The United Kingdom Glaucoma Treatment Study: a multicenter, randomized, placebo-controlled clinical trial: design and methodology

Visual field testing in glaucoma using the Swedish Interactive Threshold Algorithm

The Swedish Interactive Thresholding Algorithm (SITA) is the main measurement acquisition algorithm used on the Humphrey Field Analyser, the most commonly used instrument for visual field (VF) assessment worldwide. We compare the sensitivity outputs and reliability parameters of the three currently available SITA algorithms-SITA Standard (SS), Fast (SF), and Faster (SFR), with a focus on the newly released SFR and the 24-2C test grid. SFR displays similar sensitivity outputs to SS and SF, but may not be interchangeable with SS in eyes with more severe VF loss. The reliability metric with the greatest impact on VF reliability is the level of false positives, although the recommended 15% false positive cut off may be inappropriate as a threshold for judging whether a test is reliable and should be included for use in SFR. Finally, the 24-2C grid may be useful in flagging the presence of a clustered central VF defect, while the 10-2 grid can be used to more comprehensively characterize central field defects. We also discuss strategies to improve testing frequency in clinical practice.

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.

Peripheral blood mononuclear cell respiratory function is associated with progressive glaucomatous vision loss

Intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma and all licensed treatments lower IOP. However, many patients continue to lose vision despite IOP-lowering treatment. Identifying biomarkers for progressive vision loss would have considerable clinical utility. We demonstrate that lower peripheral blood mononuclear cell (PBMC) oxygen consumption rate (OCR) is strongly associated with faster visual field (VF) progression in patients treated by lowering IOP (P < 0.001, 229 eyes of 139 participants), explaining 13% of variance in the rate of progression. In a separate reference cohort of untreated patients with glaucoma (213 eyes of 213 participants), IOP explained 16% of VF progression variance. OCR is lower in patients with glaucoma (n = 168) than in controls (n = 50; P < 0.001) and is lower in patients with low baseline IOP (n = 99) than those with high baseline IOP (n = 69; P < 0.01). PBMC nicotinamide adenine dinucleotide (NAD) levels are lower in patients with glaucoma (n = 29) compared to controls (n = 25; P < 0.001) and strongly associated with OCR (P < 0.001). Our results support PBMC OCR and NAD levels as new biomarkers for progressive glaucoma.

Long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma: a single-surgeon experience

PURPOSE

To evaluate and compare the long-term outcomes of canaloplasty and phaco-canaloplasty in the treatment of open angle glaucoma and assess the prognostic factors associated with surgical outcome.

METHODS

A 48-month retrospective analysis was performed on n = 133 open angle glaucoma eyes treated with canaloplasty and n = 57 open angle glaucoma eyes treated with phaco-canaloplasty by a single surgeon. Surgical success was defined according to six criteria, achieving a target intraocular pressure (IOP) ≤ 21, 18 or 15 mmHg on glaucoma medications (qualified success) or without any further treatment (complete success), including laser therapy or surgery. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate surgical success and preoperative factors associated with surgical outcome. Surgical complications in the early postoperative period were compared between canaloplasty and phaco-canaloplasty.

RESULTS

Canaloplasty and phaco-canaloplasty significantly reduced postoperative IOP and number of glaucoma medications (p = 0.001 for both). Phaco-canaloplasty showed higher rates of cumulative surgical success over canaloplasty, but only for target IOP ≤ 21 and ≤ 18 (p = 0.018 and p = 0.011, respectively). A preoperative number of > 4 glaucoma medications predicted surgical failure. Phaco-canaloplasty was associated with a higher rate of IOP peaks in the first month compared with canaloplasty (40.4% vs 12.7%, p = 0.000).

CONCLUSION

Canaloplasty and phaco-canaloplasty demonstrated long-term efficacy in the treatment of open angle glaucoma, with phaco-canaloplasty showing higher rates of surgical success compared to canaloplasty, but not for target IOPs lower than 16 mmHg. Patients on more than 4 preoperative glaucoma medications may not be good candidates for canaloplasty and may benefit from other surgical options.

Effect of intraocular pressure reduction on progressive high myopia (PHM study): study protocol of a randomised controlled trial

BACKGROUND

In adult patients with high myopia (HM), progressive axial elongation poses a significant risk for the development of subsequent ocular complications that may lead to visual impairment. Effective strategies to reduce or prevent further axial elongation in highly myopic adult patients have not been available so far. Recent studies suggested that medically lowering intraocular pressure (IOP) may reduce axial elongation.

OBJECTIVE

This clinical randomised controlled trial (RCT) aims to evaluate the efficacy of medical IOP reduction in adult patients with progressive HM (PHM).

TRIAL DESIGN

Single-centre, open-label, prospective RCT.

METHODS

This RCT will recruit 152 participants with PHM at the Zhongshan Ophthalmic Center (ZOC). Randomised in a ratio of 1:1, participants will receive IOP-lowering eyedrops (intervention group) or will be followed without treatment (control group) for 12 months. Follow-up visits will be conducted at 1, 6 and 12 months after baseline. Only one eye per eligible participant will be included for analysis. The primary outcome is the change in axial length (AL) within the study period of 12 months. Secondary outcomes include the incidence and progression of visual field (VF) defects, changes in optic disc morphology and incidence and progression of myopic maculopathy. Difference in AL changes between the two groups will be analysed using linear regression analysis. For the secondary outcomes, a multifactor Poisson regression within a generalised linear model will be used to estimate the relative risk of progression in VF defects and myopic maculopathy, and the rate of thinning in retinal nerve fibre layer and ganglion cell-inner plexiform will be assessed through Kaplan-Meier curves and log-rank tests.

ETHICS AND DISSEMINATION

Full ethics approval for this trial has been obtained from the Ethics Committee of ZOC, Sun Yat-sen University, China (ID: 2023KYPJ110). Results of this trial will be disseminated through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05850936.

Visual Field Evaluation Using Zippy Adaptive Threshold Algorithm (ZATA) Standard and ZATA Fast in Patients With Glaucoma and Healthy Individuals

Purpose

To evaluate visual fields obtained with Zippy Adaptive Threshold Algorithm (ZATA) Standard and ZATA Fast from patients with glaucoma and healthy individuals.

Methods

Fifty-five patients with glaucoma (median mean deviation [MD], -7.6 dB; interquartile range [IQR], -15.3 to -2.6 dB) and 22 healthy participants (median MD, -0.6 dB; IQR, -1.7 to 0.2 dB) performed ZATA Standard and ZATA Fast tests on a Henson 9000 perimeter and Swedish Interactive Thresholding Algorithm (SITA) Standard and SITA Fast tests on a Humphrey Field Analyzer. Tests were repeated within 90 days (median, 14 days; range, 7-26 days) to evaluate the test-retest variability.

Results

The mean difference between the MD of the ZATA Standard and SITA Standard tests was 1.7 dB (95% confidence interval [CI], 0.9-2.4). Between ZATA Fast and SITA Fast, it was 0.9 dB (95% CI, 0.2-1.5 dB). Although there were systematic differences between the distributions of sensitivity estimates with ZATA and SITA, they did not affect the overall representation of damage by these tests. ZATA Standard and ZATA Fast were approximately 30% and 6% faster, respectively, than the corresponding SITA tests.

Conclusions

ZATA Standard and ZATA Fast are suitable for clinical practice. However, differences between ZATA and SITA tests suggest that they should not be used interchangeably when patients with glaucoma are followed over time.

Translational Relevance

This study examined the characteristics of ZATA visual field tests in a clinical population, and it supports the adoption of these tests for assessing patients with glaucoma.

