Prevalence of glaucoma. The Beaver Dam Eye Study

Postmortem Digital Image Correlation and Finite Element Modeling Demonstrate Posterior Scleral Deformations during Optic Nerve Adduction Tethering

Postmortem human eyes were subjected to optic nerve (ON) traction in adduction and elevated intraocular pressure (IOP) to investigate scleral surface deformations. We incrementally adducted 11 eyes (age 74.1 ± 9.3 years, standard deviation) from 26° to 32° under normal IOP, during imaging of the posterior globe, for analysis by three-dimensional digital image correlation (3D-DIC). In the same eyes, we performed uniaxial tensile testing in multiple regions of the sclera, ON, and ON sheath. Based on individual measurements, we analyzed eye-specific finite element models (FEMs) simulating adduction and IOP loading. Analysis of 3D-DIC showed that the nasal sclera up to 1 mm from the sheath border was significantly compressed during adduction. IOP elevation from 15 to 30 mmHg induced strains less than did adduction. Tensile testing demonstrated ON sheath stiffening above 3.4% strain, which was incorporated in FEMs of adduction tethering that was quantitatively consistent with changes in scleral deformation from 3D-DIC. Simulated IOP elevation to 30 mmHg did not induce scleral surface strains outside the ON sheath. ON tethering in incremental adduction from 26° to 32° compressed the nasal and stretched the temporal sclera adjacent to the ON sheath, more so than IOP elevation. The effect of ON tethering is influenced by strain stiffening of the ON sheath.

Molecular genetics of inherited normal tension glaucoma

Normal tension glaucoma (NTG) is a complex optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, despite normal intraocular pressure (IOP). This condition poses a unique clinical challenge due to the absence of elevated IOP, a major risk factor in typical glaucoma. Recent research indicates that up to 21% of NTG patients have a family history of glaucoma, suggesting a genetic predisposition. In this comprehensive review using PubMed studies from January 1990 to December 2023, our focus delves into the genetic basis of autosomal dominant NTG, the only known form of inheritance for glaucoma. Specifically exploring optineurin ( OPTN ), TANK binding kinase 1 ( TBK1 ), methyltransferase-like 23 ( METTL23 ), and myocilin ( MYOC ) mutations, we summarize their clinical manifestations, mutant protein behaviors, relevant animal models, and potential therapeutic pathways. This exploration aims to illuminate the intricate pathogenesis of NTG, unraveling the contribution of these genetic components to its complex development.

Aging and intraocular pressure homeostasis in mice

Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.

Prevalence and Severity of Glaucoma in the California Medicare Population

PURPOSE

To examine the prevalence of glaucoma by type and severity in the 2019 California (CA) Medicare population, and to identify associated demographic and systemic factors.

DESIGN

Retrospective cross-sectional design.

METHODS

The study population included all 2019 CA Medicare beneficiaries ≥65 years of age with Part A and Part B coverage. Outcomes included prevalence of any glaucoma, primary open angle glaucoma (POAG), secondary open angle glaucoma (SOAG), and angle closure glaucoma (ACG). Covariates included age, sex, race and ethnicity, Charlson Comorbidity Index (CCI) score, pseudophakia, and age-related macular degeneration. Logistic regression modeling was used to examine multivariable predictors of each type of glaucoma.

RESULTS

Of 5,856,491 beneficiaries in the 2019 California Medicare population, there were 220,662 (3.8%) with any glaucoma, 171,988 (2.9%) with POAG, 8,827 (0.2%) with SOAG, and 12,978 (0.2%) with ACG. The largest proportion of beneficiaries had moderate to severe glaucoma (68,553 of 220,662 [31.0%] for any glaucoma moderate stage, 3,168 of 12,978 [24.4%] for ACG severe stage). Multivariable predictors of any glaucoma included age ≥85 years vs 65 to 69 years (adjusted odds ratio [aOR] = 2.03, 95% CI = 2.00, 2.06), female vs male sex (aOR = 1.03, 95% CI = 1.02, 1.04), Black vs non-Hispanic White race and ethnicity (aOR = 1.70, 95% CI = 1.67, 1.73), and CCI ≥5 vs 0 (aOR = 5.59, 95% = 5.51, 5.67).

CONCLUSIONS

In the 2019 CA Medicare population, multiple demographic and systemic factors were associated with increased likelihood of glaucoma, and beneficiaries with glaucoma had a high prevalence of moderate to severe disease. Strategies are needed to improve early screening and diagnosis for elderly individuals at risk for glaucoma in California.

Prevalence and Risk Factors of Blindness Among Primary Angle Closure Glaucoma Patients in the United States: An IRIS Registry Analysis

PURPOSE

To assess the prevalence and risk factors of blindness among patients newly diagnosed with primary angle closure glaucoma (PACG) in the United States.

DESIGN

Retrospective cross-sectional study.

METHODS

Eligible patients from the American Academy of Ophthalmology (AAO) Intelligent Research in Sight (IRIS) Registry had newly diagnosed PACG, defined as: 1) observable during a 24-month lookback period from index date of PACG diagnosis; 2) no history of eye drops, laser, or cataract surgery unless preceded by a diagnosis of anatomical narrow angle (ANA); and 3) no history of glaucoma surgery. Logistic regression models were developed to identify risk factors for any (one or both eyes) or bilateral (both eyes) blindness (visual acuity ≤20/200) at first diagnosis of PACG.

RESULTS

Among 43,901 eligible patients, overall prevalence of any and bilateral blindness were 11.5% and 1.8%, respectively. Black and Hispanic patients were at higher risk of any (odds ratios [ORs] 1.42 and 1.21, respectively; P < .001) and bilateral (ORs 2.04 and 1.53, respectively; P < .001) blindness compared with non-Hispanic White patients adjusted for ocular comorbidities. Age <50 or >80 years, male sex, Medicaid or Medicare insurance product, and Southern or Western practice region also conferred a higher risk of blindness (OR > 1.28; P ≤ .01).

CONCLUSIONS

Blindness affects 1 of 9 patients with newly diagnosed PACG in the IRIS Registry. Black and Hispanic patients and Medicaid and Medicare recipients are at significantly higher risk. These findings highlight the severe ocular morbidity among patients with PACG and the need for improved disease awareness and detection methods.

Association of GNB3, ACE polymorphisms with POAG and NTG

PURPOSE

Primary open-angle glaucoma (POAG) represents the most prevalent form of glaucoma and stands as a foremost contributor to irreversible vision impairment on a global scale. Despite notable strides made in comprehending the genetic underpinnings of POAG, investigations within the context of Russia remain constrained.

METHODS

The study cohort comprised a total of 235 individuals, with 135 of them exhibiting various forms of glaucoma encompassing both POAG and (NTG, while the remaining 100 individuals served as control subjects. Each participant underwent a comprehensive ocular examination to ascertain their ocular health status. Genotyping of the relevant single nucleotide polymorphisms (SNPs) was carried out using the Taq Man genotyping assay. Specifically, the two SNPs under scrutiny were GNB3 rs5443 gene and ACE rs4646994. Statistical analysis was performed to evaluate the association of these SNPs with glaucoma risk.

RESULTS

The presence of the T allele of rs5443 was found to be associated with NTG (p = .004). However, no statistically significant correlation was identified between this SNP and POAG (p = .88).

CONCLUSION

This study provides evidence of an association between the T allele of rs5443 and a reduced susceptibility NTG within the Russian population. These observations augment the comprehension of the genetic underpinnings of glaucoma and hold potential implications for the prospective development of targeted therapeutic interventions.

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia

PURPOSE

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters.

METHODS

We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL.

RESULTS

Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD.

CONCLUSION

NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Treatment Preferences and Factors Influencing the Management of Primary Angle-Closure Suspect in China: A National Survey Study

INTRODUCTION

This study explored the current views of ophthalmologists in China on the preferred strategy and the primary influencing factors in managing primary angle-closure suspect (PACS).

METHODS

An online survey was distributed via WeChat to ophthalmologists working in hospitals at all levels throughout China to investigate the optimal management strategy and factors influencing the strategy for treating PACS from February to March 2023. Management strategies examined included regular observation (RO), laser peripheral iridectomy (LPI), and phacoemulsification with intraocular lens implantation (PEI). The study explored the factors that influenced clinical decision-making processes and collected demographic information from the respondents for analysis.

