The Effective Dynamic Ranges for Glaucomatous Visual Field Progression With Standard Automated Perimetry and Stimulus Sizes III and V

Relating Standardized Automated Perimetry Performed with Stimulus Sizes III and V in Eyes With Field Loss due to Glaucoma and NAION

Objective

Standard automated perimetry (SAP) visual field (VF) results are more repeatable using Goldmann stimulus size V (stimV) in eyes with moderate/severe deficits due to glaucoma. There are few reports relating VFs using stimulus size V and III, typically used in the clinic for glaucoma, and none for non-arteritic anterior ischemic optic neuropathy (NAION). We hypothesized that we could compare and relate the VFs with both stimuli for glaucoma and NAION.

Methods

We utilized 1992 same-day pairs of stimIII and stimV SAP VFs using the 24-2 strategy for eyes with glaucoma or NAION. We explored the optimal threshold to censor the raw sensitivities, prior to calculating age-standardized total deviations (TD). We determined the mean and standard deviation of the differences among all TD pairs. We computed a line of best fit to determine closeness to the line of unity.

Results

The ideal censoring conversion threshold was 21 dB for stimIII and 24 dB for stimV. The difference between stimV and stimIII censored (0.0 ± 1.9 dB) and uncensored (0.4 ± 2.6 dB) TD pairings strongly correlate with each other (r2 = 0.70, p < 0.001). The line of best fit from these pairings has a slope of 0.92, which is similar to that of the line of unity (m = 1).

Conclusion

Censoring plus age correction is a valid method of comparison between stimIII and stimV SAP VFs with moderate to severe VF loss due to optic nerve disorders.

Translational Relevance

StimIII and stimV TDs are interchangeable in clinical practice.

Which glaucoma patients benefit from 10-2 visual field testing? Proposing the functional vulnerability zone framework

CLINICAL RELEVANCE

A method for determining 10-2 deployment in glaucoma with the goal of detecting additional visual field sensitivity for the purpose of functional monitoring is proposed.

BACKGROUND

To provide a pilot method for determining when to deploy the 10-2 visual field (VF) test grid in glaucoma by characterising the 'functional vulnerability zone'.

METHODS

The cross-sectional 24-2 (central 12 locations) and 10-2 VF results from 133 eyes of 133 glaucoma subjects were used to describe the central Hill of Vision using VF sensitivity. The 'volume' (defined using arbitrary units, A.U.) under the Hill was calculated. A greater A.U. on the 10-2 indicated a functional vulnerability zone (FVZ), signifying additional clinical dynamic range for potential future monitoring. The main outcome measures were calculated A.U. and 24-2 factors which were significantly related to A.U. differences between 24-2 and 10-2.

RESULTS

Over 55% of patients had an FVZ (A.U. greater using 10-2). Several 24-2 features (worse mean deviation, worse central 24-2 mean defect, and a higher proportion of defective locations) were significant in the FVZ cohort compared to non-FVZ. 24-2 mean deviation levels at which 10-2 may be favoured were low at -3.16 to -3.62 dB. Specifically, 5 or more defective central 24-2 test locations were associated with an FVZ. Subjects exhibiting a less severe defect on the 10-2 were more likely to have an FVZ, indicating its potential for future VF monitoring.

CONCLUSIONS

The authors propose several clinical markers, focussing on the 24-2, which can guide clinicians on when the 10-2 may have utility in glaucoma assessment. The authors provide a pilot reference spreadsheet for clinicians to visualise the likelihood of 10-2 utility in the context of an FVZ.

Understanding and identifying visual field progression

Detecting deterioration of visual field sensitivity measurements is important for the diagnosis and management of glaucoma. This review surveys the current methods for assessing progression that are implemented in clinical devices, which have been used in clinical trials, alongside more recent advances proposed in the literature. Advice is also offered to clinicians on what they can do to improve the collection of perimetric data to help analytical progression methods more accurately predict change. This advice includes a discussion of how frequently visual field testing should be undertaken, with a view towards future developments, such as digital healthcare outside the standard clinical setting and more personalised approaches to perimetry.

