Evaluation of Glaucoma Progression in Large-Scale Clinical Data: The Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG)

Association of Long-Term Intraocular Pressure Variability and Rate of Ganglion Complex Thinning in Patients With Glaucoma

PURPOSE

To evaluate the association of mean intraocular pressure (IOP) and IOP variability (IOP fluctuation [SD of IOP] and the IOP range) with the rate of ganglion cell complex (GCC) layer thinning over time in patients with glaucoma.

DESIGN

Prospective cohort study.

METHODS

Participants with at least 4 visits and 2 years of follow-up of optical coherence tomography tests were included. A linear mixed-effect model was used to investigate the association of IOP parameters with the rates of GCC thinning. Subgroup analyses were conducted for eyes with early (MD ≥ -6 dB), and moderate to advanced stage (MD < -6 dB) at baseline.

RESULTS

The cohort consisted of 369 eyes of 249 glaucoma patients (282 early glaucoma and 87 moderate to advanced glaucoma) with mean (standard deviation [SD]) age of 68.2 (10.7) years over 5.1 years of follow-up. The mean rate of GCC change was -0.59 (95% confidence interval [CI], -0.67 to -0.52) µm per year. In multivariable models, faster annual rate of GCC thinning was associated with a higher IOP fluctuation (-0.17 [95% CI, -0.23 to -0.11] µm per 1-mmHg higher, P < .001) or higher IOP range (-0.07 [95% CI, -0.09 to -0.05] µm per 1-mmHg higher, P < .001) after adjustment for mean IOP and other confounding factors. Similar results were found for early and moderate to advanced stages of glaucoma.

CONCLUSIONS

IOP variability showed an independent association with macular change in patients with glaucoma regardless of severity at baseline, even after adjustment for mean IOP, supporting its potential value as a therapeutic target for clinical decision-making.

Rates of visual field change and functional progression in glaucoma following trabecular microbypass implantation of iStent technologies: a meta-analysis

BACKGROUND/AIM

While intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma progression, the ultimate goal of glaucoma management is to preserve patients' functional vision and quality of life. To this end, minimally invasive glaucoma surgeries (MIGSs) aim to reduce IOP with minimal eye trauma. Commonly used MIGS devices include iStent technologies, which have well-documented IOP-reducing potential and favourable safety profiles. However, no study concluded on their effect on the rates of visual field (VF) changes. The aim of this meta-analysis is to determine the long-term effect of iStent technology implantation on glaucoma functional progression.

METHODS

Electronic medical literature databases were searched to identify studies reporting on iStent technologies. Reports with follow-up durations <12 months, retention rates <75% and missing VF data were excluded. Fifteen studies reporting on 1115 eyes were identified. The overall weighted mean VF mean deviation (MD) progression, IOP reduction and follow-up duration were calculated.

RESULTS

Weighted mean IOP at baseline was 19.0±3.1 mm Hg. At the end of a 37.9-month mean follow-up (range 12-96 months), a weighted mean 26.6% IOP reduction was achieved (range 15.2%-42.3%). Over the same duration, the weighted mean VF MD progression rate was -0.02±0.34 dBs/year, from a mean baseline of -5.76±5.68 dBs.

CONCLUSION

In this review, which examines functional stability of 1115 eyes, iStent technologies achieved a mean rate of progression of -0.024 dBs/year with serial standard automated perimetry, which is similar to that reported in non-glaucomatous eyes and slower than that reported in medically treated glaucoma.

Relationship between Intraocular Pressure Fluctuation and Visual Field Progression Rates in the United Kingdom Glaucoma Treatment Study

PURPOSE

To investigate whether intraocular pressure (IOP) fluctuation is associated independently with the rate of visual field (VF) progression in the United Kingdom Glaucoma Treatment Study.

DESIGN

Randomized, double-masked, placebo-controlled multicenter trial.

PARTICIPANTS

Participants with ≥5 VFs (213 placebo, 217 treatment).

METHODS

Associations between IOP metrics and VF progression rates (mean deviation [MD] and five fastest locations) were assessed with linear mixed models. Fluctuation variables were mean Pascal ocular pulse amplitude (OPA), standard deviation (SD) of diurnal Goldmann IOP (diurnal fluctuation), and SD of Goldmann IOP at all visits (long-term fluctuation). Fluctuation values were normalized for mean IOP to make them independent from the mean IOP. Correlated nonfluctuation IOP metrics (baseline, peak, mean, supine, and peak phasing IOP) were combined with principal component analysis, and principal component 1 (PC1) was included as a covariate. Interactions between covariates and time from baseline modeled the effect of the variables on VF rates. Analyses were conducted separately in the two treatment arms.

MAIN OUTCOME MEASURES

Associations between IOP fluctuation metrics and rates of MD and the five fastest test locations.

RESULTS

In the placebo arm, only PC1 was associated significantly with the MD rate (estimate, -0.19 dB/year [standard error (SE), 0.04 dB/year]; P < 0.001), whereas normalized IOP fluctuation metrics were not. No variable was associated significantly with MD rates in the treatment arm. For the fastest five locations in the placebo group, PC1 (estimate, -0.58 dB/year [SE, 0.16 dB/year]; P < 0.001), central corneal thickness (estimate, 0.26 dB/year [SE, 0.10 dB/year] for 10 μm thicker; P = 0.01) and normalized OPA (estimate, -3.50 dB/year [SE, 1.04 dB/year]; P = 0.001) were associated with rates of progression; normalized diurnal and long-term IOP fluctuations were not. In the treatment group, only PC1 (estimate, -0.27 dB/year [SE, 0.12 dB/year]; P = 0.028) was associated with the rates of progression.

CONCLUSIONS

No evidence supports that either diurnal or long-term IOP fluctuation, as measured in clinical practice, are independent factors for glaucoma progression; other aspects of IOP, including mean IOP and peak IOP, may be more informative. Ocular pulse amplitude may be an independent factor for faster glaucoma progression.

FINANCIAL DISCLOSURE(S)

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

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

Purpose

To predict Humphrey Field Analyzer 24-2 test (HFA 24-2) results using 10-2 results.

Methods

A total of 175 advanced glaucoma eyes (175 patients) with HFA 24-2 mean deviation (MD24-2) of < -20 dB were prospectively followed up for five years using HFA 10-2 and 24-2 (twice and once in a year, respectively). Using all the HFA 24-2 and 10-2 test result pairs measured within three months (350 pairs from 85 eyes, training dataset), a formula to predict HFA 24-2 result using HFA 10-2 results was constructed using least absolute shrinkage and selection operator regression (LASSO). Using 90 different eyes (testing dataset), the absolute differences between the actual and LASSO-predicted MD24-2 and that between the slopes calculated using five actual and LASSO-predicted MD24-2 values, were adopted as the prediction error. Similar analyses were performed for the mean total deviation values (mTD) of the superior (or inferior) hemifield [hemi-mTDsup.24-2(-hemi-mTDinf.24-2)].

Results

The prediction error for the LASSO-predicted MD24-2 and its slope were 2.98 (standard deviation [SD] = 1.90) dB and 0.32 (0.33) dB/yr, respectively. The LASSO-predicted hemi-mTDsup.24-2 (hemi-mTDinf.24-2), and its slope were 3.02 (2.89) and 3.76 (2.72) dB, and 0.37 (0.41) and 0.44 (0.38) dB/year, respectively. These prediction errors were within two times SD of repeatability of the simulated stable HFA 24-2 VF parameter series.

Conclusions

HFA 24-2 results could be predicted using the paired HFA 10-2 results with reasonable accuracy using LASSO in patients with advanced glaucoma.

Translational Relevance

It is useful to predict HFA24-2 test from HFA10-2 test, when the former is not available, in advanced glaucoma.

Longitudinal evaluation of advanced glaucoma: ten year follow-up cohort study

This study focused on patients with advanced open-angle glaucoma (OAG) and aimed to identify key factors for monitoring them. We included 127 such patients who were followed for seven years or more, undergoing annual ophthalmic examinations. Glaucoma progression was defined as a deterioration in either structure or function. The progression rates and risk factors were evaluated. The patients were divided into upper- and lower-half subgroups based on the reduction in intraocular pressure (IOP) from the baseline. Over an 11-year period, glaucoma progression was detected in 59 eyes (46.5%). The rate of change in mean deviation (MD) was - 0.43 dB/year for the entire population; - 0.67 dB/year for progressors; and - 0.20 dB/year for non-progressors. Hypertension and disc hemorrhage (DH) were more common in progressors compared to non-progressors (45.8 vs. 23.5%, 11.9 vs. 1.5%; P = 0.008 and P = 0.016). Multivariate Cox's proportional hazard model revealed that the presence of DH and a better baseline MD were associated with glaucoma progression. Additionally, patients with a higher percentage reduction in IOP (> 20.94%) had a lower risk of progression compared to those with less reduction. Inadequate IOP reduction, better baseline MD, presence of DH, and lower central corneal thickness were identified as risk factors for progression in advanced OAG patients.

