The Frontloading Fields Study (FFS): Detecting Changes in Mean Deviation in Glaucoma Using Multiple Visual Field Tests Per Clinical Visit

Retinal sensitivity changes in early/intermediate AMD: a systematic review and meta-analysis of visual field testing under mesopic and scotopic lighting

Visual fields under mesopic and scotopic lighting are increasingly being used for macular functional assessment. This review evaluates its statistical significance and clinical relevance, and the optimal testing protocol for early/intermediate age-related macular degeneration (AMD). PubMed and Embase were searched from inception to 14/05/2022. All quality assessments were performed according to GRADE guidelines. The primary outcome was global mean sensitivity (MS), further meta-analysed by: AMD classification scheme, device, test pattern, mesopic/scotopic lighting, stimuli size/chromaticity, pupil dilation, testing radius (area), background luminance, adaptation time, AMD severity, reticular pseudodrusen presence, and follow-up visit. From 1489 studies screened, 42 observational study results contributed to the primary meta-analysis. Supported by moderate GRADE certainty of the evidence, global MS was significantly reduced across all devices under mesopic and scotopic lighting with large effect size (-0.9 [-1.04, -0.75] Hedge's g, P < 0.0001). The device (P < 0.01) and lighting (P < 0.05) used were the only modifiable factors affecting global MS, whereby the mesopic MP-1 and MAIA produced the largest effect sizes and exceeded test-retest variabilities. Global MS was significantly affected by AMD severity (intermediate versus early AMD; -0.58 [-0.88, -0.29] Hedge's g or -2.55 [3.62, -1.47] MAIA-dB) and at follow-up visit (versus baseline; -0.62 [-0.84, -0.41] Hedge's g or -1.61[-2.69, -0.54] MAIA-dB). Magnitudes of retinal sensitivity changes in early/intermediate AMD are clinically relevant for the MP-1 and MAIA devices under mesopic lighting within the central 10° radius. Other factors including pupil dilation and dark adaptation did not significantly affect global MS in early/intermediate AMD.

Quantification and Predictors of Visual Field Variability in Healthy, Glaucoma Suspect, and Glaucomatous Eyes Using SITA-Faster

PURPOSE

The newly released Swedish Interactive Thresholding Algorithm (SITA)-Faster (SFR) has significantly shorter testing durations compared with older SITA algorithms, but its variability is uncertain. This study quantified and established threshold limits of test-retest variability across the 24-2 test grid using SFR.

DESIGN

Cross-sectional study with prospective longitudinal arm.

PARTICIPANTS

1426 eyes of 787 patients with healthy, suspected glaucoma, or manifest glaucoma eyes from hospital- and university- eye clinics.

METHODS

Two SFR tests per eye at a baseline visit and at two follow-up visits.

MAIN OUTCOME MEASURES

Pointwise variability measured by test-retest difference in pointwise sensitivity between tests one and two, mean global variability (test-retest variance) measured by average of pointwise variability for each participant, global sensitivity, and reliability indices of each eye.

RESULTS

Of the 1426 eyes, 540 eyes (37.9%) had a diagnosis of glaucoma, 753 eyes (52.8%) were suspected of having glaucoma, and the remaining 133 eyes (9.3%) were healthy. Of 74 152 pointwise sensitivities obtained, the mean test-retest difference was 2.17 ± 2.9 dB, whereas the mean test-retest variance for each participant was 2.17 ± 1.2 dB. Pointwise and global variability increased with worsening threshold sensitivity and (MD), respectively, and was greater for peripheral compared with central test locations. In the longitudinal cohort, no significant difference in mean test-retest variance was found across the 3 visits (mean variability, 2.10 dB vs. 2.16 dB vs. 2.16 dB at visits F0 vs. F1 vs. F2; P = 0.53, repeated-measures analysis of variance). Baseline MD (-0.19 dB; 95% CI, -0.22 to 0.16 dB; P < 0.0001) and abnormally high sensitivity on glaucoma hemifield test (1.14 dB; 95% CI, 0.78-1.51 dB; P < 0.0001) were significantly associated with increased variability. Finally, test-retest MD showed minimal change around the recommended 15% false-positive cutoff threshold.

