Demographic and geographic features of exfoliation glaucoma in 2 United States-based prospective cohorts

A Multitrait Open-Angle Glaucoma Polygenic Risk Score Stratifies Risk of Glaucoma Diagnosis and Severity in Eyes with Pseudoexfoliation

PURPOSE

Pseudoexfoliation syndrome (PEX) is a known risk factor for glaucoma, but its individual clinical course ranges from no glaucoma to total blindness. This study investigated whether polygenic risk scores (PRSs) built from variants collectively associated with open-angle glaucoma, intraocular pressure (IOP), and vertical cup-to-disc ratio (VCDR) can stratify individuals with pseudoexfoliation for the risk of glaucoma development.

DESIGN

Retrospective multicohort study of 2 glaucoma registries and 1 population-based cohort.

PARTICIPANTS

For the primary analysis, participants (n = 828) were classified as having PEX with glaucoma, PEX with suspected glaucoma, or PEX with no glaucoma. For the secondary analysis, a cohort of participants (n = 2460) were classified as having PEX with glaucoma, having PEX with no glaucoma, and being unaffected, and an independent cohort of participants (n = 3372) were classified as having primary open-angle glaucoma (POAG) or suspected POAG.

METHODS

Previously published and validated PRSs for open-angle glaucoma, IOP, and VCDR were expressed as a percentile, decile, or tertile of an ancestrally matched healthy population. Multivariable logistic and linear regressions and survival analyses were performed.

MAIN OUTCOME MEASURES

The main outcome measures were odds of pseudoexfoliative glaucoma (PEX-G) and odds of clinically relevant outcomes.

RESULTS

Participants in the top tertile of the glaucoma PRS showed greater odds of receiving a PEX-G diagnosis (adjusted odds ratio [aOR], 4.22; 95% confidence interval [CI], 2.62-6.88; P < 0.001), greater odds of bilateral central vision loss (aOR, 3.43; 95% CI, 1.49-8.99; P = 0.007), and greater odds of bilateral incisional surgery (aOR, 3.35; 95% CI, 1.33-10.24; P = 0.018). Age at PEX-G diagnosis was 1 year younger with each increasing glaucoma PRS decile (1.06 years; 95% CI, 0.59-1.53 years; P < 0.001). Participants with manifest glaucoma and pseudoexfoliation showed a comparatively lower glaucoma PRS than counterparts with POAG.

CONCLUSIONS

The PRSs for open-angle glaucoma, IOP, and VCDR stratify risk of glaucoma development and disease severity among individuals with PEX.

FINANCIAL DISCLOSURE(S)

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

One-year results of trabeculectomy with emphasis on the effect of patients' age

PURPOSE

This study investigated the association between one-year surgical outcomes following trabeculectomy and age, accounting for confounding factors.

STUDY DESIGN

Retrospective observational study.

METHOD

Analyzing data from 305 patients undergoing initial trabeculectomy from 2019 onward, we employed three approaches to adjust variables: stratified analysis, regression analysis, and propensity score matching. Surgical success at 1-year post-surgery was defined by two criteria: achieving intraocular pressure of between 5 and 15 mmHg with a ≥ 20% reduction compared to pre-surgery levels and no additional glaucoma surgery (Criterion A); achieving intraocular pressure of between 5 and 12 mmHg with a ≥ 30% reduction compared to pre-surgery levels and no additional glaucoma surgery (Criterion B).

RESULTS

Stratified analysis by age unveiled a significant increase in exfoliation glaucoma (XFG) and a trend towards shorter axial lengths with advancing age (both p < 0.0001). Older age groups were more likely to experience surgical failure in both Criterion A and B (p = 0.21, < 0.01). Univariate analysis showed age as a significant factor in surgical failure for Criterion A (p < 0.05) and a nearly significant factor for Criterion B (p = 0.12). However, this trend was not evident in multivariate analysis (p = 0.23/0.88), where XFG became a significant factor for surgical failure (both p < 0.001) in Criteria A and B. Propensity score matching revealed no significant differences in surgical success rates for Criteria A and B between younger and older patients (p = 1.00 and 0.88).

CONCLUSION

Age is not a primary determinant of failure in trabeculectomy; however, the increasing incidence of XFG with aging suggests a potential for poorer outcomes.

Exfoliation syndrome genetics in the era of post-GWAS

Exfoliation syndrome (XFS), or pseudoexfoliation syndrome, is considered a systemic disorder that leads to glaucoma with progressive visual field loss. A better insight into the underlying pathogenic mechanism will help diagnose the disease and prevent and slow progression. Here, we provide an overview of disease pathogenesis in the light of GWAS and multi-omics research. We discuss possible environmental interactions related to XFS. We investigate the potential interactions in differentially expressed genes from RNA-Seq by using Ingenuity Pathway Analysis. MAPK pathway was identified as the top network of these genes. Further investigation is needed to verify our results in vivo. It is necessary to establish an animal model mimicking exfoliation syndrome phenotypes.

Minimal phenotypes in transgenic mice with the human LOXL1/LOXL1-AS1 locus associated with exfoliation glaucoma

Exfoliation syndrome is a leading cause of secondary glaucoma worldwide. Among the risk-factors for exfoliation syndrome and exfoliation glaucoma that have been investigated, a genetic association with 15q24.1 is among the most striking. The leading candidates for the causal gene at this locus are LOXL1 and/or LOXL1-AS1, but studies have not yet coalesced in establishing, or ruling out, either candidate. Here, we contribute to studies of the 15q24.1 locus by making a partially humanized mouse model in which 166 kb of human genomic DNA from the 15q24.1 locus was introduced into the mouse genome via BAC transgenesis (B6-Tg(RP11-71M11)Andm). Transgenic expression of human genes in the BAC was only detectable for LOXL1-AS1. One cohort of 34 mice (21 experimental hemizygotes and 13 non-carrier control littermates) was assessed by slit-lamp exams and SD-OCT imaging at early (1-2 months) and mid (4-5 months) time points; fundus exams were performed at 5 months of age. A second smaller cohort (3 hemizygotes) were aged extensively (>12 months) to screen for overt abnormalities. Across all genotypes and ages, 136 slit-lamp exams, 128 SD-OCT exams, and 42 fundus exams detected no overt indices of exfoliation syndrome. Quantitatively, small, but statistically significant, age-related declines in ganglion cell complex thickness and total retinal thickness were detected in the hemizygotes at 4 months of age. Overall, this study demonstrates complexity in gene regulation from the 15q24.1 locus and suggests that LOXL1-AS1 is unlikely to be a monogenic cause of exfoliation syndrome but may contribute to glaucomatous retinal damage.

Identification of potential core genes in pseudoexfoliation using bioinformatics analysis and retrospective analysis of 84 patients with this disease

BACKGROUND

Pseudoexfoliation (XFS) is a common cause of glaucoma in nowadays. Because of XFS causing irreversible blindness secondary to glaucoma (XFG), this study aims to identify the current prevalence of XFS among Xinjiang Province of China, and identify the hub genes involved in XFS.

METHODS

A retrospective chart review was conducted from 2007 to 2019 for patients aged 50 and older. All patients with XFS or XFG diagnosed by slit lamp exam were identified through chart review.

RESULTS

Of the 84 patient charts available for review, 50% of the patients identified as male, with a mean age of 67 years. The top ten genes evaluated by connectivity degree in the PPI network were identified. The results showed that Tyrobp was the most outstanding gene, followed by Ptprc, Fcgr3, Itgb2, Emr1, Cd68, Syk, Fcerlg, Hck, and Lyz2. All of these hub genes were downregulated in XFS.