Comparing a head-mounted virtual reality perimeter and the Humphrey Field Analyzer for visual field testing in healthy and glaucoma patients

PURPOSE

To compare clinical visual field outputs in glaucoma and healthy patients returned by the Humphrey Field Analyzer (HFA) and virtual reality (Virtual Field, VF) perimetry.

METHODS

One eye of 54 glaucoma patients and 41 healthy subjects was prospectively tested (three times each in random order) using the HFA and VF perimeters (24-2 test grids). We extracted and compared global indices (mean deviation [MD] and pattern standard deviation [PSD]), pointwise sensitivity (and calculated 'equivalent' sensitivity after accounting for differences in background luminance) and pointwise defects. Bland-Altman (mean difference [Mdiff ] and 95% limits of agreement [LoA]) and intraclass correlation analyses were performed.

RESULTS

The VF test was shorter (by 76 s) and had lower fixation losses (by 0.08) and false-positive rate (by 0.01) compared to the HFA (all p < 0.0001). Intraclass correlations were 0.86, 0.82 and 0.47 for MD, PSD and pointwise sensitivity between devices, respectively. Test-retest variability was higher for VF (Mdiff 0.3 dB, LoA -7.6 to 8.2 dB) compared to the HFA (Mdiff -0.3 dB, LoA -6.4 to 5.9 dB), indicating greater test-retest variability. When using each device's underlying normative database, the HFA detected, on average, 7 more defects (at the p < 0.05 level) out of the 52 test locations compared to this iteration of VF in the glaucoma cohort.

CONCLUSIONS

Virtual Field returns global results that are correlated with the HFA, but pointwise sensitivities were more variable. Differences in test-retest variability and defect detection by its current normative database raise questions about the widespread adoption of VF in lieu of the HFA.

Utility of Central 10 Degrees Visual Field Test With Size V Stimulus in End-Stage Glaucoma

PRCIS

In end-stage glaucoma, the central 10-degree visual field test with a size V stimulus provided useful information, including the number of points with detectable retinal sensitivity threshold values and retinal sensitivity threshold values.

PURPOSE

The purpose of this study was to evaluate the clinical utility of the central 10-degree visual field test with a size V stimulus in end-stage glaucoma.

MATERIALS AND METHODS

A total of 73 eyes with end-stage glaucoma (visual field limited to a radius of <10 degrees from fixation) were included. Central 10 degrees visual field tests were performed using both size III and V stimuli. Reliability indices, test duration, number of points with detectable retinal sensitivity threshold values, and retinal sensitivity threshold values at 4 central points, 4 quadrants, and 3 clusters (papillomacular area, superior half, and inferior half) were compared between the test results using size III and V stimuli.

RESULTS

When the size V stimulus was used, the mean test duration increased from 7.8 to 13.3 minutes ( P < 0.001), the mean number of test points with detectable retinal sensitivity threshold values in total area increased from 19.0 to 37.3 ( P < 0.001), and the mean retinal sensitivity threshold values in total area increased from 3.9 to 9.3 dB ( P < 0.001) compared with the test results with the size III stimulus. Significant increase in the visual field parameters was found in all quadrants and clusters ( P < 0.001), and a greater increase was associated with better visual acuity and greater mean deviation of the visual field ( P < 0.05).

CONCLUSIONS

The central 10-degree visual field test with a size V stimulus provided more information than the test with a size III stimulus in end-stage glaucoma.

Validation of the Iowa Head-Mounted Open-Source Perimeter

Purpose

To assess the validity of visual field (VF) results from the Iowa Head-Mounted Display (HMD) Open-Source Perimeter and to test the hypothesis that VF defects and test-retest repeatability are similar between the HMD and Octopus 900 perimeters.

Methods

We tested 20 healthy and nine glaucoma patients on the HMD and Octopus 900 perimeters using the Open Perimetry Interface platform with size V stimuli, a custom grid spanning the central 26° of the VF, and a ZEST thresholding algorithm. Historical data from the Humphrey Field Analyzer (HFA) were also analyzed. Repeatability was analyzed with the repeatability coefficient (RC), and VF defect detection was determined through side-by-side comparisons.