CONCLUSIONS

The variability of SFR increases with worsening threshold sensitivity, is stable over time, and is greater for peripheral compared with central test locations. Worse baseline MD and abnormally high sensitivity are significant predictors of increased variability. A cutoff of 15% in false-positive results may be inappropriate as a threshold for judging test reliability in SFR.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Predictors of Glaucomatous Progression in Individuals with Small and Large Optic Discs

PURPOSE

To identify factors associated with glaucomatous progression in individuals with small and large optic discs.

DESIGN

Retrospective review.

SUBJECTS

4505 individuals with glaucoma at UCLA; 233 (59.7%) with small discs, 157 (40.3%) with large discs.

METHODS

Small and large disc sizes were defined by OCT or Heidelberg Retinal Tomography as disc area ≤ 5% (≤ 1.3 mm2) and ≥ 95% (≥ 2.9 mm2), respectively. Medical records were reviewed for demographics, systemic comorbidities, glaucoma type, ocular comorbidities, and ocular surgery. Logistic regression was used to identify predictors of visual field (VF) progression in individuals with small and large discs and predictors of large versus small discs.

MAIN OUTCOME MEASURES

The VF deterioration with mean deviation, pointwise linear regression, and glaucoma rate index (GRI); large vs. small disc.

RESULTS

In individuals with small discs, Asian versus non-Hispanic White ethnicity was associated with increased progression (adjusted odds ratio [aOR] = 4.05; 95% confidence interval [CI] = 1.12-14.59 for GRI). Higher intraocular pressure (IOP) range and peak were associated with increased progression in individuals with both small discs (aOR = 1.12; 95% CI = 1.00-1.27 and aOR = 1.05; 95% CI = 1.00-1.10 per 1 mmHg for range and peak with GRI) and large discs (aOR = 1.35; 95% CI = 1.12-1.66 and aOR = 1.11; 95% CI = 1.03-1.20 per 1 mmHg for range and peak with GRI). Multivariable predictors of having large vs. small discs included vasospastic phenotype (aOR = 2.58; 95% CI = 1.35-5.19) and Black (aOR = 20.46; 95% CI = 8.33-61.84), Hispanic/Latino (aOR = 9.65; 95% CI = 4.14-25.39), Asian (aOR = 4.87; 95% CI = 2.96-8.1), and other (aOR = 2.79; 95% CI = 1.69-4.63) versus non-Hispanic White ethnicity.

CONCLUSIONS

Increased odds of glaucomatous progression were associated with Asian vs. non-Hispanic White ethnicity in glaucoma patients with small optic discs, as well as with increased IOP range and peak in those with small and large discs. Individuals with a vasospastic phenotype and those from racial and ethnic minority backgrounds had increased odds of having large vs. small optic discs. Further characterization of discernible phenotypes would improve disease prognostication and help individualize glaucoma treatment.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Frontloading visual field tests detect earlier mean deviation progression when applied to real-world-derived early-stage glaucoma data

PURPOSE

To examine the diagnostic accuracy of performing two (frontloaded) versus one (clinical standard) visual field (VF) test per visit for detecting the progression of early glaucoma in data derived from clinical populations.

METHODS

A computer simulation model was used to follow the VFs of 10,000 glaucoma patients (derived from two cohorts: Heijl et al., Swedish cohort; and Chauhan et al., Canadian Glaucoma Study [CGS]) over a 10-year period to identify patients whose mean deviation (MD) progression was detected. Core data (baseline MD and progression rates) were extracted from two studies in clinical cohorts of glaucoma, which were modulated using SITA-Faster variability characteristics from previous work. Additional variables included follow-up intervals (six-monthly or yearly) and rates of perimetric data loss for any reason (0%, 15% and 30%). The main outcome measures were the proportions of progressors detected.

