Detection of Progression With 10-2 Standard Automated Perimetry: Development and Validation of an Event-Based Algorithm

Standard automated perimetry for glaucoma and diseases of the retina and visual pathways: current and future perspectives

Static automated perimetry (SAP) remains a mainstay of functional assessment of the visual field in diseases of the visual pathway, such as glaucoma and age-related macular degeneration. The fundamental psychophysical task of responding to stimuli of different levels of contrast has remained minimally changed since its inception in the 1980s, and this is potentially the root of several unresolved issues involving the technique. Enduring issues include the optimisation of SAP parameters for maximising defect detection, the influence of subjective behaviour on the response, structure-function discordance, and ageing- and disease-related changes of the visual pathway. Addressing these issues has been a focus of our research program and is the subject of this manuscript. We will review some of the basic psychophysical principles and methods that have contributed to the development of SAP and their contributions to its output measurements. Parameters that are interrogated include stimulus size and background luminance and their modification to improve defect defection in glaucoma and age-related macular degeneration. We propose frameworks for optimising testing parameters and leveraging the results for changing clinical care. In our pursuit of optimising the structure-function relationship in the eye, several areas of research have been developed and explored, including: the reconciliation of subjective responses in perimetry; by minimising sources of biases, such as Method of Limits we have been able to equate static and kinetic perimetry outputs in relation to underlying structural loci. This also formed the basis for our clustering framework, which groups together statistically similar structural and functional test locations to maximise structure-function concordance. Throughout the manuscript, we review the scientific underpinnings of clinical measurements, framing application into real-world patients to improve clinical practice.

Evaluation of the long-term variability of macular OCT/OCTA and visual field parameters

BACKGROUND/AIMS

To assess the long-term variability of macular optical coherence tomography (OCT)/OCT angiography (OCTA) and visual field (VF) parameters.

METHODS

Healthy and glaucoma eyes with ≥1-year follow-up were included. 24-2 VF and macular OCT/OCTA parameters, including VF mean deviation (MD), whole-image vessel density (wiVD) and ganglion cell complex thickness (wiGCC) were analysed. Intraclass correlation coefficient (ICC), root mean squared error (RMSE), within-subject test-retest SD (Sw) and test-retest variability were calculated for stable eye cohort (max follow-up=1.5 years). Rates of change and RMSE were evaluated in the extended cohort including all eyes (unlimited follow-up).

RESULTS

From a total of 230 eyes (150 participants; age=67.7 years), 86 eyes (37%, 62 participants) were stable. In stable eyes, OCT parameters showed the highest mean (95%) ICC (wiGCC=0.99 (0.99, 0.99)), followed by VF (VF MD=0.91 (0.88, 0.93)) and OCTA (wiVD=0.82 (0.75, 0.87)). RMSE and Sw for VF MD were 0.92 dB and 0.81 dB, respectively, for wiVD were 1.64% and 1.48%, respectively, and for wiGCC, 0.91 µm and 0.78 µm, respectively. The long-term test-rest variability of VF MD, wiVD and wiGCC was 2.2 dB, 4.1% and 2.2 µm, respectively. In the extended cohort (mean follow-up=3.0 years), all parameters had significant rates of change (p<0.001), and compared with the stable cohort, only slightly higher RMSE (VF MD=1.07 dB; wiGCC=2.03 µm; wiVD=2.57%) were found.

CONCLUSIONS

VF and macular OCT/OCTA, particularly OCT parameters, showed small long-term variability in all eyes, including stable ones, supporting the use of these instruments in glaucoma follow-up. Changes in macular VD and GCC greater than 4%-5% and 2 µm, respectively, indicate possible progression.

TRIAL REGISTRATION NUMBER

NCT00221897.

Five-Year Visual Field Outcomes of the HORIZON Trial

PURPOSE

To compare visual field (VF) progression between glaucoma patients receiving cataract surgery alone (CS) or with a Hydrus microstent (CS-HMS).