Results

The pointwise RCs were 2.6 dB and 3.4 dB for the HMD and Octopus 900 perimeters in ocular healthy subjects, respectively. Likewise, the RCs were 4.2 dB and 3.5 dB, respectively, in glaucomatous patients. Limits of agreement between the HMD and Octopus 900 perimeters were ±4.6 dB (mean difference, 0.4 dB) for healthy patients and ±8.9 dB (mean difference, 0.1 dB) for glaucomatous patients. Retrospective analysis showed that pointwise RCs on the HFA2 perimeter were between 3.4 and 3.7 dB for healthy patients and between 3.9 and 4.7 dB for glaucoma patients. VF defects were similar between the HMD and Octopus 900 for glaucoma subjects.

Conclusions

The Iowa Virtual Reality HMD Open-Source Perimeter is as repeatable as the Octopus 900 perimeter and is a more portable and less expensive alternative than traditional perimeters.

Translational Relevance

This study demonstrates the validity of the visual field results from the Iowa HMD Open-Source Perimeter which may help expand perimetry access.

Visual Field Pointwise Analysis of the Idiopathic Intracranial Hypertension Weight Trial (IIH:WT)

Purpose

This study was designed to determine if point analysis of the Humphrey visual field (HVF) is an effective outcome measure for people with idiopathic intracranial hypertension (IIH) compared with mean deviation (MD).

Methods

Using the IIH Weight Trial data, we performed a pointwise analysis of the numerical retinal sensitivity. We then defined a medically treated cohort as having MDs between -2 dB and -7 dB and calculated the number of points that would have the ability to change by 7 dB.

Results

The HVF 24-2 mean ± SD MD in the worse eye was -3.5 ± 1.1 dB (range, -2.0 to -6.4 dB). Total deviation demonstrated a preference for the peripheral and blind spot locations to be affected. Points between 0 dB and -10 dB demonstrated negligible ability to improve, compared with those between -10 dB and -25 dB. For the evaluation of the feasibility for a potential medical intervention trial, only 346 points were available for analysis between -10 dB and -25 dB bilaterally, compared with 4123 points in baseline sensitivities of 0 to -10 dB.

Conclusions

Patients with IIH have mildly affected baseline sensitivities in the visual field based on HVF analyzer findings, and the majority of points do not show substantial change over 24 months in the setting of a randomized clinical trial. Most patients with IIH who are eligible for a medical treatment trial generally have the mildest affected baseline sensitivities. In such patients, pointwise analysis offers no advantage over MD in detection of visual field change.

Longitudinal Signal-to-Noise Ratio of Perimetry at Different Severities of Glaucoma

Purpose

Automated perimetry is relied on for functional assessment of patients with glaucoma, but questions remain about its effective dynamic range and its utility for quantifying rates of progression at different stages of the disease. This study aims to identify the bounds within which estimates of rate are most reliable.

Methods

Pointwise longitudinal signal-to-noise ratios (LSNR), defined as the rate of change divided by the standard error of the trend line, were calculated for 542 eyes of 273 patients with glaucoma/suspects. The relations between the mean sensitivity within each series and lower percentiles of the distribution of LSNRs (representing progressing series) were analyzed by quantile regression, with 95% confidence intervals derived by bootstrapping.

Results

The 5th and 10th percentiles of LSNRs reached a minimum at sensitivities 17 to 21 dB. Below this, estimates of rate became more variable, making LSNRs of progressing series less negative. A significant step change in these percentiles also occurred at approximately 31 dB, above which LSNRs of progressing locations became less negative.

Conclusions

The lower bound of maximum utility for perimetry was ∼17 to 21dB, coinciding with previous results suggesting that below this point, retinal ganglion cell responses saturate and noise overwhelms remaining signal. The upper bound was ∼30 to 31 dB, coinciding with previous results suggesting that above this point, the size III stimulus used is larger than Ricco's area of complete spatial summation.

