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Primary open-angle glaucoma (POAG) is a leading cause of blindness worldwide. Using genome-wide association single-nucleotide polymorphism data from the Glaucoma Genes and Environment study and National Eye Institute Glaucoma Human Genetics Collaboration comprising 3,108 cases and 3,430 controls, we assessed biologic pathways as annotated in the KEGG database for association with risk of POAG. After correction for genic overlap among pathways, we found 4 pathways, butanoate metabolism (hsa00650), hematopoietic cell lineage (hsa04640), lysine degradation (hsa00310) and basal transcription factors (hsa03022) related to POAG with permuted p

AimsVascular perfusion may be impaired in primary open-angle glaucoma (POAG); thus, we evaluated a panel of markers in vascular tone-regulating genes in relation to POAG.MethodsWe used Illumina 660W-Quad array genotype data and pooled P-values from 3108 POAG cases and 3430 controls from the combined National Eye Institute Glaucoma Human Genetics Collaboration consortium and Glaucoma Genes and Environment studies. Using information from previous literature and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, we compiled single-nucleotide polymorphisms (SNPs) in 186 vascular tone-regulating genes. We used the 'Pathway Analysis by Randomization Incorporating Structure' analysis software, which performed 1000 permutations to compare the overall pathway and selected genes with comparable randomly generated pathways and genes in their association with POAG.ResultsThe vascular tone pathway was not associated with POAG overall or POAG subtypes, defined by the type of visual field loss (early paracentral loss (n=224 cases) or only peripheral loss (n=993 cases)) (permuted P≥0.20). In gene-based analyses, eight were associated with POAG overall at permuted P

Individuals with pseudoexfoliation (PEX) syndrome exhibit various connective tissue pathologies associated with dysregulated extracellular matrix homeostasis. PEX glaucoma is a common, aggressive form of open-angle glaucoma resulting from the deposition of fibrillary material in the conventional outflow pathway. However, the molecular mechanisms that drive pathogenesis and genetic risk remain poorly understood. PEX glaucoma-associated single-nucleotide polymorphisms are located in and affect activity of the promoter of LOXL1-AS1, a long non-coding RNA (lncRNA). Nuclear and non-nuclear lncRNAs regulate a host of biological processes, and when dysregulated, contribute to disease. Here we report that LOXL1-AS1 localizes to the nucleus where it selectively binds to the mRNA processing protein, heterogeneous nuclear ribonucleoprotein-L (hnRNPL). Both components of this complex are critical for the regulation of global gene expression in ocular cells, making LOXL1-AS1 a prime target for investigation in PEX syndrome and glaucoma., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

SIX1/SIX6 polymorphism has been shown to be associated with glaucoma. Studies have also found that, in older adults, retinal nerve fibre layer (RNFL) thickness is significantly thinned with each copy of the risk allele in SIX1/SIX6. However, it is not known whether these genetic variants exert their effects in younger individuals. Comparing a healthy young adult with an older adult cohort (mean age 20 vs 63 years), both of Northern European descent, we found that there was no significant RNFL thinning in each copy of the risk alleles in SIX1/SIX6 in the eyes of younger individuals. The older cohort showed an unexpectedly thicker RNFL in the nasal sector with each copy of the risk allele for both the SIX1 (rs10483727) and SIX6 (rs33912345) variants. In the temporal sector, thinner RNFL was found with each copy of the risk allele in rs33912345 with a decrease trend observed in rs10483727. Our results suggest that SIX1/SIX6 gene variants exert their influence later in adult life.

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders., Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma., Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma., Exposures: Genetic variants associated with primary open-angle glaucoma., Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data., Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry., Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.

