visual Field Progression Using Large-Scale Real-World Data

PURPOSE

To compare rates of visual field (VF) loss in uveitis patients with glaucoma against patients with primary open-angle glaucoma (POAG) and explore the association between intraocular pressure (IOP) and rate of VF loss.

DESIGN

Retrospective cohort study.

METHODS

Anonymized VFs and IOP measurements extracted from the electronic medical records of 5 regionally different glaucoma clinics in England. A total of 205 eyes with diagnosis of uveitis plus glaucoma were compared with 4600 eyes with POAG only. Minimum inclusion criteria were ≥4 visits within a 4-year window. Relative risk (RR) of being a "rapid progressor" (mean deviation [MD] loss ≥1.5 dB/year) was calculated. A mixed-effects model (MEM) and a pointwise VF progression analysis of pattern deviation were used to confirm differences between the groups. Longitudinal IOP mean, range, and variability were compared with rate of VF progression.

RESULTS

Median (interquartile range) baseline MD in the uveitis and POAG groups was -3.8 (-8.7, -1.5) dB and -3.1 (-6.6, -1.2) dB, respectively. The uveitis and POAG groups had 23 of 205 (11%) and 331 of 4600 (7%) "rapidly progressing" eyes, respectively. Age-adjusted RR for "rapid progression" in uveitic vs POAG eyes was 1.9 (95% confidence interval: 1.8-2.0). The MEM confirmed that uveitic eyes (-0.49 dB/year) showed higher rates of VF progression than the POAG group (-0.37 dB/year; P < .01). IOP range and variability were higher in the "rapidly progressing" uveitic eyes.

CONCLUSIONS

Our analysis suggests that VF loss occurs faster in glaucoma patients with uveitis than those without uveitis. The risk of progressing rapidly in glaucoma with uveitis is almost double than in those without uveitis. Early identification of "rapid progressors" may enable targeted intervention to preserve visual function in this high-risk group.

Correlation Between Visual Function and Performance of Simulated Daily Living Activities in Glaucomatous Patients

PURPOSE

To analyze the correlations between functional clinical tests and the performance of glaucoma patients in simulated daily living activities.

PATIENTS AND METHODS

Thirty-two patients with chronic glaucoma, followed at the Quinze-Vingts National Ophthalmology Hospital, were included. All patients had a clinical evaluation of visual function including best-corrected visual acuity, contrast sensitivity, and monocular and binocular visual field (VF) tests. Four different simulated activities of daily living were evaluated in standardized artificial platforms (StreetLab and HomeLab): "mobility" and an obstacle avoidance task in an artificial street, "reaching and grasping" large and small objects on a kitchen work surface, "localization of people" and "face orientation recognition." Patient performance in the different tasks was correlated with VF evaluation including integrated binocular visual field (IVF), VF mean deviation (MD) of the better and the worse eye, Esterman binocular VF, best-corrected visual acuity, and contrast sensitivity.

RESULTS

The IVF score was significantly correlated with "localization of people" time (r=0.49; P=0.003), "face orientation recognition" time (r=0.50; P=0.002), and "movement onset" for reaching and grasping small objects (r=0.38; P=0.029). The MD of the better eye appeared significantly correlated with "face orientation recognition" time (r=-0.44; P=0.009) and "localization of people" time (r=-0.46; P=0.005). The Esterman score appeared significantly correlated with "mobility time" (r=-0.40; P=0.018), "localization of people" (r=-0.37; P=0.030), "face orientation recognition" times (r=-0.39; P=0.024), and "movement onset" for reaching and grasping large objects (r=-0.43; P=0.015).

CONCLUSIONS

The IVF score and the MD of the better eye appeared to better evaluate "reaching and grasping," "face orientation recognition," and "localization of people" simulated tasks, whereas for the "mobility" task, the Esterman VF seemed more useful. The precise evaluation of the glaucoma patient's ability to perform everyday life tasks is complex and may require both monocular and binocular VF tests.

Auditing service delivery in glaucoma clinics using visual field records: a feasibility study

Objective

This study aimed to demonstrate that large-scale visual field (VF) data can be extracted from electronic medical records (EMRs) and to assess the feasibility of calculating metrics from these data that could be used to audit aspects of service delivery of glaucoma care.