RESULTS

When the Swedish cohort was reviewed six-monthly, the frontloaded strategy detected more progressors compared to the non-frontloaded method up to years 8, 9 and 10 of follow-up for 0%, 15% and 30% data loss conditions. The time required to detect 50% of cases was 1.0-1.5 years less for frontloading compared to non-frontloading. At 4 years, frontloading increased detection by 26.7%, 28.7% and 32.4% for 0%, 15% and 30% data loss conditions, respectively. Where both techniques detected progression, frontloading detected progressors earlier compared to the non-frontloaded strategy (78.5%-81.5% and by 1.0-1.3 years when reviewed six-monthly; 81%-82.9% and by 1.2-2.1 years when reviewed yearly). Accordingly, these patients had less severe MD scores (six-monthly review: 0.63-1.67 dB 'saved'; yearly review: 1.10-2.87 dB). The differences increased with higher rates of data loss. Similar tendencies were noted when applied to the CGS cohort.

CONCLUSIONS

Frontloaded VFs applied to clinical distributions of MD and progression led to earlier detection of early glaucoma progression.

A Bayesian Hierarchical Spatial Longitudinal Model Improves Estimation of Local Macular Rates of Change in Glaucomatous Eyes

Purpose

Demonstrate that a novel Bayesian hierarchical spatial longitudinal (HSL) model improves estimation of local macular ganglion cell complex (GCC) rates of change compared to simple linear regression (SLR) and a conditional autoregressive (CAR) model.

Methods

We analyzed GCC thickness measurements within 49 macular superpixels in 111 eyes (111 patients) with four or more macular optical coherence tomography scans and two or more years of follow-up. We compared superpixel-patient-specific estimates and their posterior variances derived from the latest version of a recently developed Bayesian HSL model, CAR, and SLR. We performed a simulation study to compare the accuracy of intercept and slope estimates in individual superpixels.

Results

HSL identified a significantly higher proportion of significant negative slopes in 13/49 superpixels and a significantly lower proportion of significant positive slopes in 21/49 superpixels than SLR. In the simulation study, the median (tenth, ninetieth percentile) ratio of mean squared error of SLR [CAR] over HSL for intercepts and slopes were 1.91 (1.23, 2.75) [1.51 (1.05, 2.20)] and 3.25 (1.40, 10.14) [2.36 (1.17, 5.56)], respectively.

Conclusions

A novel Bayesian HSL model improves estimation accuracy of patient-specific local GCC rates of change. The proposed model is more than twice as efficient as SLR for estimating superpixel-patient slopes and identifies a higher proportion of deteriorating superpixels than SLR while minimizing false-positive detection rates.

Translational Relevance

The proposed HSL model can be used to model macular structural measurements to detect individual glaucoma progression earlier and more efficiently in clinical and research settings.

Multiple (frontloaded) visual field tests increase identification of very slow mean deviation progression in glaucoma

OBJECTIVE

To determine the effect of frontloading (multiple) visual field (VF) tests at the same visit for detecting mean deviation (MD) change in slowly progressive glaucoma.

METHODS

This was a computer simulation study. Baseline MD (range, 0 to -12 dB) and progression rate (range, 0 to -0.4 dB/year, non-inclusive) were generated for 10,000 patients. Each patient had 6 simulated "stable" baseline VF tests. Then follow-up VFs (up to 10 years) were generated by incorporating progression rate and within-visit and between-visit variability. The independent variables were number of VF tests per visit (one non-frontloaded or two frontloaded), VF reliability (100%, 85%, or 70%), repeat testing because of unreliable results (yes or no), and follow-up interval (6-monthly or yearly). The outcomes were detection of progression (MD slope that was negative and significant at p < 0.05), MD at detection, and number of years to detection.

RESULTS

Frontloading identified more progressors (62.7%-79.2%) compared with non-frontloading (31.0%-36.7%) at 10 years (p < 0.0001). Six-monthly follow-ups led to greater detection than yearly intervals. Progressors detected by both methods were detected by the non-frontloaded method sooner (up to 0.26 years), but this was small and not clinically significant (MD difference, 0.06 dB). An increase (less severe) in MD, an increase (slower) in progression rate, and an increase in SD of baseline VFs decreased the likelihood of detecting progression.

CONCLUSIONS

Frontloading VF tests at 6-monthly intervals improve detection rates of MD progression in slowly progressive glaucoma patients compared with performing 1 test per visit at yearly intervals.

Assessment of visual field progression in glaucoma

PURPOSE OF REVIEW

Perimetry plays an important role in the diagnosis and management of glaucoma. This article discusses the assessment of visual field progression in patients with glaucoma.