Translational Relevance

These results quantify the impact of these two factors on the ability to monitor progression and provide quantifiable targets for attempts to improve perimetry.

[Static automated perimetry in the diagnosis of glaucoma. Assessment of disease progression]

There are several ways to assess glaucoma progression using standard automated perimetry. Most often, ophthalmologists evaluate the stability of visual functions manually when comparing several study protocols. The advantages of clinical assessment are ease of implementation and the ability to interpret data from any device. The main disadvantage of this method is its subjectivity. There are many available automated methods for assessing disease progression involving Humphrey Field Analyzer and Octopus perimeters. Event analysis allows determining glaucoma progression at the time of examination, with consideration of the possible physiological fluctuations in light sensitivity. Trend analysis of perimetric indices makes it possible to assess the rate of glaucoma progression and forecast the trend of changes in visual functions over the next five years. All these methods for assessing progression have certain advantages and disadvantages and cannot be considered ideal. Pointwise and cluster trend analysis are more sensitive in early glaucoma and are being actively researched and developed. These methods have great potential, although they are not yet sufficiently available in clinical practice.

Test Reliability and Compliance to a Twelve-Month Visual Field Telemedicine Study in Glaucoma Patients

Background: Our primary aim is to quantify test reliability and compliance of glaucoma patients to a weekly visual field telemedicine (VFTM) schedule. A secondary aim is to determine concordance of the VFTM results to in-clinic outcomes. Methods: Participants with stable glaucoma in one eye were recruited for a 12 month VFTM trial using the Melbourne Rapid Fields (MRF-home, MRFh) iPad application. Participants attended routine 6 month clinical reviews and were tasked with weekly home monitoring with the MRFh over this period. We determined compliance to weekly VFTM (7 + 1 days) and test reliability (false positives (FPs) and fixation loss (FL) <33%). A secondary aim considered concordance to in-clinic measures of visual field (MRF-clinic (MRFc) and the Humphrey Field Analyzer (HFA)) in active participants (≥10 home examinations and 5 reliable HFA examinations). The linear trend in the MRFh mean deviation (MD) was compared to the HFA guided progression analysis (GPA) using Bland−Altman methods. Data are shown as the mean ± standard deviation. Results: Forty-seven participants with a mean age of 64 ± 14.6 years were recruited for the trial. The VFTM uptake was 85% and compliance to weekly home monitoring was 75% in the presence of weekly text reminders in the analysed group (n = 20). The analysed group was composed of test subjects with five reliable in-clinic HFA examinations (GPA analysis available) and who submitted a minimum of 10 MRFh examinations from home. Of the 757 home examinations returned, approximately two-thirds were reliable, which was significantly lower than the test reliability of the HFA in-clinic (MRFh: 65% vs. HFA: 85%, p < 0.001). The HFA-GPA analysis gave little bias from the MRFh slope (bias: 0.05 dB/yr, p > 0.05). Two eyes were found to have clinical progression during the 12 month period, and both were detected by VFTM. Conclusions: VFTM over 12 months returned good compliance (75%) to weekly testing with good concordance to in-clinic assays. VFTM is a viable option for monitoring patients with glaucoma for visual field progression in between clinical visits.

The Usefulness of Assessing Glaucoma Progression With Postprocessed Visual Field Data

Purpose

Data postprocessing with statistical techniques that are less sensitive to noise can be used to reduce variability in visual field (VF) series. We evaluated the detection of glaucoma progression with postprocessed VF data generated with the dynamic structure–function (DSF) model and MM-estimation robust regression (MRR).

Method

The study included 118 glaucoma eyes with at least 15 visits selected from the Rotterdam dataset. The DSF and MRR models were each applied to observed mean deviation (MD) values from the first three visits (V_1–3) to predict the MD at V_4. MD at V₅ was predicted with data from V_1–4 and so on until the MD at V₉ was predicted, creating two additional datasets: DSF-predicted and MRR-predicted. Simple linear regression was performed to assess progression at the ninth visit. Sensitivity was evaluated by adjusting for false-positive rates estimated from patients with stable glaucoma and by using longer follow-up series (12th and 15th visits) as a surrogate for progression.