RESULTS

A total of 1009 ophthalmologists responded; 442 responders considered RO as a reasonable option for patients with PACS, while the majority opted for more positive treatments, with 460 choosing LPI and 107 selecting PEI. Further grouping analysis revealed significant differences between tertiary and lower-level hospitals (P < 0.01) and between public and private hospitals (P < 0.05). Significant differences were found among resident, attending, and senior doctors and between northern and southern hospitals. The top three considerations for ophthalmologists who selected RO were ultrasound biomicroscopy (UBM) without pupillary block, absence of a family history of glaucoma, and good compliance with regular follow-up. For LPI, the factors were UBM indicating pupillary block, glaucoma symptoms, and poor compliance with regular follow-up. For PEI the factors were age, family history of glaucoma, and poor compliance with regular follow-up.

CONCLUSION

The majority of ophthalmologists prefer aggressive treatments such as LPI or PEI over RO when dealing with patients with PACS. Disparity existed among ophthalmologists based on their level of experience, hospital ownership and level, and geographical location. The survey underscores the complexity and multifactorial nature of PACS management and highlights the need for further research and standardization of treatment protocols to ensure optimal patient outcomes.

Aging and intraocular pressure homeostasis in mice

Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.

[Epidemiological and clinical features of primary open angle glaucoma in Bejaia: "The Bejaia Eye Study"]

PURPOSE

To determine the prevalence of POAG and its clinical features in a population aged 40years and over in Bejaia.

METHODS

This was a descriptive, cross-sectional survey for analytical purposes in a representative sample from the municipality of Bejaia. The target population consists of residents of the municipality aged 40 and over who were examined in basic health facilities in the municipality of Bejaia, from May 31, 2015 to July 12, 2016. The visual field, OCT, vertical C/D and intraocular pressure (IOP) criteria were used to define whether or not primary open angle glaucoma was present.

RESULTS

A total of 1484 people (99 %) participated in the study. The mean age of the study population was 57.97±10.77years, with a median of 56years and sex ratio of 1.07. The prevalence of glaucoma in our study was 5.5 %: POAG 4.6 % (95% CI=3.5-5.7); PACG 0.3 % (95 % CI=0.1, 0.7); secondary glaucoma 0.5 % (95 % CI=0.2-0.7). The prevalence of ocular hypertension was 3.0 % (95% CI=2.2-4.0). The age-adjusted prevalence was 0.8 % between 40 and 49years of age and 6.9% between 60 and 69years of age. The mean age was 66.76±9.31years for men and 67.68±12.10years for women. The mean IOP was 17.53±5.69mm Hg. The mean pachymetry was 518.3±34.3μm in the right eye and 517.4±33.9μm in the left eye. The mean cup/disc ratio was 0.7±0.2 in both eyes. Multivariate analysis of risk factors in our study showed that age and ocular hypertension were significantly associated with the presence of POAG.

DISCUSSION

The prevalence of POAG is disparate in relation to the age difference, the method of recruitment and the diagnostic criteria: in Bejaia, it is 4.6 %; in Morocco: Marrakech 2.0 %, Fez 6.4 %; in Tunisia: Bardo 2.7 %, Mahdia 2.4 %. The prevalence of POAG increases exponentially with age without significant gender difference. The inclusion of suspect cases influences the prevalence (Beaver Dam, Namil Study). We found that the prevalence of OHT in our study approximates that of the BMES, but it did not show a significant increase with age. The mean CCT in Bejaia (526.35±34.86 microns) and Fez (522.16±41.45 microns) are comparable. The mean vertical C/D ratio in Bejaia was also comparable to data in the literature. A significant difference was observed in the mean median deviation (MD) between subjects with glaucoma and normal subjects. The retinal nerve fiber layer as well as the mean ganglion cell complex thickness in glaucoma subjects was significantly thinner than in healthy subjects.

CONCLUSION

The prevalence of POAG is high, similar to that of people of African descent, but at older ages and among men. The rate of glaucoma in Bejaia rises significantly with age. Glaucoma is a major ocular health problem and will become increasingly important as the population ages.

Glaucoma: now and beyond

The glaucomas are a group of conditions leading to irreversible sight loss and characterised by progressive loss of retinal ganglion cells. Although not always elevated, intraocular pressure is the only modifiable risk factor demonstrated by large clinical trials. It remains the leading cause of irreversible blindness, but timely treatment to lower intraocular pressure is effective at slowing the rate of vision loss from glaucoma. Methods for lowering intraocular pressure include laser treatments, topical medications, and surgery. Although modern surgical innovations aim to be less invasive, many have been introduced with little supporting evidence from randomised controlled trials. Many cases remain undiagnosed until the advanced stages of disease due to the limitations of screening and poor access to opportunistic case finding. Future research aims to generate evidence for intraocular pressure-independent neuroprotective treatments, personalised treatment through genetic risk profiling, and exploration of potential advanced cellular and gene therapies.

[Use of antiglaucomatous drugs in the urban adult population : New Insights into the prevalence of glaucoma from the Hamburg City Health Study]

BACKGROUND

Glaucoma is a widespread ophthalmological disease. Knowledge about the spread of the disease in the population is necessary with respect to further questions on comorbidities, risk factors and the provision of care.

OBJECTIVE

An analysis of the use of glaucoma medications and the prevalence of glaucoma in an urban adult population was carried out.

MATERIAL AND METHODS

The Hamburg City Health Study (HCHS) is a prospective, long-term, population-based cohort study that includes a random sample of 45,000 participants aged between 45 and 79 years from the general population of Hamburg, Germany. Apart from various medical parameters, data include premedication and the medical history of the participants. The use of antiglaucomatous medication among the first 10,000 study participants was analyzed and the prevalence of glaucoma was estimated according to the use of medications as well as by the self-reported history of glaucoma. Descriptive analysis and logistic regression analysis were performed to analyze the data and to calculate correlations by age and gender.

RESULTS

In the study population 319 persons were on medication to lower the intraocular pressure (IOP, mean age 67.1 years, SD = 7.57 years), which is equivalent to an estimated prevalence of 3.35% (95% confidence interval, CI 3.00-3.70%). A positive correlation was observed between age and the use of IOP-lowering medication, which is statistically highly significant (p = < 0.001). The analysis by gender showed a slightly higher prevalence among women, which was not statistically significant. The estimated prevalence according to glaucoma medication and history were only partly congruent.

DISCUSSION

This estimated prevalence of glaucoma is comparable to other epidemiological studies. The study results cover not only patients with manifest glaucoma but also persons who were treated for ocular hypertension. The inconsistency between the prevalence of glaucoma medication and the diagnosis of glaucoma can be explained by different treatment strategies and also by information deficits.

The Application of MicroRNAs in Glaucoma Research: A Bibliometric and Visualized Analysis

Glaucoma is similar to a neurodegenerative disorder and leads to global irreversible loss of vision. Despite extensive research, the pathophysiological mechanisms of glaucoma remain unclear, and no complete cure has yet been identified for glaucoma. Recent studies have shown that microRNAs can serve as diagnostic biomarkers or therapeutic targets for glaucoma; however, there are few bibliometric studies that focus on using microRNAs in glaucoma research. Here, we have adopted a bibliometric analysis in the field of microRNAs in glaucoma research to manifest the current tendencies and research hotspots and to present a visual map of the past and emerging tendencies in this field. In this study, we retrieved publications in the Web of Science database that centered on this field between 2007 and 2022. Next, we used VOSviewer, CiteSpace, Scimago Graphica, and Microsoft Excel to present visual representations of a co-occurrence analysis, co-citation analysis, tendencies, hotspots, and the contributions of authors, institutions, journals, and countries/regions. The United States was the main contributor. Investigative Ophthalmology and Visual Science has published the most articles in this field. Over the past 15 years, there has been exponential growth in the number of publications and citations in this field across various countries, organizations, and authors. Thus, this study illustrates the current trends, hotspots, and emerging frontiers and provides new insight and guidance for searching for new diagnostic biomarkers and clinical trials for glaucoma in the future. Furthermore, international collaborations can also be used to broaden and deepen the field of microRNAs in glaucoma research.

Corneal Biomechanical Measures for Glaucoma: A Clinical Approach

Over the last two decades, there has been growing interest in assessing corneal biomechanics in different diseases, such as keratoconus, glaucoma, and corneal disorders. Given the interaction and structural continuity between the cornea and sclera, evaluating corneal biomechanics may give us further insights into the pathogenesis, diagnosis, progression, and management of glaucoma. Therefore, some authorities have recommended baseline evaluations of corneal biomechanics in all glaucoma and glaucoma suspects patients. Currently, two devices (Ocular Response Analyzer and Corneal Visualization Schiempflug Technology) are commercially available for evaluating corneal biomechanics; however, each device reports different parameters, and there is a weak to moderate agreement between the reported parameters. Studies are further limited by the inclusion of glaucoma subjects taking topical prostaglandin analogues, which may alter corneal biomechanics and contribute to contradicting results, lack of proper stratification of patients, and misinterpretation of the results based on factors that are confounded by intraocular pressure changes. This review aims to summarize the recent evidence on corneal biomechanics in glaucoma patients and insights for future studies to address the current limitations of the literature studying corneal biomechanics.