Purpose: To test the hypothesis that the anatomic correlate of the gray optic disc crescent is pigmentation of externally oblique border tissue of Elschnig., Design: Retrospective study., Participants: African-American adult men with or without clinically apparent gray optic disc crescents., Methods: McNemar's test for paired data and kappa statistic with 95% confidence intervals were used to examine the relationships between eyes with or without gray optic disc crescents and corresponding spectral-domain (SD) OCT images with enhanced depth imaging (EDI)., Main Outcome Measures: Correlation between clinical gray optic disc crescents and hyperreflectivity of externally oblique border tissue of Elschnig by SD OCT with EDI., Results: Twenty-five eyes had clinically apparent gray optic disc crescents, of which SD OCT with EDI revealed hyperreflectivity (interpreted as increased pigmentation) of externally oblique (obtuse angle) border tissue of Elschnig in 22 eyes, that is, extending into Bruch's membrane opening and presumably visible by funduscopy. Thirty-two eyes from matched participants had no apparent gray optic disc crescent, of which SD OCT with EDI revealed hyperreflectivity of the border tissue of Elschnig in 23 eyes, but with a nonoblique (right angle) or internal (acute angle) angle, which would presumably obstruct funduscopic visualization., Conclusions: Observations by SD OCT with EDI suggest that the anatomic correlate of the gray optic disc crescent is pigmentation of externally oblique border tissue of Elschnig., (Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: Exfoliation syndrome (XFS) is associated with genetic variants of lysyl oxidase-like 1 (LOXL1), a key enzyme in the stabilization of extracellular matrix (ECM) and elastin, and in connective tissue repair. Because patients with chronic obstructive pulmonary disease (COPD) have increased and altered elastin degradation, an association between XFS and COPD was hypothesized and analyzed. Impact of XFS on survival in patients with COPD was evaluated., Design: Case-case and case-control comparison with 5:1 age- and sex-matched controls., Subjects: Total of 2943 patients with XFS, 20 589 patients with COPD, and 162 patients with both disorders seen between 1996 and 2015 were identified from Utah Population Database-linked medical records. Controls were selected and matched by sex and birth year to patients in a 5:1 ratio., Methods: Unconditional logistic regression, using International Classification of Diseases, Ninth Revision codes (365.52 and 366.11) to define XFS and an outcome of COPD (496.0), was used to calculate the odds ratio (OR) to estimate risk of COPD in patients with XFS, adjusting for age and sex. Model covariates included race, obesity, and tobacco use., Main Outcome Measures: Whether XFS patients have an increased risk of developing COPD; whether COPD patients have an increased risk of XFS; and, in COPD patients, whether survival differs between those with XFS and those without., Results: In XFS patients, risk of a COPD diagnosis was increased compared with that of non-XFS controls (OR = 1.41; 95% confidence interval [CI], 1.17-1.70; P < 0.0004), particularly in a tobacco users subset (OR = 2.17; 95% CI, 1.15-4.09; P = 0.02). COPD patients and controls with no COPD did not differ in their risk of an XFS diagnosis. COPD patients with XFS had significantly better survival than patients with COPD and no XFS history., Conclusions: XFS patients may have an increased risk of a COPD diagnosis compared with non-XFS individuals. In COPD patients, risk of XFS was not increased compared with those with no COPD history. In COPD patients with XFS, survival is significantly improved compared with COPD patients with no XFS history., (Published by Elsevier Inc.)

Importance: Exfoliation syndrome (XFS) is a systemic connective tissue disease, and abnormal connective tissue metabolism is implicated in inguinal hernias (IH). Associating XFS with comorbid conditions may illuminate their underlying pathophysiology and affect clinical screening and treatment. Exfoliation syndrome involves altered systemic extracellular matrix (ECM) homeostasis involving elastin metabolism. Hernias occur owing to abnormal ECM synthesis, metabolism, or repair. Inguinal hernias involve weakening or rupture of the abdominal/groin wall., Objective: To determine an association between patients with XFS and patients with IH in Utah, possibly differing between direct or indirect hernia., Design, Setting, and Participants: Cross-sectional study in a large health care system of Utah hospitals and clinics. Conditional logistic regression odds ratios were used to estimate risk of XFS in patients with IH overall and by subtype (direct or indirect) compared with control individuals. Codes specific to direct and indirect IH with additional medical records review of 186 procedures were used to classify IH subtypes that were not prespecified. Bootstrap resampling with jackknife estimation used to calculate 95% confidence intervals. The model accounted for matching on sex and age and adjusted for body mass index and tobacco use. Population-based sample using medical records from 1996 to 2015 that identified 2594 patients 40 years or older on January 1, 1996, with surgical IH repair and 12 966 random control patients with no IH history matched 5:1 on sex and birth year. Data were analyzed between September 10, 2017, and October 23, 2017., Main Outcomes and Measures: Exfoliation syndrome outcome defined by diagnosis codes for XFS or exfoliation glaucoma from 1996 to 2015., Results: Participants were primarily white (2532 of 2594 patients, [96.1%]; 12 454 of 12 966 control individuals [97.6%]) and non-Hispanic (2396 of 2594 patients [92.4%]); 250 participants were women (9.6%). Of study participants, 22 patients with IH and 43 control individuals were diagnosed as having XFS, respectively. Patients with IH had a 2.3-fold risk for an XFS diagnosis compared with control individuals (95% CI, 1.4-3.5; P = .03), and XFS risk with indirect IH appeared especially pronounced., Conclusions and Relevance: Inguinal hernia was associated with an increased risk of XFS in this Utah population. Further work is needed to understand the pathophysiology, genetics, and environmental factors contributing to both diseases.

Primary open angle glaucoma (POAG) is a complex disease with a major genetic contribution. Its prevalence varies greatly among ethnic groups, and is up to five times more frequent in black African populations compared to Europeans. So far, worldwide efforts to elucidate the genetic complexity of POAG in African populations has been limited. We conducted a genome-wide association study in 1113 POAG cases and 1826 controls from Tanzanian, South African and African American study samples. Apart from confirming evidence of association at TXNRD2 (rs16984299; OR [T] 1.20; P = 0.003), we found that a genetic risk score combining the effects of the 15 previously reported POAG loci was significantly associated with POAG in our samples (OR 1.56; 95% CI 1.26-1.93; P = 4.79 × 10 -5 ). By genome-wide association testing we identified a novel candidate locus, rs141186647, harboring EXOC4 (OR [A] 0.48; P = 3.75 × 10 -8 ), a gene transcribing a component of the exocyst complex involved in vesicle transport. The low frequency and high degree of genetic heterogeneity at this region hampered validation of this finding in predominantly West-African replication sets. Our results suggest that established genetic risk factors play a role in African POAG, however, they do not explain the higher disease load. The high heterogeneity within Africans remains a challenge to identify the genetic commonalities for POAG in this ethnicity, and demands studies of extremely large size.