CONCLUSION

Our findings show a considerably biomarkers of XFS for diagnosis and treatment.

Characteristic Differences between Normotensive and Hypertensive Pseudoexfoliative Glaucoma

PURPOSE

To compare the differences between eyes with pseudoexfoliative glaucoma (PXG) when they are divided into two groups (hypertensive PXG and normotensive PXG) according to the intraocular pressure (IOP).

METHODS

This is a retrospective study. Data from 86 hypertensive PXG eyes and 80 normotensive PXG eyes were included. Hypertensive PXG was defined as PXG with IOP ≥ 22 mmHg, and normotensive PXG was defined as with IOP ≤ 21 mmHg). Central corneal thickness (CCT) was measured by ultrasound pachymetry. Lamina cribrosa thickness (LT) was evaluated using swept-source optical coherence tomography.

RESULTS

No significant differences were observed between hypertensive and normotensive PXG in terms of age, gender, axial length, hypertension, or diabetes. Normotensive PXG eyes had thinner CCT than hypertensive PXG eyes (p = 0.02). To compare LT, a sub-analysis was performed after matching age, VF MD and retinal nerve fiber layer thickness. The normotensive PXG group (n = 32) demonstrated significantly thinner LT compared with the hypertensive PXG group (n = 32) at similar ages and levels of glaucoma severity (p < 0.001).

CONCLUSIONS

Eyes with normotensive PXG demonstrated thinner CCT and LT compared with those with hypertensive PXG, suggesting structural vulnerability to glaucoma.

Evaluation of the effects of environmental factors and eating habits on exfoliation syndrome and glaucoma in a Turkish population

PURPOSE

This study aimed to assess the possible effect of environmental factors and eating habits on patients with the exfoliation syndrome (XFS) and exfoliative glaucoma (XFG) in a Turkish population.

METHODS

A questionnaire was applied to 1,000 individuals, including 290 patients with XFS, 210 patients with XFG, and 500 age- and sex-matched healthy control participants. Sociodemographic characteristics, home type and warming methods, living and working conditions (indoor-outdoor), dietary habits based on the the guidance of Turkey Dietary Guidelines, (Determination of Nutritional Status Report and Turkey National Nutrition and Health Survey) and using sunglasses were evaluated. The chi-square test, Student t test, and analysis of variance were used for the statistical analysis with SPSS v. 23.0 software.

RESULTS

The case-control groups were matched during data collection, and age and sex distribution in groups was analyzed; however, no difference was found. The average years and hours spent outdoor were statistically different between case and control groups (P < 0.05). The disease risk among individuals wearing sunglasses was 2.74 times less than that among those who did not wear sunglasses. Individuals born in the city had 1.46 times lower risk. Also, living out of the city until the age of 12 years increased the risk of getting the disease 1.36 times. In addition, while living in an apartment decreased the risk of disease, using a stove increased. The control groups had more healthy eating habits than the case groups.

CONCLUSION

This case-control study showed that time spent outdoors, wearing sunglasses, home type, heating method, and eating habits might be associated with XFS and XFG.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Long-term Alcohol Consumption and Risk of Exfoliation Glaucoma or Glaucoma Suspect Status among United States Health Professionals

PURPOSE

To assess the association between intakes of total alcohol and individual alcoholic beverages and the incidence of exfoliation glaucoma/glaucoma suspect (XFG/XFGS) status.

DESIGN

Prospective cohort study.

PARTICIPANTS

A total of 195 408 participants in the Nurses' Health Study (1980-2018), the Health Professionals Follow-up Study (1986-2018), and the Nurses' Health Study II (1991-2019) were followed biennially. Eligible participants at each 2-year risk period were ≧ 40 years and free of XFG/XFGS status with available data on diet and ophthalmic examination findings.

METHODS

Cumulatively averaged total (primary exposure) and individual alcoholic beverage (beer, wine, and liquor) intakes from validated dietary information every 2-4 years.

MAIN OUTCOME MEASURES

Confirmed incident XFG/XFGS status using medical records. We used per-eye Cox proportional hazards models, accounting for intereye correlations, to estimate multivariate-adjusted relative risks (MVRRs) and 95% confidence intervals (CIs).

RESULTS

During 6 877 823 eye-years of follow-up, 705 eyes with XFG/XFGS status were documented. Greater total alcohol consumption was associated significantly with higher XFG/XFGS status risk: the MVRR for XFG/XFGS status for cumulatively averaged alcohol consumption of ≧15 g/day or more versus nondrinking was 1.55 (95% CI, 1.17-2.07; P = 0.02 for trend). Long- and short-term alcohol intake was associated significantly with XFG/XFGS status risk, with the strongest associations with cumulatively averaged alcohol intake as of 4 years before diagnosis (MVRR ≥ 15 g/day vs. nondrinking, 1.65; 95% CI, 1.25-2.18; P = 0.002 for trend). Compared with nondrinkers, consuming ≧ 3.6 drinks of beer, wine, or liquor per week was associated with the following MVRRs for XFG/XFGS status: 1.26 (95% CI, 0.89-1.77; P = 0.40 for trend), 1.30 (95% CI, 1.00-1.68; P = 0.15 for trend), and 1.46 (95% CI, 1.15-1.85; P = 0.01 for trend), respectively. We did not observe interactions by age, latitude, residential tier, or intakes of folate or vitamin A (P > 0.40 for interaction); however, the association between alcohol and XFG/XFGS status was suggestively stronger for those without a family history of glaucoma (P = 0.10 for interaction).

CONCLUSIONS

Long-term alcohol consumption was associated with a higher risk of XFG/XFGS status. Our findings provide further clues regarding the XFG/XFGS etiology.

Head and Neck Region Dermatological Ultraviolet-Related Cancers are Associated with Exfoliation Syndrome in a Clinic-Based Population

OBJECTIVE

We assessed the relationship between ultraviolet (UV)-associated dermatological carcinomas (basal cell carcinoma [BCC] and squamous cell carcinoma [SCC]) and exfoliation syndrome (XFS) or exfoliation glaucoma (XFG).

DESIGN

Case-control study.

PARTICIPANTS

Between 2019 and 2021, 321 participants and control subjects (XFS or XFG = 98; primary open-angle glaucoma [POAG] = 117; controls = 106; ages 50-90 years) were recruited.

METHODS

A cross-sectional survey assessing medical history, maximum known intraocular pressure, cup-to-disc ratio, Humphrey visual field 24-2, the propensity to tan or burn in early life, history of BCC or SCC, and XFS or XFG diagnosis. The multivariable models adjusted for age, sex, medical history, eye color, hair color, and likeliness of tanning versus burning at a young age.

MAIN OUTCOME MEASURES

History of diagnosed XFS or XFG.

RESULTS

Any history of BCC or SCC in the head and neck region was associated with a 2-fold higher risk of having XFS or XFG versus having POAG or being a control subject (odds ratio [OR], 2.01; 95% confidence interval [CI], 1.04-3.89) in a multivariable-adjusted analysis. We observed a dose-response association in which the chance of having XFS or XFG increased by 67% per head and neck BCC or SCC occurrence (OR, 1.67; 95% CI, 1.09-2.56). When we excluded POAG participants, head and neck BCC or SCC was associated with a 2.8-fold higher risk of XFS or XFG (OR, 2.80; 95% CI, 1.12-7.02), and each additional occurrence had a 2-fold higher risk of XFS or XFG (OR, 1.97; 95% CI, 1.09-3.58). The association between head and neck region BCC or SCC and POAG compared with the control subjects was null (OR, 1.42; 95% CI, 0.58-3.48). With BCC or SCC located anywhere on the body, there was a nonsignificantly higher risk of having XFS or XFG compared with having POAG or being a control subject (OR, 1.65; 95% CI, 0.88-3.09).