Identification and functional validation of an enhancer variant in the 9p21.3 locus associated with glaucoma risk and elevated expression of p16INK4a

Glaucoma is a leading cause of irreversible blindness, with advanced age being the single most significant risk factor. However, the mechanisms underlying the relationship between aging and glaucoma remain unclear. Genome-wide association studies (GWAS) have successfully identified genetic variants strongly associated with increased glaucoma risk. Understanding how these variants function in pathogenesis is crucial for translating genetic associations into molecular mechanisms and, ultimately, clinical applications. The chromosome 9p21.3 locus is among the most replicated glaucoma risk loci discovered by GWAS. Nonetheless, the absence of protein-coding genes in the locus makes interpreting the disease association challenging, leaving the causal variant and molecular mechanism elusive. In this study, we report the identification of a functional glaucoma risk variant, rs6475604. By employing computational and experimental methods, we demonstrated that rs6475604 resides in a repressive regulatory element. Risk allele of rs6475604 disrupts the binding of YY1, a transcription factor known to repress the expression of a neighboring gene in 9p21.3, p16INK4A, which plays a crucial role in cellular senescence and aging. These findings suggest that the glaucoma disease variant contributes to accelerated senescence, providing a molecular link between glaucoma risk and an essential cellular mechanism for human aging.

Pharmaceutical Approaches to Normal Tension Glaucoma

Normal tension glaucoma (NTG) is defined as a subtype of primary open-angle glaucoma (POAG) in which the intraocular pressure (IOP) values are constantly within the statistically normal range without treatment and represents approximately the 30-40% of all glaucomatous cases. The pathophysiology of this condition is multifactorial and is still not completely well known. Several theories have been proposed to explain the onset and progression of this disease, which can be divided into IOP-dependent and IOP-independent factors, suggesting different therapeutic strategies. The current literature strongly supports the fundamental role of IOP in NTG. The gold standard treatment for NTG tends to be based on the lowering IOP even if "statistically normal". Numerous studies have shown, however, that the IOP reduction alone is not enough to slow down or stop the disease progression in all cases, suggesting that other IOP-independent risk factors may contribute to the NTG pathogenesis. In addition to IOP-lowering strategies, several different therapeutic approaches for NTG have been proposed, based on vaso-active, antioxidant, anti-inflammatory and/or neuroprotective substances. To date, unfortunately, there are no standardized or proven treatment alternatives for NTG when compared to traditional IOP reduction treatment regimes. The efficacy of the IOP-independent strategies in decreasing the risk or treating NTG still remains inconclusive. The aim of this review is to highlight strategies reported in the current literature to treat NTG. The paper also describes the challenges in finding appropriate and pertinent treatments for this potentially vision-threatening disease. Further comprehension of NTG pathophysiology can help clinicians determine when to use IOP-lowering treatments alone and when to consider additional or alternatively individualized therapies focused on particular risk factors, on a case-by-case basis.

UK Biobank retinal imaging grading: methodology, baseline characteristics and findings for common ocular diseases

BACKGROUND/OBJECTIVES

This study aims to describe the grading methods and baseline characteristics for UK Biobank (UKBB) participants who underwent retinal imaging in 2009-2010, and to characterise individuals with retinal features suggestive of age-related macular degeneration (AMD), glaucoma and retinopathy.

METHODS

Non-mydriatic colour fundus photographs and macular optical coherence tomography (OCT) scans were manually graded by Central Administrative Research Facility certified graders and quality assured by clinicians of the Network of Ophthalmic Reading Centres UK. Captured retinal features included those associated with AMD (≥1 drusen, pigmentary changes, geographic atrophy or exudative AMD; either imaging modality), glaucoma (≥0.7 cup-disc ratio, ≥0.2 cup-disc ratio difference between eyes, other abnormal disc features; photographs only) and retinopathy (characteristic features of diabetic retinopathy with or without microaneurysms; either imaging modality). Suspected cases of these conditions were characterised with reference to diagnostic records, physical and biochemical measurements.

RESULTS

Among 68,514 UKBB participants who underwent retinal imaging, the mean age was 57.3 years (standard deviation 8.2), 45.7% were men and 90.6% were of White ethnicity. A total of 64,367 participants had gradable colour fundus photographs and 68,281 had gradable OCT scans in at least one eye. Retinal features suggestive of AMD and glaucoma were identified in 15,176 and 2184 participants, of whom 125 (0.8%) and 188 (8.6%), respectively, had a recorded diagnosis. Of 264 participants identified to have retinopathy with microaneurysms, 251 (95.1%) had either diabetes or hypertension.

CONCLUSIONS

This dataset represents a valuable addition to what is currently available in UKBB, providing important insights to both ocular and systemic health.

Associations Between Niacin Intake and Glaucoma in the National Health and Nutrition Examination Survey

PRCIS

This study examined the association between dietary niacin intake and glaucoma in the 2005-2008 National Health and Nutrition Examination Survey (NHANES). Increased niacin intake was associated with lower odds of glaucoma overall and among women.

PURPOSE

To examine the association between dietary niacin intake and glaucoma in the 2005-2008 NHANES.

MATERIALS AND METHODS

This cross-sectional study included adult participants of the 2005-2008 NHANES. The exposure was dietary niacin intake, which was examined as a continuous and categorical variable. The outcome was glaucoma as defined by regraded disc images. Covariates included age, sex, race/ethnicity, education level, income, body mass index, smoking status, alcohol use, cardiovascular disease, diabetes mellitus, daily energy intake, vitamin B2 and B6 consumption, and macular degeneration. Adjusting for all covariates, logistic regression was performed to examine the association between niacin intake and glaucoma in the overall population and stratified by sex.

RESULTS

The weighted population included 5371 individuals (109,734,124 weighted), of whom 55 (1.0%) had glaucoma. Each 1 mg increase in niacin intake was associated with a 6% decreased odds of glaucoma odds [adjusted odds ratio (aOR) = 0.94, 95% CI = 0.90, 0.98]. Among women, increased niacin intake was associated with decreased odds of glaucoma both with niacin as a continuous (aOR = 0.89, 95% CI = 0.80, 0.99 per 1 mg increase in niacin intake) and binary variable (aOR = 0.35, 95% CI = 0.14, 0.90 for higher vs lower niacin intake).

CONCLUSIONS

In the 2005-2008 NHANES population, higher levels of niacin intake were associated with decreased odds of glaucoma overall and in women. Further studies are needed to examine the potential protective effects of niacin on glaucoma risk.

Identification and functional validation of an enhancer variant in the 9p21.3 locus associated with glaucoma risk and elevated expression of p16 INK4a

Glaucoma is a leading cause of irreversible blindness, with advanced age being the single most significant risk factor. However, the mechanisms underlying the relationship between aging and glaucoma remain unclear. Genome-wide association studies (GWAS) have successfully identified genetic variants strongly associated with increased glaucoma risk. Understanding how these variants function in pathogenesis is crucial for translating genetic associations into molecular mechanisms and, ultimately, clinical applications. The chromosome 9p21.3 locus is among the most replicated glaucoma risk loci discovered by GWAS. Nonetheless, the absence of protein-coding genes in the locus makes interpreting the disease association challenging, leaving the causal variant and molecular mechanism elusive. In this study, we report the identification of a functional glaucoma risk variant, rs6475604. By employing computational and experimental methods, we demonstrated that rs6475604 resides in a repressive regulatory element. Risk allele of rs6475604 disrupts the binding of YY1, a transcription factor known to repress the expression of a neighboring gene in 9p21.3, p16INK4A, which plays a crucial role in cellular senescence and aging. These findings suggest that the glaucoma disease variant contributes to accelerated senescence, providing a molecular link between glaucoma risk and an essential cellular mechanism for human aging.

Characteristics of a large, labeled dataset for the training of artificial intelligence for glaucoma screening with fundus photographs

Purpose

Significant visual impairment due to glaucoma is largely caused by the disease being detected too late.

Objective

To build a labeled data set for training artificial intelligence (AI) algorithms for glaucoma screening by fundus photography, to assess the accuracy of the graders, and to characterize the features of all eyes with referable glaucoma (RG).

Design

Cross-sectional study.

Subjects

Color fundus photographs (CFPs) of 113 893 eyes of 60 357 individuals were obtained from EyePACS, California, United States, from a population screening program for diabetic retinopathy.