Results

For specificities of 80% to 100%, the DSF-predicted dataset had greater sensitivity than the observed and MRR-predicted dataset when positive rates were normalized with corresponding false-positive estimates. The DSF-predicted and observed datasets had similar sensitivity when the surrogate reference standard was applied.

Conclusions

Without compromising specificity, the use of DSF-predicted measurements to identify progression resulted in a better or similar sensitivity compared to using existing VF data.

Translational Relevance

The DSF model could be applied to postprocess existing visual field data, which could then be evaluated to identify patients at risk of progression.

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.

Benefit of Stimulus Size V Perimetry for Patients With a Dense Central Scotoma From Leber's Hereditary Optic Neuropathy

Purpose

Leber's hereditary optic neuropathy (LHON) is the most common mtDNA optic neuropathy. It most frequently causes dense bilateral central scotomas that are often characterized in clinical studies by Humphrey visual field testing (HVF) using a stimulus size III. This provides numerical quantification of the visual field defect using the mean deviation. However, this size III testing strategy has limitations. We used stimulus size V to monitor these patients and evaluated intertest variability and dynamic range to determine the testing reliability and reproducibility.

Methods

This was a longitudinal retrospective cohort study comparing Stimulus III and Stimulus V HVF of 62 LHON patients who had reached the plateau stage of the disease. The intertest variability and mean defect were calculated for both stimulus sizes for 38 patients. The mean defect for stimulus size V was calculated using an algorithm developed by the University of Iowa Visual Field Reading Center.

Results

Stimulus size V HVFs had lower inter-test variability as measured by mean defect standard deviation (Z = 169, P < 0.01). The floor effect seen with Stimulus III HVF in LHON, was less pronounced with Stimulus V HVF. The correlation of stimulus size III and V mean defect was strong (r = 0.90, P < 0.01), and a mathematical model was constructed to calculate the Stimulus size V mean defect from the Stimulus size III results (MDstimV = 0.988 x MDStimIII + 1.35, R2 = 0.82 P < 0.01).

Conclusions

Stimulus size V HVF had lower intertest variability and a better dynamic range than Stimulus size III HVF in LHON patients. This makes the stimulus V HVF a more reliable metric to follow LHON patients especially in clinical trials. The mathematical model presented can be used to generate a Stimulus V equivalent mean defect from Stimulus III HVFs.

Translational Relevance

Using Stimulus V HVF in LHON patients increases its ability to detect and quantify a response to treatment, making it a useful metric for future LHON clinical trials and the clinical setting.

Perimetry and visual field defects

Perimetry is the quantitation of the visual field. This is done with a perimeter and usually involves measuring visual thresholds to a range of light stimuli. It is used clinically to map patterns of visual loss due to damage to the sensory visual system. This chapter discusses the types of perimetric testing and the psychophysics of perimetry. This is followed by the interpretation of perimetric results, the relevant visual system anatomy, and patterns of loss helpful for neurologic localization. Lastly, the difficult issue of deciding whether the visual field has changed is reviewed. Patterns of visual loss are the key to anatomic diagnosis. Strictly monocular defects map to the prechiasmal sensory visual system. Bitemporal hemianopia is the signature of damage to the optic chiasm. Incongruous homonymous hemianopia points to an optic tract lesion. The closer a lesion gets to the occipital cortex, the more congruous or similar are the patterns of homonymous hemianopia. Understanding these patterns, the basics of perimetry and other rules of localization will add an important dimension to the neurologist's localization arsenal.

Increasing the Spatial Resolution of Visual Field Tests Without Increasing Test Duration: An Evaluation of ARREST

Purpose

The Australian Reduced Range Extended Spatial Test (ARREST) approach was designed to improve visual field spatial resolution while maintaining a similar test duration to clinically used testing algorithms. ARREST does not completely threshold visual field locations with sensitivity < 17 dB, and uses the presentations saved to test new locations in areas of steep gradient within the visual field. Previous assessments of ARREST's performance have used computer simulation. In this study, we cross-sectionally assessed the performance of ARREST in people with visual field loss.