European Glaucoma Society - A guide on surgical innovation for glaucoma

PROLOGUE: Glaucoma surgery has been, for many decades now, dominated by the universal gold standard which is trabeculectomy augmented with antimetabolites. Tubes also came into the scene to complement what we use to call conventional or traditional glaucoma surgery. More recently we experienced a changing glaucoma surgery environment with the "advent" of what we have become used to calling Minimally Invasive Glaucoma Surgery (MIGS). What is the unmet need, what is the gap that these newcomers aim to fill? Hippocrates taught us "bring benefit, not harm" and new glaucoma techniques and devices aim to provide safer surgery compared to conventional surgery. For the patient, but also for the clinician, safety is important. Is more safety achieved with new glaucoma surgery and, if so, is it associated with better, equivalent, or worse efficacy? Is new glaucoma surgery intended to replace conventional surgery or to complement it as an 'add-on' to what clinicians already have in their hands to manage glaucoma? Which surgery should be chosen for which patient? What are the options? Are they equivalent? These are too many questions for the clinician! What are the answers to the questions? What is the evidence to support answers? Do we need more evidence and how can we produce high-quality evidence? This EGS Guide explores the changing and challenging glaucoma surgery environment aiming to provide answers to these questions. The EGS uses four words to highlight a continuum: Innovation, Education, Communication, and Implementation. Translating innovation to successful implementation is crucially important and requires high-quality evidence to ensure steps forward to a positive impact on health care when it comes to implementation. The vision of EGS is to provide the best possible well-being and minimal glaucomainduced visual disability in individuals with glaucoma within an affordable healthcare system. In this regard, assessing the changes in glaucoma surgery is a pivotal contribution to better care. As mentioned, this Guide aims to provide answers to the crucial questions above. However, every clinician is aware that answers may differ for every person: an individualised approach is needed. Therefore, there will be no uniform answer for all situations and all patients. Clinicians would need, through the clinical method and possibly some algorithm, to reach answers and decisions at the individual level. In this regard, evidence is needed to support clinicians to make decisions. Of key importance in this Guide is to provide an overview of existing evidence on glaucoma surgery and specifically on recent innovations and novel devices, but also to set standards in surgical design and reporting for future studies on glaucoma surgical innovation. Designing studies in surgery is particularly challenging because of many subtle variations inherent to surgery and hence multiple factors involved in the outcome, but even more because one needs to define carefully outcomes relevant to the research question but also to the future translation into clinical practice. In addition this Guide aims to provide clinical recommendations on novel procedures already in use when insufficient evidence exists. EGS has a long tradition to provide guidance to the ophthalmic community in Europe and worldwide through the EGS Guidelines (now in their 5th Edition). The EGS leadership recognized that the changing environment in glaucoma surgery currently represents a major challenge for the clinician, needing specific guidance. Therefore, the decision was made to issue this Guide on Glaucoma Surgery in order to help clinicians to make appropriate decisions for their patients and also to provide the framework and guidance for researchers to improve the quality of evidence in future studies. Ultimately this Guide will support better Glaucoma Care in accordance with EGS's Vision and Mission. Fotis Topouzis EGS President

Optic Nerve Subarachnoid Space Posture Dependency - An MRI Study in Subjects With Normal Tension Glaucoma and Healthy Controls

Purpose

The purpose of this study was to examine the differences of optic nerve subarachnoid space (ONSAS) volume in patients with normal tension glaucoma (NTG) and healthy controls in different body positions.

Methods

Eight patients with NTG and seven healthy controls underwent magnetic resonance imaging (MRI) examinations in head up tilt (HUT) +11 degrees and head down tilt (HDT) -5 degrees positions according to a randomized protocol determining the starting position. The ONSAS volume in both body positions was measured and compared between the two groups. The results were analyzed using a generalized linear model.

Results

Between HDT and HUT, the postural ONSAS volume change was dependent on starting position (P < 0.001) and group (P = 0.003, NTG versus healthy). A subgroup analysis of those that were randomized to HUT examination first, coming directly from an upright position, showed that the patients with NTG had significantly larger positional ONSAS volume changes compared to the healthy controls; 121 ± 22 µL vs. 65 ± 37 µL (P = 0.049). Analysis of the ONSAS volume distribution showed different profiles for patients with NTG and healthy controls.

Conclusions

There was a significant difference in ONSAS volume change between patients with NTG and healthy subjects when subjected to posture changes, specifically when going from upright to head-down posture. This indicates that patients with NTG had been exposed to a lower ONSAS pressure when they came from the upright posture, which suggests an increased translaminar pressure difference in upright position. This may support the theory that NTG has a dysfunction in an occlusion mechanism of the optic nerve sheath that could cause abnormally negative ONSAS pressures in upright posture.

Endpoints for clinical trials in ophthalmology

With the identification of novel targets, the number of interventional clinical trials in ophthalmology has increased. Visual acuity has for a long time been considered the gold standard endpoint for clinical trials, but in the recent years it became evident that other endpoints are required for many indications including geographic atrophy and inherited retinal disease. In glaucoma the currently available drugs were approved based on their IOP lowering capacity. Some recent findings do, however, indicate that at the same level of IOP reduction, not all drugs have the same effect on visual field progression. For neuroprotection trials in glaucoma, novel surrogate endpoints are required, which may either include functional or structural parameters or a combination of both. A number of potential surrogate endpoints for ophthalmology clinical trials have been identified, but their validation is complicated and requires solid scientific evidence. In this article we summarize candidates for clinical endpoints in ophthalmology with a focus on retinal disease and glaucoma. Functional and structural biomarkers, as well as quality of life measures are discussed, and their potential to serve as endpoints in pivotal trials is critically evaluated.

Prediction of visual field progression in glaucoma: existing methods and artificial intelligence

Timely treatment is essential in the management of glaucoma. However, subjective assessment of visual field (VF) progression is not recommended, because it can be unreliable. There are two types of artificial intelligence (AI) strong and weak (machine learning). Weak AIs can perform specific tasks. Linear regression is a method of weak AI. Using linear regression in the real-world clinic has enabled analyzing and predicting VF progression. However, caution is still required when interpreting the results, because whenever the number of VF data sets investigated is small, the predictions can be inaccurate. Several other non-ordinal, or modern AI methods have been constructed to improve prediction accuracy, such as clustering and more modern AI methods of Analysis with Non-Stationary Weibull Error Regression and Spatial Enhancement (ANSWERS), Variational Bayes Linear Regression (VBLR), Kalman Filter and sparse modeling (The least absolute shrinkage and selection operator regression: Lasso). It is also possible to improve the prediction performance using retinal thickness measured with optical coherence tomography by using machine learning methods, such as multitask learning.

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.

The Japan Glaucoma Society guidelines for glaucoma 5th edition

We are pleased to bring you the 5th edition of the Glaucoma Clinical Practice Guidelines. Clinical practice guidelines are based on evidence (scientific grounds). It is a document that presents the treatment that is the most appropriate for the patient. "Glaucoma Clinical Guidelines" was first published in 2003. This was the first guideline for glaucoma treatment in Japan. The principle of glaucoma treatment is to lower intraocular pressure. Means for lowering intraocular pressure includes drugs, lasers, and surgery; Glaucoma is a disease that should be considered as a complex syndrome rather than a single condition. Therefore, the actual medical treatment is not as simple as one word. This time we set the Clinical Questionnaire with a focus on glaucoma treatment. We hope that you will take advantage of the 5th edition.

Follow-up studies of the classical landmark studies in Glaucoma

PURPOSE OF REVIEW

It was not until the nineteen nineties that there was scientific evidence for the primary treatment concept of glaucoma, lowering intraocular pressure. The treatment concept of lowering intraocular pressure is now proven by randomized controlled clinical trials (landmark studies). This review provides an overview of the follow-up studies to these landmark studies from the last 18 months.

RECENT FINDINGS

The 20-year data of the ocular hypertension treatment study showed a 49% incidence of primary open-angle glaucoma. The data of this landmark study was used for developing different machine learning algorithms. Bilateral disease, disc hemorrhages, and higher intraocular pressure (IOP) were risk factors for visual field deterioration in the United Kingdom Glaucoma Treatment Study. The Advanced Glaucoma Intervention Trial and the Collaborative Initial Glaucoma Treatment Study identified demographic factors, comorbidity, and clinical variables associated with visual field damage. Analysis was performed on Chinese subsets from the Laser in Glaucoma and Ocular Hypertension Study (LiGHT). Looking at all the follow-up studies to the tube shunt landmark studies, preoperative IOP, neovascular glaucoma, Ahmed implantation, and younger age were predictors of failure. A follow-up study to the Effectiveness in Angle-Closure Glaucoma in Lens Extraction Study showed that patients were ten times more likely to maintain a drop-free target IOP after lens extraction than after laser iridotomy. A superior location for iridotomy results in significantly more significant angle widening than temporal or nasal locations, as shown by a follow-up study to the Zhongshan Angle Closure Prevention Trial using OCT and gonioscopy.

SUMMARY

The number of published follow-up studies to the landmark studies in glaucoma show the ongoing development of clinical questions in management of glaucoma.