Methods

Carefully selected graders (ophthalmologists and optometrists) graded the images. To qualify, they had to pass the European Optic Disc Assessment Trial optic disc assessment with ≥ 85% accuracy and 92% specificity. Of 90 candidates, 30 passed. Each image of the EyePACS set was then scored by varying random pairs of graders as "RG," "no referable glaucoma (NRG)," or "ungradable (UG)." In case of disagreement, a glaucoma specialist made the final grading. Referable glaucoma was scored if visual field damage was expected. In case of RG, graders were instructed to mark up to 10 relevant glaucomatous features.

Main Outcome Measures

Qualitative features in eyes with RG.

Results

The performance of each grader was monitored; if the sensitivity and specificity dropped below 80% and 95%, respectively (the final grade served as reference), they exited the study and their gradings were redone by other graders. In all, 20 graders qualified; their mean sensitivity and specificity (standard deviation [SD]) were 85.6% (5.7) and 96.1% (2.8), respectively. The 2 graders agreed in 92.45% of the images (Gwet's AC2, expressing the inter-rater reliability, was 0.917). Of all gradings, the sensitivity and specificity (95% confidence interval) were 86.0 (85.2-86.7)% and 96.4 (96.3-96.5)%, respectively. Of all gradable eyes (n = 111 183; 97.62%) the prevalence of RG was 4.38%. The most common features of RG were the appearance of the neuroretinal rim (NRR) inferiorly and superiorly.

Conclusions

A large data set of CFPs was put together of sufficient quality to develop AI screening solutions for glaucoma. The most common features of RG were the appearance of the NRR inferiorly and superiorly. Disc hemorrhages were a rare feature of RG.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Basal ganglia lesions may be a risk factor for characteristic features of a glaucomatous optic disc: population-based cohort study in Japan

Background

We conducted a study to investigate the relationship between optic nerve vertical cup-to-disc ratio (VCDR), body and ocular parameters, and brain lesions in middle-aged and above Japanese subjects, because although various risk factors for glaucoma have been previously characterised, it is theorised that there are unidentified neurological components.

Methods

In this population-based, age/gender-stratified, cross-sectional study that involved 2239 Japanese subjects (1127 men and 1112 women) aged 40 years and older (mean age: 59.3±11.7 years) living in the central geographical region of Japan who participated in the National Institute of Longevity Sciences–Longitudinal Study of Aging between 2002 and 2004, 4327 eyes and 2239 obtained MRIs of the head were evaluated. Multivariate mixed model and trend analyses were also performed.

Results

No significant relationship between VCDR and brain lesions, other than basal ganglia lesions, was found. VCDR significantly increased with the high grade of basal ganglia infarct lesions (p=0.0193) and high intraocular pressure (p<0.0001) after adjustment for influential factors using a multivariate mixed model. A significant positive linear trend was observed between the predicted VCDR and the degrees of the basal ganglia lesions (p value trend=0.0096).

Conclusion

Our findings suggest that in subjects with higher grades of basal ganglia lesions, strict attention should be paid to elevated VCDR; however, further studies are needed to support/confirm our results.

Cost-Effectiveness of Screening for Open Angle Glaucoma Compared With Opportunistic Case Finding

PRCIS

The manuscript evaluates cost-effectiveness of glaucoma screening with imaging devices and telemedicine based on a screening campaign performed in Spain. The screening strategy implemented in our analysis was cost-effective compared with opportunistic case finding.

INTRODUCTION

Open angle glaucoma is an asymptomatic ocular disease that represents one of the first causes of blindness. Diagnosis is currently made by opportunistic case finding, usually by community optometrists or general ophthalmologists. The aim of this study was to assess the cost-effectiveness of a screening strategy based on optical coherence tomography and fundus photographs in glaucoma detection.

MATERIALS AND METHODS

A cost-effectiveness analysis was carried out to compare 2 alternative strategies: opportunistic finding versus screening. A Markov tree model was carried out with 10 health states according to disease progression. Quality-adjusted life years (QALYs) were used as a measure of effectiveness. We included short-term and long-term direct health costs and a discount rate of 3%. We performed a probabilistic sensitivity analysis and several 1-way sensitivity analyses.

RESULTS

The cohort in the screening program entailed an increase in 0.097 QALYs and additional costs of €1187 versus opportunistic finding, with an incremental cost-effectiveness ratio of about €12.214/QALY. The 1-way sensitivity analysis showed that inputs related to age and screening program (cost and detection rate) were those most strongly influencing the results of the analysis. Probabilistic sensitivity analyses showed that the model was robust to significant changes in the main variables of the analysis.

CONCLUSIONS

The screening strategy implemented in our analysis was cost-effective compared with opportunistic finding in patients with glaucoma in this Spanish setting.

Evidence for Menopause as a Sex-Specific Risk Factor for Glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive loss of visual function and retinal ganglion cells (RGC). Current epidemiological, clinical, and basic science evidence suggest that estrogen plays a role in the aging of the optic nerve. Menopause, a major biological life event affecting all women, coincides with a decrease in circulating sex hormones, such as estrogen. While 59% of the glaucomatous population are females, sex is not considered a risk factor for developing glaucoma. In this review, we explore whether menopause is a sex-specific risk factor for glaucoma. First, we investigate how menopause is defined as a sex-specific risk factor for other pathologies, including cardiovascular disease, osteoarthritis, and bone health. Next, we discuss clinical evidence that highlights the potential role of menopause in glaucoma. We also highlight preclinical studies that demonstrate larger vision and RGC loss following surgical menopause and how estrogen is protective in models of RGC injury. Lastly, we explore how surgical menopause and estrogen signaling are related to risk factors associated with developing glaucoma (e.g., intraocular pressure, aqueous outflow resistance, and ocular biomechanics). We hypothesize that menopause potentially sets the stage to develop glaucoma and therefore is a sex-specific risk factor for this disease.

Prospective 12-month outcomes of combined iStent inject implantation and phacoemulsification in Asian eyes with normal tension glaucoma

Background

Glaucoma is the leading cause of irreversible blindness. Normal tension glaucoma (NTG) is a subset of open-angle glaucoma, demonstrating glaucomatous optic nerve damage in the absence of raised intraocular pressure (IOP). NTG is more prevalent in Asian populations. While generally slow-progressing, NTG may be associated with significant central visual field loss. In recent years, minimally invasive glaucoma surgery has been added to the armamentarium of glaucoma surgery. This prospective study aims to evaluate 12-month surgical outcomes of combined iStent inject (Glaukos Corporation, Laguna Hills, CA) implantation and phacoemulsification in Asian eyes with NTG.

Methods

This is a prospective, single-centre case series of 30 eyes followed up until 12 months after surgery. Outcome measures included IOP, number of glaucoma medications, best-corrected visual acuity (BCVA) and intra and postoperative complications.

Results

Mean age of subjects was 73.1 ± 6.3 years. Majority were ethnic Chinese (n = 27, 90%). Baseline medicated mean IOP was 13.8 ± 2.4 mmHg and mean number of glaucoma medications was 1.3 ± 0.7. Mean Humphrey visual field mean deviation was − 13.7 ± 7.6. The mean IOP reduction at all timepoints from postoperative month (POM) 3 onwards was statistically significant (all P < 0.05), with mean reduction of 1.2 mmHg (95% CI: 0.1–2.2, P = 0.037) by POM12. There was statistically significant reduction in mean number of medications from postoperative day (POD) 1 onwards (all P < 0.05), with mean decrease of 1.0 medication (95% CI: 0.9–1.1, P < 0.001) by POM12. By POM12, 25 (83.3%) eyes were medication-free. Three (10%) eyes had stent occlusion by iris requiring laser iridoplasty. One eye had gross hyphema which resolved on conservative management before POM1. Mean BCVA improved from the baseline 0.3 ± 0.3 logMAR to 0.1 ± 0.1 logMAR postoperatively (P < 0.001). There were no major adverse or sight-threatening events. No eyes required further glaucoma surgery during the 12-month follow-up period.

Conclusion

Asian eyes with NTG which underwent combined iStent inject implantation and phacoemulsification demonstrated a significant and sustained reduction in IOP and glaucoma medications, up to 12 months postoperatively.

Finite element modeling of effects of tissue property variation on human optic nerve tethering during adduction

Tractional tethering by the optic nerve (ON) on the eye as it rotates towards the midline in adduction is a significant ocular mechanical load and has been suggested as a cause of ON damage induced by repetitive eye movements. We designed an ocular finite element model (FEM) simulating 6° incremental adduction beyond the initial configuration of 26° adduction that is the observed threshold for ON tethering. This FEM permitted sensitivity analysis of ON tethering using observed material property variations in measured hyperelasticity of the anterior, equatorial, posterior, and peripapillary sclera; and the ON and its sheath. The FEM predicted that adduction beyond the initiation of ON tethering concentrates stress and strain on the temporal side of the optic disc and peripapillary sclera, the ON sheath junction with the sclera, and retrolaminar ON neural tissue. However, some unfavorable combinations of tissue properties within the published ranges imposed higher stresses in these regions. With the least favorable combinations of tissue properties, adduction tethering was predicted to stress the ON junction and peripapillary sclera more than extreme conditions of intraocular and intracranial pressure. These simulations support the concept that ON tethering in adduction could induce mechanical stresses that might contribute to ON damage.