Advancements in Wearable and Implantable Intraocular Pressure Biosensors for Ophthalmology: A Comprehensive Review

Glaucoma, marked by its intricate association with intraocular pressure (IOP), stands as a predominant cause of non-reversible vision loss. In this review, the physiological relevance of IOP is detailed, alongside its potential pathological consequences. The review further delves into innovative engineering solutions for IOP monitoring, highlighting the latest advancements in wearable and implantable sensors and their potential in enhancing glaucoma management. These technological innovations are interwoven with clinical practice, underscoring their real-world applications, patient-centered strategies, and the prospects for future development in IOP control. By synthesizing theoretical concepts, technological innovations, and practical clinical insights, this review contributes a cohesive and comprehensive perspective on the IOP biosensor's role in glaucoma, serving as a reference for ophthalmological researchers, clinicians, and professionals.

Long-term Impact of Immediate Versus Delayed Treatment of Early Glaucoma: Results From the Early Manifest Glaucoma Trial

PURPOSE

To compare long-term visual outcomes in the 2 arms of the Early Manifest Glaucoma Trial (EMGT) and determine if delayed treatment was associated with a penalty in terms of visual function.

DESIGN

Long-term follow-up of a prospective, randomized controlled clinical trial.

METHODS

EMGT was carried out at 2 centers in Sweden; 255 subjects with newly detected, untreated glaucoma were randomized to immediate treatment with topical betaxolol and argon laser trabeculoplasty or to no initial treatment as long as no progression was detected. Subjects were followed prospectively with standard automated perimetry, visual acuity measurements, and tonometry for up to 21 years. Outcomes included vision impairment (VI), the perimetric mean deviation (MD) index and rate of progression, and visual acuity.

RESULTS

At study end, percentages of eyes with VI or blindness were slightly higher in the treated group than in the untreated control group, 12.1% vs 11.0%, and 9.4.% vs 6.1% respectively, as were subjects with VI in at least one eye, 19.5% vs 18.7%. The differences were not statistically significant, nor were cumulative incidences of VI in at least one eye. The control group had more field loss than the treatment group, with median MD in the worse eye of -14.73 dB vs -12.85 dB, and rate of progression of -0.74 vs -0.60 dB/y, which was not statistically significant. Differences in visual acuity were minimal.

CONCLUSIONS

Delaying treatment did not result in serious penalties. VI occurred at similar proportions in both treatment arms with a slight preponderance in the treatment group, whereas visual field damage was slightly higher in the control group.

Cost-Utility Analysis of a Medication Adherence-Enhancing Educational Intervention for Glaucoma

OBJECTIVE

To evaluate the cost utility of a glaucoma medication-enhancing intervention compared to standard of care over a lifetime from the United States Department of Veterans Affairs (VA) payer perspective.

DESIGN

Model-based cost-utility analysis of a glaucoma medication-enhancing intervention from a randomized clinical trial.

SUBJECTS

Veterans with glaucoma, or suspected glaucoma who were prescribed topical glaucoma medications, had their visual field assessed within the last 9 months, and endorsed poor glaucoma medication adherence.

METHODS

Veterans were randomized either to a behavioral intervention to promote adherence or to a standard of care (control) session about general eye health. A decision analytic model was developed to simulate lifelong costs and quality-adjusted life years (QALYs) for an intervention tested in a randomized clinical trial at a single VA eye clinic. Costs included direct medical costs that the VA payer would incur, as informed initially by the clinical trial and then by published estimates. Health-state quality of life was based on published utility values. Scenario analyses included addition of booster interventions, a 3% decline in chance of staying medication adherent annually, and the combination of the two. Analyses were also conducted in the following subgroups: those with companion versus not, and those with once-daily versus more than once-daily dosing frequency.

MAIN OUTCOME MEASURES

Incremental cost-effectiveness ratio (ICER).

RESULTS

Compared to standard of care, the intervention dominated resulting in lower costs ($23 339.28 versus $23 504.02) and higher QALYs (11.62 versus 11.58). Among the 4 subgroups, the intervention dominated for 3 of them. In the fourth subgroup, those with more than once-daily dosing, the ICER was $2625/QALY. Compared to standard of care, an intervention with booster interventions led to an ICER of $3278/QALY. Assuming both a 3% annual loss in chance of continuing to be adherent and addition of booster interventions, the ICER increased to $71 371/QALY.

CONCLUSIONS

From a VA payer perspective over a lifetime, the glaucoma medication-enhancing behavioral intervention dominated standard of care in terms of generating cost savings and greater QALYs.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found after the references.

Effect of Corneal Hysteresis on the Rates of Microvasculature Loss in Glaucoma

PURPOSE

To investigate the association between corneal hysteresis (CH) and rates of optic nerve head whole image capillary density (wiCD) loss over time in open-angle glaucoma (OAG).

DESIGN

Observational cohort.

PARTICIPANTS

One hundred seventy-four eyes (122 OAG and 52 glaucoma suspect eyes) from 112 patients over more than 2 years and 4 visits or more.

METHODS

Baseline CH measurements were acquired with the Ocular Response Analyzer. Linear mixed-effect models were designed to investigate the effect of CH, average intraocular pressure (IOP) during follow-up, and baseline visual field (VF) mean deviation (MD) on the rates of wiCD loss and circumpapillary retinal nerve fiber layer (cpRNFL) thinning over time, while adjusting for confounders. Interaction between CH or baseline MD and average IOP during follow-up were included in final models to evaluate the effect of baseline MD or average IOP during follow-up on structural changes for different values of CH.

MAIN OUTCOME MEASURE

Effect of CH, IOP, and baseline MD on the rates of wiCD loss and cpRNFL thinning over time.

RESULTS

The average follow-up time was 3.9 years. In the multivariable model, non-Black race, higher average IOP during follow-up, lower baseline CH, lower baseline VF MD, and higher numbers of IOP-lowering medications were associated with faster rates of wiCD loss over time. For CH values 6 mmHg and 12 mmHg, every 1-mmHg increase in average IOP during follow-up was associated with 0.23% per year faster and 0.07% per year slower rates of wiCD loss over time, respectively. While every 1-mmHg decrease in CH was associated with 1.89% per year faster rate of wiCD loss for MD of -12 dB, it was associated with 0.81% per year faster rate of wiCD loss for MD of -3 dB.

CONCLUSION

Lower CH values were significantly associated with faster rates of wiCD loss over time. In eyes with lower CH, both higher average IOP during follow-up and more severe glaucoma damage at baseline were associated with faster rates of wiCD loss and cpRNFL thinning. These results support CH as a useful parameter for risk assessment of glaucoma progression.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Comparison of two analyzer measurements focusing on material stiffness among normal, treatment-naïve, and treated glaucoma eyes

To investigate differences in biomechanical properties focusing on stiffness parameters between normal, treatment-naïve primary open-angle glaucoma (POAG), and treated POAG eyes. Retrospective case-control study, This study included 46 treatment-naïve POAG eyes, 46 POAG eyes treated with prostaglandin analogues, and 49 normal eyes used as controls; matched in terms of age and axial length. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using an ocular response analyzer (ORA). Fifteen biomechanical parameters were measured with the Corneal Visualization Scheimpflug Technology (Corvis ST), including biomechanical glaucoma factor (BGF) and two stiffness parameters of 'SP A1' and 'stress-strain index (SSI)', which were compared among the three groups. Additionally, the area under the curve (AUC) values of the receiver-operating curve to discriminate control and treatment-naïve POAG eyes were calculated for BGF and CH. Treatment-naïve POAG eyes had higher 'SSI' than normal eyes even after controlling for IOP (p < 0.05, Tukey-Cramer test). Treated POAG eyes had significantly lower CRF, and higher BGF than treatment-naïve POAG eyes. There were also significant differences in CH or SP A1 among the three groups. BGF and CH had similar AUC values (0.61 and 0.59). Treatment-naïve POAG eyes had stiffer corneas compared to normal eyes, which seemed to result from the material/structure of the cornea rather than higher intraocular pressure. Antiglaucoma topical medication alters biomechanical properties measured with Corvis ST. These results are important for understanding the pathogenesis and improving the management of POAG.

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.

Visual Field Endpoints for Neuroprotective Trials: A Case for AI-Driven Patient Enrichment

PURPOSE

To evaluate whether an artificial intelligence (AI) model can better select candidates that would demonstrate visual field (VF) progression, in order to shorten the duration or the number of patients needed for a clinical trial.

DESIGN

Retrospective cohort study.