Blood cell traits and risk of glaucoma: A two-sample mendelian randomization study

Importance: Glaucoma is the second leading cause of blindness in the world. The causal direction and magnitude of the association between blood cell traits and glaucoma is uncertain because of the susceptibility of observational studies to confounding and reverse causation. Objective: To explore whether there is a causal relationship of blood cell traits including white blood cell (WBC) count (WBCC) and its subtypes [basophil cell count (BASO), monocyte cell count (MONO), lymphocyte cell count (LYMPH), eosinophil cell count (EOS), neutrophil cell count (NEUT)], red blood cell (RBC) count (RBCC), red blood distribution width (RDW), platelet count (PLT), and plateletcrit (PCT) on glaucoma risk. Methods: A two-sample Mendelian randomization (MR) analysis was conducted. Genome-wide significant single nucleotide polymorphisms (SNPs) from published genome-wide association studies (GWAS) on human blood cell traits were utilized as exposure instruments and the dataset for outcome was from the GWAS summary data of glaucoma. In the univariable MR analysis, we examined the association between genetic evidence of blood cell traits and glaucoma. To further investigate the potential causal mechanisms underlying the observed association, we performed multivariable MR analysis with three models, taking into account the mediator effect of inflammation and oxidative stress. According to Bonferroni-corrected for the 10 exposures in 3 methods, the MR study yielded a statistically significant p-value of 0.0017. Results: Genetically BASO, PCT, LYMPH, and PLT were potentially positively associated with glaucoma in the European ancestry [BASO: Odds ratio (OR) = 1.00122, 95% confidence interval (CI), 1.00003-1.00242, p = 0.045; PCT: OR = 1.00078, 95% CI, 1.00012-1.00143, p = 0.019; LYMPH: OR = 1.00076, 95% CI, 1.00002-1.00151, p = 0.045; PLT: OR = 1.00065, 95% CI, 1.00006-1.00123, p = 0.030], There was insufficient evidence to support a causal association of MONO, NEUT, EOS, WBCC, RBCC and RDW (MONO: OR = 1.00050, p = 0.098; NEUT: OR = 1.00028, p = 0.524; EOS: OR = 1.00020, p = 0.562; WBCC: OR = 1.00008, p = 0.830; RBCC: OR = 0.99996, p = 0.920; RDW: OR = 0.99987, p = 0.734) with glaucoma. The multivariable MR with model 1, 2, and 3 demonstrated that BASO, PCT, LYMPH, and PLT were still potentially genetically associated with the risk of glaucoma. Conclusion: Our study reveals a genetic predisposition to higher LYMPH, BASO, PLT, and PCT are associated with a higher risk of glaucoma, whereas WBCC, MONO, EOS, NEUT, RBCC, and RDW are not associated with the occurrence of glaucoma. This finding also supports previous observational studies associating immune components with glaucoma, thus provide guidance on the predication and prevention for glaucoma.

[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 2. Clinical and functional correlations, monitoring of advanced glaucoma and limitations of the method]

The purpose of this study is to analyze the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma. This review considers the structural and functional correlations observed during the progression of glaucomatous optic neuropathy, as well as the capabilities of the method in late glaucoma, describes the strengths and weaknesses of OCT and OCTA, and pays particular attention to the role of OCT in assessing the effectiveness of treatment. Optical coherence tomography is the main method for determining the progression of glaucoma, which plays a key role in the choice of treatment algorithm. However, the use of OCT in far advanced glaucoma has certain particularities and limitations. OCTA can be helpful in overcoming this problem.

Correlation between OCT-angiography and photopic negative response in patients with primary open angle glaucoma

Purpose

To evaluate the association between OCT-angiography (OCTA) and photopic negative response (PhNR) in open angle glaucoma (OAG) patients and assess the diagnostic accuracy of these parameters in early detection of glaucoma.

Methods

A total of 152 eyes were enrolled in this study, 28 eyes with mild POAG (group I), 44 eyes with moderate-severe POAG (group 2) & 80 eyes of healthy subjects (control group). Full ophthalmological examination, OCTA and PhNR measurements were underwent for all participants. RNFL, GCC thicknesses, PhNR (implicit time and amplitude) were recorded. The superficial and deep capillary plexus vessel density (SCP-VD%, DCP-VD%) were measured by using 6 × 6 mm macula OCTA scans. The peripapillary vessel density (RPC-VD %) were measured by using 4.5 × 4.5 mm optic disk head OCTA scans.

Results

There were reduction of the median Interquartile range (IQR) thickness of the GCC and RNFL in OAG eyes versus normal (P < 0.001). RPC-VD%, SCP-VD % and DCP-VD% were significantly reduced in OAG eyes versus normal (P < 0.001). Increased OAG severity was associated with more reduction in PhNR amplitude and increased implicit time. Reduced PhNR amplitude and prolonged latency were significantly correlated with reduced vascular parameters. The RCP-VD and PhNR amplitude demonstrated higher diagnostic accuracy (98.7) with the largest AUC and higher sensitivity and specificity (100% & 98.7%, respectively), followed by the PhNR implicit time with (AUC = 0.995) with a diagnostic accuracy 98.7. The SCP-VD, RNFL and GCC thickness had a diagnostic accuracy of (75.0, 81.6 & 84.2), respectively (P < 0.001).

Conclusions

OCTA vascular parameters displayed significant positive correlation with PhNR amplitude and significant negative correlation with PhNR implicit time. OCTA and PhNR parameters showed a high diagnostic accuracy for detection of glaucoma, and both may provide promising insight in early detection of glaucoma.

This study was retrospectively registered on ClinicalTrials.gov (identifier, NCT05104294).

Neuroprotection in Glaucoma: Basic Aspects and Clinical Relevance

Glaucoma is a neurodegenerative disease that affects primarily the retinal ganglion cells (RGCs). Increased intraocular pressure (IOP) is one of the major risk factors for glaucoma. The mainstay of current glaucoma therapy is limited to lowering IOP; however, controlling IOP in certain patients can be futile in slowing disease progression. The understanding of potential biomolecular processes that occur in glaucomatous degeneration allows for the development of glaucoma treatments that modulate the death of RGCs. Neuroprotection is the modification of RGCs and the microenvironment of neurons to promote neuron survival and function. Numerous studies have revealed effective neuroprotection modalities in animal models of glaucoma; nevertheless, clinical translation remains a major challenge. In this review, we select the most clinically relevant treatment strategies, summarize preclinical and clinical data as well as recent therapeutic advances in IOP-independent neuroprotection research, and discuss the feasibility and hurdles of each therapeutic approach based on possible pathogenic mechanisms. We also summarize the potential therapeutic mechanisms of various agents in neuroprotection related to glutamate excitotoxicity.

Long- and Short-Term Variability of Perimetry in Glaucoma

Purpose

Test–retest variability in perimetry consists of short-term and long-term components, both of which impede assessment of progression. By minimizing and quantifying the algorithm-dependent short-term variability, we can quantify the algorithm-independent long-term variability that reflects true fluctuations in sensitivity between visits. We do this at locations with sensitivity both < 28 dB (when the stimulus is smaller than Ricco's area and complete spatial summation can be assumed) and > 28 dB (when partial summation occurs).

Methods

Frequency-of-seeing curves were measured at four locations of 35 participants with glaucoma. The standard deviation of cumulative Gaussian fits to those curves was modeled for a given sensitivity and used to simulate the expected short-term variability of a 30-presentation algorithm. A separate group of 137 participants was tested twice with that algorithm, 6 months apart. Long-term variance at different sensitivities was calculated as the LOESS fit of observed test–retest variance minus the LOESS fit of simulated short-term variance.

Results

Below 28 dB, short-term variability increased approximately linearly with increasing loss. Long-term variability also increased with damage below this point, attaining a maximum standard deviation of 2.4 dB at sensitivity 21 dB, before decreasing due to the floor effect of the algorithm. Above 30 dB, the observed test–retest variance was slightly smaller than the simulated short-term variance.

Conclusions

Long-term and short-term variability both increase with damage for perimetric stimuli smaller than Ricco's area. Above 28 dB, long-term variability constitutes a negligible proportion of test–retest variability.

Translational Relevance

Fluctuations in true sensitivity increase in glaucoma, even after accounting for increased short-term variability. This long-term variability cannot be reduced by altering testing algorithms alone.

Classification of Visual Field Abnormalities in Highly Myopic Eyes without Pathologic Change

PURPOSE

To develop a classification system of visual field (VF) abnormalities in highly myopic eyes with and without glaucoma.

DESIGN

Secondary analysis of VF data from a longitudinal cohort study.

PARTICIPANTS

One thousand eight hundred ninety-three VF tests from 1302 eyes (825 individuals).