METTL23 mutation alters histone H3R17 methylation in normal-tension glaucoma

Normal-tension glaucoma (NTG) is a heterogeneous disease characterized by retinal ganglion cell (RGC) death leading to cupping of the optic nerve head and visual field loss at normal intraocular pressure (IOP). The pathogenesis of NTG remains unclear. Here, we describe a single nucleotide mutation in exon 2 of the methyltransferase-like 23 (METTL23) gene identified in 3 generations of a Japanese family with NTG. This mutation caused METTL23 mRNA aberrant splicing, which abolished normal protein production and altered subcellular localization. Mettl23-knock-in (Mettl23+/G and Mettl23G/G) and -knockout (Mettl23+/- and Mettl23-/-) mice developed a glaucoma phenotype without elevated IOP. METTL23 is a histone arginine methyltransferase expressed in murine and macaque RGCs. However, the novel mutation reduced METTL23 expression in RGCs of Mettl23G/G mice, which recapitulated both clinical and biological phenotypes. Moreover, our findings demonstrated that METTL23 catalyzed the dimethylation of H3R17 in the retina and was required for the transcription of pS2, an estrogen receptor α target gene that was critical for RGC homeostasis through the negative regulation of NF-κB-mediated TNF-α and IL-1β feedback. These findings suggest an etiologic role of METTL23 in NTG with tissue-specific pathology.

Association between cognitive function and large optic nerve cupping, accounting for cup-disc-ratio genetic risk score

PURPOSE

To investigate if accounting for a cup-to-disc ratio (CDR) genetic risk score (GRS) modified the association between large CDR and cognitive function among women.

DESIGN

This was a retrospective study using data from the Women's Health Initiative.

METHODS

Patients with glaucoma or ocular hypertension were excluded. Large CDR was defined as ≥ 0.6 in either eye. Cognitive function was measured by the Modified Mini-Mental State Examination (3MSE). We used the combined effects from 13 single nucleotide polymorphisms (SNPs) to formulate the GRS for CDR. We used logistic regression to investigate associations between weighted GRS and large CDR, then a linear regression to assess the association between weighted GRS and 3MSE scores, and between weighted GRS, CDR, and 3MSE scores, adjusted for demographic and clinical characteristics.

RESULTS

Final analyses included 1,196 White women with mean age of 69.60 ± 3.62 years and 7.27% with large CDR. Mean GRS in women with and without large CDR was 1.51 ± 0.31 vs. 1.41 ± 0.36, respectively (p = 0.004). The odds of large CDR for a one unit increase in GRS was 2.30 (95% CI: (1.22, 4.36), p = 0.011). Adding the CDR GRS in the model with CDR and 3MSE, women with large CDR still had statistically significantly lower 3MSE scores than those without large CDR, yielding a predicted mean difference in 3MSE scores of 0.84 (p = 0.007).

CONCLUSIONS

Independent of the CDR GRS, women with large CDR had a lower cognitive function.

Heat Shock Protein Upregulation Supplemental to Complex mRNA Alterations in Autoimmune Glaucoma

Glaucomatous optic neuropathy is a common cause for blindness. An elevated intraocular pressure is the main risk factor, but also a contribution of the immune system seems likely. In the experimental autoimmune glaucoma model used here, systemic immunization with an optic nerve homogenate antigen (ONA) leads to retinal ganglion cell (RGC) and optic nerve degeneration. We processed retinae for quantitative real-time PCR and immunohistology 28 days after immunization. Furthermore, we performed mRNA profiling in this model for the first time. We detected a significant RGC loss in the ONA retinae. This was accompanied by an upregulation of mRNA expression of genes belonging to the heat shock protein family. Furthermore, mRNA expression levels of the genes of the immune system, such as C1qa, C1qb, Il18, and Nfkb1, were upregulated in ONA animals. After laser microdissection, inner retinal layers were used for mRNA microarrays. Nine of these probes were significantly upregulated in ONA animals (p < 0.05), including Hba-a1 and Cxcl10, while fifteen probes were significantly downregulated in ONA animals (p < 0.05), such as Gdf15 and Wwox. Taken together, these findings provide further insights into the pivotal role of the immune response in glaucomatous optic neuropathy and could help to identify novel diagnostic or therapeutic strategies.

Genetic association of ANGPT2 with primary open-angle glaucoma

BACKGROUND

To determine the association of the ANGPT2 gene with primary open-angle glaucoma (POAG) in Chinese.

METHODS

Six single-nucleotide polymorphisms (SNPs) in ANGPT2 (rs2515487, rs2922869, rs13255574, rs4455855, rs13269021, and rs11775442) were genotyped in a total of 2601 study subjects from two cohorts. One is a Hong Kong Chinese cohort of 484 high tension glaucoma (HTG) and 537 normal tension glaucoma (NTG) patients, and 496 non-glaucoma control subjects. Another cohort is a Shantou Chinese cohort of 403 HTG and 135 NTG patients, and 543 non-glaucoma control subjects. Subgroup analysis by sex was conducted. Outcomes from different cohorts were combined for meta-analysis.

RESULTS

The association of SNP rs11775442 with NTG in the Hong Kong cohort [P = 0.0498, OR = 1.24, 95% confidence interval (CI) 1.00-1.55] after adjusting for age and sex did not reach statistical significance after Bonferroni correction. Other SNPs were not significantly associated with NTG, HTG and POAG in individual cohort or in the combined analyses (P > 0.05). In the subgroup analysis by sex, SNP rs13269021 in the Shantou cohort, but not in the Hong Kong cohort, was significantly associated with NTG in males (P = 0.0081, OR = 1.67, 95% CI: 1.14-2.43) but not in females (P = 0.874). In the combined analyses by sex, no SNPs were significantly associated with NTG, HTG and POAG.

CONCLUSIONS

In the subgroup analysis by sex, a significant association was shown in SNP rs13269021 with NTG in Shantou males, but not in Hong Kong males. Further studies are needed to verify the association between ANGPT2 locus (rs13269021) and NTG in Chinese males.

Evidence of impaired mitochondrial cellular bioenergetics in ocular fibroblasts derived from glaucoma patients

Glaucoma is a progressive optic neuropathy characterized by the neurodegeneration of the retinal ganglion cells (RGCs) resulting in irreversible visual impairment and eventual blindness. RGCs are extremely susceptible to mitochondrial compromise due to their marked bioenergetic requirements and morphology. There is increasing interest in therapies targeting mitochondrial health as a method of preventing visual loss in managing glaucoma. The bioenergetic profile of Tenon's ocular fibroblasts from glaucoma patients and controls was investigated using the Seahorse XF24 analyser. Impaired mitochondrial cellular bioenergetics was detected in glaucomatous ocular fibroblasts including basal respiration, maximal respiration and spare capacity. Spare respiratory capacity levels reflect mitochondrial bio-energetic adaptability in response to pathophysiological stress. Basal oxidative stress was elevated in glaucomatous Tenon's ocular fibroblasts and hydrogen peroxide (H₂O₂) induced reactive oxygen species (ROS) simulated the glaucomatous condition in normal Tenon's ocular fibroblasts. This work supports the role of therapeutic interventions to target oxidative stress or provide mitochondrial energetic support in glaucoma.

Trabeculectomy With Antimetabolite Agents for Normal Tension Glaucoma: A Systematic Review and Meta-Analysis

Background

Evidence regarding the impact on visual field (VF), intraocular pressure (IOP), and antiglaucoma medications from trabeculectomy with antimetabolites for normal tension glaucoma (NTG) is conflicting because of insufficient study sample sizes. The aim of this study is to systematically assess VF progression rate, IOP control and antiglaucoma medication use after trabeculectomy with antimetabolites for progressing NTG.

Methods

We searched published articles on PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from database inception to March 21, 2022. We selected studies that reported VF data before and after trabeculectomy with antimetabolite agents for NTG. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guidelines. Data were extracted by 2 independent reviewers, and a random-effects model was employed for the meta-analysis. Study outcomes were VF progression rates measured using the pooled mean deviation (MD) slope, changes in antiglaucoma medications, and IOP. Subgroup analyses of the MD slope according to mean age (over or under 65 years), baseline MD (over or under –12 dB), and baseline IOP (over or under 15 mmHg) were performed to determine the results’ robustness.