DESIGN

Post hoc analysis of VF data from the HORIZON multicenter randomized controlled trial.

METHODS

A total of 556 patients with glaucoma and cataract were randomized 2:1 to either CS-HMS (369) or CS (187) and followed up for 5 years. VF was performed at 6 months and then every year after surgery. We analyzed data for all participants with at least 3 reliable VFs (false positives < 15%). Average between-group difference in rate of progression (RoP) was tested using a Bayesian mixed model and a 2-sided Bayesian P value <.05 (main outcome). A multivariable model measured the effect of intraocular pressure (IOP). A survival analysis compared the probability of global VF sensitivity dropping by predefined cutoffs (2.5, 3.5, 4.5, and 5.5 dB) from baseline.

RESULTS

Data from 352 eyes in the CS-HMS arm and 165 in the CS arm were analyzed (2966 VFs). The mean RoP was -0.26 dB/y (95% credible interval -0.36, -0.16) for CS-HMS and -0.49 dB/y (95% credible interval -0.63, -0.34) for CS. This difference was significant (P = .0138). The difference in IOP only explained 17% of the effect (P < .0001). Five-year survival analysis showed an increased probability of VF worsening by 5.5 dB (P = .0170), indicating a greater proportion of fast progressors in the CS arm.

CONCLUSIONS

CS-HMS has a significant effect on VF preservation in glaucoma patients compared with CS alone, reducing the proportion of fast progressors.

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.

Baseline 10-2 Visual Field Loss as a Predictor for Future Glaucoma Progression

PRCIS

Presence of baseline 10-2 visual field (VF) loss was the strongest predictor of future rate of 24-2 VF loss and development of new 24-2 progression events, suggesting a role for 10-2 VF testing in baseline glaucoma risk analysis.

PURPOSE

The purpose of this study is to examine the relationship between baseline 10-2 VF loss and future 24-2 VF loss.

MATERIALS AND METHODS

Subjects were participating in a prospective longitudinal study within a VA Medical Center outpatient eye clinic. Eligibility required 2 good quality baseline 10-2 VF tests followed by a minimum of 5 good quality 24-2 VF tests over at least 3 years. Longitudinal 24-2 VF testing was completed every 4-6 months after baseline 10-2 testing. Mixed model regression analyses and Cox Proportional Hazard regression analyses were completed to identify predictors of 24-2 mean deviation change rate and new VF loss events.

RESULTS

We studied 394 eyes of 202 subjects (119 primary open angle glaucoma and 83 glaucoma suspect). Over 6.7 (±1.5) years, 9.9 (±2.3) good quality 24-2 VF tests were completed. In mixed model regression analyses, baseline variables that predicted faster rate of 24-2 VF loss in order of strength of association were presence of baseline 10-2 VF defect, lower 24-2 mean deviation, and higher age. When analyses were completed without 10-2 variables, predictive capability of the model was reduced compared with when 10-2 variables were included. In Cox Proportional Regression analyses evaluating progression events, baseline 10-2 VF defect demonstrated the largest hazard ratio (22 times greater risk for developing future VF loss event in eyes with vs. without baseline 10-2 VF loss).

CONCLUSIONS

Baseline 10-2 VF defect was the most effective predictor of subsequent 24-2 VF progression in this study. These findings imply that presence of baseline 10-2 VF loss may provide unique value for predicting future glaucoma progression.

Frequency of Optical Coherence Tomography Testing to Detect Progression in Glaucoma

PRCIS

With high specificity and less variability than perimetry, more frequent testing resulted in shorter time to detect progression, though a 6-month testing interval provides a reasonable trade-off for following glaucoma patients using optical coherence tomography (OCT).

PURPOSE

To investigate the time to detect progression in glaucomatous eyes using different OCT test intervals.