Purpose: A common missense variant in the SIX6 gene (rs33912345) is strongly associated with primary open-angle glaucoma (POAG). We aimed to examine the association of rs33912345 with optic disc and retinal nerve fiber layer (RNFL) measures in a European population., Methods: We examined participants of the population-based EPIC-Norfolk Eye Study. Participants underwent confocal laser scanning tomography (Heidelberg Retina Tomograph II, HRT) to estimate optic disc rim area and vertical cup-disc ratio (VCDR). Scanning laser polarimetry (GDxVCC) was used to estimate average RNFL thickness. The mean of right and left eye values was considered for each participant. Genotyping was performed using the Affymetrix UK Biobank Axiom Array. Multivariable linear regression with the optic nerve head parameter as outcome variable and dosage of rs33912345 genotype as primary explanatory variable was used, adjusted for age, sex, disc area, axial length, and intraocular pressure. We further repeated analyses stratified into age tertiles., Results: In total, 5433 participants with HRT data and 3699 participants with GDxVCC data were included. Each "C" allele of rs33912345 was associated with a smaller rim area (-0.030 mm [95% CI -0.040, -0.020]; P=5.4×10), a larger VCDR (0.025 [95% CI 0.017, 0.033]; P=3.3×10) and a thinner RNFL (-0.39 μm [95% CI -0.62, -0.15]; P=0.001). The RNFL association was strongest in the oldest age tertile, whereas rim area and VCDR associations were strongest in the youngest and oldest age tertiles., Conclusions: The protein-coding SIX6 variant rs33912345, previously associated with POAG, has a functional effect on glaucoma-associated optic nerve head traits in Europeans.

Purpose: Keratoconus (KC) is the most common corneal ectasia. We aimed to determine the differential expression of coding and long noncoding RNAs (lncRNAs) in human corneas affected with KC., Methods: From the corneas of 10 KC patients and 8 non-KC healthy controls, 200 ng total RNA was used to prepare sequencing libraries with the SMARTer Stranded RNA-Seq kit after ribosomal RNA depletion, followed by paired-end 50-bp sequencing with Illumina Sequencer. Differential analysis was done using TopHat/Cufflinks with a gene file from Ensembl and a lncRNA file from NONCODE. Pathway analysis was performed using WebGestalt. Using the expression level of differentially expressed coding and noncoding RNAs in each sample, we correlated their expression levels in KC and controls separately and identified significantly different correlations in KC against controls followed by visualization using Cytoscape., Results: Using |fold change| ≥ 2 and a false discovery rate ≤ 0.05, we identified 436 coding RNAs and 584 lncRNAs with differential expression in the KC-affected corneas. Pathway analysis indicated the enrichment of genes involved in extracellular matrix, protein binding, glycosaminoglycan binding, and cell migration. Our correlation analysis identified 296 pairs of significant KC-specific correlations containing 117 coding genes enriched in functions related to cell migration/motility, extracellular space, cytokine response, and cell adhesion. Our study highlighted the potential roles of several genes (CTGF, SFRP1, AQP5, lnc-WNT4-2:1, and lnc-ALDH3A2-2:1) and pathways (TGF-β, WNT signaling, and PI3K/AKT pathways) in KC pathogenesis., Conclusions: Our RNA-Seq-based differential expression and correlation analyses have identified many potential KC contributing coding and noncoding RNAs.

Purpose: The purpose of this study was to examine the association between oral statin use and the progression of open angle glaucoma., Methods: Medical records of 847 Veterans were reviewed to collect statin use history, record demographic and comorbid medical conditions, and review visual fields. Visual field progression was judged by an ophthalmologist masked to statin use history. Progression rates in a propensity score matched cohort were compared between statin users and nonusers using McNemar's test with the propensity model derived using associated medical and demographic factors., Results: The mean length of observation was 1324 days with a standard deviation of 464 days. Thirty-one per cent of Veterans demonstrated glaucomatous progression in at least one eye, 49% did not demonstrate progression, and 20% were indeterminate. Approximately 74% of subjects had previously used a statin, with this group having heavier burdens of several comorbid medical conditions and less severe baseline glaucoma than nonusers. The matched cohort was 196 statin users and 196 nonusers, each with similar baseline characteristics (standardised differences <0.10). Progression rates were 35% for statin users compared to 56% for nonusers in the matched cohort (McNemar's p<0.001)., Conclusions: In this population of Veterans, glaucoma patients with any history of statin use have lower visual field progression rates than statin nonusers.