Results

We included 7 retrospective observational studies (Japan: 6 studies, United States: 1 study) comprising a total of 166 eyes. Mean preoperative VF MD slopes ranged from –0.52 to –1.05 dB/year. The meta-analysis demonstrated significant MD slope improvement after trabeculectomy (pooled mean difference: 0.54 dB/year, 95% CI: 0.40 to 0.67, I² = 9%). Mean age, baseline MD, and baseline IOP subgroup analyses revealed MD slope results were consistent with those of the main analyses. The mean IOP (pooled mean difference: –5.54 mmHg, 95% CI: –6.02 to –5.06, I² = 0%) and mean number of antiglaucoma medications (pooled mean difference: –1.75, 95% CI: –2.97 to –0.53, I² = 98%) significantly decreased after trabeculectomy. The most frequently reported early complications after trabeculectomy were hypotony, hyphema, and shallow anterior chamber.

Conclusion

This systematic review and meta-analysis indicated that trabeculectomy with antimetabolites is beneficial for progressing NTG; it preserves visual function by alleviating the MD slope and reducing antiglaucoma medication use. However, several post-trabeculectomy complications should be monitored.

Fibrillin-1 mutant mouse captures defining features of human primary open glaucoma including anomalous aqueous humor TGF beta-2

Primary open angle glaucoma (POAG) features an optic neuropathy, elevated aqueous humor (AH) TGFβ2, and major risk factors of central corneal thickness (CCT), increasing age and intraocular pressure (IOP). We examined Tight skin (Tsk) mice to see if mutation of fibrillin-1, a repository for latent TGFβ, is associated with characteristics of human POAG. We measured: CCT by ocular coherence tomography (OCT); IOP; retinal ganglion cell (RGC) and optic nerve axon counts by microscopic techniques; visual electrophysiologic scotopic threshold responses (STR) and pattern electroretinogram (PERG); and AH TGFβ2 levels and activity by ELISA and MINK epithelial cell-based assays respectively. Tsk mice had open anterior chamber angles and compared with age-matched wild type (WT) mice: 23% thinner CCT (p < 0.003); IOP that was higher (p < 0.0001), more asymmetric (p = 0.047), rose with age (p = 0.04) and had a POAG-like frequency distribution. Tsk mice also had RGCs that were fewer (p < 0.04), declined with age (p = 0.0003) and showed increased apoptosis and glial activity; fewer optic nerve axons (p = 0.02); abnormal axons and glia; reduced STR (p < 0.002) and PERG (p < 0.007) visual responses; and higher AH TGFβ2 levels (p = 0.0002) and activity (p = 1E-11) especially with age. Tsk mice showed defining features of POAG, implicating aberrant fibrillin-1 homeostasis as a pathogenic contributor to emergence of a POAG phenotype.

High Blood Pressure and Intraocular Pressure: A Mendelian Randomization Study

Purpose

To test for causality with regard to the association between blood pressure (BP) and intraocular pressure (IOP) and glaucoma.

Methods

Single nucleotide polymorphisms (SNPs) associated with BP were identified in a genome-wide association study (GWAS) meta-analysis of 526,001 participants of European ancestry. These SNPs were used to assess the BP versus IOP relationship in a distinct sample (n = 70,832) whose corneal-compensated IOP (IOPcc) was measured. To evaluate the BP versus primary open-angle glaucoma (POAG) relationship, additional Mendelian randomization (MR) analyses were conducted using published GWAS summary statistics.

Results

Observational analysis revealed a linear relationship between BP traits and IOPcc, with a +0.28 mm Hg increase in IOPcc per 10-mm Hg increase in systolic BP (95% confidence interval [CI], 0.26-0.29); for diastolic blood pressure (DBP) and pulse pressure (PP), these estimates were +0.41 mm Hg and +0.36 mm Hg, respectively. An inverse-variance weighted MR analysis did not support a causal relationship, as the estimated causal effect was +0.01 mm Hg IOPcc per 10-mm Hg increase in systolic blood pressure (SBP); +0.13 mm Hg IOPcc per 10-mm Hg increase in DBP; and +0.02 mm Hg IOPcc per 10-mm Hg increase in PP (all P > 0.05). With regard to the risk of POAG, MR analyse yielded causal effect estimate of odds ratio = 0.98 (95% CI, 0.92-1.04) per 10-mm Hg increase in SBP. Neither DBP nor PP demonstrated evidence of a causal effect on POAG.

Conclusions

A range of different MR analysis methods provided evidence, in general, that the causal effect of BP on IOP (and POAG) was modest, or even zero. However, interpretation was complicated by SNPs associated with BP potentially having pleiotropic effects on IOP.

Corneal Hysteresis, Intraocular Pressure, and Progression of Glaucoma: Time for a “Hyst-Oric” Change in Clinical Practice?

It is known that as people age their tissues become less compliant and the ocular structures are no different. Corneal Hysteresis (CH) is a surrogate marker for ocular compliance. Low hysteresis values are associated with optic nerve damage and visual field loss, the structural and functional components of glaucomatous optic neuropathy. Presently, a range of parameters are measured to monitor and stratify glaucoma, including intraocular pressure (IOP), central corneal thickness (CCT), optical coherence tomography (OCT) scans of the retinal nerve fibre layer (RNFL) and the ganglion cell layer (GCL), and subjective measurement such as visual fields. The purpose of this review is to summarise the current evidence that CH values area risk factor for the development of glaucoma and are a marker for its progression. The authors will explain what precisely CH is, how it can be measured, and the influence that medication and surgery can have on its value. CH is likely to play an integral role in glaucoma care and could potentially be incorporated synergistically with IOP, CCT, and visual field testing to establish risk stratification modelling and progression algorithms in glaucoma management in the future.

The genetic basis for adult onset glaucoma: Recent advances and future directions

Glaucoma, a diverse group of eye disorders that results in the degeneration of retinal ganglion cells, is the world's leading cause of irreversible blindness. Apart from age and ancestry, the major risk factor for glaucoma is increased intraocular pressure (IOP). In primary open-angle glaucoma (POAG), the anterior chamber angle is open but there is resistance to aqueous outflow. In primary angle-closure glaucoma (PACG), crowding of the anterior chamber angle due to anatomical alterations impede aqueous drainage through the angle. In exfoliation syndrome and exfoliation glaucoma, deposition of white flaky material throughout the anterior chamber directly interfere with aqueous outflow. Observational studies have established that there is a strong hereditable component for glaucoma onset and progression. Indeed, a succession of genome wide association studies (GWAS) that were centered upon single nucleotide polymorphisms (SNP) have yielded more than a hundred genetic markers associated with glaucoma risk. However, a shortcoming of GWAS studies is the difficulty in identifying the actual effector genes responsible for disease pathogenesis. Building on the foundation laid by GWAS studies, research groups have recently begun to perform whole exome-sequencing to evaluate the contribution of protein-changing, coding sequence genetic variants to glaucoma risk. The adoption of this technology in both large population-based studies as well as family studies are revealing the presence of novel, protein-changing genetic variants that could enrich our understanding of the pathogenesis of glaucoma. This review will cover recent advances in the genetics of primary open-angle glaucoma, primary angle-closure glaucoma and exfoliation glaucoma, which collectively make up the vast majority of all glaucoma cases in the world today. We will discuss how recent advances in research methodology have uncovered new risk genes, and how follow up biological investigations could be undertaken in order to define how the risk encoded by a genetic sequence variant comes into play in patients. We will also hypothesise how data arising from characterising these genetic variants could be utilized to predict glaucoma risk and the manner in which new therapeutic strategies might be informed.

Evaluation of Spatially Targeted Scleral Stiffening on Neuroprotection in a Rat Model of Glaucoma

Purpose

Scleral stiffening may protect against glaucomatous retinal ganglion cell (RGC) loss or dysfunction associated with ocular hypertension. Here, we assess the potential neuroprotective effects of two treatments designed to stiffen either the entire posterior sclera or only the sclera adjacent to the peripapillary sclera in an experimental model of glaucoma.

Methods

Rat sclerae were stiffened in vivo using either genipin (crosslinking the entire posterior sclera) or a regionally selective photosensitizer, methylene blue (stiffening only the juxtaperipapillary region surrounding the optic nerve). Ocular hypertension was induced using magnetic microbeads delivered to the anterior chamber. Morphological and functional outcomes, including optic nerve axon count and appearance, retinal thickness measured by optical coherence tomography, optomotor response, and electroretinography traces, were assessed.