MATERIALS AND METHODS

Participants with manifest glaucoma from the African Descent and Glaucoma Evaluation Study (ADAGES), a multicenter, prospective, observational cohort study, were included. A total of 2699 OCT tests from 171 glaucomatous and 149 normal eyes of 182 participants, with at least 5 tests and 2 years of follow-up, were analyzed. Computer simulations (n=10,000 eyes) were performed to estimate time to detect progression of global circumpapillary retinal nerve fiber layer thickness (cpRNFL) measured with OCT tests. Simulations were based on different testing paradigms (every 4, 6, 12, and 24 mo) and different rates of change (µm/year). Time to detect significant progression ( P <0.05) at 80% and 90% power were calculated for each paradigm and rate of cpRNFL change.

RESULTS

As expected, more frequent testing resulted in shorter time to detect progression. Although there was clear disadvantage for testing at intervals of 24 versus 12 months (~22.4% time [25 mo] increase in time to progression detection) and when testing 12 versus 6 months (~22.1% time [20 mo] increase), the improved time to detect progression was less pronounced when comparing 6 versus 4 months (~11.5% time [10 mo] reduction).

CONCLUSION

With high specificity and less variability than perimetry, a 6-month testing interval provides a reasonable trade-off for following glaucoma patients using OCT.

The 24-2 Visual Field Guided Progression Analysis Can Miss the Progression of Glaucomatous Damage of the Macula Seen Using OCT

PURPOSE

To better understand the efficacy of the 24-2 guided progression analysis (GPA) in the detection of progression in eyes with early glaucoma (i.e., 24-2 mean deviation [MD] better than -6 dB) by comparing 24-2 GPA with a reference standard (RS) based on a combination of OCT and 24-2 and 10-2 visual field (VF) information.

DESIGN

Cross-sectional study.

PARTICIPANTS

Ninety-nine eyes from 99 individuals, including 70 suspected or early glaucomatous eyes (24-2 MD better than -6 dB) and 29 healthy controls (HCs).

METHODS

All the eyes had at least 4 OCT and VF test dates over a period that ranged from 12 to 59 months. The 24-2 VF tests included 2 baseline tests and at least 2 follow-up tests. The 2 baseline tests were performed within an average of 5.6 days (median, 7 days), and the last follow-up test was performed at least 1 year after the first baseline visit.

MAIN OUTCOME MEASURES

A commercial 24-2 GPA software, with default settings, characterized the eyes as having "likely progression" (LP) or "possible progression" (PP); both were considered "progressing" for this analysis. For RS, 3 authors graded progression using strict criteria and a combination of a custom OCT progression report and commercial 24-2 and 10-2 GPA reports for the same test dates as GPA.

RESULTS

The reference standard identified 10 (14%) of the 70 patient eyes and none of the HC eyes as having progression. The 24-2 guided progression analysis identified 13 of the 70 patient eyes as having progression (PP or LP). However, it correctly classified only 4 (40%) of the 10 RS progressors. All 6 of the RS progressors missed by the 24-2 GPA showed progression in the macula. In addition, the 24-2 GPA identified 2 of the 29 HC eyes as progressors and 9 patient eyes without progression based on the RS.

CONCLUSIONS

In eyes with early glaucoma (i.e., 24-2 MD, > -6 dB) in this study, the 24-2 GPA missed progression seen using OCT and exhibited a relatively high rate of false positives. Furthermore, the region progressing typically included the macula. The results suggest that including OCT and/or 10-2 VFs should improve the detection of progression.

Long-term reproducibility of optical coherence tomography angiography in healthy and stable glaucomatous eyes

BACKGROUND/AIMS

To assess and compare long-term reproducibility of optic nerve head (ONH) and macula optical coherence tomography angiography (OCTA) vascular parameters and optical coherence tomography (OCT) thickness parameters in stable primary open-angle glaucoma (POAG), glaucoma suspect and healthy eyes.

