Biomarkers and Surrogate Endpoints: Lessons Learned From Glaucoma

Neuroimaging Biomarkers in Addiction

As a neurobiological process, addiction involves pathological patterns of engagement with substances and a range of behaviors with a chronic and relapsing course. Neuroimaging technologies assess brain activity, structure, physiology, and metabolism at scales ranging from neurotransmitter receptors to large-scale brain networks, providing unique windows into the core neural processes implicated in substance use disorders. Identified aberrations in the neural substrates of reward and salience processing, response inhibition, interoception, and executive functions with neuroimaging can inform the development of pharmacological, neuromodulatory, and psychotherapeutic interventions to modulate the disordered neurobiology. Based on our systematic search, 409 protocols registered on ClinicalTrials.gov include the use of one or more neuroimaging paradigms as an outcome measure in addiction, with the majority (N=268) employing functional magnetic resonance imaging (fMRI), followed by positron emission tomography (PET) (N=71), electroencephalography (EEG) (N=50), structural magnetic resonance imaging (MRI) (N=35) and magnetic resonance spectroscopy (MRS) (N=35). Furthermore, in a PubMed systematic review, we identified 61 meta-analyses including 30 fMRI, 22 structural MRI, 8 EEG, 7 PET, and 3 MRS meta-analyses suggesting potential biomarkers in addictions. These studies can facilitate the development of a range of biomarkers that may prove useful in the arsenal of addiction treatments in the coming years. There is evidence that these markers of large-scale brain structure and activity may indicate vulnerability or separate disease subtypes, predict response to treatment, or provide objective measures of treatment response or recovery. Neuroimaging biomarkers can also suggest novel targets for interventions. Closed or open loop interventions can integrate these biomarkers with neuromodulation in real-time or offline to personalize stimulation parameters and deliver the precise intervention. This review provides an overview of neuroimaging modalities in addiction, potential neuroimaging biomarkers, and their physiologic and clinical relevance. Future directions and challenges in bringing these putative biomarkers from the bench to the bedside are also discussed.

Anti-VEGF therapy for the long-term management of diabetic macular edema: a treat-to-target strategy based on macular morphology

In an aging population, the prevalence and burden of diabetes mellitus, diabetic retinopathy, and vision-threatening diabetic macular edema (DME) are only expected to rise around the world. Similarly to other complications of diabetes mellitus, DME requires long-term management. This article aims to review the current challenges associated with the long-term management of DME, opportunities to improve outcomes for patients, and to develop a treat-to-target strategy based on macular morphology. At present, intravitreal anti-vascular endothelial growth factor (VEGF) therapy is the standard of care for the management of DME; however, best-achievable vision outcomes with treatment are reliant on frequent injections and close monitoring, which are difficult to maintain in current clinical practice because of the burden this imposes on patients. Achieving and maintaining good vision with treatment are the most important factors for patients with DME. Landmark trials have shown that vision gains with anti-VEGF therapy are typically accompanied by anatomical improvements (e.g., reductions in retinal thickness); therefore, multimodal imaging measures of macular morphology are often used in patients with DME to guide real-world treatment decisions. We would like to propose a hypothetical treat-to-target algorithm to guide physicians on treatment strategies for the long-term management of DME. Alternative measures of retinal fluid (e.g., persistence, stability, location) may be stronger predictors of visual acuity in DME, although further research is required to confirm whether alternate quantifiable biomarkers such as subretinal fluid and intraretinal fluid volumes can be used as a biomarker of clinical improvement. Identifying novel biomarkers and treatments that target neuroinflammation and neurodegeneration, improving patient-physician communication around treatment adherence, and using treat-to-target measures may help to ensure that the long-term benefits of treatment are realized.

Pattern electroretinogram, blue-yellow visual evoked potentials and the risk of developing visual field defects in glaucoma suspects: a longitudinal "survival" analysis with a very long follow-up

PURPOSE

Estimating glaucoma suspects' risk for visual field defects helps to avoid under- and over-treatment. In this retrospective, longitudinal cohort study with a very long follow-up, we studied whether pattern electroretinograms (PERG) amplitudes and blue-on-yellow visual evoked potential (BY-VEP) latencies can predict visual field defects.