Methods

We tested 23 people with glaucoma (mean age: 71 ± 8 years) with established visual field loss. Three visual field procedures were performed using the Open Perimetry Interface: cZEST and ARREST on the Octopus 900 perimeter (Haag-Streit AG, Switzerland), and a reference standard (best available estimate [BAE]) on the Compass perimeter (CenterVue SpA, Italy). ARREST was compared against the cZEST and the BAE.

Results

On average, ARREST added seven new locations (range = 0–15) to a visual field test. There was no significant difference in the number of stimulus presentations between procedures (mean = 259 ± 25 [ARREST] vs. 261 ± 25 [cZEST], P = 0.78). In classifying threshold values < 17 dB, ARREST performed similarly when compared against BAE.

Conclusions

This study provides empirical evidence to support conclusions from previous computer simulations that ARREST can be used to increase spatial sampling in regions of interest without increasing test time.

Translational Relevance

ARREST is a new approach that augments current visual field testing procedures to provide better spatial description of visual field defects without increasing test duration.

Improvements in Test-Retest Variability of Static Automated Perimetry by Censoring Results With Low Sensitivity in Retinitis Pigmentosa

Purpose

We evaluated whether omitting (censoring) points in more severely damaged visual field areas can reduce test–retest variability of static automated perimetry (SAP) in retinitis pigmentosa (RP), as variability creates a significant challenge when monitoring for changes.

Methods

Cohort 1 included 27 eyes in 16 RP subjects with visual acuity (VA) ranging from 20/20 to 20/70 who completed Humphrey 10-2 size III SAP, once per visit at three visits. Cohort 2 included 15 eyes in nine RP subjects with VA ≤ 20/60 who completed Humphrey 30-2 size V SAP, twice per visit at three visits. Variability was assessed using 95% coefficient of repeatability (CR) calculations for uncensored (all threshold values and data points included) and censored data.

Results

In cohort 1, the uncensored between-visit 95% CR was 11.6 decibels (dB); censoring locations with threshold values of <8 to 20 dB resulted in 31% to 53% reductions in the 95% CR. For cohort 2, uncensored 95% CRs were 8.7 and 8.0 dB for within- and between-visit variability, respectively; censoring <8 to 17 dB resulted in 15% to 41% and 15% to 43% reductions in within-visit and between-visit 95% CRs, respectively. For both cohorts, censoring at higher values yielded slightly less variability, at the expense of discarding data from a greater number of eyes and test locations.

Conclusions

For 20/20 to 20/70 VA tested with size III stimuli, censoring lower sensitivity values results in substantially lower test–retest variability, which may help detect true changes for locations without severe baseline loss.

Translational Relevance

A rule of thumb for clinical practices using SAP to monitor RP is that longitudinal losses of >9 dB for individual test locations with initial values ≥ 9 dB are likely to be real and meaningful, as they exceed typical variability.

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.

A framework for assessing glaucoma progression using structural and functional indices jointly

Purpose

While many tests and indices are available to identify glaucoma progression, using them in combinations may decrease overall specificity. The aim of this study was to develop a framework for assessing glaucoma progression using structural and functional indices jointly for a fixed specificity.

Methods

The study included 337 eyes of 207 patients with ocular hypertension or primary open-angle glaucoma selected from the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study. All patients had at least 9 visits. Each visit had retinal nerve fiber layer thickness (RNFLT) and mean sensitivity from static automated perimetry (SAP MS) measured within a one-month window. Simple linear regression was applied to assess deterioration in each index for series of 5 to 9 visits. To identify progression using the two indices jointly, marginal significance levels set at a specificity of 95% were derived for two criteria: ANY (worsening on either RNFLT or SAP MS) and ALL (worsening on both RNFLT and SAP MS). Positive rate (percentage of eyes flagged as progressing) was determined individually for each index, as well as for the ANY and ALL criteria.