METHODS

7428 eyes of 3871 patients from the University of Washington Department of Ophthalmology VF Dataset were included. Progression was defined as at least 5 locations with >7 dB of change compared with baseline on 2 consecutive tests. Progression for all patients, a subgroup of the fastest progressing based on survival curves, and patients selected based on an elastic net Cox regression model were compared. The model was trained on pointwise threshold deviation values of the first VF, age, gender, laterality, and the mean total deviation (MD) at baseline.

RESULTS

A total of 13% of all patients met the criteria for progression at 5 years. Differences in survival were observed when stratified by MD and age (P < .0001). Those at risk of progression included patients aged 60 to 80 years with an initial MD < -5.0. This subgroup decreased the sample size required to detect progression compared with the entire cohort. The AI model-selected patients required the lowest number of patients for all effect sizes and trial lengths. For a trial length of 3 years and effect size of 30%, the number of patients required was 1656 (95% CI, 1638-1674), 903 (95% CI, 884-922), and 636 (95% CI, 625-646) for the entire cohort, the subgroup, and the model-selected patients, respectively.

CONCLUSION

An AI model can identify high-risk patients to substantially reduce the number of patients needed or study duration required to meet clinical trial endpoints.

Evaluating Visual Field Progression in Advanced Glaucoma Using Trend Analysis of Targeted Mean Total Deviation

PURPOSE

Trend analysis of visual field (VF) global indices may underestimate the rate of progression in severe glaucoma because of the influence of test points without detectable sensitivity. To test this hypothesis, we compared the rates of change of VF global indices with and without exclusion of undetectable points at various disease stages.

MATERIALS AND METHODS

Six hundred and forty-eight eyes of 366 glaucoma patients with 8 or more reliable 30-2 standard automated perimetry over more than 2 years were enrolled. We calculated targeted mean total deviation (TMTD) by averaging total deviation except points which were consistently undetectable in 3 baseline tests. Eyes were classified as early (≥-6 dB), moderate (-6 dB to -12 dB), advanced (-12 dB to -20 dB), and severe (<-20 dB) based on baseline mean deviation (MD). The rates of change of MD and TMTD in each stage were statistically compared.

RESULTS

Mean age±SD at baseline was 56.9±11.9 years. The MD slope (-0.34 dB/y) in severe glaucoma was significantly slower than TMTD slope (-0.42 dB/y, P=0.028) and was slower than MD slopes in the other stages. Difference between MD slopes and TMTD slopes was most prominent in eyes with MD values less than -25 dB (P=0.002).

CONCLUSIONS

Undetectable locations in eyes with severe glaucoma may underestimate the rates of VF progression. Trend analysis of TMTD rather than global indices offers a practical and simple approach for alleviating underestimation of VF progression in severe glaucoma.

Rates of Glaucoma Progression Derived from Linear Mixed Models Using Varied Random Effect Distributions

Purpose

To compare the ability of linear mixed models with different random effect distributions to estimate rates of visual field loss in glaucoma patients.

Methods

Eyes with five or more reliable standard automated perimetry (SAP) tests were identified from the Duke Glaucoma Registry. Mean deviation (MD) values from each visual field and associated timepoints were collected. These data were modeled using ordinary least square (OLS) regression and linear mixed models using the Gaussian, Student's t, or log-gamma (LG) distributions as the prior distribution for random effects. Model fit was compared using the Watanabe–Akaike information criterion (WAIC). Simulated eyes of varying initial disease severity and rates of progression were created to assess the accuracy of each model in predicting the rate of change and likelihood of declaring progression.

Results

A total of 52,900 visual fields from 6558 eyes of 3981 subjects were included. Mean follow-up period was 8.7 ± 4.0 years, with an average of 8.1 ± 3.7 visual fields per eye. The LG model produced the lowest WAIC, demonstrating optimal model fit. In simulations, the LG model declared progression earlier than OLS (P < 0.001) and had the greatest accuracy in predicted slopes (P < 0.001). The Gaussian model significantly underestimated rates of progression among fast and catastrophic progressors.

Conclusions

Linear mixed models using the LG distribution outperformed conventional approaches for estimating rates of SAP MD loss in a population with glaucoma.

Translational Relevance

Use of the LG distribution in models estimating rates of change among glaucoma patients may improve their accuracy in rapidly identifying progressors at high risk for vision loss.

The Relationship Between Optic Disc and Retinal Artery Position and Glaucomatous Visual Field Progression

Purpose

To investigate whether retinal structural parameters, including positions of the optic disc and major retinal arteries, affect glaucomatous progression of the visual field (VF).

Methods

In this cohort study, 116 eyes of 73 patients with primary open angle glaucoma (POAG) were included. VFs were measured using the Humphrey Field Analyzer 24-2 program and the VF was divided into seven sectors according to the corresponding optic disc angle. Average total deviation (TD) was calculated in each sector. Positions of major retinal arteries in the superotemporal and inferotemporal areas were decided by identifying the points where the retinal artery intersected the 3.4-mm-diameter circle around the optic disc. The relationship between sectorial TD VF progression rate and eight variables (age, mean and standard deviation of intraocular pressure during the observation period, baseline sectorial TD value, papillomacular bundle tilt angle, and axial length, along with superior/inferior arterial angle) was investigated.

Results

The main outcome measures were the association between retinal structural parameters and glaucomatous progression of VF. The superior retinal artery angular position was positively associated with sectorial TD progression rates in two central sectors in the inferior hemifield, which suggests faster VF progression where superior retinal artery angles are narrow. Papillomacular bundle tilt was not associated with TD progression rate in any sector.

Conclusions

Progression of the inferior VF was associated with the superior retinal artery angular position in this study of POAG.

LMX1B Locus Associated with Low-Risk Baseline Glaucomatous Features in the POAAGG Study

Primary open-angle glaucoma (POAG) is the leading cause of irreversible blindness worldwide and has been associated with multiple genetic risk factors. The LMX1B gene is a genetic susceptibility factor for POAG, and several single-nucleotide polymorphisms (SNPs) were shown to be associated with POAG in our own prior Primary Open-Angle African American Glaucoma Genetics (POAAGG) study genome-wide association study (GWAS). This study evaluated the association of the LMX1B locus with baseline optic disc and clinical phenotypic characteristics of glaucoma patients from our African American cohort. Compared to the GG genotype in SNP rs187699205, the GC genotype in this SNP was found to be significantly associated with a smaller cup-to-disc ratio (CDR) and increased (better) visual field mean deviation (MD) in glaucoma cases. None of the glaucoma cases with the GC genotype had disc hemorrhages, disc notching, or beanpot disc appearance. In conclusion, glaucoma phenotypes differed significantly by LMX1B variant in African American patients with POAG, and a SNP variant was associated with certain disease features considered lower risk.

Biomechanical Glaucoma Factor and Corneal Hysteresis in Treated Primary Open-Angle Glaucoma and Their Associations With Visual Field Progression

Purpose

To investigate the relationship between biomechanical glaucoma factor (BGF) measured with Corvis ST and glaucomatous visual field (VF) progression, compared to corneal hysteresis (CH) measured with ocular response analyzer using a longitudinal dataset of primary open-angle glaucoma (POAG). The discriminative powers of BGF and CH were also compared using a cross-sectional dataset.

Methods

The longitudinal dataset included 166 POAG eyes. The rate of VF change during the follow-up period was evaluated using the mean of 52 pointwise total deviations in the Humphrey 24-2 field test. Variables associated with the VF progression rate were identified from BGF, CH, age, baseline VF severity, and intraocular pressure during the VF follow-up period by identifying the optimal model. The cross-sectional dataset included 68 POAG eyes and 68 healthy eyes. Using this dataset, the area under the curve (AUC) values of the receiver-operating curve were compared between CH and BGF.

Results

The optimal multivariate linear mixed model to describe the VF rate included age and CH, but not BGF. Between POAG and healthy eyes, CH was statistically different (P < 0.001), although this was not the case with BGF. The AUC values were 0.61 and 0.71 for BGF and CH, respectively (P = 0.027).

Conclusions

CH, but not BGF, was associated with VF progression in POAG patients under treatment. BGF was not useful to discriminate POAG between treated and normal eyes.

The Relationship Between Corneal Hysteresis and Progression of Glaucoma After Trabeculectomy

PURPOSE

The purpose of this study was to investigate the association of corneal hysteresis (CH) measured with Ocular Response Analyzer on the progression of glaucoma after trabeculectomy.