CONCLUSIONS

Head and neck region BCCs or SCCs are associated with a higher risk of having XFS or XFG. These findings support prior evidence that head and neck UV exposure may be a risk factor for XFS.

Prediagnostic Plasma Metabolomics and the Risk of Exfoliation Glaucoma

Purpose

The etiology of exfoliation glaucoma (XFG) is poorly understood. We aimed to identify a prediagnostic plasma metabolomic signature associated with XFG.

Methods

We conducted a 1:1 matched case-control study nested within the Nurses' Health Study and Health Professionals Follow-up Study. We collected blood samples in 1989-1990 (Nurses' Health Study) and 1993-1995 (Health Professionals Follow-up Study). We identified 205 incident XFG cases through 2016 (average time to diagnosis from blood draw = 11.8 years) who self-reported glaucoma and were confirmed as XFG cases with medical records. We profiled plasma metabolites using liquid chromatography-mass spectrometry. We evaluated 379 known metabolites (transformed for normality using probit scores) using multiple conditional logistic models. Metabolite set enrichment analysis was used to identify metabolite classes associated with XFG. To adjust for multiple comparisons, we used number of effective tests (NEF) and the false discovery rate (FDR).

Results

Mean age of cases (n = 205) at diagnosis was 71 years; 85% were women and more than 99% were Caucasian; controls (n = 205) reported eye examinations as of the matched cases' index date. Thirty-three metabolites were nominally significantly associated with XFG (P < 0.05), and 4 metabolite classes were FDR-significantly associated. We observed positive associations for lysophosphatidylcholines (FDR = 0.02) and phosphatidylethanolamine plasmalogens (FDR = 0.004) and inverse associations for triacylglycerols (FDR < 0.0001) and steroids (FDR = 0.03). In particular, the multivariable-adjusted odds ratio with each 1 standard deviation higher plasma cortisone levels was 0.49 (95% confidence interval, 0.32-0.74; NEF = 0.05).

Conclusions

In plasma from a decade before diagnosis, lysophosphatidylcholines and phosphatidylethanolamine plasmalogens were positively associated and triacylglycerols and steroids (e.g., cortisone) were inversely associated with XFG risk.

Emerging roles of oxidative stress in the pathogenesis of pseudoexfoliation syndrome (Review)

Pseudoexfoliation syndrome (PEXS) is a systemic disease caused by defects in the extracellular matrix (ECM) remodelling process leading to the chronic deposition of extracellular, fibrillary, white flaky pseudoexfoliation material (PEXM) throughout the body. Specifically, PEXM deposits on the lens capsule cause open-angle glaucoma, cataracts and blindness in patients with PEXS. Several gene single nucleotide polymorphisms are linked to the development of PEXS in humans, including lysyl oxidase-like 1 gene, clusterin and fibulin-5. The exact reason for the PEXM generation and its resulting pathogenesis is not well understood. However, defective ECM remodelling and oxidative stress (OS) have been hypothesized as significant events leading to the PEXM. Specifically, the link between OS and PEXS has been well studied, although the investigation is still ongoing. The present review explored recent advances in various aspects of PEXS and the involvement of OS in the eye for PEXS development.

Exfoliation Syndrome in Baja Verapaz Guatemala: A Cross-Sectional Study and Review of the Literature

There are little epidemiologic data on exfoliation syndrome (XFS) or exfoliation glaucoma (XFG) in Guatemala, especially in the underserved Baja Verapaz region. This observational study assessing XFS/XFG and demographic factors of this region aims to better understand unique exogenous and endogenous risk factors associated with XFS/XFG in Guatemala. During Moran Eye Center's global outreach medical eye camps from 2016-2017, 181 patients age 15 years and older presented for complete eye exams. These individuals were screened for eye disease and evaluated for possible surgical interventions that could occur during the camps to improve eyesight. During the dilated exams, XFS was noted as missing or present. Of those 181, 10 had insufficient data and 18 lacked a definitive diagnosis of XFS or XFG, resulting in 153 evaluable patients; 46 XFS and 9 XFG were identified. Age, gender, hometown, ancestry (languages spoken by parents and grandparents), past medical history, family medical history, and occupational data (only 2017 trip) were obtained for each patient. The most common occupations of these individuals were farming and housekeeping. Higher rates of XFS/XFG were noted in individuals of rural compared to urban settings and Mayan speaking people compared with Spanish speakers. Based on this subset of patients, with various ocular pathologies being evaluated during medical eye outreach camps, the prevalence of XFS/XFG appeared to be 36%, a high prevalence compared to other world populations. Location and higher altitude, along with a farming occupation, may contribute to XFS development and subsequent progression to XFG. To our knowledge, this is the largest study looking at the epidemiology of XFS/XFG in the Baja Verapaz region of Guatemala for those over the age of 15 years seeking eye exams and interventions.

Aqueous humor metabolite profile of pseudoexfoliation glaucoma is distinctive

Pseudoexfoliation (PEX) is a known cause of secondary open angle glaucoma. PEX glaucoma is associated with structural and metabolic changes in the eye. Despite similarities, PEX and primary open angle glaucoma (POAG) may have differences in the composition of metabolites. We analyzed the metabolites of the aqueous humor (AH) of PEX subjects sequentially first using nuclear magnetic resonance (1H NMR: HSQC and TOCSY), and subsequently with liquid chromatography tandem mass spectrometry (LC-MS/MS) implementing isotopic ratio outlier analysis (IROA) quantification. The findings were compared with previous results for POAG and control subjects analyzed using identical sequential steps. We found significant differences in metabolites between the three conditions. Principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) indicated clear grouping based on the metabolomes of the three conditions. We used machine learning algorithms and a percentage set of the data to train, and utilized a different or larger dataset to test whether a trained model can correctly classify the test dataset as PEX, POAG or control. Three different algorithms: linear support vector machines (SVM), deep learning, and a neural network were used for prediction. They all accurately classified the test datasets based on the AH metabolome of the sample. We next compared the AH metabolome with known AH and TM proteomes and genomes in order to understand metabolic pathways that may contribute to alterations in the AH metabolome in PEX. We found potential protein/gene pathways associated with observed significant metabolite changes in PEX.