Method and analysis

Humphrey visual field analyser (HFA) data were extracted from Medisoft EMRs from five regionally different clinics in England in November 2015, resulting in 602 439 records from 73 994 people. Target patients were defined as people in glaucoma clinics with measurable and sustained VF loss in at least one eye (HFA mean deviation (MD) outside normal limits ≥2 VFs). Metrics for VF reliability, stage of VF loss at presentation, speed of MD loss, predicted loss of sight years (bilateral VF impairment) and frequency of VFs were calculated.

Results

One-third of people (34.8%) in the EMRs had measurable and repeatable VF loss and were subject to analyses (n=25 760 patients). Median (IQR) age and presenting MD in these patients were 71 (61, 78) years and −6 (–10, –4) dB, respectively. In 19 264 patients with >4 years follow-up, median (IQR) MD loss was −0.2 (−0.8, 0.3) dB/year and median (IQR) intervals between VF examinations was 11 (8, 16) months. Metrics predicting loss of sight years and reliability of examinations varied between centres (p<0.001).

Conclusion

This study illustrates the feasibility of assessing aspects of health service delivery in glaucoma clinics through analysis of VF databases. Proposed metrics could be useful for blindness prevention from glaucoma in secondary care centres.

Does eye examination order for standard automated perimetry matter?

Purpose

In spite of faster examination procedures, visual field (VF) results are potentially influenced by fatigue. We use large‐scale VF data collected from clinics to test the hypothesis that perimetric fatigue effects are greater in the eye examined second.

Methods

Series of six Humphrey Swedish Interactive Testing Algorithm (SITA) VFs from 6901 patients were retrospectively extracted from a VF database from four different glaucoma clinics. Mean deviation (MD) was compared between first and second tested eyes. A surrogate measure of longitudinal MD variability over time was estimated from errors using linear regression of MD against time then compared between first and second tested eye.

Results

Right eye VF was tested consistently first throughout in 6320 (91.6%) patients. Median (interquartile range; IQR) MD in the first tested (right) eye and second tested (left) eye was −2.57 (−6.15, −0.58) dB and −2.70 (−6.34, −0.80) dB respectively (median reduction VF sensitivity of 0.13 dB; p < 0.001). Median (IQR) increase in our surrogate measure of longitudinal MD variability in the second eye tested was 3% (−43%, 50%); this effect was not associated with patient age or rest time between examinations.

Conclusion

Statistically significant perimetric fatigue effects manifest on average in the second eye tested in routine clinics using Humphrey Field Analyzer SITA examinations. However, the average effects were very small and there was enormous variation among patients. We recommend starting with a right eye examination so that any perimetric fatigue effects, if they exist in an individual, will be as constant as possible from visit to visit.

Dynamic Monitoring and Control of Irreversible Chronic Diseases with Application to Glaucoma

To manage chronic disease patients effectively, clinicians must know (1) how to monitor each patient (i.e., when to schedule the next visit and which tests to take), and (2) how to control the disease (i.e., what levels of controllable risk factors will sufficiently slow progression). Our research addresses these questions simultaneously and provides the optimal solution to a novel linear quadratic Gaussian state space model. For the objective of minimizing the relative change in state over time (i.e., disease progression), which is necessary for managing irreversible chronic diseases while also considering the cost of tests and treatment, we show that the classical two-way separation of estimation and control holds. This makes a previously intractable problem solvable by decomposition into two separate, tractable problems while maintaining optimality. The resulting optimization is applied to the management of glaucoma. Based on data from two large randomized clinical trials, we validate our model and demonstrate how our decision support tool can provide actionable insights to the clinician caring for a patient with glaucoma. This methodology can be applied to a broad range of irreversible chronic diseases to devise patient-specific monitoring and treatment plans optimally.

Cost-effectiveness analysis of iStent trabecular micro-bypass stent for patients with open-angle glaucoma in Colombia

OBJECTIVE

To estimate the cost-effectiveness of trabecular micro bypass stent vs laser trabeculoplasty or medications only, for patients with open-angle glaucoma in a setting of the Colombian System Health.