Results

Compared to SAP MS, RNFLT had higher positive rates (15% to 45%) for all series lengths. For the joint analyses, the positive rate was on average 12% higher for the ANY criterion compared to the ALL criterion. While RNFLT-alone had comparable positive rates and time-to-detection as the ANY criterion, each uniquely identified a subset of eyes (Kappa = 0.55 to 0.75).

Conclusions

This study provides a simple framework for assessing glaucoma progression with data from two tests jointly, without compromising specificity. This framework can be extended to include two or more parameters, can accommodate global or regional indices, and can eventually be used with novel parameters identified as predictive of glaucoma progression.

Threshold Static Automated Perimetry of the Full Visual Field in Idiopathic Intracranial Hypertension

Purpose

To characterize visual loss across the full visual field in idiopathic intracranial hypertension (IIH) patients with mild central visual loss.

Methods

We tested the full visual field (50° nasal, 80° temporal, 30° superior, 45° inferior) of 1 eye of 39 IIH patients by using static perimetry (size V) with the Open Perimetry Interface. Participants met the Dandy criteria for IIH and had at least Frisén grade 1 papilledema with better than -5 dB mean deviation (MD) centrally. Two observers (MW and AS) evaluated the visual field defects, adjudicated any differences, and reviewed optical coherence tomography data.

Results

We found a greater MD loss peripherally than centrally (central 26°). The median MD (and corresponding median absolute deviations) was -1.37 dB (1.61 dB) for the periphery and -0.77 dB (0.87 dB) for the central 26°, P < 0.001. There were about 30% more abnormal test locations identified in the periphery (P = 0.12), and the mean defect depth increased with eccentricity (P < 0.001). The most frequent defect found was a temporal wedge (23% of cases) in the periphery with another 23% that included this sector with inferior temporal loss. Although the presence of papilledema limited correlation, 55% of the temporal wedge defects had optical coherence tomography retinal nerve fiber layer deficits in the corresponding superonasal location. Other common visual field defects were inferonasal loss, superonasal loss, and superior and inferior arcuate defects. Seven patients (18%) had visual field defects in the periphery with normal central visual field testing.

Conclusion

In IIH patients, we found substantial visual loss both outside 30° of the visual field and inside 30° with the depth of the defect increasing linearly with eccentricity. Temporal wedge defects were the most common visual field defect in the periphery. Static threshold perimetry of the full visual field appears to be clinically useful in IIH patients.

Neutralizing Peripheral Refraction Eliminates Refractive Scotomata in Tilted Disc Syndrome

SIGNIFICANCE

We demonstrate that the visual field defects in patients with tilted disc syndrome can be reduced or eliminated by neutralizing the peripheral scotoma in the area of posterior retinal bowing, which may allow differentiation between a congenital anomaly and acquired pathology.

PURPOSE

Tilted disc syndrome is a congenital and unchanging condition that may present with visual field defects mimicking loss seen in neurological diseases, such as transsynaptic retrograde degeneration. Our purpose was to systematically investigate the ability of a neutralized peripheral refraction to eliminate refractive visual field defects seen in tilted disc syndrome. This was compared with the same technique performed on patients with neurological deficits.

METHODS

The Humphrey Field Analyzer was used to measure sensitivities across the 30-2 test grid in 14 patients with tilted disc syndrome using four refractive corrections: habitual near correction and with an additional -1.00, -2.00 or -3.00 D negative lens added as correction lenses. Peripheral refractive errors along the horizontal meridian were determined using peripheral retinoscopy and thus allowed calculation of residual peripheral refraction with different levels of refractive correction. Visual field defects were assessed qualitatively and quantitatively using sensitivities and probability scores in both patient groups.

RESULTS

A smaller residual refractive error after the application of negative addition lenses correlated with improvement in visual field defects in terms of sensitivity and probability scores in patients with tilted disc syndrome. Patients with established neurological deficits (retrograde degeneration) showed improvement in sensitivities but not in probability scores.

CONCLUSIONS

Neutralizing the refractive error at the region of posterior retinal bowing due to tilted disc syndrome reduces the apparent visual field defect. This may be a useful and rapid test to help differentiate between tilted disc syndrome and other pathological causes of visual field defects such as neurological deficits.