Metabolomics Reveals Differences in Aqueous Humor Composition in Patients With and Without Pseudoexfoliation Syndrome

Pseudoexfoliation syndrome (XFS) is stress- or inflammation-induced elastosis accompanied by excessive production of microfibrils and their deposition in the anterior segment of the eye. Approximately 60–70 million people are affected by XFS worldwide. It is a component of a systemic disorder, considered a major risk factor for accelerated cataract formation, cataract surgery complications and development of glaucoma, which untreated or inadequately treated may lead to blindness. Moreover, XFS has been associated with cardiovascular and cerebrovascular morbidity, dementia, sensorineural hearing loss and pelvic organ prolapse. The pathogenesis of XFS has not been fully elucidated yet. Aqueous humor (AH) is a transparent fluid filling the anterior and posterior chambers of the eye. Determination of AH metabolites that are characteristic for XFS may provide valuable information about the molecular background of this ocular disorder. The aim of this study was to compare the composition of AH in XFS and non-XFS patients undergoing cataract surgery. The AH samples from 34 patients (15 with XFS and 19 without) were analyzed using liquid chromatography coupled to a Quadrupole Time-of-Flight mass spectrometer (LC-QTOF-MS). The obtained metabolic fingerprints were analyzed using multivariate statistics. Eleven statistically significant metabolites were identified. Compared with the non-XFS group, the AH of patients with XFS contained significantly lower levels of amino acids and their derivatives, for example, arginine (−31%, VIP = 2.38) and homo-arginine (−19%, VIP = 1.38). Also, a decrease in the levels of two acylcarnitines, hydroxybutyrylcarnitine (−29%, VIP = 1.24) and decatrienoylcarnitine (−46%, VIP = 1.89), was observed. However, the level of indoleacetaldehyde in XFS patients was significantly higher (+96%, VIP = 2.64). Other significant metabolites were two well-recognized antioxidants, ascorbic acid (−33%, VIP = 2.11) and hydroxyanthranilic acid (−33%, VIP = 2.25), as well as S-adenosylmethionine, a compound with anti-inflammatory properties (−29%, VIP = 1.93). Metabolic pathway analysis demonstrated that the identified metabolites belonged to eight metabolic pathways, with cysteine and methionine metabolism as well as arginine and proline metabolism being the most frequently represented. XFS can be associated with enhanced oxidative stress and inflammation, as well as with the disturbances of cellular respiration and mitochondrial energy production. Implementation of non-targeted metabolomics provided a better insight into the still not fully understood pathogenesis of XFS.

Early-onset Exfoliation Syndrome: A Literature Synthesis

PRECIS

We conducted a literature review of younger patients with exfoliation syndrome (XFS) in an attempt to identify case similarities and better understand disease etiology.

PURPOSE

XFS that predisposes to secondary glaucoma is a strongly age-related condition. We performed a literature review of XFS and exfoliation glaucoma (XFG) in patients aged younger than 40 years to examine potential common characteristics and gain clues to its etiology.

METHODS

We conducted a broad literature search with appropriate keywords and manually extracted key demographic and ocular features on younger XFS and XFG cases. Articles that did not provide past ocular history on early-onset XFS/XFG were excluded.

RESULTS

We identified 12 cases of XFS and XFG in patients from 13 to 40 years old (8 females; 11 White; 5 from Iran). All had past ocular history remarkable for intraocular surgery for other glaucoma conditions (7 cases), other ocular diseases (3 cases), or ocular trauma (2 cases).

CONCLUSIONS

All reported early-onset XFS and XFG cases arise in the setting of events that produced a significant disruption of the blood-aqueous barrier. Understanding the metabolic alterations of aqueous humor from such cases could provide clues regarding how exfoliation material forms.

The association between ethnicity, environmental and lifestyle factors and chronic disease in the development of pseudoexfoliation syndrome

Objectives

To determine the association between ethnicity, environmental factors, lifestyle factors, chronic diseases and pseudoexfoliation syndrome (PEX).

Methods

A case control study conducted at four major hospitals in Pakistan from January to November 2019, with 241 cases and 294 controls, aged ≥ 40 years, who were administered a questionnaire assessing demographics, lifestyle factors, chronic diseases and ethnicity. Multivariate binary logistic regression was applied to calculate the odds ratio between cases and controls.

Results

PEX was found to be positively associated with ethnicity (p<0.001), time spent outdoors (p<0.001), educational status (p<0.001), asthma (p<0.001), mean age (p<0.001), daily tea intake (p=0.003), weighted maximum temperature (p<0.001) and weighted mean temperature (p=0.004). Poor association was found with weighted latitude (p=0.526) and weighted minimum temperature (p=0.079). Odds ratios for patients with asthma (OR=7.366, regression coefficient=1.993, p<0.001) Pathan ethnicity (OR=1.616, regression coefficient=0.48, p=0.016) and mean weighted temperature (OR=0.907, regression coefficient-0.097, p=0 .000) were significant in diagnosed cases of PEX.

Conclusion

Individuals with Pathan ethnicity and asthmatics should be made aware of the risk of developing PEX and the importance of periodic screening. Limiting exposure to sunlight and cold and reducing the intake of tea may help in reducing in the chances of developing PEX.

Molecular Genetics of Glaucoma: Subtype and Ethnicity Considerations

Glaucoma, the world’s leading cause of irreversible blindness, is a complex disease, with differential presentation as well as ethnic and geographic disparities. The multifactorial nature of glaucoma complicates the study of genetics and genetic involvement in the disease process. This review synthesizes the current literature on glaucoma and genetics, as stratified by glaucoma subtype and ethnicity. Primary open-angle glaucoma (POAG) is the most common cause of glaucoma worldwide, with the only treatable risk factor (RF) being the reduction of intraocular pressure (IOP). Genes associated with elevated IOP or POAG risk include: ABCA1, AFAP1, ARHGEF12, ATXN2, CAV1, CDKN2B-AS1, FOXC1, GAS7, GMDS, SIX1/SIX6, TMCO1, and TXNRD2. However, there are variations in RF and genetic factors based on ethnic and geographic differences; it is clear that unified molecular pathways accounting for POAG pathogenesis remain uncertain, although inflammation and senescence likely play an important role. There are similar ethnic and geographic complexities in primary angle closure glaucoma (PACG), but several genes have been associated with this disorder, including MMP9, HGF, HSP70, MFRP, and eNOS. In exfoliation glaucoma (XFG), genes implicated include LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. Despite tremendous progress, major gaps remain in resolving the genetic architecture for the various glaucoma subtypes across ancestries. Large scale carefully designed studies are required to advance understanding of genetic loci as RF in glaucoma pathophysiology and to improve diagnosis and treatment options.

Cohort Study of Nonmelanoma Skin Cancer and the Risk of Exfoliation Glaucoma

PRECIS

In a cohort study of 120,307 participants with 25+ years of follow-up, a history of nonmelanoma skin cancer (NMSC) was associated with a 40% higher exfoliation glaucoma (XFG) risk.

PURPOSE

The purpose of this study was to evaluate the relationship between NMSC (a marker of ultraviolet radiation exposure) and XFG.

METHODS

We performed a cohort study of US women (n=79,102; 1980-2014) and men (n=41,205; 1986-2014), aged 40+ years and at risk for glaucoma who reported eye examinations. From 1984 (women)/1988 (men), we asked about basal cell carcinoma or squamous cell carcinoma history separately; in prior years, we asked about any NMSC history in a single question. Squamous cell carcinoma was confirmed with histopathology reports while basal cell carcinoma and any early (<1984/<1988) NMSC history was self-reported. Incident XFG cases (362 women and 83 men) were confirmed with medical records. Using pooled data, we estimated multivariable-adjusted relative risks [MVRRs; 95% confidence intervals (CIs)] with Cox proportional hazards models that were stratified by age (in mo), 2-year time period at risk and average lifetime residential latitude.

RESULTS

In multivariable-adjusted analyses, we observed a 40% higher XFG risk with any NMSC history (MVRR=1.40; 95% CI=1.08-1.82); the association was observed even with 4 and 8-year lags in NMSC history. Also, the NMSC association was stronger in younger (below 65 y; MVRR=2.56; 95% CI=1.62-4.05) versus older participants (65 y and above; MVRR=1.25; 95% CI=0.94-1.66; P for interaction=0.01) and those living in the northern latitudes (≥42°N; MVRR=1.92; 95% CI=1.28-2.88) versus more southern latitudes (<42°N; MVRR=1.19; 95% CI=0.86-1.66; P for interaction=0.04).

CONCLUSION

NMSC was associated with higher XFG risk, particularly among younger participants and those living in the Northern US.