MATERIALS AND METHODS

Twenty-four eyes of 19 patients with primary open-angle glaucoma underwent trabeculectomy. A series of visual fields (Humphery Field Analyzer 24-2 SITA-standard) were measured starting after 6 months after trabeculectomy (4.2±5.0 y, mean±SD). The mean total deviation (mTD) of the 52 test points were calculated. In addition, the mTD was divided into the following areas: central area (within central 10 degrees), superior area and inferior area: mTDcentre, mTDsuperior, and mTDinferior, respectively. The relationship between each area's progression rate of mTD and the 7 variables of baseline age, central corneal thickness, baseline mTD, mean intraocular pressure (IOP), SD of IOP divided by the mean IOP, the difference between baseline IOP obtained before the initiation of any treatment, mean IOP, and CH were analyzed using the linear mixed model, and the optimal model was selected using the model selection method with the second ordered Akaike Information Criterion.

RESULTS

In the optimal model for mTD progression rate, only CH was selected with the coefficient of 0.11. The optimal model for the mTDcentre progression rate included mean IOP with the coefficient of -0.043 and CH with the coefficient of 0.12, and that for mTDinferior included only CH with the coefficient of 0.089. There was no variable selected in the optimal model for the mTDsuperior progression rate.

CONCLUSION

CH is a useful measure in the management of glaucoma after trabeculectomy.

Longitudinal Growth Differentiation Factor 15 (GDF15) and Long-term Intraocular Pressure Fluctuation in Glaucoma: A Pilot Study

Purpose

Growth Differentiation Factor 15 (GDF15) was previously identified as a molecular marker of retinal ganglion cell stress in rodent models of glaucoma and was elevated in the aqueous humor (AH) of patients with primary open-angle glaucoma as a possible risk factor for glaucoma progression. The purpose of this study was to determine whether changes in the AH GDF15 levels were associated with intraocular pressure (IOP) changes in eyes undergoing glaucoma surgery.

Methods

Here, we performed a prospective, longitudinal pilot study in nine patients to determine whether changes in AH GDF15 levels from surgery to post-surgery follow-up were associated with IOP fluctuation. An initial AH sample was taken from the peripheral corneal paracentesis during planned glaucoma surgery, and a second sample was taken during an outpatient follow-up visit, approximately six months later.

Results

There was a statistically significant correlation between GDF15 fold change and IOP standard deviation (r = 0.87, P = 0.003), IOP range (r = 0.87, P = 0.003), and maximum IOP (r = 0.86, P = 0.003). There was no correlation between the GDF15 fold change and baseline IOP (r = 0.50, P = 0.17), final IOP (r = 0.038, P = 0.92), or mean IOP (r = 0.40, P = 0.28).

Conclusion

Our findings in this pilot study suggest that longitudinal changes in AH GDF15 may be associated with IOP fluctuation during the postoperative period. Further studies are necessary to corroborate these findings in a larger patient population and to explore the possibility that AH GDF15 may be used not only to improve treatment algorithms but also as a surrogate endpoint in clinical trials.

Evaluation of a Primary Open-Angle Glaucoma Prediction Model Using Long-term Intraocular Pressure Variability Data: A Secondary Analysis of 2 Randomized Clinical Trials

Importance

The contribution of long-term intraocular pressure (IOP) variability to the development of primary open-angle glaucoma is still controversial.

Objective

To assess whether long-term IOP variability data improve a prediction model for the development of primary open-angle glaucoma (POAG) in individuals with untreated ocular hypertension.

Design, Setting, and Participants

This post hoc secondary analysis of 2 randomized clinical trials included data from 709 of 819 participants in the observation group of the Ocular Hypertension Treatment Study (OHTS) followed up from February 28, 1994, to June 1, 2002, and 397 of 500 participants in the placebo group of the European Glaucoma Prevention Study (EGPS) followed up from January 1, 1997, to September 30, 2003. Data analyses were completed between January 1, 2019, and March 15, 2020.

Exposures

The original prediction model for the development of POAG included the following baseline factors: age, IOP, central corneal thickness, vertical cup-disc ratio, and pattern SD. This analysis tested whether substitution of baseline IOP with mean follow-up IOP, SD of IOP, maximum IOP, range of IOP, or coefficient of variation IOP would improve predictive accuracy.

Main Outcomes and Measures

The C statistic was used to compare the predictive accuracy of multivariable landmark Cox proportional hazards regression models for the development of POAG.

Results

Data from the OHTS consisted of 97 POAG end points from 709 of 819 participants (416 [58.7%] women; 177 [25.0%] African American and 490 [69.1%] white; mean [SD] age, 55.7 [9.59] years; median [range] follow-up, 6.9 [0.96-8.15] years). Data from the EGPS consisted of 44 POAG end points from 397 of 500 participants in the placebo group (201 [50.1%] women; 397 [100%] white; mean [SD] age, 57.8 [9.76] years; median [range] follow-up, 4.9 [1.45-5.76] years). The C statistic for the original prediction model was 0.741. When a measure of follow-up IOP was substituted for baseline IOP in this prediction model, the C statistics were as follows: mean follow-up IOP, 0.784; maximum IOP, 0.781; SD of IOP, 0.745; range of IOP, 0.741; and coefficient of variation IOP, 0.729. The C statistics in the EGPS were similarly ordered. No measure of IOP variability, when added to the prediction model that included mean follow-up IOP, age, central corneal thickness, vertical cup-disc ratio, and pattern SD, increased the C statistic by more than 0.007 in either cohort.

Conclusions and Relevance

Evidence from the OHTS and the EGPS suggests that long-term variability does not add substantial explanatory power to the prediction model as to which individuals with untreated ocular hypertension will develop POAG.

Cost-effectiveness and budget impact analysis of a patient visit support system for blindness reduction in Japanese patients with glaucoma

AIM

To evaluate the cost-effectiveness (CE) and budget impact (BI) of introducing a patient visit support system (ACT Pack) along with standard of care (SoC), in glaucoma treatment in Japan.

METHODS

A Markov model was designed to estimate the CE and BI of introducing the support system from Japanese payer and governmental perspective, respectively. Inputted data for CE and BI analysis were referred from published literature and based on medical specialists' inputs. Base case scenario for CE considered the support system cost of 30,000 yen per patient per year and a time horizon of 45 years. BI analysis compared the financial impact due to introduction of support system with SoC compared to SoC alone scenario on Japanese healthcare system with a time horizon of 20 years.

RESULTS

The base case of CE analysis showed the incremental cost per quality-adjusted life years (QALYs) gained with the support system was 3,241,729 yen/QALY (29,470 USD/QALY). The sensitivity analysis showed that the probability of this support system being cost-effective at a threshold of 5 million yen/QALY (45,455 USD/QALY) was 53.26%. Blindness reduction after introduction of this support system was 8.68%. The BI analysis showed that the introduction of support system will lead to a cumulative cost savings of 1,132 billion yen (10 billion US dollars) for Japanese healthcare system over 20 years of time horizon.

LIMITATION

Due to paucity of similar comparative studies, some assumptions were made based on medical specialists' inputs. Death status was not considered in the analysis.

CONCLUSION

Introduction of this support system with SoC is cost-effective and will lead to blindness reduction in Japanese patients with glaucoma. Over a 20 year period, it will lead to an overall cost savings of 1,132 billion yen (10 billion US dollars) for the Japanese healthcare system.

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.

Baseline Age and Mean Deviation Affect the Rate of Glaucomatous Vision Loss

PURPOSE

The purpose of this study was to assess the relationship between the rate of the glaucomatous visual field (VF) worsening and baseline age and baseline VF mean deviation (MD).

DESIGN

This study was a retrospective, multisite cohort.

PARTICIPANTS

A total of 84,711 reliable Swedish Interactive Thresholding Algorithm 24-2 VF tests from 8167 eyes from 5644 patients with ≥6 VF tests, ≥5 years of follow-up, baseline age 18 years or above and baseline MD ≥-10 dB, and at least 2 abnormal VF tests were included from the Glaucoma Research Network Database.

METHODS

The global mean deviation rates (MDRs) and pointwise total deviation rates (TDRs) of VF progression (dB/y) were calculated for each eye using linear regression. The relationships between MDR and baseline age and MD were determined using linear mixed-effects models and logistic regression, with rapid progression defined as an MDR≤-1.0 dB/y. The relationships between TDR and baseline age and baseline MD were determined using linear mixed-effects models.

MAIN OUTCOME MEASURES

Coefficients of the regression models.

RESULTS

In individual mixed-effects models both baseline age (β=-0.0079 dB/y; P<0.001) and baseline MD (β=0.012/y; P<0.001) were associated with faster progression. All parameters were statistically significant in the full model with both parameters and their interaction (β=0.00065; P=0.0017) as covariates. With logistic regression, each year increase in baseline age increased the odds of belonging to the rapid-progressing group by a factor of 1.033, and each unit increase in baseline MD (less severe visual loss) decreased the odds by a factor of 0.8821. The mean pointwise TDR ranged from -0.21 to -0.55 dB/y, with the most rapid pointwise progression observed in the nasal and paracentral regions of the field.