Comparison of Methods to Detect and Measure Glaucomatous Visual Field Progression

PURPOSE

To compare methods to assess visual field (VF) progression in glaucoma.

METHODS

4,950 VFs of 253 primary open angle-glaucoma patients were evaluated for progression with the following methods: clinical evaluation, guided progression analysis (GPA), mean deviation (MD), and visual field index (VFI) rates, Advanced Glaucoma Intervention Study (AGIS) and Collaborative Initial Glaucoma Treatment Study (CIGTS) scores, pointwise linear regression (PLR), permutation of PLR (PoPLR), and glaucoma rate index (GRI). A separate simulated series of longitudinal VFs was assessed with all methods except for GPA and clinical evaluation.

RESULTS

The average (±SD) age of the patients at baseline was 65.4 (±11.5) years. The average (±SD) follow-up was 11.8 (±4.6) years, and the mean (±SD) number of VFs was 16.8 (±7.0). Proportion of series detected as progressing was 65% for PoPLR, 58% for GRI, 41% for GPA, 40% for PLR, 36% for CIGTS, 35% for clinicians, 31% for MD rate, 29% for AGIS, and 22% for VFI rate. Median times to detection of progression were 7.3 years for PoPLR, 7.5 years for GRI, 11 years for clinicians, 14 years for GPA, 16 years for PLR, 17 years for CIGTS, 19 years for AGIS, and more than 20 years for MD and VFI rates. In simulated VF series, GRI had the highest partial area under the receiver operator characteristic curve (0.040) to distinguish between glaucoma progression and aging/cataract decay, followed by VFI rate (0.028), MD rate (0.024), and PoPLR (0.006).

CONCLUSIONS

GRI and PoPLR showed the highest proportion of series detected as progressing and shortest times to progression detection. GRI exhibited the best ability to detect progression in the simulated VF series.

TRANSLATIONAL RELEVANCE

Knowledge of the properties of every method would allow tailoring application in both clinical and research settings.

Expediency of the Automated Perimetry Using the Goldmann V Stimulus Size in Visually Impaired Patients with Glaucoma

Introduction

White-on-white standard automated perimetry (AP) uses a white round stimulus with 0.43° diameter and 4.0 mm² area (Goldmann size III). Patients with low vision have difficulty seeing such a small stimulus and are often tested with perimetry using the size V stimulus with 1.72° diameter and 64 mm² area. We undertook an observational case-control study to compare the performance of patients on AP using two differently sized stimuli.

Methods

Patients with glaucoma and visual acuity worse than 20/100 underwent AP using the standard size III stimulus Swedish Interactive Threshold Algorithm (SITA) standard test and size V stimulus full threshold test. All patients were familiar with the procedure, having done the test at least twice previously. Another group of glaucoma patients with visual acuity better than 20/40 served as controls. The main outcome measures included test time, mean retinal sensitivity (MRS), foveal sensitivity (FS), fixation loss (FL), false positive (FP), false negative (FN), and the patient's subjective preference.

Results

Fifty patients were included in the study. Most preferred the size V stimulus target size test. For glaucoma patients, test time was shorter with size III; MRS and FS were higher with size V; FL, FP, and FN did not differ between the tests.

Conclusion

AP with stimulus size V may be a good alternative to standard size III in selected visually debilitated patients who report difficulty undergoing a standard SITA 24-2 test.

Electronic supplementary material

The online version of this article (10.1007/s40123-019-0175-9) contains supplementary material, which is available to authorized users.

Data obtained with an open-source static automated perimetry test of the full visual field in healthy adults

The data were gathered from 98 eyes of 98 ocular healthy subjects. The subject ages ranged from 18 to 79 years with a mean (and standard deviation) of 47 (17) years. Each subject underwent two visual field tests, one of the central visual field (64 locations within 26° of fixation) and one of the peripheral visual field (64 locations with eccentricity from 26° to up to 81°). Luminance thresholds for the Goldmann size V stimulus (with a diameter of 1.72° of visual angle) were obtained with the ZEST Bayesian test procedure. Each test was conducted twice within 90 days.