Characteristics of Patients with Pseudoexfoliation Syndrome at a Tertiary Eye Care Center in Jordan: A Retrospective Chart Review

PURPOSE

To present the clinical profile of patients with pseudoexfoliation (PXF) and describe its association with pseudoexfoliation glaucoma and cataract surgery complications at a university hospital in Jordan.

METHODS

Electronic chart search was performed among patients aged ≥ 50 years who attended the Jordan University Hospital between January 2015 and March 2018, to identify patients with pseudoexfoliation. Data derived from history and ophthalmic examination regarding laterality of pseudoexfoliation, presence of glaucoma, glaucoma surgery, cataract, cataract surgery, lens instability, and complications of cataract surgery were collected and analyzed.

RESULTS

Of 19,753 patient records searched, 962 (477 male and 485 female) had PXF (4.9%). The mean (SD) age was 71.8 (8.1) years. Pseudoexfoliation was unilateral in 539 patients (56.0%). The mean age of patients with clinically bilateral PXF was significantly higher than those with clinically unilateral PXF (p = 0.001). Pseudoexfoliation glaucoma was present in 237 of 962 (25.4%) patients with PXF and was significantly associated with clinically bilateral PXF (p < 0.001) and male gender (p = 0.001). In 454 (48.9%) patients (638 eyes) who underwent cataract surgery, there was no statistically significant difference in the rate of intraoperative complications between PXF eyes and the fellow eyes of clinically unilateral PXF eyes (p = 0.37), or between patients with clinically unilateral and clinically bilateral PXF (p = 0.78).

CONCLUSION

In this large hospital-based study, the frequency of PXF was 4.9%. Glaucoma was present in one fourth of patients and was significantly associated with clinically bilateral PXF and male gender. Cataract surgery complication rates were not statistically different between PXF and the fellow eyes of clinically unilateral PXF eyes. Surgeons need to be aware of the potential increased risk of intraoperative complications in both groups.

Association between Obstructive Sleep Apnea and Exfoliation Syndrome: The Utah Project on Exfoliation Syndrome

PURPOSE

Exfoliation syndrome (XFS), the most common recognizable cause of open-angle glaucoma worldwide, is a systemic disorder with genetic predisposition due to variations in lysyl oxidase-like 1 (LOXL1) function, leading to altered elastin matrices in ocular and systemic tissues. Obstructive sleep apnea (OSA) is a highly prevalent disorder also involving elastic tissue dysfunction and is associated with glaucoma. Because of the similarities between the disorders, we sought to uncover any relationship in the prevalence of these diagnoses.

DESIGN

Case-control, retrospective cohort study.

PARTICIPANTS

A cohort of 81 735 patients diagnosed with OSA at ages 50 to 90 years was identified from medical records from 1996 to 2017 in the Utah Population Database. Case subjects were matched to random controls on sex and birth year in a 4:1 ratio.

METHODS

International Classification of Diseases, Ninth Revision (ICD-9) codes or their Tenth Revision equivalent were used to define a diagnosis of OSA (ICD-9 327.23) and a diagnosis of XFS (ICD-9 365.52 and 366.11). Conditional logistic regression odds ratios (ORs) accounting for individual matching on sex and birth year were used to estimate the risk of XFS in patients with OSA. Models included adjustment for race, obesity, tobacco use, hypertension (HTN), atrial fibrillation (AF), and chronic obstructive pulmonary disease (COPD).

MAIN OUTCOME MEASURE

Whether patients with OSA have an increased risk of diagnosis of XFS compared with controls without OSA.

RESULTS

There was an increased risk of an XFS diagnosis in patients with OSA compared with non-OSA controls (OR, 1.27; 95% confidence interval [CI], 1.02-1.59; P = 0.03). In a stratification of patients by HTN diagnosis history, patients with OSA and HTN exhibited an increased risk of XFS compared with non-OSA controls with HTN (OR, 2.67; 95% CI, 2.06-3.46; P < 0.0001).

CONCLUSIONS

Patients with OSA may be at an increased risk of XFS compared with patients without OSA, particularly in patients with a history of HTN.

Personalising surgical treatments for glaucoma patients

Surgical treatments for glaucoma have relied for decades on traditional filtering surgery such as trabeculectomy and, in more challenging cases, tubes. Antifibrotics were introduced to improve surgical success in patients at increased risk of failure but have been shown to be linked to a greater incidence of complications, some being potentially vision-threatening. As our understanding of glaucoma and its early diagnosis have improved, a more individualised management has been suggested. Recently the term "precision medicine" has emerged as a new concept of an individualised approach to disease management incorporating a wide range of individual data in the choice of therapeutic modalities. For glaucoma surgery, this involves evaluation of the right timing, individual risk factors, targeting the correct anatomical and functional outflow pathways and appropriate prevention of scarring. As a consequence, there is an obvious need for better knowledge of anatomical and functional pathways and for more individualised surgical approaches with new, less invasive and safer techniques allowing for earlier intervention. With the recent advent of minimally invasive glaucoma surgery (MIGS) a large number of novel devices have been introduced targeting potential new sites of the outflow pathway for lowering intraocular pressure (IOP). Their popularity is growing in view of the relative surgical simplicity and apparent lack of serious side effects. However, these new surgical techniques are still in an era of early experiences, short follow-up and lack of evidence of their superiority in safety and cost-effectiveness over the traditional methods. Each year several new devices are introduced while others are withdrawn from the market. Glaucoma continues to be the primary cause of irreversible blindness worldwide and access to safe and efficacious treatment is a serious problem, particularly in the emerging world where the burden of glaucoma-related blindness is important and concerning. Early diagnosis, individualised treatment and, very importantly, safe surgical management should be the hallmarks of glaucoma treatment. However, there is still need for a better understanding of the disease, its onset and progression, the functional and structural elements of the outflow pathways in relation to the new devices as well as their long-term IOP-lowering efficacy and safety. This review discusses current knowledge and the future need for personalised glaucoma surgery.

Lysyl Oxidase Like 1: Biological roles and regulation

Lysyl Oxidase Like 1 (LOXL1) is a gene that encodes for the LOXL1 enzyme. This enzyme is required for elastin biogenesis and collagen cross-linking, polymerising tropoelastin monomers into elastin polymers. Its main role is in elastin homeostasis and matrix remodelling during injury, fibrosis and cancer development. Because of its vast range of biological functions, abnormalities in LOXL1 underlie many disease processes. Decreased LOXL1 expression is observed in disorders of elastin such as Cutis Laxa and increased expression is reported in fibrotic disease such as Idiopathic Pulmonary Fibrosis. LOXL1 is also downregulated in the lamina cribrosa in pseudoexfoliation glaucoma and genetic variants in the LOXL1 gene have been linked with an increased risk of developing pseudoexfoliation glaucoma and pseudoexfoliation syndrome. However the two major risk alleles are reversed in certain ethnic groups and are present in a large proportion of the normal population, implying complex genetic and environmental regulation is involved in disease pathogenesis. It also appears that the non-coding variants in intron 1 of LOXL1 may be involved in the regulation of LOXL1 expression. Gene alteration may occur via a number of epigenetic and post translational mechanisms such as DNA methylation, long non-coding RNAs and microRNAs. These may represent future therapeutic targets for disease. Environmental factors such as hypoxia, oxidative stress and ultraviolet radiation exposure alter LOXL1 expression, and it is likely a combination of these genetic and environmental factors that influence disease development and progression. In this review, we discuss LOXL1 properties, biological roles and regulation in detail with a focus on pseudoexfoliation syndrome and glaucoma.