METHODS

Participants of the Erlangen Glaucoma Study were examined with PERG and BY-VEP between 9/1991 and 8/2001. Stimuli were created using an optical bench with Maxwellian view and consisted of vertical gratings (0,88 cpd) in a 32° field for both PERG and BY-VEP. Patients were treated according to clinical standards and performed standard automated perimetry (SAP) annually. Retrospectively, patients with normal SAP at baseline were selected. Primary endpoint was conversion to perimetric glaucoma. Predictive value was modeled using Kaplan-Meier analyses and a multivariate cox proportional hazards model with the continuous variables PERG amplitude, BY-VEP peak time and SAP square-root of loss variance (sLV) after stratification for Jonas classification of the optic discs.

RESULTS

Of 412 patients (288: Jonas 0, 103: I, and 21: II; baseline age: 20-60 years), 65 converted to perimetric glaucoma during follow-up (0.5-23.3 years; median 5.5 years). Optic disc classification was a strong risk factor for conversion (log rank p < 0.0001), and patients with more advanced changes progressed earlier. In the multivariate analysis (log rank p = 0.005), only PERG amplitude remained an independent risk factor after stratification for optic disc morphology (p = 0.021), with a ~ 30% higher risk per μV amplitude decrease.

CONCLUSIONS

PERG helps to estimate glaucoma suspects' risk for visual field defects.

Evidence at time of regulatory approval and cost of new antibiotics in 2016-19: cohort study of FDA approved drugs

Objective

To review the clinical evidence, regulatory background, and cost of antibiotics approved by the US Food and Drug Administration (FDA), 2016-19.

Design

Cohort study of FDA approved drugs.

Data sources

FDA databases, ClinicalTrials.gov, and drug labelling. Launch prices were extracted from IBM Micromedex Red Book.

Eligibility criteria for selecting studies

Antibiotics approved by the FDA from October 2016 to December 2019 were identified, and key features of their clinical development were extracted from publicly available FDA databases, ClinicalTrials.gov, and drug labelling. Launch prices were extracted from IBM Micromedex Red Book to evaluate the cost of treatment against comparators.

Results

15 new antibiotics received at least one special regulatory designation and were supported by a median of two pivotal trials. More than half of the pivotal trials used an active control non-inferiority design. All drugs were approved based on surrogate outcome measures. 52 postmarketing requirements and commitments were included across the cohort (median 3 for each drug). From January 2021, 27 postmarketing requirements and commitments were listed as pending, seven as ongoing, three as delayed, one as submitted, eight as released, and four as fulfilled. The most expensive new antibiotic was pretomanid at $36 399 (£29 618; €34 582) for a course of treatment, and the least expensive was rifamycin ($176). Cost ratios between study drugs and comparators ranged from 0.48 to 134.

Conclusions

New antibiotics have been approved by the FDA in recent years mostly based on fewer, smaller, and non-inferiority pivotal trials that often used surrogate outcome measures but were commonly more costly. Efforts to incentivise the development of antibiotics should balance growing the antibiotic development pipeline with ensuring that clinical trials provide clinically relevant evidence of effectiveness in showing added benefits for the patient.

The Value of Macular Optical Coherence Tomography in Watchful Waiting of Suprasellar Masses: A 2-Year Observational Study

BACKGROUND

A possible benefit of optical coherence tomography (OCT) in the approach to tumors involving the optic chiasm may be the ability to foresee visual deterioration. This study investigated the value of OCT in watchful waiting for compressive optic neuropathy as the primary management of suprasellar masses.

METHODS

The research was conducted as a 2-year observational study of a patient cohort with conservatively managed mass lesions involving the optic chiasm on MRI. Threshold perimetry and macular OCT were performed at baseline and each follow-up examination. Univariate Cox regression was used to determine the effect of baseline and longitudinal covariates upon development of visual field (VF) loss compatible with chiasmal dysfunction.