CONCLUSIONS

Older age and worse MD at baseline are associated with more rapid VF progression in this large dataset. The effect of age on MDR is influenced by baseline MD severity, supporting the importance of early detection and more aggressive therapy in older patients with worse VF damage. The pointwise rate of VF loss varies across the VF, providing a means for physicians to more effectively monitor progression.

The usefulness of the Deep Learning method of variational autoencoder to reduce measurement noise in glaucomatous visual fields

The aim of the study was to investigate the usefulness of processing visual field (VF) using a variational autoencoder (VAE). The training data consisted of 82,433 VFs from 16,836 eyes. Testing dataset 1 consisted of test-retest VFs from 104 eyes with open angle glaucoma. Testing dataset 2 was series of 10 VFs from 638 eyes with open angle glaucoma. A VAE model to reconstruct VF was developed using the training dataset. VFs in the testing dataset 1 were then reconstructed using the trained VAE and the mean total deviation (mTD) was calculated (mTDVAE). In testing dataset 2, the mTD value of the tenth VF was predicted using shorter series of VFs. A similar calculation was carried out using a weighted linear regression where the weights were equal to the absolute difference between mTD and mTDVAE. In testing dataset 1, there was a significant relationship between the difference between mTD and mTDVAE from the first VF and the difference between mTD in the first and second VFs. In testing dataset 2, mean squared prediction errors with the weighted mTD trend analysis were significantly smaller than those form the unweighted mTD trend analysis.

Usefulness of data augmentation for visual field trend analyses in patients with glaucoma

AIM

To investigate the usefulness of data augmentation in visual field (VF) trend analyses in patients with glaucoma.

METHOD

This study included 6380 VFs from 638 eyes of 417 patients with open-angle glaucoma. Various affine transformations were applied to augment the VF data: (1) rotation, (2) scaling, (3) vertical and horizontal shift and (4) a combination of these different transformations. Using pointwise linear regression (PLR), the total deviation (TD) values of a patient's 10th VF were predicted using TD values from shorter VF series (from first to third VFs (VF1-3) to first to ninth VFs (VF1-9)) with and without VF data augmentation, and the root mean squared error (RMSE) was calculated.

RESULTS

With PLR, mean RMSE without VF augmentation averaged from 3.95 (VF1-3) to 19.01 (VF1-9) dB. The RMSE was significantly improved by applying the different transformations: (1) rotation (from VF1-3 to VF1-7), (2) scaling (from VF1-3 to VF1-6), (3) vertical and horizontal shifts (from VF1-3 to VF1-4) and (iv) a combination of these (from VF1-3 to VF1-7). Progression rates in VF1-10 had better agreement with those in shorter VF series when a combination of affine transformation was applied. The differences in rates were between 1.9 (VF1-3) and 0.39 (VF1-9) dB if augmentation was used, which was significantly smaller than that observed when augmentation was not applied (from 2.6 with VF1-3 to 0.26 dB with VF1-9).

CONCLUSION

It is useful to apply VF data augmentation techniques when predicting future VF progression in glaucoma using PLR, especially with short VF series.

Risk Factors for Fast Visual Field Progression in Glaucoma

PURPOSE

To identify baseline and longitudinal risk factors for fast visual field (VF) decay in patients with open-angle glaucoma.

DESIGN

Retrospective cohort study.

METHODS

Patients with open-angle glaucoma with ≥6 VFs and ≥4 years of follow-up were included. VF decay rates were measured with the following methods: mean deviation (MD) rate, VF index (VFI) rate, and the Glaucoma Rate Index (GRI). The relationship between VF rates and clinical variables were investigated with linear mixed models. Logistic regression analysis was performed to determine which factors were associated with fast progression.

RESULTS

A total of 1317 eyes of 745 patients with a mean (± SD) age of 63.3 (±10.9) years and a median (interquartile range) MD -2.4 (-0.7 to -5.6) dB at baseline were analyzed. The median (interquartile range) number of VFs was 12 (9 to 16), and mean follow-up duration was 11.5 (±3.7) years. Older age (P < .001), higher peak intraocular pressure (IOP) (P < .001), and glaucoma surgery during the study period (P < .001) were associated with faster rates of progression regardless of the method used. Worse baseline MD was associated with MD rate (P = .02), but neither with VFI rate (P = .37) nor GRI (P = .31); whereas pseudoexfoliative glaucoma was associated with faster rates of progression with MD (P = .008) and VFI (P = .01) rates, but not with GRI. Higher peak IOPs (P = .005) was a significant predictor for fast progression.

CONCLUSION

In this cohort, older age, peak IOP, pseudoexfoliative glaucoma, and baseline MD were associated with the rate of glaucomatous VF worsening. Fast progressors had a higher peak IOP than non-fast progressors. The identification and appropriately aggressive treatment of fast progressors would reduce visual disability from glaucoma.

Cost-Utility Analysis of Glaucoma Medication Adherence

PURPOSE

The majority of patients with glaucoma do not take their medications as prescribed. Estimates of the cost-utility value of adherence to prescribed glaucoma medication are vital to implement potentially effective interventions.

DESIGN

Cost-utility analysis using Monte Carlo microsimulations incorporating a series of Markov cycles (10 000 iterations per strategy).

PARTICIPANTS

Patients with glaucoma aged ≥40 years with a full lifetime horizon (up to 60 years).

METHODS

The analysis estimated glaucomatous progression on the basis of data from the United Kingdom Glaucoma Treatment Study. Participants with glaucoma entered the model at age 40 years with a mean deviation in the better-seeing eye of -1.4±-1.9 decibels (dB) and -4.3±-3.4 dB in the worse-seeing eye. Participants whose glaucoma worsened each year accumulate -0.8 dB loss compared with -0.1 dB loss for those who remained stable. Data from the Glaucoma Laser Trial and the Tube versus Trabeculectomy Studies were used to assign probabilities of worsening disease among treated patients. Claims data estimating rates of glaucoma medication adherence over 4 years were used to assign probability of adherence. Those with poor adherence were modeled as having outcomes similar to the placebo arm of the clinical trials. As patients' mean deviation deteriorated, they transitioned between health states from mild (≥-6 dB), to moderate (<-6 to ≥-12 dB), to severe glaucoma (<-12 to ≥23 dB), to unilateral (<-20 dB) and bilateral blindness. At each health state, patients incurred the costs of treatment and established health utilities; ultimately, societal costs of low vision and blindness were included.

MAIN OUTCOME MEASURES

Cost and quality-adjusted life year (QALY) of glaucoma medication adherence.

RESULTS

Beginning at an initial glaucoma diagnosis at age 40 years, patients proceeded to single-eye blindness as early as 19 years among those who were nonadherent and 23 years for those remaining adherent. Total healthcare costs for adherent patients averaged $62 782 (standard deviation [SD], 34 107), and those for nonadherent patients averaged $52 722 (SD, 38 868). Nonadherent patients had a mean loss of 0.34 QALYs, resulting in a cost-effectiveness ratio of $29 600 per QALY gained.

CONCLUSION

At a conservative willingness to pay of $50 000/QALY, there is room to expand services to improve patient adherence.

Validating the efficacy of the binomial pointwise linear regression method to detect glaucoma progression with multicentral database

BACKGROUND/AIM

We previously reported the benefit of applying binomial pointwise linear regression (PLR: binomial PLR) to detect 10-2 glaucomatous visual field (VF) progression. The purpose of the current study was to validate the usefulness of the binomial PLR to detect glaucomatous VF progression in the central 24°.

METHODS

Series of 15 VFs (Humphrey Field Analyzer 24-2 SITA-standard) from 341 eyes of 233 patients, obtained over 7.9±2.1 years (mean±SD), were investigated. PLR was performed by regressing the total deviation of all test points. VF progression was determined from the VF test points analyses using the binomial test (one side, p<0.025). The time needed to detect VF progression was compared across the binomial PLR, permutation analysis of PLR (PoPLR) and mean total deviation (mTD) trend analysis.

RESULTS

The binomial PLR was comparable with PoPLR and mTD trend analyses in the positive predictive value (0.18-0.87), the negative predictive value (0.89-0.95) and the false positive rate (0.057-0.35) to evaluate glaucomatous VF progression. The time to classify progression with binomial PLR (5.8±2.8 years) was significantly shorter than those with mTD trend analysis (6.7±2.8 years) and PoPLR (6.6±2.7 years).

CONCLUSIONS

The binomial PLR method, which detected glaucomatous VF progression in the central 24° significantly earlier than PoPLR and mTD trend analyses, shows promise for improving our ability to detect visual field progression for clinical management of glaucoma and in clinical trials of new glaucoma therapies.

Self-monitoring of intraocular pressure using Icare HOME tonometry in clinical practice

Purpose: To determine the value of self-monitoring of diurnal intraocular pressure (IOP) by Icare Home rebound tonometer in patients with glaucoma and ocular hypertension.