Genetics of Exfoliation Syndrome

Exfoliation syndrome (XFS) is an age-related systemic disorder of the extracellular matrix with important ocular manifestations. In this disorder, exfoliation material (XFM) is deposited in the anterior chamber of the eye on the lens, iris, ciliary body, as well as other intraocular structures. This accumulation of XFM can obstruct the trabecular meshwork, resulting in elevated intraocular pressure and eventually causing glaucomatous optic neuropathy. In itself a highly hereditable condition, XFS is also the commonest recognizable cause of open-angle glaucoma worldwide, accounting for a majority of cases in some countries. Outside the eye, XFM deposits around blood vessels, particularly in association with elastic connective tissue, are found in numerous organs, including the skin, heart, and lungs. Long suspected to be a genetic disorder on the basis of familial aggregation studies, recent genome-wide association studies uncovered strong association between 7 genetic loci (LOXL1, CACNA1A, FLT1-POMP, TMEM136-ARHGEF12, AGPAT1, RBMS3, and SEMA6A) and increased risk of XFS. At the same time, a lower than usual sibling relative risk for XFS compared with other inherited conditions suggests XFS to be a complex disorder. The evidence to date suggests that additional genetic loci and biological insights for XFS remain to be identified through larger studies.

Frequency and surgical difficulties associated with pseudoexfoliation syndrome among Indian rural population scheduled for cataract surgery: Hospital-based data

Purpose:

To study the frequency and intraoperative difficulties associated with pseudoexfoliation (PXF) syndrome at a tertiary eye care center in a rural central India.

Methods:

This study included patients scheduled for cataract surgery who were diagnosed with PXF syndrome. All patients underwent a complete ophthalmologic evaluation, including slit-lamp examination, tonometry, gonioscopy, and ophthalmoscopy before the surgery. Cataract surgeries were performed by a single surgeon who reported the intraoperative difficulties.

Results:

In total, 1022 phakic eyes of 1823 patients were evaluated, 226 of whom (22.1%) were diagnosed with PXF syndrome. Most eyes (n = 81, 35.8%) with PXF syndrome were ≥81 years old. Eighty-six eyes (38.1%) had bilateral involvement, whereas 70 (30.9%) had right or left eye involvement. Further, PXF material was distributed on the iris, pupil, and lens in 70 eyes (30.9%) and on the pupillary margin in 36 eyes (15.9%). The mean pupillary dilation was 5.1 (±1.4) mm in patients with PXF syndrome compared with 7.2 (±1.6) mm in those without it (P = 0.03). Grade VI cataract was observed in 93 eyes (41.2%) and hypermature cataract was the most commonly observed cataract stage. Twenty-one eyes (9.3%) had increased intraocular pressure. Intraoperative difficulties were encountered in 62 eyes (27.4%) with poor pupillary dilation being the most common problem (32 eyes, 14.2%), followed by zonular dehiscence (18 eyes, 8%).

Conclusion:

This hospital-based study showed that PXF syndrome is common in Indian rural population and that the intraoperative complication rate in these patients is high.

The clinical features in patients with newly diagnosed pseudoexfoliative glaucoma in Serbia

PURPOSE

To evaluate the clinical characteristics of newly diagnosed pseudoexfoliative glaucoma and compare them with those pertaining to newly diagnosed primary open-angle glaucoma as well as pseudoexfoliation syndrome.

METHODS

This case-control study involved 306 participants, including patients with newly diagnosed pseudoexfoliative glaucoma, age- and sex-matched normal controls, patients with newly diagnosed primary open-angle glaucoma, and subjects with pseudoexfoliation syndrome. The study was conducted at the Glaucoma Department of Clinic for Eye Diseases, Clinical Center of Serbia, as the referral center for glaucoma in Serbia.

RESULTS

The mean age in the pseudoexfoliative glaucoma, primary open-angle glaucoma, pseudoexfoliation syndrome, and normal control groups was 73.61 ± 8.46, 65.50 ± 8.97, 74.81 ± 6.80, and 73.58 ± 9.34 years, respectively (pseudoexfoliative glaucoma vs primary open-angle glaucoma, p < 0.001). Unilateral pseudoexfoliative glaucoma was diagnosed in 35 patients (42.2%). The intraocular pressure was higher in the eyes affected by pseudoexfoliative glaucoma (32.0 ± 9.5 mmHg) than that in the primary open-angle glaucoma eyes (28.8 ± 5.9 mmHg) (p < 0.001). In pseudoexfoliative glaucoma and primary open-angle glaucoma eyes, glaucoma severity was determined via the vertical cup-to-disk ratio (C/D) 0.65 (0.45-1.0) versus 0.60 (0.45-1.0), p = 0.048 and visual field mean deviation -5.68 (-1.58 to -30.9) versus -4.70 (-1.39 to -31.0), p = 0.045. Alzheimer's was the only systemic disease associated with pseudoexfoliative glaucoma in the study sample, with an odds ratio of 0.021 (95% confidence interval = 0.00-21.52, p = 0.022).

CONCLUSION

At the time of diagnosis, pseudoexfoliative glaucoma exhibits different clinical features compared with primary open-angle glaucoma. Higher intraocular pressure, narrow or occludable angle, increased trabecular pigmentation, phacodonesis, and poorer pupillary dilatation emerged as the factors associated with pseudoexfoliative glaucoma.

Association between Chronic Obstructive Pulmonary Disease and Exfoliation Syndrome: The Utah Project on Exfoliation Syndrome

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.

LOXL1 Polymorphisms: Genetic Biomarkers that Presage Environmental Determinants of Exfoliation Syndrome

An agnostic high throughput search of the genome revealed a robust association between LOXL1 genetic polymorphisms and exfoliation syndrome (XFS), a discovery that likely would not have been possible with candidate or family-based gene search strategies. While questions remain regarding how LOXL1 gene variants contribute to XFS pathogenesis, it is clear that the frequencies of disease-related alleles do not track with the varying disease burden throughout the world, prompting a search for environmental risk factors. A geo-medicine approach revealed that disease load seemed to increase as a function of the distance from the equator. The exact reason for this extraequatorial disease distribution pattern remains unclear, but a greater amount of time spent outdoors is a robust risk factor for XFS, suggesting climatic factors such as ocular solar exposure and colder ambient temperature may be involved in disease pathogenesis. Prospective studies have also implicated higher coffee consumption and lower dietary folate intake in association with incident XFS. The discovery of environmental risk factors for XFS suggests that preventive measures may help to reduce ocular morbidity from XFS.

A Role for Clusterin in Exfoliation Syndrome and Exfoliation Glaucoma?

The multifunctional protein clusterin (CLU) is a secreted glycoprotein ubiquitously expressed throughout the body, including in the eye. Its primary function is to act as an extracellular molecular chaperone, preventing the precipitation and aggregation of misfolded extracellular proteins. Clusterin is commonly identified at fluid-tissue interfaces, and has been identified in most body fluids. It is a component of exfoliation material, and CLU mRNA is reduced in eyes with exfoliation syndrome compared with controls. SNPs located in the CLU genomic region have been associated with Alzheimer disease (AD) at the genome-wide level and several CLU SNPs located in an apparent regulatory region have been nominally associated with XFS/XFG in Caucasians with European ancestry and in south Indians. Interestingly, clusterin associates with altered elastic fibers in human photoaged skin and prevents UV-induced elastin aggregation in vitro. In light of the known geographic risk factors for XFS/XFG, which could include UV light, investigations of CLU-geographic interactions could be of interest. Future studies investigating rare CLU variation and other complex interactions including gene-gene interactions in XFS/XFG cases and controls may also be fruitful. Although CLU has been considered as a therapeutic target in AD, cancer and dry eye, a role for clusterin in XFS/XFG needs to be better defined before therapeutic approaches involving CLU can be entertained.