RESULTS

Nineteen eyes of 19 patients were included. The optic chiasm-tumor relationship on baseline MRI was abutment in 6 cases and compression in 13 cases. Seven eyes developed VF loss. None of the baseline covariates were predictors of VF loss. The longitudinal decrease in mean macular ganglion cell complex (mGCC) thickness on OCT was 2.5 μm/yr for eyes that developed VF loss and 0.2 μm/yr for eyes that did not develop VF loss (P = 0.02). The hazard ratio for VF loss per 1-μm/yr decrease in mGCC thickness was 1.30 (95% confidence interval [CI] 1.04-1.62; P = 0.02) for the inferior nasal quadrant and 1.45 (95% CI 1.02-2.07; P = 0.04) for the inferior temporal quadrant.

CONCLUSIONS

OCT offers a valuable complement to perimetry in monitoring for compressive optic neuropathy. Longitudinal mGCC thinning can anticipate VF loss.

The Uprising of Mitochondrial DNA Biomarker in Cancer

Cancer is a heterogeneous group of diseases, the progression of which demands an accumulation of genetic mutations and epigenetic alterations of the human nuclear genome or possibly in the mitochondrial genome as well. Despite modern diagnostic and therapeutic approaches to battle cancer, there are still serious concerns about the increase in death from cancer globally. Recently, a growing number of researchers have extensively focused on the burgeoning area of biomarkers development research, especially in noninvasive early cancer detection. Intergenomic cross talk has triggered researchers to expand their studies from nuclear genome-based cancer researches, shifting into the mitochondria-mediated associations with carcinogenesis. Thus, it leads to the discoveries of established and potential mitochondrial biomarkers with high specificity and sensitivity. The research field of mitochondrial DNA (mtDNA) biomarkers has the great potential to confer vast benefits for cancer therapeutics and patients in the future. This review seeks to summarize the comprehensive insights of nuclear genome cancer biomarkers and their usage in clinical practices, the intergenomic cross talk researches that linked mitochondrial dysfunction to carcinogenesis, and the current progress of mitochondrial cancer biomarker studies and development.

[Antiangiogenic therapy of neovascular age-related macular degeneration]

The problem associated with the prevalence of retinal diseases, and age-related macular degeneration (AMD) in particular, is undoubtedly relevant. This aspect is based on steadily growing statistics on morbidity, a high number of randomized controlled trials (RCT) and published real world data (RWD). The analysis of RCT results being published by researchers on 15.05.19 showed 2915 studies were registered on the subject of retinal diseases; that exceeds the number of studies on glaucoma by approximately 1.38 times (2118 studies) and conjunctival lesions by 2.37 times (1230 studies). AMD is one of the leading causes of irreversible vision loss and blindness; its neovascular form leads to blindness in 80-90% of all cases. Even though the topic of nAMD therapy is widely highlighted in modern ophthalmology, today there are many aspects that require targeted solutions. The main controversial issues that determine the complexity of therapy and patient management include discrepancies in determination of reference points (disease activity criteria) for implementation of anti-VEGF dosing regimens, patients' compliance, prioritization issues in treatment, its continuity with potential for the increase of intervals between injections and monitoring visits.

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.

Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials

Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments.

Microinvasive glaucoma surgery: A review of 3476 eyes

Microinvasive glaucoma surgery (MIGS) is a potentially safer and more efficacious method studied in patients with mild-to-moderate open-angle glaucoma requiring less invasive treatment goals; however, the literature on MIGS must be thoroughly evaluated. We conducted a review of MIGS by searching MEDLINE, EMBASE, and Cochrane CENTRAL. Primary efficacy indicators were reductions in intraocular pressure and topical medication use postoperatively. While all comparative randomized controlled trials assessing MIGS in English peer-reviewed journals were included, only observational studies with a target follow-up of at least one year and a high priority score were analyzed, resulting in a total of 3476 eyes across 20 trials. The mean age was 69.5 ± 2.9 years, 53.7% were female, and 77.4% were Caucasian. One study had last follow-up at less than one year, fifteen studies had follow-up extending 1-2 years, and four had longer than two years of follow-up. A pattern of more significant intraocular pressure and medication reduction was observed in patients who underwent MIGS (n = 2170) relative to control (n = 1306) interventions. iStent had the most literature supporting its efficacy, followed by Hydrus. The most common adverse events after MIGS implantation included stent obstruction, inflammation, and subsequent surgical intervention. Surgical complication rates and efficacy are favorable after MIGS. This review helps to consolidate the high-quality evidence that exists for various MIGS procedures and to identify gaps where further research is needed.