Results

Both local (juxtaperipapillary) and global (whole posterior) scleral stiffening treatments were successful at increasing scleral stiffness, but neither provided demonstrable neuroprotection in hypertensive eyes as assessed by RGC axon counts and appearance, optomotor response, or electroretinography. There was a weak indication that scleral crosslinking protected against retinal thinning as assessed by optical coherence tomography.

Conclusions

Scleral stiffening was not demonstrated to be neuroprotective in ocular hypertensive rats. We hypothesize that the absence of benefit may in part be due to RGC loss associated with the scleral stiffening agents themselves (mild in the case of genipin, and moderate in the case of methylene blue), negating any potential benefit of scleral stiffening.

Translational Relevance

The development of scleral stiffening as a neuroprotective treatment will require the identification of better tolerated stiffening protocols and further preclinical testing.

MRI findings suggestive of Alzheimer's disease in patients with primary open angle glaucoma - a single sequence analysis using rapid 3D T1 spoiled gradient echo

OBJECTIVE

Primary open-angle glaucoma (POAG) is a degenerative optic neuropathy disease which has somewhat similar pathophysiology to Alzheimer's disease (AD). This study aims to determine the presence of medial temporal atrophy and parietal lobe atrophy in patients with POAG compared to normal controls using medial temporal atrophy (MTA) scoring and posterior cortical atrophy (PCA) scoring system on T1 magnetization-prepared rapid gradient-echo.

METHODS

50 POAG patients and 50 normal subjects were recruited and an MRI brain with T1-magnetization-prepared rapid gradient-echo was performed. Medial temporal lobe and parietal lobe atrophy were by MTA and PCA/Koedam scoring. The score of the PCA and MTA were compared between the POAG group and the controls.

RESULTS

There was a significant statistical difference between PCA score in POAG and the healthy control group (p-value = 0.026). There is no statistical difference between MTA score in POAG compared to the healthy control group (p-value = 0.58).

CONCLUSION

This study suggests a correlation between POAG and PCA score. Potential application of this scoring method in clinical diagnosis and monitoring of POAG patients.

ADVANCES IN KNOWLEDGE

The scoring method used in AD may also be applied in the diagnosis and monitoring of POAGMRI brain, specifically rapid volumetric T1 spoiled gradient echo sequence, may be applied in POAG assessment.

Risk factors for undergoing surgery in patients with newly diagnosed open-angle glaucoma

Despite the clinical importance of glaucoma surgery, studies on its prevalence and risk factors are limited. We analyzed a database comprising approximately 1,000,000 Korean residents to investigate the prevalence and risk factors for undergoing glaucoma surgery within 5 years of diagnosis with open-angle glaucoma. Of the 4,303 patients evaluated, 226 (5.3%) underwent glaucoma surgery. Factors associated with the likelihood of glaucoma surgery included the use of two or more eye drops (odds ratio [OR], 30.30; 95% confidence interval [CI], 10.95–83.84), intake of oral carbonic anhydrase inhibitor (OR, 1.79; 95% CI, 1.23–2.61), age > 55 years (55–65 years: OR, 1.71; 95% CI, 1.06–2.76; > 65 years: OR 1.72; 95% CI, 1.10–2.70), female sex (OR, 1.46; 95% CI, 1.10–1.94), middle- and high-income (OR, 2.36; 95% CI, 1.30–4.28, OR, 1.86; 95% CI, 1.03–3.35, respectively), and metropolitan residence (OR, 1.61; 95% CI, 1.14–2.26). Our nomogram for predicting the likelihood of glaucoma surgery showed an acceptable result. In conclusion, older age, female sex, and the intensity of intraocular pressure lowering treatment increased the likelihood of undergoing glaucoma surgery. Our findings indicated that a lower socioeconomic status may forestall receiving this necessary surgery, which requires further attention.

Thinner Central Corneal Thickness is Associated with a Decreased Parapapillary Vessel Density in Normal Tension Glaucoma

This retrospective cross-sectional study, which enrolled 124 normal tension glaucoma (NTG) eyes and 68 healthy eyes as the control, determined the association between central corneal thickness (CCT) and ocular parameters in NTG. CCT was measured using the Pentacam® system, optical coherence tomography angiography (OCT-A) was adopted to measure the peripapillary and macular area VDs, and spatial data were based on the Garway–Heath map as illustrated in OCT-A. Univariate and multivariate linear regressions were used to statistically analyze for associations between CCT and other factors. In this study, the mean age was similar for both the NTG and control groups. The mean CCT of the NTG group was significantly thinner than that of the control group (533.97 ± 33.11 µm vs. 546.78 ± 38.21 µm; $p$  = .022). Considering all the factors, CCT negatively correlated with visual field (VF) pattern standard deviation (univariate, $p$  = .045). To analyze structural and functional factors separately, we found a significant positive correlation between CCT and whole disc radial peripapillary capillary VD (VDRPC; multivariate, $p$  = .019). To analyze the relationship between all factors and sectoral changes in VDRPC, a significant positive correlation was observed between CCT and inferior temporal VDRPC (univariate, $p$  = .039) and inferior nasal VDRPC (VDRPC IN; univariate, $p$  = .048). In conclusion, this novel study shows that among NTG participants, a thinner cornea correlated with weaker biomechanical properties susceptible to optic nerve tissue displacement, especially in response to mild transient elevation of IOP, leads to compromised ocular microcirculation.

Advanced Diffusion MRI of the Visual System in Glaucoma: From Experimental Animal Models to Humans

Simple Summary

This review summarizes current applications of advanced diffusion magnetic resonance imaging (MRI) throughout the glaucomatous visual system, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex. Glaucoma continues to be the leading cause of irreversible blindness worldwide and often remains undetected until later disease stages. The development of non-invasive methods for early detection of visual pathway integrity could pave the way for timely intervention and targeted treatment strategies. Principles of diffusion have been integrated with MRI protocols to produce a diffusion-weighted imaging modality for studying changes to tissue microstructures by quantifying the movement of water molecules in vivo. The development and applications of diffusion MRI in ophthalmology have allowed a better understanding of neural pathway changes in glaucoma. The feasibility of translating diffusion MRI techniques to assess both humans and experimental animal models of glaucoma and other optic neuropathies or neurodegenerative diseases is discussed. Recent research focuses on overcoming limitations in imaging quality, acquisition times, and biological interpretation suggest that diffusion MRI can provide an important tool for the non-invasive evaluation of glaucomatous changes in the visual system.

Abstract

Glaucoma is a group of ophthalmologic conditions characterized by progressive retinal ganglion cell death, optic nerve degeneration, and irreversible vision loss. While intraocular pressure is the only clinically modifiable risk factor, glaucoma may continue to progress at controlled intraocular pressure, indicating other major factors in contributing to the disease mechanisms. Recent studies demonstrated the feasibility of advanced diffusion magnetic resonance imaging (dMRI) in visualizing the microstructural integrity of the visual system, opening new possibilities for non-invasive characterization of glaucomatous brain changes for guiding earlier and targeted intervention besides intraocular pressure lowering. In this review, we discuss dMRI methods currently used in visual system investigations, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex. We evaluate how conventional diffusion tensor imaging, higher-order diffusion kurtosis imaging, and other extended dMRI techniques can assess the neuronal and glial integrity of the visual system in both humans and experimental animal models of glaucoma, among other optic neuropathies or neurodegenerative diseases. We also compare the pros and cons of these methods against other imaging modalities. A growing body of dMRI research indicates that this modality holds promise in characterizing early glaucomatous changes in the visual system, determining the disease severity, and identifying potential neurotherapeutic targets, offering more options to slow glaucoma progression and to reduce the prevalence of this world’s leading cause of irreversible but preventable blindness.

[Normal Tension Glaucoma]

Normal tension glaucoma (NTG) is a subvariant of primary open angle glaucoma (POAG) or a separate entity. NTG is defined as chronic open angle glaucoma without elevated intraocular pressure or normal intraocular pressure. Normal intraocular pressure is between 10 and 21 mmHg and is defined as two times the standard deviation of the mean intraocular pressure in the normal population. In addition to the absence of elevated intraocular pressure, all the classic symptoms of glaucoma are otherwise present. These include a conspicuous glaucomatous optic disc excavation, nerve fibre bundle defects, and corresponding visual field defects. Papillary rim haemorrhages are frequently found. The visual field defects in NDG are usually more central compared to POAG and are therefore described as more disturbing by the patient. The anterior chamber angle is open and there are no other changes suggestive of secondary glaucoma (pigment dispersion, pseudo-exfoliation). The exact pathophysiology of NDG is not well understood. Pathophysiologically, circulatory disturbances in the sense of arterial hypo- as well as hypertension may play an essential role or at least increase the susceptibility of the optic nerve to intraocular pressure fluctuations as well as blood pressure dips. Therefore, this requires not only a purely ophthalmologic but also interdisciplinary treatment of the patient with confirmed NDG. The primary goal of treatment is the reduction of intraocular pressure, which can stop the disease. This article gives an overview of epidemiology, aetiology, clinical findings and therapies.