METHODS

This is a cost-effectiveness analysis that based its assumptions in external data sources, used to extrapolate the quality-of-life related to health, survival, and costs. A Markov model, with stages from 0 (ocular hypertension without glaucoma) to 5 and bilateral blindness, was developed inclusive of Colombians older than 40 years in 2018, from a societal perspective, comparing trabecular micro-bypass stents vs laser trabeculoplasty, timolol + dorzolamide + brimonidine, timolol + dorzolamide + latanoprost, or timolol + dorzolamide + brimatoprost, in terms of clinical and economic outcomes over a lifetime horizon. Both costs and health outcomes had an annual rate discount of 5%. Health outcomes were evaluated in terms of QALYs related with loss of visual acuity. Trabecular micro-bypass costs include the joint use of timolol, and the costs of laser trabeculoplasty include the combined use of timolol + dorzolamide.

RESULTS

Trabecular micro-bypass stents were estimated to have 127,971 more discounted QALYs vs laser trabeculoplasty; 405,982 vs timolol + dorzolamide + brimonidine; and 378,287 vs timolol + dorzolamide + latanoprost or timolol + dorzolamide + brimatoprost. Cumulative costs with trabecular micro-bypass stents at 40 years was $13,252,318 lower than laser trabeculoplasty; $6,403,534, lower than timolol + dorzolamide + brimonidine; $22,311,064, lower than timolol + dorzolamide + latanoprost; and $29,156,113 lower than timolol + dorzolamide + brimatoprost.

CONCLUSIONS

The trabecular micro-bypass stent is a highly cost-saving strategy due to more QALYs related to a lower rate of the population with loss of visual acuity in the long-term, and because the costs associated with additional medications and complications are lower with trabecular micro-bypass stents.

Embedded deep learning in ophthalmology: making ophthalmic imaging smarter

Deep learning has recently gained high interest in ophthalmology due to its ability to detect clinically significant features for diagnosis and prognosis. Despite these significant advances, little is known about the ability of various deep learning systems to be embedded within ophthalmic imaging devices, allowing automated image acquisition. In this work, we will review the existing and future directions for 'active acquisition'-embedded deep learning, leading to as high-quality images with little intervention by the human operator. In clinical practice, the improved image quality should translate into more robust deep learning-based clinical diagnostics. Embedded deep learning will be enabled by the constantly improving hardware performance with low cost. We will briefly review possible computation methods in larger clinical systems. Briefly, they can be included in a three-layer framework composed of edge, fog, and cloud layers, the former being performed at a device level. Improved egde-layer performance via 'active acquisition' serves as an automatic data curation operator translating to better quality data in electronic health records, as well as on the cloud layer, for improved deep learning-based clinical data mining.

Twenty-year outcomes in patients with newly diagnosed glaucoma: mortality and visual function

Background/aims

To determine the mortality within 20 years of diagnosis of chronic open-angle glaucoma (COAG) and visual acuity and visual field progression of a cohort followed for 20 years.

Methods

Twenty years following the diagnosis of COAG in 68 of 436 (16%) patients seen in a glaucoma case-finding clinic, visual and mortality outcomes were audited from medical records. Causes of death were obtained from general practitioner records and death certificates. Probability of death was calculated using a Kaplan-Meier survival curve. The visual field of each eye of survivors was graded using a nine-stage severity scale. Visual outcome was analysed at the 20-year follow-up visit.

Results

From 68, 14 (21%) were lost to follow-up. In the remaining 54, 20 (37%) were alive 20 years after diagnosis. Of 63% who died, mean age of death was 84 years, most commonly due to vascular disease. Mean age at presentation of those who died was 73.7 years versus 63.2 years for survivors (P=0.001). The median time to death was 16 years. On visual field analysis, nearly half (48.9%) of eyes did not deteriorate, but 28.3% eyes deteriorated by more than two stages. Those who died had worse final visual acuity than survivors (P<0.001). Three who died were registered severely visually impaired mainly from macular disease, but no survivors were registered (P<0.001).

Conclusion

In this cohort, approximately two-thirds of patients with glaucoma died within 20 years of diagnosis. In most older patients with glaucoma, the overall goal of preventing visual handicap and blindness is achievable 20 years after diagnosis.