Computational Analysis of Clinical and Molecular Markers and New Theranostic Possibilities in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is a paramount cause of irreversible visual disability worldwide. We focus on identifying clinical and molecular facts that may help elucidating the pathogenic mechanisms of the disease. By using ophthalmological approaches (biomicroscopy, ocular fundus, optical coherence tomography, and perimetry) and experimental tests (enzyme-linked immunosorbent assay (ELISA), high performance liquid chromatography (HPLC), and Western blot/immunoblotting) directed to evaluate the oxidative stress, inflammation, apoptosis, and neurodegeneration processes, we gather information to build a network of data to perform a computational bioinformatics analysis. Our results showed strong interaction of the above players and its downstream effectors in POAG pathogenesis. In conclusion, specific risk factors were identified, and molecules involved in multiple pathways were found in relation to anterior and posterior eye segment glaucoma changes, pointing to new theranostic challenges for better managing POAG progression.

Systemic Alterations of Immune Response-Related Proteins during Glaucoma Development in the Murine Model DBA/2J

Animal models of glaucoma, a neurodegenerative disease affecting the retina, offer the opportunity to study candidate molecular biomarkers throughout the disease. In this work, the DBA/2J glaucomatous mouse has been used to study the systemic levels of several proteins previously identified as potential biomarkers of glaucoma, along the pre- to post-glaucomatous transition. Serum samples obtained from glaucomatous and control mice at 4, 10, and 14 months, were classified into different experimental groups according to the optic nerve damage at 14 months old. Quantifications of ten serum proteins were carried out by enzyme immunoassays. Changes in the levels of some of these proteins in the transition to glaucomatous stages were identified, highlighting the significative decrease in the concentration of complement C4a protein. Moreover, the five-protein panel consisting of complement C4a, complement factor H, ficolin-3, apolipoprotein A4, and transthyretin predicted the transition to glaucoma in 78% of cases, and to the advanced disease in 89%. Our data, although still preliminary, suggest that disease development in DBA/2J mice is associated with important molecular changes in immune response and complement system proteins and demonstrate the utility of this model in identifying, at systemic level, potential markers for the diagnosis of glaucoma.

Sample Size Requirements of Glaucoma Clinical Trials When Using Combined Optical Coherence Tomography and Visual Field Endpoints

Glaucoma clinical trials using visual field (VF) endpoints currently require large sample sizes because of the slowly-progressive nature of this disease. We sought to examine whether the combined use of VF testing and non-invasive optical coherence tomography (OCT) imaging of the neuroretinal tissue could improve the feasibility of such trials. To examine this, we included 192 eyes of 121 glaucoma participants seen at ≥5 visits over a 2-year period to extract real-world estimates of the rates of change and variability of VF and OCT imaging measurements for computer simulations to obtain sample size estimates. We observed that the combined use of VF and OCT endpoints led to a 31-33% reduction in sample size requirements compared to using VF endpoints alone for various treatment effect sizes. For example, 189 participants would be required per group to detect a 30% treatment effect with 90% power with combined VF and OCT endpoints, whilst 276 and 285 participants would be required when using VF and OCT endpoints alone respectively. The combined use of OCT and VF endpoints thus has the potential to effectively improve the feasibility of future glaucoma clinical trials.

Prioritizing outcome preferences in patients with ocular hypertension and open-angle glaucoma using best-worst scaling

Purpose

To quantify patients' preferences for glaucoma outcomes and use this information to prioritize outcomes that are important to patients.

Design

A cross-sectional study using best-worst scaling object case (BWS).

Participants

Two hundred seventy-four participants newly diagnosed with ocular hypertension or mild to moderate open angle glaucoma from three private practices and one academic medical center in the United States.