Primary open-angle glaucoma (POAG) is the leading cause of irreversible blindness worldwide for which 15 disease-associated loci had been discovered. Among them, only 5 loci have been associated with POAG in Asians. We carried out a genome-wide association study and a replication study that included a total of 7378 POAG cases and 36 385 controls from a Japanese population. After combining the genome-wide association study and the two replication sets, we identified 11 POAG-associated loci, including 4 known (CDKN2B-AS1, ABCA1, SIX6 and AFAP1) and 7 novel loci (FNDC3B, ANKRD55-MAP3K1, LMX1B, LHPP, HMGA2, MEIS2 and LOXL1) at a genome-wide significance level (P < 5.0×10-8), bringing the total number of POAG-susceptibility loci to 22. The 7 novel variants were subsequently evaluated in a multiethnic population comprising non-Japanese East Asians (1008 cases, 591 controls), Europeans (5008 cases, 35 472 controls) and Africans (2341 cases, 2037 controls). The candidate genes located within the new loci were related to ocular development (LMX1B, HMGA2 and MAP3K1) and glaucoma-related phenotypes (FNDC3B, LMX1B and LOXL1). Pathway analysis suggested epidermal growth factor receptor signaling might be involved in POAG pathogenesis. Genetic correlation analysis revealed the relationships between POAG and systemic diseases, including type 2 diabetes and cardiovascular diseases. These results improve our understanding of the genetic factors that affect the risk of developing POAG and provide new insight into the genetic architecture of POAG in Asians.

Purpose: To characterize the transcriptional landscape of human adult and fetal trabecular meshwork (TM), cornea, and ciliary body (CB) tissues, and to evaluate the expression level of candidate genes selected from genetic association studies of primary-open angle glaucoma, central corneal thickness, intraocular pressure, vertical cup to disc ratio, and optic nerve parameters., Methods: Deep RNA sequencing was performed on the selected human tissues. Transcriptome analyses were performed to 1) characterize the total number of expressed genes, 2) identify the most highly expressed genes, 3) estimate the number of novel transcripts, and 4) evaluate the expression of candidate genes in each tissue. Finally, a differential gene expression analysis was conducted to compare the adult and fetal ocular tissues., Results: There was an average of 12,362 protein coding genes and 3725 novel transcripts expressed in each tissue. The top most expressed genes in each tissue included SPARC (fetal cornea and TM), APOD (adult TM), CLU (adult cornea), and PTGDS (adult and fetal CB). Twenty-nine candidate genes selected from genetic association studies primarily showed high expression levels in the trabecular meshwork and cornea. Comparison of adult and fetal samples identified 2012 and 1261 differentially expressed protein-coding genes within the cornea and trabecular meshwork, respectively., Conclusions: This study has provided an unbiased glimpse into the transcriptome of three essential anterior ocular tissues, resulting in the development of several novel hypotheses. These data can be used in the future to better guide ocular research questions., (Copyright © 2016. Published by Elsevier Ltd.)

Purpose: Sex hormones may be associated with primary open-angle glaucoma (POAG), although the mechanisms are unclear. We previously observed that gene variants involved with estrogen metabolism were collectively associated with POAG in women but not men; here we assessed gene variants related to testosterone metabolism collectively and POAG risk., Methods: We used two datasets: one from the United States (3853 cases and 33,480 controls) and another from Australia (1155 cases and 1992 controls). Both datasets contained densely called genotypes imputed to the 1000 Genomes reference panel. We used pathway- and gene-based approaches with Pathway Analysis by Randomization Incorporating Structure (PARIS) software to assess the overall association between a panel of single nucleotide polymorphisms (SNPs) in testosterone metabolism genes and POAG. In sex-stratified analyses, we evaluated POAG overall and POAG subtypes defined by maximum IOP (high-tension [HTG] or normal tension glaucoma [NTG])., Results: In the US dataset, the SNP panel was not associated with POAG (permuted P = 0.77), although there was an association in the Australian sample (permuted P = 0.018). In both datasets, the SNP panel was associated with POAG in men (permuted P ≤ 0.033) and not women (permuted P ≥ 0.42), but in gene-based analyses, there was no consistency on the main genes responsible for these findings. In both datasets, the testosterone pathway association with HTG was significant (permuted P ≤ 0.011), but again, gene-based analyses showed no consistent driver gene associations., Conclusions: Collectively, testosterone metabolism pathway SNPs were consistently associated with the high-tension subtype of POAG in two datasets.