[Multi-level analysis of the prevalence of pseudoexfoliative syndrome and pseudoexfoliative glaucoma]

Epidemiological investigation of pseudoexfoliative syndrome (PEX) as a glaucoma predictor is necessary for antiglaucoma treatment planning.

AIM

To study the prevalence of PEX and pseudoexfoliative glaucoma (PXFG) among healthy people, naïve patients, and patients under observation as well as to evaluate the hypotensive efficacy of bimatoprost/timolol fixed combination (FCBT) over 4 months in PXFG.

MATERIAL AND METHODS

Epidemiological analysis, ophthalmological examination, statistical analysis.

RESULTS

The prevalence of PEX among healthy Novosibirsk and Novosibirsk region citizens is 19.9%. In ophthalmologically compromised population and first-time patients, the prevalence of PEX is 24%, of which PXFG constitutes 57.2%. Retrospectively, the prevalence of PXFG in PEX patients who were treated and followed up appeared to be as high as 60.8%. PXFG also accounts for 70% of all open-angle glaucoma cases in the Novosibirsk region, which is much higher than the corresponding rates in the European part of Russia. A 4-month FCBT therapy in 5 groups of PXFG patients (no treatment, monotherapy, another fixed combination, two drugs, three drugs) has yielded an evident hypotensive effect in most patients. The decrease in intraocular pressure was clinically significant in all groups.

CONCLUSION

There has been found a high prevalence of PEX and PXFG in the Novosibirsk region. FCBT has demonstrated high hypotensive efficacy at all stages of PXFG and was beneficial even in patients treated with other medications or fixed combinations and in refractory cases.

What have we learned about exfoliation syndrome since its discovery by John Lindberg 100 years ago?

Exfoliation syndrome (XFS) is a systemic disease with significant ocular manifestations, including glaucoma and cataract. The disease impacts close to 70 million people globally and is now recognised as the most common identifiable cause of open-angle glaucoma. Since the discovery of XFS 100 years ago by Dr John G. Lindberg, there has been considerable advancement in understanding its pathogenesis and resulting clinical implications. The purpose of this paper is to summarise information regarding the epidemiology, pathophysiology, ocular manifestations and systemic associations of XFS with the objective of sharing clinical pearls to assist in early detection and enhanced management of patients.

[Pseudoexfoliation syndrome and pseudoexfoliation glaucoma]

Pseudoexfoliation syndrome is an age-related systemic disease that mainly affects the anterior structures of the eye. Despite a worldwide distribution, reported incidence and prevalence of this syndrome vary widely between ethnicities and geographical areas. The exfoliative material is composed mainly of abnormal cross-linked fibrils that accumulate progressively in some organs such as the heart, blood vessels, lungs or meninges, and particularly in the anterior structures of the eye. The exact pathophysiological process still remains unclear but the association of genetic and environmental factors are thought to play a role in the development and progressive extracellular accumulation of exfoliative material. Hence, LOXL1 gene polymorphisms, responsible for metabolism of some components of elastic fibers and extracellular matrix, and increased natural exposure to ambient ultraviolet or caffeine consumption have been associated with pseudoexfoliation syndrome. Ophthalmological manifestations are commonly bilateral with an asymmetric presentation and can lead to severe visual impairment and blindness more frequently than in the general population, mainly related to glaucoma and cataract. Pseudoexfoliation glaucoma is a major complication of pseudoexfoliation syndrome and represents the main cause of identifiable glaucoma worldwide. Visual field progression is more rapid than that observed in primary open angle glaucoma, and filtering surgery is more frequently required. Nuclear cataract is more frequent and occurs earlier than in the general population. Owing to poorer pupil dilation and increased zonular instability, cataract surgery with pseudoexfoliation is associated with a 5- to 10-fold increase in surgical complications compared to cataract surgery without pseudoexfoliation. Some specific treatments targeting production, formation or accumulation of exfoliative material could improve the prognosis of this syndrome.

Genetics of glaucoma

Genetic and genomic studies, including genome-wide association studies (GWAS) have accelerated the discovery of genes contributing to glaucoma, the leading cause of irreversible blindness world-wide. Glaucoma can occur at all ages, with Mendelian inheritance typical for the rare early onset disease (before age 40) and complex inheritance evident in common adult-onset forms of disease. Recent studies have suggested possible therapeutic targets for some patients with early-onset glaucoma based on the molecular and cellular events caused by MYOC, OPTN and TBK1 mutations. Diagnostic genetic tests using early-onset glaucoma genes are also proving useful for pre-symptomatic disease detection and genetic counseling. Recent GWAS completed for three types of common adult-onset glaucoma have identified novel loci for POAG (primary-open-angle glaucoma) (ABCA1, AFAP1, GMDS, PMM2, TGFBR3, FNDC3B, ARHGEF12, GAS7, FOXC1, ATXN2, TXNRD2); PACG (primary angle-closure glaucoma (EPDR1, CHAT, GLIS3, FERMT2, DPM2-FAM102); and exfoliation syndrome (XFS) glaucoma (CACNA1A). In total sixteen genomic regions have been associated with POAG (including the normal tension glaucoma (NTG) subgroup), 8 with PACG and 2 with XFS. These studies are defining important biological pathways and processes that contribute to disease pathogenesis.

The Prevalence of Pseudoexfoliation and the Long-term Changes in Eyes With Pseudoexfoliation in a South Indian Population

PURPOSE

To report the prevalence, long-term changes and associated factors for pseudoexfoliation (PEX) in a population aged 40 years and above from rural and urban south India.

MATERIALS AND METHODS

At baseline (the Chennai Glaucoma Study), 7774 subjects were examined. After 6 years, as a part of the incidence study, 133 of the 290 subjects diagnosed with PEX at baseline were reexamined for long-term changes. Participants had detailed examination at base hospital.

RESULTS

At baseline PEX was noted in 290 [3.73%, 95% confidence interval (CI), 3.3-4.2] subjects. It was associated with glaucoma in 24 (8.3%), ocular hypertension (OHT) in 21 (7.2%), and occludable angles in 24 (8.3%) subjects. The age-adjusted and sex-adjusted prevalence was 3.41% (95% CI, 3.39-3.43). Increasing age was a significant associated factor. Using the 40- to 49-year age group as a reference, the odds ratio increased from 8.4 (95% CI, 4.1-17.1) for the 50- to 59-year age group to 51.2 (95% CI, 25.8-101.6) for the 70 years and above age group. Other associated factors were rural residence (P<0.001), higher intraocular pressure (P<0.001), cataract (P<0.001), being underweight (P=0.01), manual labor (P=0.03), and aphakia (P<0.001). Of the 133 subjects reexamined, 8 (6.0%) subjects developed glaucoma and all had OHT at baseline. Rates of cataract surgery were (P<0.001) higher in subjects with PEX.

CONCLUSION

Prevalence of PEX was higher in rural population and baseline OHT was a significant factor for conversion to glaucoma.

Genetics, Diagnosis, and Monitoring of Pseudoexfoliation Glaucoma

Recent studies have shed new light on the genetic factors underlying pseudoexfoliation syndrome, growing our understanding of the role of the lysyl oxidase-like 1 (LOXL1) gene and its various polymorphisms as well as identifying new genetic associations. Recent years have brought new insight on how these genetic factors interact with other factors, including environmental, to confer risk to individuals and populations worldwide. All of these findings may hold importance to the screening, diagnosis, and monitoring of pseudoexfoliation and may also help lead to the identification of novel therapeutic targets. This review serves as an update on the recent trends and findings in pseudoexfoliation syndrome.