Methods

We designed a preference-elicitation survey based on findings from 25 semi-structured, qualitative interviews with patients with glaucoma (reported elsewhere). The survey asked participants to rate the importance of 13 glaucoma outcomes on a Likert scale as a warm-up exercise followed by completion of 13 BWS tasks. For each task, we presented participants a subset of four outcomes from the possible thirteen, and participants chose the most important and least important outcome. Outcomes included in the survey pertain to maintaining ability to perform vision-dependent activities of daily living (e.g., driving), maintaining visual function and perception (e.g., depth perception), minimizing need to take glaucoma drops, not experiencing ocular surface symptoms (e.g., red eyes, teary eyes), and having adequate control of intraocular pressure (IOP). We administered the survey online and analyzed response patterns using conditional logistic regression to determine the relative importance of different outcomes.

Main outcome

Ordinal ranking of glaucoma outcomes based on preference weights.

Results

Between September 1, 2017 and February 28, 2018, we invited 1035 patients to complete our survey, among whom 274 (26%) responded. Most participants were older than 65 years of age (146/274, 53%) and currently on IOP-lowering drops (179/274, 65%). Participants identified that outcomes with the largest relative importance weight were having "adequate IOP control" and ability to "drive a car during the day," and the outcomes with the smallest relative importance weights were "maintaining appearance of the eye" and "reducing the number of IOP-lowering drops".

Conclusions

Determining the relative importance of glaucoma outcomes to patients can help researchers design studies that may better inform clinical and regulatory decision-making. Although IOP is an outcome that researchers often measure in glaucoma clinical trials, patients also prioritized outcomes related to the ability to perform vision-dependent activities such as driving.

Precision medicine to prevent glaucoma-related blindness

PURPOSE OF REVIEW

Approximately 10% of patients become blind despite using evidence-based guidelines developed from clinical trials and epidemiology studies. Our purpose is to review opportunities to decrease glaucoma-related blindness using the emerging principles of precision medicine.

RECENT FINDINGS

The current review focuses on three topics: first, candidate biomarkers for angle-based surgeries, second, head-mounted display (HMD) technology for vision and testing, and third, glaucoma risk alleles discovered by genome-wide association studies. First, in angle-based surgeries, tracers injected into the anterior chamber or Schlemm's canal have allowed visualization of aqueous veins. We describe an innovative use of optical coherence tomography angiography to visualize aqueous veins in a case with 6-year successful outcome following catheter-based trabeculotomy. Second, HMD technology can augment perceived vision and can be used for perimetry testing. Third, developing genetic risk scores that characterize patients who are at highest risk for blindness is a priority. Such biomarker risk scores will integrate genome-wide association study-based risk alleles for glaucoma along with well known demographic and clinical risk factors.

SUMMARY

As we gain more knowledge, precision medicine will enable clinicians to decrease glaucoma-related blindness by providing more timely interventions to those patients who are at highest risk for progression to blindness. VIDEO ABSTRACT: http://links.lww.com/COOP/A29.

Ophthalmic medicine regulatory approvals through the European Centralised Procedure, 1999-2017: Clinical efficacy considerations

OBJECTIVES

Regulatory approval of new medicines requires a thorough assessment of the potential clinical benefits and risks. Study end-points are expected to demonstrate a clinically relevant treatment effect that will translate into direct patient benefits. This study sought to review the ophthalmic medicines with European Union-wide approval granted via the Centralised Procedure and characterise the key efficacy end-points underpinning the demonstration of clinical benefit.

METHODS

This study was a retrospective review of published data pertaining to the European regulatory authorisation of centrally approved ophthalmic products between 1999 and 2017, inclusive. All sources and data consulted are in the public domain. European Public Assessment Reports published by the European Medicines Agency were consulted for data concerning the pivotal clinical efficacy studies supporting the applications. Data analyses were descriptive.