Methods: Patients with open-angle glaucoma or ocular hypertension, controlled IOP at office visits, and at least 3 years of follow-up in the glaucoma clinic were included. Progression of glaucoma was based on medical records and defined by documented structural and/or visual field change. Patients were trained to correctly perform self-tonometry and instructed to measure diurnal IOP in a home setting for 3 days. IOP characteristics (mean, peak IOP, fluctuation of IOP as range, and SD of IOP) were documented and compared between the progressive and stable eyes.

Results: Ninety-four patients (50 females) with a mean (SD) age of 57.1 (14.7) years were included. Among the 94 eyes from 94 subjects, 72 (76.6%) eyes had primary open-angle glaucoma, ten (10.6%) had pigmentary glaucoma, four (4.3%) had exfoliative glaucoma, and eight (8.5%) eyes had ocular hypertension. Thirty-six eyes showed progression and 58 eyes were stable. Patients with progression were older than those with stable disease (mean (SD) 65.8 (8.4) years vs 51.7 (15.3) years, P<0.001). The progression group had higher average IOP (mean (SD) 15.8 (4.0) mmHg vs 13.3 (3.7) mmHg, P=0.002), peak IOP (mean (SD) 21.8 (5.8) mmHg vs 18.6 (4.8) mmHg, P=0.01), and greater IOP fluctuation range (mean (SD) 11.6 (4.8) vs 9.1 (3.5) mmHg, P=0.011) compared to non-progression group.

Conclusion: Self-monitoring of IOP using Icare Home tonometry provides more complete data on variability of IOP to assist in the management of glaucoma.

Validating Variational Bayes Linear Regression Method With Multi-Central Datasets

Purpose

To validate the prediction accuracy of variational Bayes linear regression (VBLR) with two datasets external to the training dataset.

Method

The training dataset consisted of 7268 eyes of 4278 subjects from the University of Tokyo Hospital. The Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG) dataset consisted of 271 eyes of 177 patients, and the Diagnostic Innovations in Glaucoma Study (DIGS) dataset includes 248 eyes of 173 patients, which were used for validation.

Prediction accuracy was compared between the VBLR and ordinary least squared linear regression (OLSLR). First, OLSLR and VBLR were carried out using total deviation (TD) values at each of the 52 test points from the second to fourth visual fields (VFs) (VF2–4) to 2nd to 10th VF (VF2–10) of each patient in JAMDIG and DIGS datasets, and the TD values of the 11th VF test were predicted every time. The predictive accuracy of each method was compared through the root mean squared error (RMSE) statistic.

Results

OLSLR RMSEs with the JAMDIG and DIGS datasets were between 31 and 4.3 dB, and between 19.5 and 3.9 dB. On the other hand, VBLR RMSEs with JAMDIG and DIGS datasets were between 5.0 and 3.7, and between 4.6 and 3.6 dB. There was statistically significant difference between VBLR and OLSLR for both datasets at every series (VF2–4 to VF2–10) (P < 0.01 for all tests). However, there was no statistically significant difference in VBLR RMSEs between JAMDIG and DIGS datasets at any series of VFs (VF2–2 to VF2–10) (P > 0.05).

Conclusions

VBLR outperformed OLSLR to predict future VF progression, and the VBLR has a potential to be a helpful tool at clinical settings.

Improving the Feasibility of Glaucoma Clinical Trials Using Trend-Based Visual Field Progression Endpoints

Purpose

There have been concerns that short-term clinical trials for evaluating new treatments in glaucoma would require prohibitively large sample sizes when using visual field endpoints, given that glaucoma is often a slowly progressive disease. This study sought to determine the required sample size for such trials using event-based analyses, and whether it can be reduced using trend-based analyses.

Design

Longitudinal, observational study.

Participants

321 eyes of 240 glaucoma participants followed under routine clinical care using 242 visual field for an average of 10 years.

Methods

Sample size requirements were derived using computer simulations that reconstructed "real-world" visual fields by combining estimates of point-wise variability according to different threshold levels and rates of change obtained from the clinical glaucoma cohort. A clinical trial lasting 2 years with testing every 3 months was simulated, assuming that the new treatment halted visual field change in various percentages of participants (or "responders"). Treatment efficacy was evaluated by: (a) Difference in incidence of point-wise event-based progression (similar to the commercially available Guided Progression Analysis), and (b) Difference in rate of visual field mean deviation (MD) change between groups using linear mixed models (LMMs).

Main Outcome Measures

Sample size to detect a statistically significance difference between groups.

Results

Between-group trend-based analyses using LMMs reduced sample size requirements by 85-90% across the range of new treatment effects when compared to the conventional point-wise event-based analysis. To detect the effect of a new treatment that halted progression in 30% of the participants under routine clinical care (equal to a 30% reduction in average rate of MD change) with 90% power, for example, 1924 participants would be required per group using event-based analysis, but only 277 participants per group if LMMs were used.

Conclusions

The feasibility of future glaucoma clinical trials can be substantially improved by evaluating differences in the rate of visual field change between groups.

Development of a Novel Corneal Concavity Shape Parameter and Its Association with Glaucomatous Visual Field Progression

PURPOSE

To develop a novel Corvis ST (Oculus Co. Ltd, Wetzlar, Germany) corneal concavity shape parameter (concavity shape index [CSI]) and investigate its association with glaucomatous visual field (VF) progression.

DESIGN

Retrospective longitudinal study.

PARTICIPANTS

A total of 103 eyes with primary open-angle glaucoma in 68 patients with 8 reliable VFs using the Humphrey Field Analyzer (HFA) (Carl Zeiss Meditec Inc, Dublin, CA).

METHODS

The mean total deviation (mTD) of the 52 test points in the 24-2 HFA test pattern was calculated for each VF, and the mTD progression rate was determined. A Corvis ST measurement was performed, and CSI was calculated as the ratio of (peak distance × curvature radius at the time of highest concavity [HC] state) to (the deflection amplitude at the time of HC × curvature radius at the undeformed state). The association between mTD progression rate and CSI, as well as other variables (including age, intraocular pressure, corneal hysteresis [CH], and 35 standard Corvis ST parameters), was investigated using the linear mixed model. The optimal linear mixed model to describe mTD progression rate was selected using the Random Forest method followed by variable selection using the second order bias corrected Akaike Information Criterion (AICc) index.

MAIN OUTCOME MEASURES

Optimal linear mixed models for the mTD progression rate, as determined by AICc index.

RESULTS

Univariate analysis revealed mTD progression rate was significantly associated with CSI (P = 0.0042), CH, HC radius, A1 deflection length, max inverse radius, and integrated radius. The optimal model to describe mTD progression rate included CSI, max inverse radius, Ambrósio rational thickness horizontal, and age (AICc = 41.59).

CONCLUSIONS

A novel corneal concavity shape parameter, CSI, was closely related to glaucomatous VF progression.

Correlation between elastic energy stored in an eye and visual field progression in glaucoma

PURPOSE

To investigate whether the elastic energy stored in an eyeball at highest concavity (highest concavity energy; HCE), calculated with Corivs ST (CST, OCULUS), correlates with glaucomatous visual field (VF) progression.

METHODS

108 eyes from 70 primary open angle-glaucoma patients were studied. The HCE was calculated using CST parameters. For each eye, the mean total deviation (mTD) of the 52 test points in the 24-2 Humphrey Field Analyzer test pattern was calculated and the mTD progression rate was determined from eight reliable VFs. Eyes were subdivided into: subgroups with low- or high-whole eye motion maximal length (WEM-d) and subgroups with short- or long-time taken to reach WEM-d (WEM-t), as measured with CST. The associations between mTD progression rate and HCE and other ocular/systemic parameters including age, Goldmann applanation tonometry based-intraocular pressure [GAT-IOP], and corneal hysteresis [CH] from the Ocular Response Analyzer (ORA®, Reichert) were investigated using the linear mixed model. The optimal model to describe mTD progression rate was selected from all possible combinations according to the second order bias corrected Akaike Information Criterion index.

RESULTS

Optimal models to describe mTD progression rate included: CH in the model for all eyes, age and HCE in the model for the WEM-d low group, HCE in the model for the WEM-t short group, mean GAT-IOP in the model for the WEM-d high group, and age in the model for the WEM-t long-group.

CONCLUSIONS

HCE was associated with glaucomatous VF progression in eyes with minimal whole eye motion (low WEM-d and WEM-t subgroups).