Serum insulin-like growth factor-1 levels in patients with pseudoexfoliation syndrome and glaucoma

Insulin-like growth factor-1 (IGF-1) is altered in several neurodegenerative diseases, the association between serum IGF-1 levels and glaucoma has not been evaluated. This study was designed to evaluate whether serum IGF-1 levels are different in patients with Pseudoexfoliation (PEX) with or without glaucoma. The study was conducted with 110 participants aged 65 years or older who were divided into three groups: group 1, patients with PEX syndrome; group 2, patients with PEX glaucoma; and group 3, participants without PEX or glaucoma. All participants underwent full ophthalmological examination and a detailed medical history was recorded. Patients with known neurodegenerative diseases other than PEX glaucoma were excluded. Serum IGF-1 levels were measured by automated chemiluminescent assay. Groups 1, 2, and 3 included 35, 34, and 41 patients, respectively; there were no differences regarding age, gender, or systemic disease status. There were also no statistically significant differences between the groups in terms of IGF-1 levels, which were 91.7 ± 39.1, 101.1 ± 40.2, and 107.2 ± 43.8 ng/ml for groups 1, 2, and 3, respectively (p = 0.276). Serum IGF-1 levels were similar by gender, the presence of systemic disease, status of diabetes mellitus, and laterality of the PEX material. There was no correlation between the cup-to-disk ratios and IGF-1 levels (r = -0.214, p = 0.223). IGF-1 levels in the circulation did not differ in the presence of PEX syndrome with or without glaucoma. This may indicate that the neurodegenerative process is local rather than systemic.

Prevalence of Pseudoexfoliation Syndrome and Associated Factors in South Koreans: The Korean National Health and Nutrition Examination Survey

PURPOSE

To investigate the prevalence of pseudoexfoliation syndrome (PXS) and factors associated with PXS in South Koreans by analyzing data from the Korean National Health and Nutrition Examination Survey (KNHANES).

METHODS

Using the KNHANES database of 2009-2012, 13,223 participants aged 50 years or older were included. Participants underwent standardized interviews and systemic and ocular examinations. Systemic factors analyzed included age, sex, daily length of sun exposure, presence of Raynaud phenomenon or migraine, hypertension, diabetes mellitus, body mass index, serum lipid profile, duration and frequency of smoking, and alcohol consumption. Evaluated ocular factors were refractive error, presence of cataract and glaucoma, intraocular pressure, and peripheral anterior chamber depth. Logistic regression analysis was performed to identify factors associated with the presence of PXS.

RESULTS

PXS was found in 16 participants (0.12%). When compared with the non-PXS group, eyes with PXS showed a higher prevalence of cataract (p = 0.020). In logistic regression analysis, age (odds ratio, OR, 1.04, 95% confidence interval, CI, 0.99-1.09; p = 0.016) and the presence of cataract (OR 8.17, 95% CI 1.06-62.84; p = 0.044) were associated with the presence of PXS. Sun exposure for ≥5 hours/day was marginally associated with the presence of PXS (OR 2.76, 95% CI 0.96-7.95; p = 0.060).

CONCLUSION

The prevalence of PXS per 1000 persons was 1.10 in South Koreans aged ≥50 years. Participants with PXS had a higher prevalence of cataract, were older, and were more likely to be exposed to the sun for ≥5 hours/day than participants without PXS.

Genetic variants and cellular stressors associated with exfoliation syndrome modulate promoter activity of a lncRNA within the LOXL1 locus

Exfoliation syndrome (XFS) is a common, age-related, systemic fibrillinopathy. It greatly increases risk of exfoliation glaucoma (XFG), a major worldwide cause of irreversible blindness. Coding variants in the lysyl oxidase-like 1 (LOXL1) gene are strongly associated with XFS in all studied populations, but a functional role for these variants has not been established. To identify additional candidate functional variants, we sequenced the entire LOXL1 genomic locus (∼40 kb) in 50 indigenous, black South African XFS cases and 50 matched controls. The variants with the strongest evidence of association were located in a well-defined 7-kb region bounded by the 3'-end of exon 1 and the adjacent region of intron 1 of LOXL1. We replicated this finding in US Caucasian (91 cases/1031 controls), German (771 cases/1365 controls) and Japanese (1484 cases/1188 controls) populations. The region of peak association lies upstream of LOXL1-AS1, a long non-coding RNA (lncRNA) encoded on the opposite strand of LOXL1. We show that this region contains a promoter and, importantly, that the strongly associated XFS risk alleles in the South African population are functional variants that significantly modulate the activity of this promoter. LOXL1-AS1 expression is also significantly altered in response to oxidative stress in human lens epithelial cells and in response to cyclic mechanical stress in human Schlemm's canal endothelial cells. Taken together, these findings support a functional role for the LOXL1-AS1 lncRNA in cellular stress response and suggest that dysregulation of its expression by genetic risk variants plays a key role in XFS pathogenesis.

Age-related eye disease and gender

Worldwide, the prevalence of moderate to severe visual impairment and blindness is 285 millions, with 65% of visually impaired and 82% of all blind people being 50 years and older. Meta-analyses have shown that two out of three blind people are women, a gender discrepancy that holds true for both developed and developing countries. Cataract accounts for more than half of all blindness globally and gender inequity in access to cataract surgery is the major cause of the higher prevalence of blindness in women. In addition to gender differences in cataract surgical coverage, population-based studies on the prevalence of lens opacities indicate that women have a higher risk of developing cataract. Laboratory as well as epidemiologic studies suggest that estrogen may confer antioxidative protection against cataractogenesis, but the withdrawal effect of estrogen in menopause leads to increased risk of cataract in women. For the other major age-related eye diseases; glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy, data are inconclusive. Due to anatomic factors, angle closure glaucoma is more common in women, whereas the dominating glaucoma type; primary open-angle glaucoma (POAG), is more prevalent in men. Diabetic retinopathy also has a male predominance and vascular/circulatory factors have been implied both in diabetic retinopathy and in POAG. For AMD, data on gender differences are conflicting although some studies indicate increased prevalence of drusen and neovascular AMD in women. To conclude, both biologic and socioeconomic factors must be considered when investigating causes of gender differences in the prevalence of age-related eye disease.

Cataract surgery in pseudoexfoliation syndrome

Pseudoexfoliation (PXF) syndrome is characterized by the deposition of distinctive fibrillar material in the anterior segment of the eye. It is an age-related process that is associated with open and narrow angle glaucomas and the formation of cataracts. Not only is PXF associated with the formation of dense nuclear cataracts, it is also well known that those presenting with PXF are at a higher risk of developing complications during, and even after, cataract surgery. Complications associated with cataract surgery in PXF can occur from poor pupillary dilation, zonular weakness leading to intraoperative or postoperative lens dislocation and vitreous loss, postoperative intraocular pressure (IOP) spikes potentiating glaucomatous damage, capsular phimosis, prolonged inflammation, and postoperative corneal decompensation. The surgeon should be prepared to encounter the various potential intraoperative and postoperative complications in eyes with pseudoexfoliation syndrome during cataract surgery. In this way, the surgeon can plan his/her surgical technique to help avoid surprises during cataract surgery and be prepared to manage the potential postoperative complications that can occur in pseudoexfoliation eyes.