RESULTS

The European Medicines Agency have authorised 30 products via the Centralised Procedure between 1999 and 2017. For these products, a total of 24 additional approvals for line extensions or additional therapeutic indications were granted. Four products have been approved for orphan indications, including one approval 'under exceptional circumstances' and one 'Conditional Marketing Authorisation'. Approvals for products in retina (36%) and glaucoma (28%) indications together accounted for the majority of authorisations, with trial end-points predominantly based on visual acuity and intraocular pressure parameters, respectively. Products were also approved for indications in ocular surface disease, inflammation, optic neuropathy and surgical adjuncts, with a range of functional and anatomical end-points.

CONCLUSION

Approvals for ophthalmic medicines have been granted for a range of clinical indications, representing a considerable portion of available major therapeutics for practitioners. Benefit-risk assessments rely on clinical trial data demonstrating a clearly relevant patient benefit.

Oral Memantine for the Treatment of Glaucoma: Design and Results of 2 Randomized, Placebo-Controlled, Phase 3 Studies

PURPOSE

To evaluate the effectiveness and safety of oral memantine as a potential neuroprotective agent in open-angle glaucoma (OAG) at risk for progression.

DESIGN

Two randomized, double-masked, placebo-controlled, parallel-group, multicenter, 48-month studies identically designed, initiated 1 year apart, and completed in 2006. Protocol amendments included a 1-year extension (first study) and change in primary endpoint and analysis (second study).

PARTICIPANTS

Patients (2298 total) with bilateral OAG; glaucomatous optic disc damage and visual field loss in 1 eye; glaucomatous optic disc damage and/or visual field loss in the contralateral eye (at screening), topically treated or untreated intraocular pressure (IOP) of 21 mmHg or less (at baseline); and at risk of glaucomatous progression (per prespecified criteria).

METHODS

Patients were randomized 3:2:2 to receive memantine 20 mg, memantine 10 mg, or placebo tablets daily. Glaucomatous progression was assessed in the intent-to-treat population by full-threshold standard automated perimetry (SAP), frequency doubling technology (FDT), and stereoscopic optic disc photographs, standardized by quality control assessment at centralized reading centers. Safety evaluations included adverse events (AEs), best-corrected visual acuity, biomicroscopy, IOP, and ophthalmoscopy. Efficacy data from each study were analyzed per protocol. Pooled analyses of efficacy and safety data were also performed.

MAIN OUTCOME MEASURES

The predefined primary efficacy measure was glaucomatous visual field progression, as measured by SAP. Additional efficacy measures included glaucomatous progression of visual field (FDT) and optic nerve damage (stereoscopic optic disc photographs).

RESULTS

The proportion of patients who completed the studies was similar among groups (80%-83%). Compared with placebo, daily treatment with memantine 10 mg or 20 mg for 48 months did not delay glaucomatous progression significantly in the individual studies and pooled analyses. The pooled risk reduction ratio (95% confidence interval) assessed by SAP was -0.13 (-0.40, 0.09) and -0.17 (-0.46, 0.07) for memantine 10 mg and 20 mg, respectively. Results were similar per FDT and stereoscopic optic disc photographs. The most common AEs leading to treatment discontinuations were dizziness, headache, fatigue, and nausea.

CONCLUSIONS

With technologies available when the studies were conducted, daily treatment with memantine over 48 months was not shown to prevent glaucomatous progression in this patient population.

Effectiveness of a Qualitative Approach Toward Evaluating OCT Imaging for Detecting Glaucomatous Damage

Purpose

The purpose of this study was to determine whether a qualitative approach toward evaluating optical coherence tomography (OCT) imaging improves the ability to detect glaucomatous damage compared to a conventional metric of global circumpapillary retinal nerve fiber layer (cpRNFL) thickness.

Methods

A total of 394 healthy eyes and 272 glaucoma eyes were evaluated. Glaucoma eyes were categorized as perimetric (156 eyes) based on a history of three or more consecutive abnormal 24-2 visual field tests or suspected glaucoma if they did not (116 eyes). Customized one-page reports derived using OCT volume scans of the optic disc and macula from these eyes were qualitatively graded for the probability of optic neuropathy affecting the eye.