RECENT FINDINGS

Selecting the best visual field test strategy and establishing a baseline of visual fields will assist clinicians in the detection of glaucomatous progression. Repeat testing serves to confirm or refute changes on visual field testing. More frequent testing after initial diagnosis is recommended to establish a baseline and to identify patients with rapid progression who may need more aggressive management. Statistically significant changes on event analysis can prompt examination of a patient's trend analysis to determine whether clinically significant deterioration may be occurring. Future applications of machine learning can complement existing methods of visual field interpretation.

SUMMARY

Many treated patients with glaucoma will experience visual field progression. Optimal utilization of visual field testing strategy and analytical software can help clinicians identify patients with glaucomatous progression likely to cause functional visual disability.

Visual fields in glaucoma: Where are we now?

Visual fields are an integral part of glaucoma diagnosis and management. COVID has heightened the awareness of the potential for viral spread with the practice of visual fields modified. Mask artefacts can occur due to fogging of the inferior rim of the trail lens. Fortunately, the risk of airborne transmission when field testing is low. The 24-2c may be useful to detect early disease and the 10-2 more sensitive to detect advanced loss. The SITA faster test algorithm is able to reduce testing time thereby improving clinic efficiency, however, may show milder results for moderate or severe glaucoma. The technician has an important role of supervising the visual field performance to achieve reliable output. Home monitoring can provide earlier detection of progression and thus improve monitoring of glaucoma as well as reduce the burden of in-clinic assessments. Artificial Intelligence has been found to have high sensitivity and specificity compared to expert observers in detecting field abnormalities and progression as well as integrating structure with function. Although these advances will improve efficiency and guide accuracy, there will remain a need for clinicians to interpret the results and instigate management.

Online Circular Contrast Perimetry: A Comparison to Standard Automated Perimetry

PURPOSE

The aim was to validate and compare the diagnostic accuracy of a novel 24-degree, 52-loci online circular contrast perimetry (OCCP) application to standard automated perimetry (SAP).

DESIGN

Prospective cohort study.

METHODS

Two hundred and twenty participants (125 normal controls, 95 open angle glaucoma patients) were included. Agreement, correlation, sensitivity, specificity, and area under receiver operating curves (AUC) were compared for parameters of OCCP, SAP, and optical coherence tomography (OCT) for the retinal nerve fiber layer and macular ganglion cell complex inner plexiform layer.

RESULTS

Pointwise sensitivity for OCCP was greater than SAP by 1.02 log units (95% CI: 0.95-1.08); 95% limits of agreement 0.860 to 1.17. Correlation and agreement for global indices and regional zones between OCCP and SAP were strong. OCCP mean deviation (MD) AUC was 0.885±0.08, similar to other instruments' parameters with the highest AUC: SAP MD (0.851±0.08), OCT retinal nerve fiber layer inferior thickness (0.908±0.07), OCT ganglion cell complex inner plexiform layer inferior thickness (0.849±0.08), P>0.05. At best cutoff, OCCP MD sensitivity/specificity were comparable to SAP MD (90/74 vs 94/65%).

CONCLUSIONS

OCCP demonstrates similar perimetric sensitivities to SAP and similar AUC to SAP and OCT in distinguishing glaucoma patients from controls. OCCP holds promise as a glaucoma surveillance and screening tool, with the potential to be utilized for in-clinic and at-home perimetry and expand community testing.

Gaze tracker parameters have little association with visual field metrics of intrasession frontloaded SITA-Faster 24-2 visual field results

PURPOSE

To determine the usefulness of Humphrey Field Analyser (HFA) SITA-Faster 24-2 gaze tracker outputs on interpreting intra-visit visual field (VF) result pairs.

METHODS

Analysis of 1380 right-left eye pairs and 1432 pairs of test 1-test 2 intrasession VF results of patients seen within a university-based glaucoma service was undertaken to understand gaze deviation distributions. Output gaze tracker results were aggregated into total ticks, sum of amplitudes and average amplitudes. Correlations between visual field indices (mean deviation [MD], "events" and overall hill of vision) and independent variables (age and test order) were performed using one eye from each subject.