METHODS

All participants underwent VF testing (Humphrey 24-2 Swedish interactive threshold algorithm standard program; Carl Zeiss Meditec) and detailed ophthalmic examination. A comprehensive set of VF defect patterns was defined via observation of the 1893 VF reports, literature review, and consensus meetings. The classification system comprised 4 major types of VF patterns, including normal type, glaucoma-like defects (paracentral defect, nasal step, partial arcuate defect, arcuate defect), high myopia-related defects (enlarged blind spot, vertical step, partial peripheral rim, nonspecific defect), and combined defects (nasal step with enlarged blind spot). A subset (n = 1000) of the VFs was used to evaluate the interobserver and intraobserver agreement and weighted κ values of the classification system by 2 trained readers. The prevalence of various VF patterns and their associated factors were determined.

MAIN OUTCOME MEASURES

The classification of VF in highly myopic eyes and its associated risk factors.

RESULTS

We found that normal type, glaucoma-like defects, high myopia-related defects, and combined defects accounted for 74.1%, 10.8%, 15.0%, and 0.1% of all unique VF tests, respectively. The interobserver and intraobserver agreements were > 89%, and the corresponding κ values were 0.86 or more between readers. Both glaucoma-like and high myopia-related VF defects were associated with older age (odds ratios [ORs], 1.07 [95% confidence interval (CI), 1.04-1.10; P < 0.001] and 1.06 [95% CI, 1.04-1.10; P < 0.001]) and longer axial length (ORs, 1.65 [95% CI, 1.32-2.07; P < 0.001] and 1.37 [95% CI, 1.11-1.68; P = 0.003]). Longer axial length showed a stronger effect on the prevalence of glaucoma-like VF defects than on the prevalence of high myopia-related VF defects (P = 0.036).

CONCLUSIONS

We propose a new and reproducible classification system of VF abnormalities for nonpathologic high myopia. Applying a comprehensive classification system will facilitate communication and comparison of findings among studies.

Comparing Five Criteria for Evaluating Glaucomatous Visual Fields

PURPOSE

No consensus exists on the relative superiority among criteria for evaluating glaucomatous visual field (VF) damage. We compared the sensitivities and specificities of 5 criteria-Glaucoma Hemifield Test (GHT), Hoddap-Anderson-Parrish 2 (HAP2), Foster, United Kingdom Glaucoma Treatment Study (UKGTS), and Low-pressure Glaucoma Treatment Study (LoGTS)-across various levels of functional and structural glaucomatous damage.

DESIGN

Retrospective cross-sectional study.

METHODS

This single-center study included patients with suspect or known glaucoma with reliable VF (Humphrey 24-2 Swedish Interactive Thresholding Algorithm) and optical coherence tomography (OCT; Spectralis, Heidelberg Engineering) examinations within a 4-month period. One eye per patient was included. The level of functional and structural damage was defined by mean deviation (MD) and by an OCT score, respectively. We created the OCT score by counting the number of abnormal (MD percentile [P] <1%) global and sectoral averages of optic nerve head MRW, circumpapillary RNFL thickness, and macular GCL thickness. We inferred specificities and sensitivities from positive rates of the criteria in patients with low glaucomatous damage (MD at P ≥ 10% or OCT score = 0) and with higher damage (MD at P < 10% or OCT score > 0), respectively.

RESULTS

We included 1230 patients. In patients with low glaucomatous damage, HAP2 and UKGTS had higher positive rates, suggesting lower specificities, whereas GHT, Foster, and LoGTS had lower positive rates, suggesting higher specificities. In patients with higher glaucomatous damage, HAP2 and UKGTS had higher positive rates, indicating higher sensitivities, whereas GHT, Foster, and LoGTS had lower positive rates, indicating lower sensitivities.

CONCLUSIONS

No criteria had uniformly superior performance. Selection of criteria should consider the degree of damage anticipated and the desire for either higher sensitivity or specificity.

Testing the eligibility of glaucoma patients for potential gene therapy among a clinic population

PURPOSE

Glaucoma patients who deteriorate despite standard treatment may benefit from novel gene therapies. Key inclusion criteria for a glaucoma gene therapy trial were devised. A retrospective chart review in a glaucoma clinic population was conducted. Feasibility of gene therapy inclusion criteria and factors associated with progression and fast progression < -1 decibels/year (dB/y) were evaluated.

METHODS

Three hundred and seventy-four primary open-angle glaucoma patients all of whom had performed at least five Swedish interactive threshold algorithm standard visual fields within a 58-month period. Two definitions were applied to characterize visual field progression rate using Guided Progression Analysis for an individual patient based on A, the eye with the greatest visual field loss, or B, the eye with the most rapid progression rate.

RESULTS

Mean rate of visual field progression was  -0.50 dB/y (Definition A) and  -0.64 dB/y (Definition B). 19.0% (A) and 21.9% (B) of eyes, 71 (A) and 82 (B) eyes, were 'fast progressors' (<  -1 dB/y). 37 (A) and 43 (B) eyes met the putative gene therapy inclusion criteria (≥ 50 years; mean deviation ≤  -4 to ≥  -12 or ≤  -20 dB, progression rate between  -1 and  -4 dB/y). Beta blockers (Odds ratio (OR) with 95% Confidence Intervals (CI): 2.84 (1.39-5.80); p = 0.004) (A), (OR (95%CI): 2.48 (1.30-4.75); p = 0.006) (B) and alpha agonists (OR (95%CI): 2.18 (1.14-4.17); p = 0.02) (A), (OR (95%CI) 2.00 (1.08-3.73); p = 0.028) (B) were significantly associated with fast progression.

CONCLUSION

A substantial proportion (10%) of patients in this clinic population would meet recommended gene therapy inclusion criteria.

Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb

Optical coherence tomography angiography (OCTA) is a new technique for non-invasive imaging of blood vessels, allowing combined evaluation of both deep and surface vessels. The purpose of this study was to evaluate the post-trabeculectomy longitudinal changes in complete avascular area (CAA) of filtering blebs using anterior segment (AS-) OCTA and their association with surgical outcomes. This study included 57 eyes of 53 patients who had undergone trabeculectomy with mitomycin C. AS-OCTA images of filtering bleb were acquired at 3 and 6 months after trabeculectomy, and at 1 month in possible cases. CAAs, regions where complete blood flow was not depicted in AS-OCTA images, were evaluated for their presence, extent, and change over time. CAAs were detected in 37 eyes (65%) and 33 eyes (58%) at 3 and 6 months postoperatively, respectively. The extent of CAAs reduced over time after surgery in most cases. No parameters related to CAAs were significantly associated with surgical success (i.e., intraocular pressure (IOP) ≤ 12 mmHg and IOP reduction > 20% without medication). In conclusion, although it is difficult to predict surgical success by CAA itself, AS-OCTA may be useful for the objective evaluation of the vascularity of filtering blebs.

[Structure/function/treatment in glaucoma: progress over the last 10 years]

Since the 1990s several so-called landmark studies were carried out, which played an important role in the management of glaucoma patients due to their multicenter, randomized and masked structure. The Ocular Hypertension Treatment Study (OHTS) and the Collaborative Initial Treatment Glaucoma Study (CIGTS) and their follow-up studies are especially important in the conservative glaucoma management and in the evaluation of structure and function. The OHTS examined if lowering of the intraocular pressure (IOP) treatment reduces the progression from ocular hypertension to primary open angle glaucoma and what risk factors influence the progression. The CIGTS examined the progression of glaucoma in patients treated either with pharmacotherapy or with surgery. The recent studies, the United Kingdom Glaucoma Treatment Study (UKGTS) and Glaucoma Automated Test Evaluation (GATE) investigated the influence of treatment with latanoprost on the development of visual field defects and examination of different screening tests in glaucoma, respectively. The OHTS provided results that justify prophylactic treatment as well as watchful waiting. The results of CIGTS showed that under certain conditions surgical treatment of a newly discovered glaucoma can be recommended for moderate to advanced glaucoma. In the UKGTS treatment with latanoprost reduced the intraocular pressure and also the progression of visual field defects in beginning and moderate glaucoma damage. The GATE study found no clear-cut advantage of screening examinations, with cost effectiveness and without a substantial proportion of diagnoses being missed.

Association between topical β-blocker use and asthma attacks in glaucoma patients with asthma: a cohort study using a claims database

PURPOSE

To investigate the association between the use of topical β-blockers and subsequent asthma attacks in glaucoma patients with asthma.