METHODS

Eighty-eight eyes (15 healthy, 38 glaucoma suspect and 35 non-progressing POAG) of 68 subjects who had at least three visits within 1-1.5 years with OCTA and OCT imaging (Angiovue; Optovue, Fremont, California, USA) on the same day were included. A series of vascular and thickness parameters were measured including macular parafoveal vessel density (pfVD), ONH circumpapillary capillary density (cpCD), macular parafoveal ganglion cell complex (pfGCC) and ONH circumpapillary retinal nerve fibre layer (cpRNFL). A random effects analysis of variance model was used to estimate intraclass correlation (ICC) coefficients and long-term variability estimates.

RESULTS

ICC was lower for OCTA (pfVD 0.823 (95% CI 0.736 to 0.888) and cpCD 0.871 (0.818 to 0.912)) compared with OCT (pfGCC 0.995 (0.993 to 0.997) and cpRNFL 0.975 (0.964 to 0.984)). Within-subject test-retest SD was 1.17% and 1.22% for pfVD and cpCD, and 0.57 and 1.22 µm for pfGCC and cpRNFL. Older age and lower signal strength index were associated with decreasing long-term variability of vessel densities.

CONCLUSIONS

OCTA-measured macula and ONH vascular parameters have good long-term reproducibility, supporting the use of this instrument for longitudinal analysis. OCTA long-term reproducibility is less than OCT-measured thickness reproducibility. This needs to be taken into consideration when serial OCTA images are evaluated for change.

TRIAL REGISTRATION NUMBER

NCT00221897.

Characteristics of Central Visual Field Progression in Eyes with Optic Disc Hemorrhage

PURPOSE

To investigate the characteristics and rate of central visual field loss after optic disc hemorrhage (DH).

DESIGN

Prospective cohort study.

METHODS

Three hundred forty-three eyes of 220 subjects who had ≥3 years of follow-up with a minimum of 5 visits with 10-2 and 24-2 visual field (VF) were recruited. Rates of 10-2 mean deviation (MD) loss in each hemifield and predefined zones were compared using linear mixed-effects models in DH and non-DH eyes. Clustered pointwise regression analysis was also used to define central VF progressors and compared with 24-2 VF loss using guided progression analysis.

RESULTS

Thirty-nine eyes with DH and 304 eyes without DH had a mean follow-up of 5.2 years. Eyes with DH had rates of 10-2 MD loss that were 3 times faster than non-DH eyes (mean difference -0.36 dB/year [95% confidence interval 0.54-0.18]; P < .001) and were 3.7 times more likely to progress (P = .002). A larger proportion of glaucomatous eyes showed central VF progression rather than peripheral VF progression in the DH group (30.8% vs. 20.5%) compared with the non-DH group (10.9% vs. 9.2%). In early glaucoma, the rate of 10-2 MD loss was 5.5 times faster in DH eyes than in non-DH eyes (P < .001). Superonasal and superotemporal central VF regions progressed more rapidly than other regions, especially in DH eyes.

CONCLUSION

Central VF loss is accelerated in glaucoma eyes with DH and it corresponds topographically to the DH location. In patients with glaucoma with DH, one should consider supplementing 10-2 VFs with 24-2 VFS to monitor the disease.

Investigation of progression pattern and associated risk factors in glaucoma patients with initial paracentral scotomas using Humphrey 10-2