Effect of quantitative intraocular pressure reduction on visual field defect progression in normal tension glaucoma under medical therapy applying Markov model

Purpose

To quantitatively evaluate the association of intraocular pressure (IOP) reduction with visual field defect (VFD) progression in normal tension glaucoma (NTG) under medical therapy.

Patients and methods

Clinical data for 622 eyes of 311 primary open-angle glaucoma and NTG patients were collected from April 2006 to March 2016. Of these patients, those with normal IOP, glaucomatous VFD by Anderson’s criteria, corrected visual acuity ≥0.7, >5 years of medical therapy, ≥5 visual field tests at least five times at 12-month intervals, visual field testing reliability coefficients of ≤33%, and mean deviation (MD) exceeding below −20 dB in the initial visual field test were included in this retrospective data analysis. MD and IOP data were collected at baseline and after 5 years. Following MD categorization into stages I to IV, stage transition matrices were generated using a Markov model to evaluate VFD changes. Eyes were divided based on IOP reduction (0%, 10%, 15%, 20%, 25%, 30%) from baseline. VFD aggravations were compared using the Markov model and MD slopes with IOP reduction rates as cutoff values.

Results

Overall, 132 eyes of 132 NTG patients fulfilled the eligibility criteria. MD decreased significantly (P<0.0001) at 5 years vs baseline. During follow-up, visual field stage using the Markov model was constant in ~60%, with transitions in ~40%. IOP decreased significantly (P>0.001) at 5 years vs baseline. Though MD slopes did not differ significantly between each of the groups that achieved the various IOP reduction cut-off values and the corresponding group that did not achieve the cut-off values, a significant difference (P=0.0432) in VFD was found between the group that achieved the 25% cut-off value and the group that did not when evaluated using the Markov model.

Conclusion

In NTG patients, VFD aggravation was significantly suppressed in groups with IOP reductions of ≥25% from baseline.

A New Graphical Tool for Assessing Visual Field Progression in Clinical Populations

Purpose

We demonstrate a new approach for assessing and visualizing visual field (VF) progression in clinics.

Methods

Two summary measures for VF progression, Rate of Progression (RP) and Loss of Sight Years (LSY), are combined with a novel visualization (Hedgehog Plots). RP is calculated per eye using linear regression of mean deviation (MD) against time of follow-up. LSY is a novel parameter, linked to actuarial data, which estimates the number of years that a patient will have advanced bilateral VF loss in their predicted remaining lifetime. Every eye is given a rank within the sample based on RP and LSY allowing for “priority” patients to be identified. We illustrate differences between the parameters with an experiment comparing the cases flagged as “priority” by each method using data from 1263 VF records.

Results

RP for every eye in a “clinic” can be visualized and assessed using a Hedgehog Plot. Eyes are ranked against all other eyes by RP and LSY; these parameters provide different and complementary information on a patient's VF progression status. A purpose written interactive application demonstrating the techniques is available in the public domain at https://crabblab.shinyapps.io/hedgehog.

Conclusion

Hedgehog Plots provide a tool for visualizing VF progression in groups of patients and can be used potentially to prioritize monitoring resources.

Translational Relevance

This study illustrates a novel visualization technique and an interactive application that can be used to help determine VF progression in large groups of patients.

Prospective study of glaucoma referrals across Europe: are we using resources wisely?

BACKGROUND

To investigate the outcomes of glaucoma referrals across different European countries.

METHODS

250 patients newly referred to tertiary referral glaucoma specialist practices in the UK, Hungary, Slovenia, Italy and Greece were prospectively enrolled (50 consecutive patients per centre). Referral accuracy and predictive value of referral criteria for an intervention or further monitoring (positive predictive value) were analysed.