Central corneal thickness (CCT) is one of the most heritable ocular traits and it is also a phenotypic risk factor for primary open angle glaucoma (POAG). The present study uses the BXD Recombinant Inbred (RI) strains to identify novel quantitative trait loci (QTLs) modulating CCT in the mouse with the potential of identifying a molecular link between CCT and risk of developing POAG. The BXD RI strain set was used to define mammalian genomic loci modulating CCT, with a total of 818 corneas measured from 61 BXD RI strains (between 60-100 days of age). The mice were anesthetized and the eyes were positioned in front of the lens of the Phoenix Micron IV Image-Guided OCT system or the Bioptigen OCT system. CCT data for each strain was averaged and used to QTLs modulating this phenotype using the bioinformatics tools on GeneNetwork (www.genenetwork.org). The candidate genes and genomic loci identified in the mouse were then directly compared with the summary data from a human POAG genome wide association study (NEIGHBORHOOD) to determine if any genomic elements modulating mouse CCT are also risk factors for POAG.This analysis revealed one significant QTL on Chr 13 and a suggestive QTL on Chr 7. The significant locus on Chr 13 (13 to 19 Mb) was examined further to define candidate genes modulating this eye phenotype. For the Chr 13 QTL in the mouse, only one gene in the region (Pou6f2) contained nonsynonymous SNPs. Of these five nonsynonymous SNPs in Pou6f2, two resulted in changes in the amino acid proline which could result in altered secondary structure affecting protein function. The 7 Mb region under the mouse Chr 13 peak distributes over 2 chromosomes in the human: Chr 1 and Chr 7. These genomic loci were examined in the NEIGHBORHOOD database to determine if they are potential risk factors for human glaucoma identified using meta-data from human GWAS. The top 50 hits all resided within one gene (POU6F2), with the highest significance level of p = 10-6 for SNP rs76319873. POU6F2 is found in retinal ganglion cells and in corneal limbal stem cells. To test the effect of POU6F2 on CCT we examined the corneas of a Pou6f2-null mice and the corneas were thinner than those of wild-type littermates. In addition, these POU6F2 RGCs die early in the DBA/2J model of glaucoma than most RGCs. Using a mouse genetic reference panel, we identified a transcription factor, Pou6f2, that modulates CCT in the mouse. POU6F2 is also found in a subset of retinal ganglion cells and these RGCs are sensitive to injury.

Purpose: Vogt-Koyanagi-Harada (VKH) syndrome is a systemic inflammatory autoimmune disease with associated ophthalmic pathology. Glaucoma has been reported in patients with VKH. The purpose of this report is to examine the frequency and types of glaucoma associated with VKH., Methods: This was a retrospective case series. Electronic medical records of patients with VKH were reviewed from two medical centers: Duke University and the University of North Carolina., Results: Of 45 eyes with VKH, 28 (62%) developed ocular hypertension (OHT) or glaucoma. In the patients with VKH and OHT/glaucoma, 18/28 (64%) had posterior synechiae and/or peripheral anterior synechiae., Conclusions: We have shown a high prevalence of OHT and glaucoma in eyes with VKH. Furthermore, in addition to secondary open angle from corticosteroid treatment and uveitis, secondary angle closure resulting from posterior synechiae, frequently associated with iris bombé configuration, is an important cause of glaucoma in VKH eyes.

Primary open-angle glaucoma (POAG) is the most common chronic optic neuropathy worldwide. Epidemiological studies show a robust positive relation between intraocular pressure (IOP) and POAG and modest positive association between IOP and blood pressure (BP), while the relation between BP and POAG is controversial. The International Glaucoma Genetics Consortium (n=27 558), the International Consortium on Blood Pressure (n=69 395), and the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (n=37 333), represent genome-wide data sets for IOP, BP traits and POAG, respectively. We formed genome-wide significant variant panels for IOP and diastolic BP and found a strong relation with POAG (odds ratio and 95% confidence interval: 1.18 (1.14-1.21), P=1.8 × 10 -27 ) for the former trait but no association for the latter (P=0.93). Next, we used linkage disequilibrium (LD) score regression, to provide genome-wide estimates of correlation between traits without the need for additional phenotyping. We also compared our genome-wide estimate of heritability between IOP and BP to an estimate based solely on direct measures of these traits in the Erasmus Rucphen Family (ERF; n=2519) study using Sequential Oligogenic Linkage Analysis Routines (SOLAR). LD score regression revealed high genetic correlation between IOP and POAG (48.5%, P=2.1 × 10 -5 ); however, genetic correlation between IOP and diastolic BP (P=0.86) and between diastolic BP and POAG (P=0.42) were negligible. Using SOLAR in the ERF study, we confirmed the minimal heritability between IOP and diastolic BP (P=0.63). Overall, IOP shares genetic basis with POAG, whereas BP has limited shared genetic correlation with IOP or POAG.

Glaucoma represents a group of multifactorial diseases with a unifying pathology of progressive retinal ganglion cell (RGC) degeneration, causing irreversible vision loss. To test the hypothesis that RGCs are intrinsically vulnerable in glaucoma, we have developed an in vitro model using the SIX6 risk allele carrying glaucoma patient-specific induced pluripotent stem cells (iPSCs) for generating functional RGCs. Here, we demonstrate that the efficiency of RGC generation by SIX6 risk allele iPSCs is significantly lower than iPSCs-derived from healthy, age- and sex-matched controls. The decrease in the number of RGC generation is accompanied by repressed developmental expression of RGC regulatory genes. The SIX6 risk allele RGCs display short and simple neurites, reduced expression of guidance molecules, and immature electrophysiological signature. In addition, these cells have higher expression of glaucoma-associated genes, CDKN2A and CDKN2B, suggesting an early onset of the disease phenotype. Consistent with the developmental abnormalities, the SIX6 risk allele RGCs display global dysregulation of genes which map on developmentally relevant biological processes for RGC differentiation and signaling pathways such as mammalian target of rapamycin that integrate diverse functions for differentiation, metabolism, and survival. The results suggest that SIX6 influences different stages of RGC differentiation and their survival; therefore, alteration in SIX6 function due to the risk allele may lead to cellular and molecular abnormalities. These abnormalities, if carried into adulthood, may make RGCs vulnerable in glaucoma. Stem Cells 2017;35:2239-2252., (© 2017 AlphaMed Press.)

Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results across populations, and to identify new variants associated with XFS. We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10 -14 ) through deep resequencing of XFS cases and controls from nine countries. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 × 10 -8 ). We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.

Glaucoma is a leading cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG), the most common type, is a complex inherited disorder that is characterized by progressive retinal ganglion cell death, optic nerve head excavation, and visual field loss. The discovery of a large, and growing, number of genetic and chromosomal loci has been shown to contribute to POAG risk, which carry implications for disease pathogenesis. Differential gene expression analyses in glaucoma-affected tissues as well as animal models of POAG are enhancing our mechanistic understanding in this common, blinding disorder. In this review we summarize recent developments in POAG genetics and molecular genetics research., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Sustained-release drug delivery systems that replace the need for daily glaucoma medications will improve outcomes for those who are nonadherent and reduce the inconvenience of having to take medications on a recurring basis.The objective is to estimate uptake (i.e., demand) for a new technology that delivers sustained-release glaucoma medication and to investigate how uptake varies by product attributes, physician recommendations, peer adoption (i.e., percentage of patients seen in a clinic using the new technology), and patient characteristics.In a web-enabled discrete-choice experiment survey, glaucoma patients in the United States were asked to choose between continuing eye drop use or purchasing the new delivery system. In a cross-sectional web-enabled survey, ophthalmologists were asked their likelihood of recommending the new technology based on product and patient characteristics.Study participants were 500 glaucoma patients who were on topical administration of daily eye drops and 155 ophthalmologists who practice in the US.Main outcomes were predicted uptake for patients and likelihood of recommending a new drug delivery system for ophthalmologists. Logistic models were used to analyze the choice data.Uptake was estimated to be 18% at an annual cost of $1000 and to be 24% when the cost was $500. A physician's recommendation increased uptake by 6% to 12%, whereas an increase in peer adoption from 5% to 50% increased uptake by 3% to 7%. Patients aged ≥ 65 and those with lower income were more likely to remain on eye drops. Physicians were more likely to recommend a product if the interval between administrations is 6 months or longer and when long-term safety and efficacy data are available. They were less likely to recommend it to patients with lower income and no adherence problems.Results suggest a significant interest in an injectable solution or other sustained-release alternatives to daily eye drops. However, in this survey, patient uptake was greatly influenced by out-of-pocket cost and the interval between treatment administrations. Few physicians were willing to recommend sustained-release technology if the treatment interval was less than 3 months.

Purpose: Vascular endothelial growth factor (VEGF) regulates microvascular endothelial permeability, and the permeability of Schlemm's canal (SC) endothelium influences conventional aqueous humor outflow. We hypothesize that VEGF signaling regulates outflow facility., Methods: We measured outflow facility (C) in enucleated mouse eyes perfused with VEGF-A164a, VEGF-A165b, VEGF-D, or inhibitors to VEGF receptor 2 (VEGFR-2). We monitored VEGF-A secretion from human trabecular meshwork (TM) cells by ELISA after 24 hours of static culture or cyclic stretch. We used immunofluorescence microscopy to localize VEGF-A protein within the TM of mice., Results: VEGF-A164a increased C in enucleated mouse eyes. Cyclic stretch increased VEGF-A secretion by human TM cells, which corresponded to VEGF-A localization in the TM of mice. Blockade of VEGFR-2 decreased C, using either of the inhibitors SU5416 or Ki8751 or the inactive splice variant VEGF-A165b. VEGF-D increased C, which could be blocked by Ki8751., Conclusions: VEGF is a paracrine regulator of conventional outflow facility that is secreted by TM cells in response to mechanical stress. VEGF affects facility via VEGFR-2 likely at the level of SC endothelium. Disruption of VEGF signaling in the TM may explain why anti-VEGF therapy is associated with decreased outflow facility and sustained ocular hypertension.

Objective: Several attributes of female reproductive history, including age at natural menopause (ANM), have been related to primary open-angle glaucoma (POAG). We assembled 18 previously reported common genetic variants that predict ANM to determine their association with ANM or POAG., Methods: Using data from the Nurses' Health Study (7,143 women), we validated the ANM weighted genetic risk score in relation to self-reported ANM. Subsequently, to assess the relation with POAG, we used data from 2,160 female POAG cases and 29,110 controls in the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (NEIGHBORHOOD), which consists of 8 datasets with imputed genotypes to 5.6+ million markers. Associations with POAG were assessed in each dataset, and site-specific results were meta-analyzed using the inverse weighted variance method., Results: The genetic risk score was associated with self-reported ANM (P = 2.2 × 10) and predicted 4.8% of the variance in ANM. The ANM genetic risk score was not associated with POAG (Odds Ratio (OR) = 1.002; 95% Confidence Interval (CI): 0.998, 1.007; P = 0.28). No single genetic variant in the panel achieved nominal association with POAG (P ≥0.20). Compared to the middle 80 percent, there was also no association with the lowest 10 percentile or highest 90 percentile of genetic risk score with POAG (OR = 0.75; 95% CI: 0.47, 1.21; P = 0.23 and OR = 1.10; 95% CI: 0.72, 1.69; P = 0.65, respectively)., Conclusions: A genetic risk score predicting 4.8% of ANM variation was not related to POAG; thus, genetic determinants of ANM are unlikely to explain the previously reported association between the two phenotypes., Competing Interests: Financial disclosure/conflicts of interest: Please see section at the end of the article.