Central visual field (VF) progression could directly threaten patientss visual function compared to glaucomatous damage. This study was designed to investigate visual field (VF) progression pattern and associated risk factors including optical coherence topography angiographic (OCT-A) findings in glaucoma patients with initial paracentral scotoma. This prospective, observational study included 122 eyes presenting as initial paracentral scotomas with serial 24-2 and 10-2 VF tests at the glaucoma clinic of Seoul St Mary's Hospital between November 2017 and August 2020. The participants underwent at least 5 serial VF exams and OCT-A at baseline. Numerical values of the initial and final 10-2 VF tests were averaged for each VF test point using the total deviation map. Innermost 10-2 VF progression was defined as three or more new contiguous points at the central 12 points on 10-2 VF. Other clinical characteristics were collected including history of disc hemorrhage and vessel density (VD) was measured from OCT-A images. Linear regression analysis was performed to obtain the change of mean deviation and a cut-off for progression was defined for both 24-2 and 10-2 VFs. The average total deviation maps of the initial 10-2 VF tests shows initial paracentral scotoma located in the superior region in an arcuate pattern that was deep in the 4°–6° region above fixation. This arcuate pattern was more broadly located in the 4°–10° region in the primary open-angle glaucoma (POAG) group, while it was closer to fixation in 0°–4° region in the normal-tension glaucoma (NTG) group. The final average map shows deepening of scotomas in the 4°–10° region in POAG, which deepened closer to the region of fixation in NTG. The diagnosis of NTG (β 1.892; 95% CI 1.225–2.516; P = 0.035) and lower choroidal VD in the peripapillary atrophy (PPA) region (β 0.985; 95% CI 0.975 to 0.995; P = 0.022) were significantly related to innermost 10-2 VF progression. Initial paracentral scotomas in NTG tended to progress closer to the region of fixation, which should be monitored closely. Important progression risk factors related to paracentral scotoma near the fixation were the diagnosis of NTG and reduced choroidal VD in the β-zone PPA region using OCT-A. We should consider vascular risk factors in NTG patients presenting with initial paracentral scotoma to avoid vision threatening progression of glaucoma.

Advances in perimetry for glaucoma

PURPOSE OF REVIEW

Perimetry remains important for the diagnosis and management of glaucoma despite advances in imaging technology. The purpose of this review is to describe advances in the acquisition and analysis of visual field data and highlight novel techniques for performing perimetry.

RECENT FINDINGS

Studies have focused on improving the detection of patients at highest risk of severe vision loss and the development of innovative testing strategies that allow for more frequent testing. Artificial intelligence has been utilized in research settings to improve detection and characterization of glaucomatous field damage. Furthermore, tablet-based strategies and virtual reality headsets show promise for glaucoma screening and remote monitoring of patients with glaucoma.

SUMMARY

New testing strategies and research findings have improved our ability to identify patients with both paracentral and mid-peripheral visual field progression. New strategies have the potential to make visual field testing more efficient, reliable and accessible for patients with glaucoma.

Detection of Glaucoma Deterioration in the Macular Region with Optical Coherence Tomography: Challenges and Solutions

PURPOSE

Macular imaging with optical coherence tomography (OCT) measures the most critical retinal ganglion cells (RGCs) in the human eye. The goal of this perspective is to review the challenges to detection of glaucoma progression with macular OCT imaging and propose ways to enhance its performance.

DESIGN

Perspective with review of relevant literature.

METHODS

Review of challenges and issues related to detection of change on macular OCT images in glaucoma eyes. The primary outcome measures were confounding factors affecting the detection of change on macular OCT images.

RESULTS

The main challenges to detection of structural progression in the macula consist of the magnitude of and the variable amount of test-retest variability among patients, the confounding effect of aging, lack of a reliable and easy-to-measure functional outcome or external standard, the confounding effects of concurrent macular conditions including myopia, and the measurement floor of macular structural outcomes. Potential solutions to these challenges include controlling head tilt or torsion during imaging, estimating within-eye variability for individual patients, improved data visualization, the use of artificial intelligence methods, and the implementation of statistical approaches suitable for multidimensional longitudinal data.

CONCLUSIONS

Macular OCT imaging is a crucial structural imaging modality for assessing central RGCs. Addressing the current shortcomings in acquisition and analysis of macular volume scans can enhance its utility for measuring the health of central RGCs and therefore assist clinicians with timely institution of appropriate treatment.