METHODS

This was a retrospective longitudinal cohort study using an administrative claims database. All patients aged 20 years or older who were registered in the health insurance claims database updated and managed by JMDC Inc. (Tokyo, Japan). Patients who were newly prescribed eye drops for glaucoma treatment were identified between 2011 and 2017. The patients with glaucoma were divided into two groups: β-blocker users and non-β-blocker users, based on the presence of a β-blocker in the prescribed eye drops. We investigated whether the incidence of asthma attacks in patients with previously treated asthma differed between the two groups.

RESULTS

We categorized 17,666 patients in the β-blocker-user group and 12,609 patients in the non-β-blocker-user group. A total of 580 patients in the β-blocker group (3.28%) and 847 in the non-β-blocker group (6.72%) underwent asthma treatment before the prescription of anti-glaucoma eye drops (P < 0.001). Furthermore, 94 patients in the β-blocker-user group (0.53%) and 278 in the non-β-blocker user group (2.20%) were undergoing current treatment for asthma (P < 0.001). The adjusted hazard ratios of asthma attacks were 0.73 (95% confidence interval, 0.46-1.16, P = 0.18) in patients with a history of asthma treatment and 1.22 (95% confidence interval, 0.56-2.70, P = 0.62) in patients with current asthma treatment, compared to the non-β-blocker-user group.

CONCLUSION

Our results clarified that several patients with asthma were prescribed topical β-blockers for glaucoma treatment. However, asthma attacks may not be significantly attributed to topical β-blockers, even in glaucoma patients under current asthma treatment. The administration of topical β-blockers to asthma patients could be a treatment option in the absence of other treatment options, if adequate informed consent is obtained. Further studies are needed to draw a firm conclusion on this clinical question.

Estimated Utility of the Short-term Assessment of Glaucoma Progression Model in Clinical Practice

IMPORTANCE

Clinical trials of glaucoma therapies focused on protecting the optic nerve have required large sample sizes and lengthy follow-up to detect clinically relevant change due to its slow rate of progression. Whether shorter trials may be possible with more frequent testing and use of rate of change as the end point warrants further investigation.

OBJECTIVE

To describe the design for the Short-term Assessment of Glaucoma Progression (STAGE) model and provide guidance on sample size and power calculations for shorter clinical trials.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study of patients with mild, moderate, or advanced open-angle glaucoma recruited from the Diagnostic Innovations in Glaucoma Study at the University of California, San Diego. Enrollment began in May 2012 with follow-up for every 3 months for 2 years after baseline examination. Follow-up was concluded in September 2016. Data were analyzed from July 2019 to January 2021. Visual fields (VF) and optic coherence tomography (OCT) scans were obtained at baseline and for 2 years with visits every 3 months.

EXPOSURES

Glaucoma was defined as glaucomatous appearing optic discs classified by disc photographs in at least 1 eye and/or repeatable VF damage at baseline.

MAIN OUTCOMES AND MEASURES

Longitudinal rates of change in retinal nerve fiber layer (RNFL) thickness and VF mean deviation (MD) are estimated in study designs of varying length and observation frequency. Power calculations as functions of study length, observation frequency, and sample size were performed.

RESULTS

In a total referred sample of 97 patients with mild, moderate, or advanced glaucoma (mean [SD] age, 69 [11.4] years; 50 [51.5%] were female; 19 [19.6%]), over the 2-year follow-up, the mean VF 24-2 MD slope was -0.32 dB/y (95% CI, -0.43 to -0.21 dB/y) and the mean RNFL thickness slope was -0.54 μm/y (95% CI, -0.75 to -0.32 μm/y). Sufficient power (80%) to detect similar group differences in the rate of change in both outcomes was attained with total follow-up between 18 months and 2 years and fewer than 300 total participants.

CONCLUSIONS AND RELEVANCE

In this cohort study, results from the STAGE model with reduction of the rate of progression as the end point, frequent testing, and a moderate effect size, suggest that clinical trials to test efficacy of glaucoma therapy can be completed within 18 months of follow-up and with fewer than 300 participants.

New perspectives of immunomodulation and neuroprotection in glaucoma

Glaucoma is the neurodegenerative disease of retinal ganglion cells. The main risk factor for glaucoma is increased intraocular pressure. The processes leading to cell death due to presence of the injury factor comprise multiple molecular mechanisms, as well as the immunological response. The knowledge of immunological mechanisms occurring in glaucomatous degeneration makes it possible to introduce glaucoma treatment modulating the cellular degradation. The glaucoma treatment of the future will make it possible not only to lower the intraocular pressure, but also to moderate the intracellular mechanisms in order to prevent retinal cell degeneration. Citicoline is a drug modulating glutamate excitotoxicity that is already in use. Rho kinase inhibitors were found to stimulate neurite growth and axon regeneration apart from lowering intraocular pressure. The complementary action of brimonidine is to increase neurotrophic factor (NTF) concentrations and inhibit glutamate toxicity. Immunomodulatory therapies with antibodies and gene therapies show promising effects in the current studies. The supplementation of NTFs prevents glaucomatous damage. Resveratrol and other antioxidants inhibit reactive oxygen species formation. Cell transplantation of stem cells, Schwann cells and nerve extracts was reported to be successful so far. Our review presents the most promising new strategies of neuroprotection and immunomodulation in glaucoma.

Glaucoma in Adults-Screening, Diagnosis, and Management: A Review

IMPORTANCE

Glaucoma is the most common cause of irreversible blindness worldwide. Many patients with glaucoma are asymptomatic early in the disease course. Primary care clinicians should know which patients to refer to an eye care professional for a complete eye examination to check for signs of glaucoma and to determine what systemic conditions or medications can increase a patient's risk of glaucoma. Open-angle and narrow-angle forms of glaucoma are reviewed, including a description of the pathophysiology, risk factors, screening, disease monitoring, and treatment options.

OBSERVATIONS

Glaucoma is a chronic progressive optic neuropathy, characterized by damage to the optic nerve and retinal nerve fiber layer, that can lead to permanent loss of peripheral or central vision. Intraocular pressure is the only known modifiable risk factor. Other important risk factors include older age, nonwhite race, and a family history of glaucoma. Several systemic medical conditions and medications including corticosteroids, anticholinergics, certain antidepressants, and topiramate may predispose patients to glaucoma. There are 2 broad categories of glaucoma, open-angle and angle-closure glaucoma. Diagnostic testing to assess for glaucoma and to monitor for disease progression includes measurement of intraocular pressure, perimetry, and optical coherence tomography. Treatment of glaucoma involves lowering intraocular pressure. This can be achieved with various classes of glaucoma medications as well as laser and incisional surgical procedures.

CONCLUSIONS AND RELEVANCE

Vision loss from glaucoma can be minimized by recognizing systemic conditions and medications that increase a patient's risk of glaucoma and referring high-risk patients for a complete ophthalmologic examination. Clinicians should ensure that patients remain adherent with taking glaucoma medications and should monitor for adverse events from medical or surgical interventions used to treat glaucoma.

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.

Improving statistical power of glaucoma clinical trials using an ensemble of cyclical generative adversarial networks

Albeit spectral-domain OCT (SDOCT) is now in clinical use for glaucoma management, published clinical trials relied on time-domain OCT (TDOCT) which is characterized by low signal-to-noise ratio, leading to low statistical power. For this reason, such trials require large numbers of patients observed over long intervals and become more costly. We propose a probabilistic ensemble model and a cycle-consistent perceptual loss for improving the statistical power of trials utilizing TDOCT. TDOCT are converted to synthesized SDOCT and segmented via Bayesian fusion of an ensemble of GANs. The final retinal nerve fibre layer segmentation is obtained automatically on an averaged synthesized image using label fusion. We benchmark different networks using i) GAN, ii) Wasserstein GAN (WGAN) (iii) GAN + perceptual loss and iv) WGAN + perceptual loss. For training and validation, an independent dataset is used, while testing is performed on the UK Glaucoma Treatment Study (UKGTS), i.e. a TDOCT-based trial. We quantify the statistical power of the measurements obtained with our method, as compared with those derived from the original TDOCT. The results provide new insights into the UKGTS, showing a significantly better separation between treatment arms, while improving the statistical power of TDOCT on par with visual field measurements.

Effect of medically lowering intraocular pressure in glaucoma suspects with high myopia (GSHM study): study protocol for a randomized controlled trial

Background

Currently, whether and when intraocular pressure (IOP)-lowering medication should be used in glaucoma suspects with high myopia (GSHM) remains unknown. Glaucoma suspects are visual field (VF) defects that cannot be explained by myopic macular changes or other retinal and neurologic conditions. Glaucoma progression is defined by VF deterioration. Here we describe the rationale, design, and methodology of a randomized controlled trial (RCT) designed to evaluate the effects of medically lowering IOP in GSHM (GSHM study).