Exfoliation syndrome (XFS) is a common age-related disorder that leads to deposition of extracellular fibrillar material throughout the body. The most recognized disease manifestation is exfoliation glaucoma (XFG), which is a common cause of blindness worldwide. Recent developments in XFS genetics, cell biology and epidemiology have greatly improved our understanding of the etiology of this complex inherited disease. This review summarizes current knowledge of XFS pathogenesis, identifies gaps in knowledge, and discusses areas for future research., (Copyright © 2016. Published by Elsevier Ltd.)

Importance: Exfoliation syndrome, an inherited systemic disorder of elastin and extracellular matrix (ECM), is associated with the LOXL1 gene locus. Pelvic organ prolapse is a common connective tissue disorder that affects women. The presence of an association between exfoliation syndrome (exfoliation of the lens capsule) and pelvic organ prolapse was investigated as part of the Utah Project on Exfoliation Syndrome (UPEXS)., Objective: To examine the association between exfoliation syndrome and pelvic organ prolapse using the Utah Population Database, a comprehensive resource linked to medical records., Design, Setting, and Participants: A 2-pronged approach was used. In substudy A, a cross-sectional analysis was performed to determine the association between pelvic organ prolapse and exfoliation syndrome in women enrolled in Medicare in Utah from calendar year 1992 to 2009 (n = 132 772). In substudy B, the risk of incident exfoliation syndrome from January 1, 1995, to December 31, 2014, was estimated in a cohort of women aged 30 to 65 years at baseline with a diagnosis of pelvic organ prolapse (n = 5130) compared with birth year-matched women serving as controls who did not have pelvic organ prolapse (n = 15 338)., Main Outcomes and Measures: Exfoliation syndrome outcome was defined by International Classification of Diseases, Ninth Revision, diagnosis codes for exfoliation syndrome or exfoliation glaucoma (366.11 or 365.52, respectively). In substudy A, odds ratios (ORs) from unconditional logistic regression models were used to estimate the exfoliation syndrome risk in women with pelvic organ prolapse compared with those without pelvic organ prolapse. In substudy B, hazard ratios (HRs) from Cox proportional hazards models were used to estimate incident exfoliation syndrome risk in patients with pelvic organ prolapse (without exfoliation syndrome history) compared with unaffected controls. Models were adjusted for age, years enrolled, parity, and race/ethnicity., Results: Of the 132 772 women enrolled in Utah Medicare from 1992 to 2009, the mean [SD] age at the last enrollment was 82.2 [7.7] years. Pelvic organ prolapse was associated with a 1.56-fold increased risk of exfoliation syndrome in Medicare beneficiaries (OR, 1.56; 95% CI, 1.42-1.72) in substudy A. We observed a 48% increased incident risk of exfoliation syndrome in women aged 30 to 65 years at baseline who had a pelvic organ prolapse diagnosis compared with controls during 20 years of follow-up (HR, 1.48; 95% CI, 1.14-1.91)., Conclusions and Relevance: The diagnosis of exfoliation syndrome was more frequent in women with pelvic organ prolapse in the Utah Population Database, a robust population-based resource, thus supporting an association of exfoliation syndrome with a nonocular systemic condition. Systemic conditions with altered ECM metabolism, such as pelvic organ prolapse, may share common biological pathways with exfoliation syndrome. LOXL1 dysregulation, thought to occur in exfoliation syndrome, may be a contributing factor.

Purpose: To evaluate a frequently used regression model and a new, modified regression model to estimate cerebrospinal fluid pressure (CSFP)., Methods: Datasets from the Beijing iCOP study from Tongren Hospital, Beijing, China, and the Mayo Clinic, Rochester, Minnesota, were tested in this retrospective, case-control study. An often-used regression model derived from the Beijing iCOP dataset, but without radiographic data, was used to predict CSFP by using demographic and physiologic data. A regression model was created using the Mayo Clinic dataset and tested against a validation group. The Mayo Clinic-derived formula was also tested against the Beijing Eye Study population. Intraclass correlation was used to assess predicted versus actual CSFP., Results: The Beijing-derived regression equation was reported to have an intraclass correlation coefficient (ICC) of 0.71, indicating strong correlation between predicted and actual CSFP in the study population. The Beijing iCOP regression model poorly predicted CSFP in the Mayo Clinic population with an ICC of 0.14. The Mayo Clinic-derived regression model similarly did not predict CSFP in its Mayo Clinic validation group (ICC 0.28 ± 0.04) nor in the Beijing Eye Study population (ICC 0.06)., Conclusions: Formulae used to predict CSFP derived from clinical data fared poorly against a large retrospective dataset. This may be related to differences in lumbar puncture technique, in the populations tested, or the timing of collection of physiologic variables in the Mayo Clinic dataset. Caution should be used when interpreting results based on formulaic derivation of CSFP.