Results

The sensitivity of detecting perimetric glaucoma eyes with the global circumpapillary RNFL thickness metric and qualitative evaluation of the OCT imaging results were 86.5% and 95.5% at a specificity of 95%, being significantly higher for the latter (P < 0.001). There were seven eyes with perimetric glaucoma missed by the qualitative evaluation. Based upon examination of all available visual fields, at least four of these seven eyes had visual fields that either improved or had abnormalities that were inconsistent over time or with patterns of glaucomatous damage.

Conclusions

Qualitative evaluation of OCT imaging results allows glaucoma eyes with repeatable visual field abnormalities to be detected with a high level of accuracy, performing better than a conventional summary metric of global cpRNFL thickness.

Translational Relevance

Clinical detection of glaucomatous damage with OCT imaging can be optimized through a qualitative evaluation of its results.

Development of a Visual Field Simulation Model of Longitudinal Point-Wise Sensitivity Changes From a Clinical Glaucoma Cohort

Purpose

To develop a new visual field simulation model that can recreate real-world longitudinal results at a point-wise level from a clinical glaucoma cohort.

Methods

A cohort of 367 glaucoma eyes from 265 participants seen over 10.1 ± 2.5 years were included to obtain estimates of “true” longitudinal visual field point-wise sensitivity and estimates of measurement variability. These two components were then combined to reconstruct visual field results in a manner that accounted for correlated measurement error. To determine how accurately the simulated results reflected the clinical cohort, longitudinal variability estimates of mean deviation (MD) were determined by calculating the SD of the residuals from linear regression models fitted to the MD values over time for each eye in the simulated and clinical cohorts. The new model was compared to a previous model that does not account for spatially correlated errors.

Results

The SD of all the residuals for the clinical and simulated cohorts was 1.1 dB (95% confidence interval [CI]: 1.1–1.2 dB) and 1.1 dB (95% CI: 1.1–1.1 dB), respectively, whereas it was 0.4 dB (95% CI: 0.4–0.4 dB) using the previous simulation model that did not account for correlated errors.

Conclusions

A new simulation model accounting for correlated measurement errors between visual field locations performed better than a previous model in estimating visual field variability in glaucoma.

Translational Relevance

This model can provide a powerful framework to better understand use of visual field testing in clinical practice and trials and to evaluate new methods for detecting progression.

Comparison of Widefield and Circumpapillary Circle Scans for Detecting Glaucomatous Neuroretinal Thinning on Optical Coherence Tomography

PURPOSE

Our purpose was to compare the effectiveness of detecting progressive retinal nerve fiber layer (RNFL) thickness changes using widefield scans compared to circumpapillary circle scans derived from optic disc volume scans when using a manual region-of-interest (ROI) approach.

METHODS

In a prospective observational study, a total of 125 eyes diagnosed clinically with glaucoma or suspected glaucoma that had both widefield (12 × 9 mm) and optic disc (6 × 6 mm) scans obtained at least one year apart were included. Changes in the RNFL thickness between the two visits were evaluated within region(s) of observed or suspected glaucomatous damage, which were manually outlined after reviewing key features from each scan on the second visit (described as a manual ROI approach). Within ROI(s), changes in the widefield and circumpapillary RNFL thickness (wfRNFLROI and cpRNFLROI), as well as in the global circumpapillary RNFL thickness (cpRNFLG), were determined. The performance of these three methods for detecting progressive changes was compared using longitudinal signal-to-noise ratios (SNRs), whereby the rate of change determined by each method was normalized by individualized estimates of measurement variability and age-related change.

RESULTS

On average, the longitudinal SNRs for the wfRNFLROI, cpRNFLROI, and cpRNFLG methods were -0.57, -0.38, and -0.23 y-1, respectively, being significantly more negative for the wfRNFLROI than the latter two methods (P ≤ 0.009).

CONCLUSIONS

Progressive RNFL thickness changes were more effectively detected on widefield optical coherence tomography (OCT) scans using a manual ROI approach compared to conventional derived circumpapillary circle scans.

TRANSLATIONAL RELEVANCE

Widefield OCT scans show promise for improving the detection of glaucomatous progression.