Methods

The GSHM study is an open-label, single-center, RCT for GSHM. Overall, 264 newly diagnosed participants, aged 35 to 65 years, will be recruited at the Zhongshan Ophthalmic Center, Sun Yat-sen University, between 2020 and 2021. Participants will be randomly divided into two arms at a 1:1 ratio. Participants in the intervention arm will receive IOP-lowering medication, while participants in the control arm will be followed up without treatment for 36 months or until they reach the end point. Only one eye per participant will be eligible for the study. If both eyes are eligible, the eye with the worse VF will be recruited. The primary outcome is the incidence of glaucoma suspect progression by VF testing over 36 months. The secondary outcomes include the incidence of changes in the optic nerve head morphology including the retinal nerve fiber layer, and retinal ganglion cell-inner plexiform layer loss, progression of myopic maculopathy, visual function loss, and change in the quality of life. Statistical analyses will include baseline characteristics comparison between the intervention and control groups using a two-sample t-test and Wilcoxon rank sum test; generalized linear models with Poisson regression for the primary outcome; Kaplan-Meier curve and log-rank test for the incidence of the secondary outcome; and longitudinal analyses to assess trends in outcomes across time.

Discussion

To the best of our knowledge, the GSHM study is the first RCT to investigate the impact of medically lowering IOP in GSHM. The results will have implications for the clinical management of GSHM.

Trial registration

ClinicalTrials.gov NCT04296916. Registered on 4 March 2020

Presumed activated retinal astrocytes and Müller cells in healthy and glaucomatous eyes detected by spectral domain optical coherence tomography

Purpose

To investigate presumed activated retinal astrocytes and Müller cells (ARAM) detected by scanning laser ophthalmoscopy (SLO) and spectral domain optical coherence tomography, and to investigate its presence in healthy controls as well as its relationship to posterior vitreal detachment (PVD) and glaucoma.

Methods

This retrospective study involved 1337 eyes of 805 controls between ages 8 and 90, and 250 eyes of 146 patients with glaucoma between the ages of 28 and 95. Subjects were counted as possessing ARAM only if they met the following criteria: (1) a patchy, discrete, glittering appearance on SLO, (2) a distinct, flat, hyper‐reflective layer at the internal limiting membrane on at least one B‐scan crossing the glittering area and (3) absence of any surface wrinkling retinopathy. The diagnosis of PVD was based on both the patient’s clinical examination and imaging data. Frequency tables were used to describe categorical variables and differences were compared by means of χ². Analyses were separated based on right and left eye, first on controls and then between glaucomatous eyes and age‐similar sex‐matched controls.

Results

ARAM was found in both healthy controls and patients with glaucoma at similar frequencies. There was no association between having glaucoma and the presence of ARAM. ARAM was not different between the sexes but was associated with age and having a PVD.

Conclusions

This large retrospective study found that ARAM can be seen in healthy controls, is associated with PVD and possibly independently with age, and occurred at similar frequency in glaucomatous eyes.

Comparisons of retinal vessel density and glaucomatous parameters in optical coherence tomography angiography

PURPOSE

To compare the retinal vessel density and glaucomatous parameters in primary angle closure glaucoma (PACG), to evaluate the diagnostic and monitoring abilities of the peripapillary and macular vessel density in the progression of glaucoma.

METHODS

This was a observational, prospective and cross-sectional study. According to Glaucoma Staging System, 218 eyes (116 participants) were divided into 5 groups: no glaucoma, early glaucoma, moderate glaucoma, advance glaucoma, severe glaucoma. All participants underwent a comprehensive ocular examination, which included corrected distance visual acuity measurement, slit-lamp biomicroscopy, intra ocular pressure (IOP), gonioscopy, fundus examination, stereoscopic optic disc photography, Humphrey visual field test(VF), peripapillary and macular optical coherence tomography angiography(OCTA) scan. SPSS software was used to calculate and compare retinal vessel density (peripapillary vessel density, PVD and macular vessel density, MVD) and glaucomatous parameters (mean deviation (MD),pattern standard deviation(PSD), retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer(GCIPL),rim area, average cup/disc(C/D) ratio).

RESULTS

The GCIPL thickness, RNFL thickness, PVD and MVD are significantly reduced in PACG. There were significant differences in all measurements among the groups (P<0.01).Reduced peripapillary and macular vessel density in glaucoma were detected and a statistically significant correlation with glaucoma stages (P<0.01). In addition, the results of retinal vessel density, reduced RNFL thickness and GCIPL thickness were also statistically related to the stage of glaucoma. As expected, the rim area was significantly smaller with higher C/D area ratios in glaucomatous eyes corresponding to the severity of disease.

CONCLUSIONS

The changes of PVD and MVD had strongly positive correlation with GCIPL thickness and RNFL thickness, had negative correlation with the severity of glaucoma, which meant the more severe the glaucoma was, the lower PVD and MVD were. Compared to traditional glaucoma staging system judged by VF, the changes of PVD and MVD obtained by OCTA might be a new method to grade the stage of glaucoma. These findings theorize that the changes of PVD and MVD may be better facilitated for the observation and monitoring of glaucoma progression.

Pulse Waveform Analysis of the Ocular Blood Flow Using Laser Speckle Flowgraphy before and after Glaucoma Treatment

Although reduction in intraocular pressure (IOP) is the principle of glaucoma treatment, impaired ocular blood flow is believed to play a role in the progression of glaucoma. This study evaluated the effect of glaucoma treatment on pulse waveforms for optic nerve head (ONH) microcirculation in patients with glaucoma. Fifty-one subjects were included on the basis of the glaucoma treatment administered, which involved instillation of prostaglandin (PG) analogs (PG group; n = 28) or trabeculectomy (trabeculectomy group; n = 23). ONH blood flow, represented by the mean blur rate (MBR_T) and pulse waveforms, was measured using laser speckle flowgraphy before and 1 and 3 months after treatment. Three months after treatment, IOP exhibited a significant decrease (p < 0.05). Although there was no significant change in MBR_T after treatment, the acceleration time index (ATI) significantly decreased (p=0.034) in the PG group. In the trabeculectomy group, there was no significant change in the MBR_T after treatment, while fluctuation (p=0.019) and blowout score (BOS) (p=0.036) exhibited significant decrease and increase, respectively. Multiple regression analysis showed that mean deviation was significantly associated with the rate of change in the BOS (p=0.013), age was a significant contributing factor for the rate of change in fluctuation in the trabeculectomy group, reflection was significantly associated with the ATI (p=0.037) in the in the PG group. Both glaucoma treatments can change the pulse waveforms, with MBR_T remaining unchanged, and IOP reduction owing to the treatment may contribute to stable blood flow in the tissue area of the ONH. As impaired ocular blood flow plays a role in the progression of glaucomatous damage, it would be beneficial if glaucoma treatment could improve the stability of ONH microcirculation.

Specificity of various cluster criteria used for the detection of glaucomatous visual field abnormalities

Purpose

This study aimed to evaluate the specificity of commonly used cluster criteria for defining the presence of glaucomatous visual field abnormalities and the impact of variations in the criterion used.

Methods

This is an observational study including 607 eyes from 384 healthy participants, and 501 eyes of 345 participants with glaucoma, with at least two reliable 24–2 visual field tests. An abnormal visual field cluster was defined as the presence of ≥3 contiguous abnormal locations. Variations in this definition were evaluated and included (1) whether abnormalities were based on total deviation and/or pattern deviation values; (2) probability cut-off for defining an abnormal location; and (3) whether abnormalities were required to be repeatable (within the same hemifield or at the same locations) or not. These definitions were also compared against pattern standard deviation (PSD) values.

Results

False-positive rates of various cluster criteria ranged between 9% and 46% depending on the specific definitions used. Only definitions that required abnormalities to be repeatable at the same location achieved a false-positive rate of ≤6%. The various cluster criteria generally performed similarly or worse at detecting glaucoma eyes compared with the PSD values.

Conclusions

Commonly used visual field cluster criteria have high false-positive rates that vary widely depending on the definition used. These findings highlight the need to carefully consider the criteria used when designing and interpreting glaucoma clinical studies.

Trial registration number

NCT00221923.