Purpose: To use anterior segment optical coherence tomography (AS-OCT) to evaluate the anterior chamber after intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections., Methods: Preinjection and immediate postinjection AS-OCT images were taken and measurements were compared including angle opening distance (AOD) and trabeculo-iris space area (TISA) at 500 μm and 750 μm from the scleral spur (AOD500, AOD750, TISA500 and TISA750, respectively), and the scleral spur angle., Results: Twenty-one eyes from 21 patients were studied. There was significant narrowing of the temporal AOD500, AOD750, and temporal angle after injection (P = 0.03, 0.01, and 0.02, respectively). The percentage of narrowing of the nasal TISA500 and TISA750 was significantly greater in phakic versus pseudophakic eyes (P = 0.03 and 0.02, respectively). A higher postinjection IOP was correlated with increased narrowing of the nasal AOD500, TISA500, TISA750, and nasal angle (R = 0.22, 0.28, 0.34 and 0.20; P = 0.03, 0.01, 0.005 and 0.04, respectively) and a smaller preinjection anterior chamber depth in phakic eyes (R = 0.53, P = 0.01)., Conclusion: After an anti-vascular endothelial growth factor injection, there is significant narrowing of the temporal anterior chamber angle in all eyes and increased narrowing of the nasal angle in phakic compared with pseudophakic eyes. Physicians performing intravitreal injections should be aware of these associations as they may contribute to our understanding of prolonged elevation of IOP after injections.

Purpose: Recent studies indicate that mitochondrial proteins may contribute to the pathogenesis of primary open-angle glaucoma (POAG). In this study, we examined the association between POAG and common variations in gene-encoding mitochondrial proteins., Methods: We examined genetic data from 3430 POAG cases and 3108 controls derived from the combination of the GLAUGEN and NEIGHBOR studies. We constructed biological-system coherent mitochondrial nuclear-encoded protein gene-sets by intersecting the MitoCarta database with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We examined the mitochondrial gene-sets for association with POAG and with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) subsets using Pathway Analysis by Randomization Incorporating Structure., Results: We identified 22 KEGG pathways with significant mitochondrial protein-encoding gene enrichment, belonging to six general biological classes. Among the pathway classes, mitochondrial lipid metabolism was associated with POAG overall (P = 0.013) and with NTG (P = 0.0006), and mitochondrial carbohydrate metabolism was associated with NTG (P = 0.030). Examining the individual KEGG pathway mitochondrial gene-sets, fatty acid elongation and synthesis and degradation of ketone bodies, both lipid metabolism pathways, were significantly associated with POAG (P = 0.005 and P = 0.002, respectively) and NTG (P = 0.0004 and P < 0.0001, respectively). Butanoate metabolism, a carbohydrate metabolism pathway, was significantly associated with POAG (P = 0.004), NTG (P = 0.001), and HTG (P = 0.010)., Conclusions: We present an effective approach for assessing the contributions of mitochondrial genetic variation to open-angle glaucoma. Our findings support a role for mitochondria in POAG pathogenesis and specifically point to lipid and carbohydrate metabolism pathways as being important.

Purpose: Noncoding microRNAs (miRNAs) have been implicated in the pathogenesis of glaucoma. We aimed to identify common variants in miRNA coding genes (MIR) associated with primary open-angle glaucoma (POAG)., Methods: Using the NEIGHBORHOOD data set (3853 cases/33,480 controls with European ancestry), we first assessed the relation between 85 variants in 76 MIR genes and overall POAG. Subtype-specific analyses were performed in high-tension glaucoma (HTG) and normal-tension glaucoma subsets. Second, we examined the expression of miR-182, which was associated with POAG, in postmortem human ocular tissues (ciliary body, cornea, retina, and trabecular meshwork [TM]), using miRNA sequencing (miRNA-Seq) and droplet digital PCR (ddPCR). Third, miR-182 expression was also examined in human aqueous humor (AH) by using miRNA-Seq. Fourth, exosomes secreted from primary human TM cells were examined for miR-182 expression by using miRNA-Seq. Fifth, using ddPCR we compared miR-182 expression in AH between five HTG cases and five controls., Results: Only rs76481776 in MIR182 gene was associated with POAG after adjustment for multiple comparisons (odds ratio [OR] = 1.23, 95% confidence interval [CI]: 1.11-1.42, P = 0.0002). Subtype analysis indicated that the association was primarily in the HTG subset (OR = 1.26, 95% CI: 1.08-1.47, P = 0.004). The risk allele T has been associated with elevated miR-182 expression in vitro. Data from ddPCR and miRNA-Seq confirmed miR-182 expression in all examined ocular tissues and TM-derived exosomes. Interestingly, miR-182 expression in AH was 2-fold higher in HTG patients than nonglaucoma controls (P = 0.03) without controlling for medication treatment., Conclusions: Our integrative study is the first to associate rs76481776 with POAG via elevated miR-182 expression.