Normaldruckglaukome

Das Normaldruckglaukom wird definiert wird als primär chronisches Offenwinkelglaukom, bei dem kein erhöhter Augeninnendruck vorliegt. Trotz normalem Augeninnendruck ist das primäre Ziel der Behandlung die Augeninnendrucksenkung, mit der es gelingen kann, die Erkrankung aufzuhalten. Dieser Artikel soll eine Übersicht über Epidemiologie, Ätiologie, Pathogenese, klinische Befunde sowie Therapien geben.

Primary glaucomas in adults: Epidemiology and public health-A review

Glaucoma is a mixed group of optic neuropathies that lead to irreversible visual field loss and blindness if left untreated. It is estimated that 3.5% of the global population aged 40 to 80 years have any glaucoma, being the primary open-angle and the primary angle-closure glaucoma the most prevalent forms. Although the age-standardised prevalence of blindness caused by glaucoma has decreased substantially over the last decades, population growth and ageing impose many challenges in preventing glaucoma-related morbidities on a global level. In addition, difficulties in diagnoses and treatment, along with its chronic and irreversible nature, urge the development and implementation of innovative approaches in confronting the disease. This manuscript reviews recent literature related to the epidemiology of primary glaucomas in adults, the risk factors attributed to the development of the disease, and discuss challenges and potential solutions from a public health perspective.

National Health Care data system analysis of glaucoma surgery activity in France in 2016

PURPOSE

To describe the glaucoma surgery offer in France in 2016.

METHODS

We used the French National Health Care System database to identify all medical procedures carried out in 2016. The study investigated the entire population aged 30 years and older that had undergone glaucoma surgery, alone or combined with another surgery. We calculated the incidence of surgeries per 100 000 inhabitants 30 years of age and older performed by ophthalmologists carrying out at least 50 procedures annually, the number of surgeons doing these surgeries, the mean age of these practitioners, and the number of surgeons older than 55 years.

RESULTS

In 2016, 16 854 glaucoma surgeries were performed in patients aged 30 years and older, for an incidence of 40.8 per 100 000 inhabitants aged 30 years and older. The most frequent procedure performed was trabeculectomy followed by non-penetrating deep sclerectomy (16.7 and 11.7, respectively, per 100 000 inhabitants 30 years of age and older). Private practice glaucoma surgery accounted for 47% of the activity of surgeons performing at least 50 surgeries per year and 60% of the total surgical activity. Of the private practice ophthalmologists performing at least 50 glaucoma surgery procedures per year, 58.5% were over 55 years of age, and 23.5% of public hospital ophthalmologists were over 55 years of age.

CONCLUSIONS

This study demonstrates that surgeons performing glaucoma surgeries are often older. It is necessary to take note of the country's educational capacity to ensure that the number of ophthalmological surgeons remains adapted to demand.

Special Cerebral and Cerebrospinal Features in Primary Open Angle Glaucoma and Normal Tension Glaucoma

In addition to aqueous humour and blood, cerebrospinal fluid also plays an important part in the pathophysiology of primary open-angle glaucoma (POAG) and, in particular, normal-tension glaucoma (NTG). Apart from the important role of CSF pressure in papillary congestion, the composition of the CSF and its flow rate are relevant. CSF is in contact with the brain, the spinal canal and the optic nerve. In neurodegenerative disease, one potential pathophysiological factor, apart from an altered composition of the CSF, is a decrease in flow rate. Changes in CSF composition and flow rate have also been described in the perioptic subarachnoid space of the optic nerve in patients with normal tension glaucoma. Such findings indicate that primary open angle glaucoma and normal tension glaucoma especially, might be due to a neurodegenerative process.

Glucagon-Like Peptide 1 Receptor Agonists – Potential Game Changers in the Treatment of Glaucoma?

Glaucoma is a common ocular neurodegenerative disease characterized by the progressive loss of retinal ganglion cells and their axons. It is the most common cause of irreversible blindness. With an increasing number of glaucoma patients and disease progression despite treatment, it is paramount to develop new and effective therapeutics. Emerging new candidates are the receptor agonists of the incretin hormone glucagon-like-peptide-1 (GLP-1), originally used for the treatment of diabetes. GLP-1 receptor (GLP-1R) agonists have shown neuroprotective effects in preclinical and clinical studies on neurodegenerative diseases in both the brain (e.g., Alzheimer’s disease, Parkinson’s disease, stroke and diabetic neuropathy) and the eye (e.g., diabetic retinopathy and AMD). However, there are currently very few studies investigating the protective effects of GLP-1R agonists in the treatment of specifically glaucoma. Based on a literature search on PubMed, the Cochrane Library, and ClinicalTrials.gov, this review aims to summarize current clinical literature on GLP-1 receptor agonists in the treatment of neurodegenerative diseases to elucidate their potential in future anti-glaucomatous treatment strategies.

Prevalence of Open-angle Glaucoma in the Faroese Population

PURPOSE

The Faroe Islands are home to 50,000 genetically isolated people in the North Atlantic. The prevalence of open-angle glaucoma (OAG) in the Faroese population is unknown. Consequently, we conducted a survey to determine the prevalence of OAG in the Faroese population. We also investigated the role of known glaucoma-causing genes in Faroese OAG.

MATERIALS AND METHODS

We conducted a prospective survey of known and newly diagnosed glaucoma patients at the Faroese National Hospital, Landssjukrahusid, Tórshavn between October 1, 2015 to December 31, 2017. In addition we reviewed the only eye care provider in the Faroese Islands by scrutinizing electronic medical records between 2009 and June 15, 2014, October 1, 2015 and the partly overlapping prescriptions for ocular hypotensive medications in 2016 to identify patients with either a diagnosis of glaucoma, a diagnosis of ocular hypertension or a prescription for ocular hypotensive medications. Next, we prospectively confirmed diagnoses with complete eye examinations. Patient DNA samples were tested for variations in known glaucoma-causing genes [myocilin (MYOC), optineurin (OPTN), and TANK binding kinase 1 (TBK1)].

RESULTS

We determined the age-related prevalence of OAG January 1, 2017 in individuals 40 years or older to be 10.7/1000 (1.07%) and highly age-related. A diagnosis of OAG was present in 264 patients, of whom 211 (79.9%) had primary OAG (including normal tension glaucoma), 49 (18.6%) had pseudoexfoliation glaucoma, and 4 (1.5%) had pigmentary glaucoma. Among patients receiving medications for glaucoma, nearly 50% had primary OAG, while the majority of the rest had ocular hypertension or secondary glaucoma. No disease-causing variants were detected in MYOC, OPTN, or TBK1.

CONCLUSIONS

The calculated prevalence of OAG in the Faroe Islands was 1.07%. The absence of MYOC, OPTN, or TBK1 disease-causing variants in Faroese primary OAG patients suggests that a different, potentially unique set of genes may be contributing to the pathogenesis of glaucoma in this population.

Serum complement component 3, complement component 4 and complement component 1q levels predict progressive visual field loss in older women with primary angle closure glaucoma

AIM

To evaluate the association between serum levels of complement component (C) 3, C4 and C1q and visual field (VF) loss in patients with primary angle closure glaucoma (PACG).

METHODS

In this prospective cohort study, a total of 308 patients with PACG were included. The patients were followed up every 6 months (at least 2 years), with clinical examination and VF testing. Based on their sex and age, the subjects were stratified into male and female subgroups, and by age at <60 and ≥60 years per subgroup.

RESULTS

One hundred twenty-three (39.94%) patients showed glaucoma VF progression. The serum levels of C3, C4 and C1q were significantly lower (p<0.05) in the progression group compared with the non-progression group in the ≥60 years female subgroup. In female patients with age ≥60 years, (1) lower levels of baseline C3 (HR=0.98, p<0.001), C4 (HR=0.96, p=0.01) and C1q levels (HR=0.99, p=0.003) were associated with a greater risk of VF progression; (2) patients with lower C3 levels had significantly (p<0.05) higher rates of VF loss progression, similar to those with lower C4 and lower C1q levels; and (3) the generalised additive model revealed a negative correlation between baseline C3 (p<0.001), C4 (p<0.001) and C1q (p<0.001) levels with the risk of VF progression. No statistical significance was observed in the male (<60 and ≥60 years) and female (<60 years) subgroups.

CONCLUSION

Decreased C3, C4 and C1q levels at baseline were significantly associated with a greater risk of VF loss progression only in older women with PACG.