RESULTS

Same-day discharges occurred in 43% (95% CI 39% to 75%) (12/28) of optometrist-initiated referrals (UK only), 37% (95% CI 30% to 45%) (59/158) of ophthalmologist-initiated referrals (all centres) and 54% (95% CI 40% to 68%) (26/48) of self-referrals (Hungary, Italy and Greece). The percentages from all referral sources were 46% (95% CI 32% to 60%) in the UK, 56% (95% CI 44% to 70%) in Hungary, 30% (95% CI 17% to 43%) in Slovenia, 22% (95% CI 11% to 34%) in Italy and 60% (95% CI 46% to 74%) in Greece (p<0.001). Overall, the referring criterion was confirmed in 54% (95% CI 45% to 63%) (64/119) for intraocular pressure (IOP) >21 mm Hg, 56% (95% CI 43% to 69%) (33/59) for a suspicious optic disc and 61% (95% CI 45% to 77%) (22/36) for a suspicious visual field, with large between-country differences (p<0.05 for all comparisons). Of all referrals, 32% (95% CI 26% to 37%) were initiated on the basis of IOP >21 mm Hg only. By combining the IOP criterion with any other referring criterion, the positive predictive value increased from 56% (95% CI 45% to 67%) to at least 89% (95% CI 68% to 100%). In the UK, a hypothetical IOP threshold of >26 mm Hg, as a requirement for IOP-only referrals, would reduce IOP-only referrals by 44%, while not missing any definite glaucoma cases.

CONCLUSION

The accuracy of referrals was poor in the UK and the other countries. Requiring a combination of criteria and raising the IOP threshold for IOP-only referrals are needed to cut waste in clinical care.

Gradually Then Suddenly? Decline in Vision-Related Quality of Life as Glaucoma Worsens

Purpose. To evaluate the relationship between self-reported vision-related quality of life (VRQL) and visual field (VF) loss in people from glaucoma clinics. Methods. A postal survey using the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was administered to people with a range of VF loss identified from a UK hospital-based glaucoma service database. Trends were assessed in a composite score from NEI VFQ-25 against better-eye mean deviation (BEMD) using linear regression and a spline-fitting method that can highlight where a monotonic relationship may have different stages. Results. A total of 636 patients (median [interquartile range] BEMD -2.1 [-5.2, -0.4] dB, median age 70 [60, 77] years) were analysed. Analysis of trends in the data revealed an average patient loses approximately 2 units (out of 100) on NEI VFQ-25 for every loss of 1 dB (BEMD) as VF defects first become bilateral, up to BEMD -5 dB. NEI VFQ-25 deterioration then appears to slow before a more rapid phase of change (4-5 units per 1 dB loss) after BEMD worsens beyond -15 dB. Conclusions. Relationship between decline in VRQL and VF worsening in glaucoma is unlikely to be linear; it more likely has different phases, and these should be further explored in longitudinal studies.

Frequency of Testing to Detect Visual Field Progression Derived Using a Longitudinal Cohort of Glaucoma Patients

PURPOSE

To determine the time required to detect statistically significant progression for different rates of visual field loss using standard automated perimetry (SAP) when considering different frequencies of testing using a follow-up scheme that resembles clinical practice.

DESIGN

Observational cohort study.

PARTICIPANTS

One thousand seventy-two eyes of 665 patients with glaucoma followed up over an average of 4.3±0.9 years.

METHODS

Participants with 5 or more visual field tests over a 2- to 5-year period were included to derive the longitudinal measurement variability of SAP mean deviation (MD) using linear regressions. Estimates of variability then were used to reconstruct real-world visual field data by computer simulation to evaluate the time required to detect progression for various rates of visual field loss and different frequencies of testing. The evaluation was performed using a follow-up scheme that resembled clinical practice by requiring a set of 2 baseline tests and a confirmatory test to identify progression.

MAIN OUTCOME MEASURES

Time (in years) required to detect progression.

RESULTS

The time required to detect a statistically significant negative MD slope decreased as the frequency of testing increased, albeit not proportionally. For example, 80% of eyes with an MD loss of -2 dB/year would be detected after 3.3, 2.4, and 2.1 years when testing is performed once, twice, and thrice per year, respectively. For eyes with an MD loss of -0.5 dB/year, progression can be detected with 80% power after 7.3, 5.7, and 5.0 years, respectively.

CONCLUSIONS

This study provides information on the time required to detect progression using MD trend analysis in glaucoma eyes when different testing frequencies are used. The smaller gains in the time to detect progression when testing is increased from twice to thrice per year suggests that obtaining 2 reliable tests at baseline followed by semiannual testing and confirmation of progression through repeat testing in the initial years of follow-up may provide a good compromise for detecting progression, while minimizing the burden on health care resources in clinical practice.