Simplifying "target" intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma

Lowering of intraocular pressure is currently the only therapeutic measure for Glaucoma management. Many longterm, randomized trials have shown the efficacy of lowering IOP, either by a percentage of baseline, or to a specified level. This has lead to the concept of 'Target" IOP, a range of IOP on therapy, that would stabilize the Glaucoma/prevent further visual field loss, without significantly affecting a patient's quality of life. A clinical staging of Glaucoma by optic nerve head evaluation and perimetric parameters, allows a patient's eye to be categorized as having - mild, moderate or severe Glaucomatous damage. An initial attempt should be made to achieve the following IOP range for both POAG or PACG after an iridotomy. In mild glaucoma the initial target IOP range could be kept as 15-17 mmHg, for moderate glaucoma 12-15 mmHg and in the severe stage of glaucomatous damage 10-12 mmHg. Factoring in baseline IOP, age, vascular perfusion parameters, and change on perimetry or imaging during follow up, this range may be reassessed over 6 months to a year. "Target" IOP requires further lowering when the patient continues to progress or develops a systemic disease such as a TIA. Conversely, in the event of a very elderly or sick patient with stable nerve and visual field over time, the target IOP could be raised and medications reduced. An appropriate use of medications/laser/surgery to achieve such a "Target" IOP range in POAG or PACG can maintain visual fields and quality of life, preventing Glaucoma blindness.

Effect of body position on the pathogenesis of asymmetric primary open angle glaucoma

AIM

To explore the pathogenesis of asymmetric primary open angle glaucoma (POAG) in both eyes by comparing the intraocular pressure (IOP) of patients who sleep in different positions and to investigate the relationship between IOP variations and sleep positions.

METHODS

One hundred and thirty-one patients with asymmetric POAG and forty-six healthy volunteers were enrolled. All participants completed a questionnaire that provided information about their sleep laterality. The cup disc ratio (C/D) and visual field defect established binocular asymmetry. The IOP of both eyes was measured using iCare parameters after the patients were asked to change body position. The "worse" and "better" eyes were identified according to the diagnosis, whereas the "dependent" and "independent" eyes were defined according to the lateral position.

RESULTS

No significant difference in sleep laterality was observed between healthy people and patients with POAG (F=3.195, P=0.362). Among the enrolled patients, the IOP of the dependent eye was always greater than that of the independent eye in the lateral position (P<0.05). In the patients with binocular asymmetric POAG, the questionnaire clearly showed that 85.7% of left side preferences were found their left eyes to be the worse eyes and the right eyes of 71.4% patients with a right side preference were the more serious. When the asymmetric C/D ratio was greater than or equal to 0.2, the worse eye of patients with POAG and a preferred sleeping position was the dependent eye (χ² =16.762, P=0.001).

CONCLUSION

A higher IOP was measured in the dependent eye in the lateral position. The long-term tendency to choose a lateral sleeping position might lead the dependent eye to manifest more severe symptoms than the independent eye. Thus, the lateral sleeping position might be one cause of asymmetric POAG.

Detecting glaucomatous progression with infrequent visual field testing

PURPOSE

Previous work has investigated whether a significant regression slope in the first 2 years for the summary index Mean Deviation (MD) is predictive of rapid (≤-2 dB year^-1 ) glaucomatous visual field progression. This work assumed six visual fields were obtained as per management guidelines, but in clinical practice commonly only two or three fields are measured. We used simulation methods to investigate how reducing test frequency influences the prediction of rapid visual field progression, along with the influence of including criteria based on regression slope.

METHODS

We simulated visual field series (N = 100 000) spaced annually in the first 2 years and then biennially. We calculated positive and negative predictive values (PPV & NPV) for detecting rapid progression, based on a criterion of a significant negative regression slope of any magnitude, or of a magnitude less than a particular limit. We performed a second simulation using test frequency and disease prevalence parameters from a dataset of 255 glaucoma patients from The University of Tokyo Hospital, to check the validity of our method.

RESULTS

Prediction values at 2 years were slightly less than those obtained using six visual fields. An addition of an appropriate slope based criterion materially improved PPV, with little detrimental effect on NPV. Simulated prediction values for the Tokyo dataset were similar to those determined empirically.

CONCLUSION

Infrequent visual field testing does not dramatically alter predictive values at 2 years, but does substantially delay when significant progression may first be detected.

The Relationship between the Waveform Parameters from the Ocular Response Analyzer and the Progression of Glaucoma

PURPOSE

To investigate the usefulness of waveform parameters measured with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY) in assessing the progression of glaucomatous visual field (VF).

DESIGN

Observational cross-sectional study.

PARTICIPANTS

One hundred and one eyes with primary open-angle glaucoma in 68 patients with 8 reliable VFs using the Humphrey Field Analyzer (Carl Zeiss Meditec, Inc., Dublin, CA).

METHODS

The mean of total deviation (mTD) value of the 52 test points in the 24-2 Humphrey Field Analyzer VF test pattern was calculated, and the progression rate of mTD was determined using 8 VFs. Ocular Response Analyzer measurement was performed 3 times in the same day, and the average values of the 3 measurements were used in the analysis. Then, the optimal linear mixed model was selected using 7 parameters: age, mean and standard deviation of intraocular pressure with the Goldmann applanation tonometry during the observation period, central corneal thickness, axial length, mTD in the initial VF, and corneal hysteresis (CH) other than waveform parameters, henceforth known as the basic model. In addition, using the 37 waveform parameters, the optimal model for the mTD progression rate was identified, according to the second-order bias-corrected Akaike information criterion (AICc) index, using 15 preselected waveform parameters with the least absolute shrinkage and selection operator regression (henceforth known as the waveform model).

MAIN OUTCOME MEASURES

Optimal linear mixed models for the mTD progression rate, as determined by AICc index.

RESULTS

The mean ± standard deviation mTD progression rate was -0.25±0.31 dB/year. The basic model was mTD progression rate = -0.94 + 0.075 × CH (AICc = 46.71). The waveform model was mTD progression rate = 1.25 - 0.066 × path2 - 0.000099 × p2area + 0.0021 × mslew2 (AICc = 44.95). The relative likelihood of the latter model being the optimal model was 6.23 times greater than that of the former model.

CONCLUSIONS

Ocular Response Analyzer waveform parameters were correlated significantly with glaucomatous VF progression and showed a stronger than correlation with VF progression than CH.

Intraocular Pressure Fluctuation: Is It Important?

Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of glaucoma. Previous prospective, randomized, long-term studies have demonstrated the strength of IOP reduction in slowing the progression of disease. It is well known that IOP is not a fixed value but fluctuates considerably over time. Although there have been some studies on IOP fluctuation and the progression of glaucoma, whether IOP fluctuation is an independent risk factor for glaucomatous damage and disease progression remains controversial. In this article, we reviewed the definition of IOP fluctuation, and both the evidence and the speculation for and against the effect of IOP fluctuation on glaucoma progression. Although conclusions seem to vary from study to study, we considered that different studies examined different groups of patients, at different stages of disease, and at different IOP levels. Our conclusion is that these apparently disparate results are not conflicting, but rather can be viewed as complementary. In clinical care, we recommend the consideration of IOP “modulation” rather than just IOP “reduction” when glaucoma patients are treated. Quality-based IOP control may be more effective than quantity-based IOP reduction to prevent or retard disease progression.

Measuring Rates of Visual Field Progression in Linear Versus Nonlinear Scales: Implications for Understanding the Relationship Between Baseline Damage and Target Rates of Glaucoma Progression

PURPOSE

The purpose of this study is to test the hypothesis that the relationship between baseline visual field damage and the rate of progression depends upon the use of logarithmic (dB) versus linear (1/Lambert) scale.

METHODS

A total of 60 eyes (60 patients) with treated, established glaucoma and at least 5 reliable 24-2 visual fields were included. Baseline visual field mean deviation (MD) in dB was transformed to 1/Lambert using standard equation. Mixed effects linear regression was used to calculate the slopes (MD rates of progression over time) with linear and nonlinear scales. We tested the relationship between baseline MD and MD slopes for each scale of measure.

RESULTS

In dB scale, worse baseline visual field loss was associated with faster MD slopes (P=0.037), whereas the opposite effect was seen in 1/Lambert (P=0.001). For a similar rate of progression in dB/y, eyes with mild visual field damage lost more linear sensitivity over a given period of time than those with more severe baseline damage.

CONCLUSIONS

There is a significant relationship between baseline visual field severity and rates of MD progression, although the direction of this association depends on the scale sensitivity is measured. The definition of fast versus slow visual field progression should be revised and take into account that sensitivity in linear scales show a better correlation with structural loss than when conventionally measured in nonlinear scale.

Applying "Lasso" Regression to Predict Future Glaucomatous Visual Field Progression in the Central 10 Degrees

PURPOSE OF THE STUDY

We recently reported that it is beneficial to apply least absolute shrinkage and selection operator (Lasso) regression to predict future 24-2 visual field (VF) progression. The purpose of the current study was to investigate the usefulness of Lasso regression to predict VF progression in the central 10 degrees (10-2) in glaucoma patients.