The role of self-dependent tonometry in improving diagnostics and treatment of patients with open angle glaucoma

Monitoring intraocular pressure in patients with open-angle glaucoma at different stages of the deve­lopment of the disease using self-measurement by a portable Icare® HOME tonometer. In study, patients were divided into 3 groups depending on the treatment prescribed. With the help of near-day monitoring, hidden IOP elevations that are not recorded during a single IOP measurement on an outpatient appointment with a doctor were detected. Perspective possibilities of prescribing drugs and regulating the mode of instillation on the basis of individual time periods of increasing intraocular pressure on the example of one of the patient. Assessment of the convenience of the method from the personal experience of using the device by patients.

Combining optical coherence tomography with visual field data to rapidly detect disease progression in glaucoma: a diagnostic accuracy study

BACKGROUND

Progressive optic nerve damage in glaucoma results in vision loss, quantifiable with visual field (VF) testing. VF measurements are, however, highly variable, making identification of worsening vision ('progression') challenging. Glaucomatous optic nerve damage can also be measured with imaging techniques such as optical coherence tomography (OCT).

OBJECTIVE

To compare statistical methods that combine VF and OCT data with VF-only methods to establish whether or not these allow (1) more rapid identification of glaucoma progression and (2) shorter or smaller clinical trials.

DESIGN

Method 'hit rate' (related to sensitivity) was evaluated in subsets of the United Kingdom Glaucoma Treatment Study (UKGTS) and specificity was evaluated in 72 stable glaucoma patients who had 11 VF and OCT tests within 3 months (the RAPID data set). The reference progression detection method was based on Guided Progression Analysis™ (GPA) Software (Carl Zeiss Meditec Inc., Dublin, CA, USA). Index methods were based on previously described approaches [Analysis with Non-Stationary Weibull Error Regression and Spatial enhancement (ANSWERS), Permutation analyses Of Pointwise Linear Regression (PoPLR) and structure-guided ANSWERS (sANSWERS)] or newly developed methods based on Permutation Test (PERM), multivariate hierarchical models with multiple imputation for censored values (MaHMIC) and multivariate generalised estimating equations with multiple imputation for censored values (MaGIC).

SETTING

Ten university and general ophthalmology units (UKGTS) and a single university ophthalmology unit (RAPID).

PARTICIPANTS

UKGTS participants were newly diagnosed glaucoma patients randomised to intraocular pressure-lowering drops or placebo. RAPID participants had glaucomatous VF loss, were on treatment and were clinically stable.

INTERVENTIONS

24-2 VF tests with the Humphrey Field Analyzer and optic nerve imaging with time-domain (TD) Stratus OCT™ (Carl Zeiss Meditec Inc., Dublin, CA, USA).

MAIN OUTCOME MEASURES

Criterion hit rate and specificity, time to progression, future VF prediction error, proportion progressing in UKGTS treatment groups, hazard ratios (HRs) and study sample size.

RESULTS

Criterion specificity was 95% for all tests; the hit rate was 22.2% for GPA, 41.6% for PoPLR, 53.8% for ANSWERS and 61.3% for sANSWERS (all comparisons p ≤ 0.042). Mean survival time (weeks) was 93.6 for GPA, 82.5 for PoPLR, 72.0 for ANSWERS and 69.1 for sANSWERS. The median prediction errors (decibels) when the initial trend was used to predict the final VF were 3.8 (5th to 95th percentile 1.7 to 7.6) for PoPLR, 3.0 (5th to 95th percentile 1.5 to 5.7) for ANSWERS and 2.3 (5th to 95th percentile 1.3 to 4.5) for sANSWERS. HRs were 0.57 [95% confidence interval (CI) 0.34 to 0.90; p = 0.016] for GPA, 0.59 (95% CI 0.42 to 0.83; p = 0.002) for PoPLR, 0.76 (95% CI 0.56 to 1.02; p = 0.065) for ANSWERS and 0.70 (95% CI 0.53 to 0.93; p = 0.012) for sANSWERS. Sample size estimates were not reduced using methods including OCT data. PERM hit rates were between 8.3% and 17.4%. Treatment effects were non-significant in MaHMIC and MaGIC analyses; statistical significance was altered little by incorporating imaging.

LIMITATIONS

TD OCT is less precise than current imaging technology; current OCT technology would likely perform better. The size of the RAPID data set limited the precision of criterion specificity estimates.

CONCLUSIONS

The sANSWERS method combining VF and OCT data had a higher hit rate and identified progression more quickly than the reference and other VF-only methods, and produced more accurate estimates of the progression rate, but did not increase treatment effect statistical significance. Similar studies with current OCT technology need to be undertaken and the statistical methods need refinement.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN96423140.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 4. See the NIHR Journals Library website for further project information. Data analysed in the study were from the UKGTS. Funding for the UKGTS was provided through an unrestricted investigator-initiated research grant from Pfizer Inc. (New York, NY, USA), with supplementary funding from the NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK. Imaging equipment loans were made by Heidelberg Engineering, Carl Zeiss Meditec and Optovue (Fremont, CA, USA). Pfizer, Heidelberg Engineering, Carl Zeiss Meditec and Optovue had no input into the design, conduct, analysis or reporting of any of the UKGTS findings or this work. The sponsor for both the UKGTS and RAPID data collection was Moorfields Eye Hospital NHS Foundation Trust. David F Garway-Heath, Tuan-Anh Ho and Haogang Zhu are partly funded by the NIHR Biomedical Research Centre based at Moorfields Eye Hospital and UCL Institute of Ophthalmology. David F Garway-Heath's chair at University College London (UCL) is supported by funding from the International Glaucoma Association.

Estimating the Reliability of Glaucomatous Visual Field for the Accurate Assessment of Progression Using the Gaze-Tracking and Reliability Indices

PURPOSE

To investigate the usefulness of visual field (VF) reliability indices and gaze tracking (GT) for the accurate assessment of progression in glaucoma.

DESIGN

Institutional practice.

PARTICIPANTS

Four hundred eighty-three eyes of 304 patients with open-angle glaucoma.

METHODS

In each eye, a series of 10 VFs were examined. Using the GT chart at the bottom of the VF printout (Humphrey Field Analyzer, Swedish interactive threshold algorithm standard), average tracking failure frequency (TFF), average blinking frequency (BF), and the total amount of eye movement per stimulus (MPS) were calculated. Mean total deviation (mTD) was calculated based on the 52 total deviation values in each 24-2 VF, and linear regression was applied to the series of mTD measurements over time. Progression was deemed to have occurred based on 2 separate definitions: (1) the mTD rate across all 10 VFs (VF_1-10) was significant (P < 0.05) and less than 0 dB/year and (2) the mTD rate was less than -0.5 dB/year and significant at P < 0.05. The mTD rate also was calculated in shorter VF series (VF_1-5-VF_1-9). The area under the receiver operating characteristic curve (AUC) was calculated from the relationship between mTD rates of shorter VF series (n < 10) and the diagnosis of progression in all 10 VFs. This analysis was iterated after excluding eyes with increasingly strict cutoff values for the standard VF reliability indices (fixation loss [FL], false-positive [FP] rate, and false-negative [FN] rate) and the GT parameters (TFF, BF, and MPS).

MAIN OUTCOME MEASURES

Area under the receiver operating characteristic curve values with different exclusion criteria for GT and standard reliability indices.

RESULTS

The AUC was largely unchanged according to stricter FL and FP criteria. The AUC increased with a more stringent FN criterion, but only when progression was described using the second definition (a rate of less than -0.5 dB/year). The AUC increased with stricter criteria for TFF, BF, and, to some extent, MPS.

CONCLUSIONS

Mean total deviation progression rates are more reliable when FN, TFF, BF, and MPS indices are stricter. Gaze-tracking results should be considered when assessing glaucomatous progression.

A New SITA Perimetric Threshold Testing Algorithm: Construction and a Multicenter Clinical Study

PURPOSE

To describe a new time-saving threshold visual field-testing strategy-Swedish Interactive Thresholding Algorithm (SITA) Faster, which is intended to replace SITA Fast-and to report on a clinical evaluation of this new strategy.

DESIGN

Description and validity analysis for modifications applied to SITA Fast.

METHODS

Five centers tested 1 eye of each of 126 glaucoma and glaucoma suspect patients with SITA Faster, SITA Fast, and SITA Standard at each of 2 visits. Outcomes included test time, mean deviation, and the visual field index (VFI), significant test points in probability maps, and intertest threshold variability.