RESULTS

There was no association of test order (right-left, test 1-test 2) with eye movements. There was a significant, but weak correlation between eye movements and age (r = 0.16). Correlations of eye movements with MD were driven by more severe MD values. There were no significant correlations between intrasession difference in eye movements and the change in MD, number of "events" and hill of vision, or in the root mean square of sensitivity and total deviation values. There was also no significant correlation between gaze tracker outputs and another commonly used "reliability" metric, false positive rate.

CONCLUSIONS

Eye movement parameters as currently reported by the HFA do not appear to be correlated with key sensitivity parameters when considering the repeatability of intrasession SITA-Faster 24-2 VF results. Thus, current gaze tracker outputs do not appear to provide clinically meaningful information for interpretation of intra-visit visual field results that cannot already be garnered using other strategies.

The Frontloading Fields Study: The Impact of False Positives and Seeding Point Errors on Visual Field Reliability When Using SITA-Faster

Purpose

The purpose of this study was to evaluate the impact of two conventional reliability criteria (false positives [FPs] and seeding point errors [SPEs]) and the concurrent effect of low sensitivity points (≤19 dB) on intrasession SITA-Faster visual field (VF) result correlations.

Methods

There were 2320 intrasession SITA-Faster VF results from 1160 eyes of healthy, glaucoma suspects, and subjects with glaucoma that were separated into “both reliable” or “reliable-unreliable” pairs. VF results (mean deviation and pointwise sensitivity) were analyzed against the spectrum of FP rates and SPE, with and without censorship of sensitivity results ≤19 dB. Segmental linear regression was used to identify critical points where visual field results were significantly different between tests due to FP levels.

Results

There was a significant, but small (0.09 dB per 1% exceeding 12%) increase in mean deviation, and an increase in the number of points showing a >3 dB sensitivity increase (0.25–0.28 locations per 1% exceeding 12%). SPEs were almost exclusively related to a decrease in sensitivity at the primary seeding points but did not result in significant differences in other indices. Censoring sensitivity results ≤19 dB significantly improved the correlation between reliable and unreliable results.

Conclusions

Current criteria for judging an unreliable VF result (FP rate >15% and SPE) can lead to data being erroneously excluded, as many results do not show significant differences compared to those deemed “reliable.” Censoring of sensitivity results ≤19 dB improves intrasession correlations in VF results.

Translational Relevance

We provide guidelines for assessing the impact of FP, SPE, and low sensitivity results on VF interpretation.

Glaucoma Suspects: The Impact of Risk Factor-Driven Review Periods on Clinical Load, Diagnoses, and Healthcare Costs

Purpose

To model the healthcare impact (clinical attendance time and financial cost) and clinical outcomes (glaucoma diagnoses) of different risk factor–driven review frequencies for glaucoma suspect patients up until the point of discharge or diagnosis.

Methods

Medical records of 494 glaucoma suspects were examined to extract the clinical diagnosis. Two criteria for review periods were defined, based on contrasting stringency from established clinical guidelines: American Academy of Ophthalmology (AAO), more stringent/less frequent; and the Australian National Health and Medical Research Council (NHMRC), less stringent/more frequent. We used these data to model patient outcomes and healthcare costs using a Markov model.

Results

The less stringent/more frequent criterion resulted in more high-risk glaucoma suspects requiring more frequent review compared with the more stringent/less frequent criterion. Across the 15 Markov cycles (7.5 years), the less stringent/more frequent review criterion resulted in 6.6% more diagnoses and fewer overall clinical visits (14.7%) and reduced cost per diagnosis by 12% to 32% (P < 0.0001). The number of glaucoma diagnoses made using each criterion converged at 2.5 to 3 years.

Conclusions

The stringency of risk assessments for glaucoma suspects impacts review periods and therefore clinical load, healthcare costs, and diagnosis rates. Using current testing methods, more frequent review periods appear advantageous for diagnostic efficiency, with both lower clinic load and lower cost up until the point of discharge or glaucoma diagnosis.

Translational Relevance

A less stringent criterion for assessing the risk of developing glaucoma potentially offers a more cost-effective method for reviewing glaucoma suspects, especially within the first 2.5 years.