METHODS

Series of 10 VFs (Humphrey Field Analyzer 10-2 SITA-standard) from each of 149 eyes in 110 open angle glaucoma patients, obtained over 5.7±1.4 years (mean±SD) were investigated. Mean deviation values of the 10th VF were predicted using varying numbers of VFs (ranging from the first to third VFs to the first to ninth VFs), applying ordinary least square regression (OLSLR) and Lasso regression. Absolute prediction errors were then compared.

RESULTS

With OLSLR, prediction error varied between 5.4±5.0 (using first to third VFs) and 1.1±1.6 dB (using first to ninth VFs). Significantly smaller prediction errors were obtained with Lasso regression, in particular with small numbers of VFs (from 2.1±2.8: first to third VFs, to 1.0±1.6 dB: first to ninth VFs). A large λ value, which is an index showing the degree of penalty in Lasso regression, was observed when a small number of VFs were used for prediction.

CONCLUSION

Mean deviation prediction using OLSLR with a small number of VFs resulted in large prediction errors. It was useful to apply Lasso regression when predicting future progression of the central 10 degrees, compared to OLSLR.

Using CorvisST tonometry to assess glaucoma progression

Purpose

To investigate the utility of the Corneal Visualization Scheimpflug Technology instrument (CST) to assess the progression of visual field (VF) damage in primary open angle glaucoma patients.

Method

A total of 75 eyes from 111 patients with primary open-angle glaucoma were investigated. All patients underwent at least nine VF measurements with the Humphrey Field Analyzer, CST measurements, axial length (AL), central corneal thickness (CCT) and intraocular pressure (IOP) with Goldmann applanation tonometry (GAT). Mean total deviation (mTD) progression rates of the eight VFs, excluding the first VF, were calculated and the association between progression rate and the other listed measurements was analyzed using linear regression, and the optimal to describe mTD progression rate was selected based on the second order bias corrected Akaike Information Criterion (AICc) index.

Results

VF progression was described best in a model that included CST parameters as well as other ocular measurements. The optimal linear model to describe mTD progression rate was given by the equation: -8.9–0.068 x mean GAT + 0.68 x A1 time + 0.31 x A2 time -0.39 x A2 length– 1.26 x highest deformation amplitude.

Conclusion

CST measurements are useful when assessing VF progression in glaucoma patients. In particular, careful consideration should be given to patients where: (i) an eye is observed to be applanated fast in the first and second applanations, (ii) the applanated area is wide in the second applanation and (iii) the indentation is deep at the maximum deformation, since these eyes appear to be at greater risk of VF progression.

Investigating the usefulness of a cluster-based trend analysis to detect visual field progression in patients with open-angle glaucoma

BACKGROUND/AIMS

To investigate the usefulness of the Octopus (Haag-Streit) EyeSuite's cluster trend analysis in glaucoma.

METHODS

Ten visual fields (VFs) with the Humphrey Field Analyzer (Carl Zeiss Meditec), spanning 7.7 years on average were obtained from 728 eyes of 475 primary open angle glaucoma patients. Mean total deviation (mTD) trend analysis and EyeSuite's cluster trend analysis were performed on various series of VFs (from 1st to 10th: VF1-10 to 6th to 10th: VF6-10). The results of the cluster-based trend analysis, based on different lengths of VF series, were compared against mTD trend analysis.

RESULT

Cluster-based trend analysis and mTD trend analysis results were significantly associated in all clusters and with all lengths of VF series. Between 21.2% and 45.9% (depending on VF series length and location) of clusters were deemed to progress when the mTD trend analysis suggested no progression. On the other hand, 4.8% of eyes were observed to progress using the mTD trend analysis when cluster trend analysis suggested no progression in any two (or more) clusters.

CONCLUSION

Whole field trend analysis can miss local VF progression. Cluster trend analysis appears as robust as mTD trend analysis and useful to assess both sectorial and whole field progression. Cluster-based trend analyses, in particular the definition of two or more progressing cluster, may help clinicians to detect glaucomatous progression in a timelier manner than using a whole field trend analysis, without significantly compromising specificity.

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.

The usefulness of CorvisST Tonometry and the Ocular Response Analyzer to assess the progression of glaucoma

Corneal Visualization Scheimpflug Technology (CST) and Ocular Response Analyzer (ORA) measurements were carried out in 105 eyes of 69 patients with primary open-angle glaucoma. All patients had axial length (AL), central corneal thickness (CCT), intraocular pressure (IOP) with Goldmann applanation tonometry (GAT) and eight visual fields (VF)s with the Humphrey Field Analyzer. VF progression was summarized using a time trend analysis of mean total deviation (mTD) and the association between mTD progression rate and a number of ocular parameters (including CST and ORA measurements) was assessed using mixed linear regression analysis. The optimal model of VF progression selected based on the corrected Akaike Information Criteria (AICc) included ORA’s corneal hysteresis (CH) parameter as well as a number of CST measurements: mTD progression rate = 1.2–0.070 * mean GAT + 0.090 * CH–1.5 * highest concavity deformation amplitude with CST + 9.4 * A1 deformation amplitude with CST–0.05 * A2 length with CST (AICc = 125.8). Eyes with corneas that experience deep indentation at the maximum deformation, shallow indentation at the first applanation and wide indentation at the second applanation in the CST measurement are more likely to experience faster rates of VF progression.

Biomechanics of the sclera and effects on intraocular pressure

Accumulating evidence indicates that glaucoma is a multifactorial neurodegenerative disease characterized by the loss of retinal ganglion cells (RGC), resulting in gradual and progressive permanent loss of vision. Reducing intraocular pressure (IOP) remains the only proven method for preventing and delaying the progression of glaucomatous visual impairment. However, the specific role of IOP in optic nerve injury remains controversial, and little is known about the biomechanical mechanism by which elevated IOP leads to the loss of RGC. Published studies suggest that the biomechanical properties of the sclera and scleral lamina cribrosa determine the biomechanical changes of optic nerve head, and play an important role in the pathologic process of loss of RGC and optic nerve damage. This review focuses on the current understanding of biomechanics of sclera in glaucoma and provides an overview of the possible interactions between the sclera and IOP. Treatments and interventions aimed at the sclera are also discussed.

Effects of ocular and systemic factors on the progression of glaucomatous visual field damage in various sectors

BACKGROUND/AIM

To investigate the effects of ocular and systemic risk factors for glaucomatous progression in different sectors of the visual field (VF).

METHOD

409 eyes from 268 patients with 10 reliable VFs from the Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG) were investigated. VFs were divided into six sectors (mean total deviation (mTD)_s20+, mTD_s10-20 and mTD_s0-10, >20°, 10-20° and <10° in the superior hemifield, respectively; and mTD_i20+, mTD_i10-20 and mTD_i0-10, >20°, 10-20° and <10° in the inferior hemifield, respectively). The relationship between sectorial progression rate and eight variables (age, mTD at baseline VF, average intraocular pressure (IOP), SD of IOP, systemic hypertension, migraine, family history of glaucoma and smoking status) was investigated.

RESULT

The mTD progression rate was -0.21 dB/year. Older age was related to progression of mTD_s20+, mTD_s10-20, mTD_i20+ and mTD_i10-20. Mean IOP was not related to progression in any VF sector; however, a larger SD of IOP was related to progression of mTD_s20+, mTD_i0-10, mTD_i10-20 and mTD_i20+. Smoking status was related to progression in all inferior VF sectors (mTD_i0-10, mTD_i10-20 and mTD_i20+).

CONCLUSIONS

Smoking status is related to glaucomatous VF progression in all sectors of the inferior hemifield.

A novel method to predict visual field progression more accurately, using intraocular pressure measurements in glaucoma patients

Visual field (VF) data were retrospectively obtained from 491 eyes in 317 patients with open angle glaucoma who had undergone ten VF tests (Humphrey Field Analyzer, 24-2, SITA standard). First, mean of total deviation values (mTD) in the tenth VF was predicted using standard linear regression of the first five VFs (VF_1-5) through to using all nine preceding VFs (VF_1-9). Then an ‘intraocular pressure (IOP)-integrated VF trend analysis’ was carried out by simply using time multiplied by IOP as the independent term in the linear regression model. Prediction errors (absolute prediction error or root mean squared error: RMSE) for predicting mTD and also point wise TD values of the tenth VF were obtained from both approaches. The mTD absolute prediction errors associated with the IOP-integrated VF trend analysis were significantly smaller than those from the standard trend analysis when VF_1-6 through to VF_1-8 were used (p < 0.05). The point wise RMSEs from the IOP-integrated trend analysis were significantly smaller than those from the standard trend analysis when VF_1-5 through to VF_1-9 were used (p < 0.05). This was especially the case when IOP was measured more frequently. Thus a significantly more accurate prediction of VF progression is possible using a simple trend analysis that incorporates IOP measurements.