RESULTS

Mean (standard deviation) test times were 171.9 (45.3) seconds for SITA Faster, 247.0 (56.7) for SITA Fast, and 369.5 (64.5) for SITA Standard (P < .001). SITA Faster test times averaged 30.4 % shorter than SITA Fast and 53.5 % shorter than SITA Standard. Mean deviation was similar among all 3 tests.VFI did not differ between SITA Fast and SITA Faster tests, mean difference 0%, but VFI values were 1.2% lower with SITA Standard compared to both SITA Fast (P = .007) and SITA Faster (P = .002). A similar trend was seen with a slightly higher number of significant test points with SITA Standard than with SITA Fast and SITA Faster. All 3 tests had similar test-retest variability over the entire range of threshold values.

CONCLUSIONS

SITA Faster saved considerable test time. SITA Faster and SITA Fast gave almost identical results. There were small differences between SITA Faster and SITA Standard, of the same character as previously shown for SITA Fast vs SITA Standard.

Mouse model of ocular hypertension with retinal ganglion cell degeneration

Objectives

Ocular hypertension is a primary risk factor for glaucoma and results in retinal ganglion cell (RGC) degeneration. Current animal models of glaucoma lack severe RGC cell death as seen in glaucoma, making assessment of physiological mediators of cell death difficult. We developed a modified mouse model of ocular hypertension whereby long-lasting elevation of intraocular pressure (IOP) is achieved, resulting in significant reproducible damage to RGCs.

Results

In this model, microbeads are mixed with hyaluronic acid and injected into the anterior chamber of C57BL/6J mice. The hyaluronic acid allows for a gradual release of microbeads, resulting in sustained blockage of Schlemm’s canal. IOP elevation was bimodal during the course of the model’s progression. The first peak occurred 1 hours after beads injection, with an IOP value of 44.69 ± 6.00 mmHg, and the second peak occurred 6–12 days post-induction, with an IOP value of 34.91 ± 5.21 mmHg. RGC damage was most severe in the peripheral retina, with a loss of 64.1% compared to that of untreated eyes, while the midperiphery exhibited a 32.4% loss, 4 weeks following disease induction.

Conclusions

These results suggest that sustained IOP elevation causes more RGC damage in the periphery than in the midperiphery of the retina. This model yields significant and reproducible RGC degeneration.

Diagnostic Performance of Macular Versus Peripapillary Vessel Parameters by Optical Coherence Tomography Angiography for Glaucoma

PURPOSE

To compare the diagnostic ability of the vessel parameters in macular and peripapillary regions measured using spectral-domain optical coherence tomography angiography (SD-OCTA) in differentiating primary open-angle glaucoma (POAG) from healthy eyes.

METHODS

POAG patients and healthy subjects underwent 6 × 6-mm scans centered on the macula and optic nerve head. Commercially available automatic segmentation created en face images from SD-OCTA of the superficial retinal layer (SRL) of the macular (m) and peripapillary (cp) regions. Vessel area density (VAD), vessel skeleton density (VSD), vessel complexity index (VCI), and flux were calculated. Area under curve (AUC) statistics controlled for age and intereye correlation.

RESULTS

Of 126 eyes from 79 patients who underwent SD-OCTA macula and peripapillary imaging, 50 eyes from 35 POAG patients and 37 healthy eyes from 25 control subjects had good quality imaging and were studied. Diagnostic accuracies of four perfusion parameters, VAD, VSD, VCI, and flux, were significantly greater in the peripapillary compared with the macular regions. For VAD, the cpAUC was 0.84 and mAUC was 0.73 (AUC difference: P = 0.026). For VSD, the cpAUC was 0.84 and mAUC was 0.72 (ΔP = 0.015). For VCI, the cpAUC was 0.80 and mAUC was 0.70 (ΔP = 0.045). For flux, the cpAUC = 0.87 and mAUC was 0.76 (ΔP = 0.0091).

CONCLUSIONS

Peripapillary perfusion parameters performed better than macular perfusion parameters for glaucoma diagnosis, supporting the idea that glaucomatous superficial retinal vascular changes are more pronounced in the peripapillary region.

TRANSLATIONAL RELEVANCE

The diagnostic accuracy of OCTA perfusion parameters of the superficial retinal microcirculation was greater for the peripapillary region than the macular region in the diagnosis of glaucoma.

Application of Pattern Recognition Analysis to Optimize Hemifield Asymmetry Patterns for Early Detection of Glaucoma

Purpose

To assess the diagnostic utility of a new hemifield asymmetry analysis derived using pattern recognition contrast sensitivity isocontours (CSIs) within the Humphrey Field Analyzer (HFA) 24-2 visual field (VF) test grid. The performance of an optimal CSI-derived map was compared against a commercially available clustering method (Glaucoma Hemifield Test, GHT).

Methods

Five hundred VF results of 116 healthy subjects were used to determine normative distribution limits for comparisons. Pattern recognition analysis was applied to HFA 24-2 sensitivity data to determine CSI theme maps delineating clusters for hemifield comparisons. Then, 1019 VF results from 228 glaucoma patients were assessed using different clustering methods to determine the true-positive rate. We also assessed additional 354 VF results of 145 healthy subjects to determine the false-positive rate.

Results

The optimum clustering method was the CSI-derived seven-theme class map, which identified more glaucomatous VFs compared with the GHT map. The seven-class theme map also identified more cases compared with the five-, six-, and eight-class maps, suggesting no effect of number of clusters. Integrating information regarding the location of glaucomatous defects to the CSI clusters did not improve detection rate.

Conclusions

A clustering map derived using CSIs improved detection of glaucomatous VFs compared with the currently available GHT. An optimized CSI-derived map may serve as an additional means to aid earlier detection of glaucoma.

Translational Relevance

Pattern recognition–derived theme maps provide a means for guiding test point selection for asymmetry analysis in glaucoma assessment.

The Glaucoma Intensive Treatment Study (GITS), a randomized clinical trial: design, methodology and baseline data

PURPOSE

The primary objective of the ongoing Glaucoma Intensive Treatment Study (GITS) is to evaluate the effectiveness of immediate intensive treatment in comparison with the commonly recommended stepped regimen on the predicted visual field. The two treatment arms are also being compared regarding quality of life (QoL), intraocular pressure (IOP) reduction, frequency of reported side-effects, adverse events and adherence to prescribed treatment.

DESIGN

A randomized, two-centre, prospective open-labelled treatment trial for open-angle glaucoma.

PARTICIPANTS

Individuals aged 40-78 years with previously untreated and newly diagnosed glaucoma with early to moderate visual field loss were eligible.

METHODS

Patients were randomized to initial treatment either using drug monotherapy in accordance with common glaucoma guidelines or using a more intensive approach including eyedrops containing drugs from three different classes combined with 360° laser trabeculoplasty. The patients are to be followed for 5 years at visits including standard automated perimetry, optical coherence tomography (OPT) and tonometry. Change of treatment is allowed and decided upon jointly with the patient as in conventional glaucoma management.

MAIN OUTCOME

The estimated predicted preserved visual field and QoL at end of expected lifetime.

RESULTS

A total of 242 patients, 45% females, mean age 68 years, were randomized. The median untreated IOP was 24 mm Hg, and the median visual field index (VFI), indicating the percentage of a full field, was 92%.

CONCLUSION

Glaucoma Intensive Treatment Study is a clinical trial in which two groups of patients randomized to different initial intensities of IOP-reducing treatment are being compared with regard to rate of visual field progression and prediction of serious glaucomatous visual field loss at estimated at end of life.

Impact of Different Visual Field Testing Paradigms on Sample Size Requirements for Glaucoma Clinical Trials

Visual field testing is an important endpoint in glaucoma clinical trials, and the testing paradigm used can have a significant impact on the sample size requirements. To investigate this, this study included 353 eyes of 247 glaucoma patients seen over a 3-year period to extract real-world visual field rates of change and variability estimates to provide sample size estimates from computer simulations. The clinical trial scenario assumed that a new treatment was added to one of two groups that were both under routine clinical care, with various treatment effects examined. Three different visual field testing paradigms were evaluated: a) evenly spaced testing, b) United Kingdom Glaucoma Treatment Study (UKGTS) follow-up scheme, which adds clustered tests at the beginning and end of follow-up in addition to evenly spaced testing, and c) clustered testing paradigm, with clusters of tests at the beginning and end of the trial period and two intermediary visits. The sample size requirements were reduced by 17–19% and 39–40% using the UKGTS and clustered testing paradigms, respectively, when compared to the evenly spaced approach. These findings highlight how the clustered testing paradigm can substantially reduce sample size requirements and improve the feasibility of future glaucoma clinical trials.