Social, health and ocular factors associated with primary open-angle glaucoma amongst Chinese Singaporeans

Impact of smoking on glaucoma

PURPOSE OF REVIEW

Assessing whether lifestyle related factors play a role in causing primary open-angle glaucoma (POAG) is of great value to clinicians, public health experts and policy makers. Smoking is a major global public health concern and contributes to ocular diseases such as cataracts, and age-related macular degeneration through ischemic and oxidative mechanisms. Recently, smoking has been investigated as a modifiable risk factor for glaucoma. In the presence of an association with glaucoma, provision of advice and information regarding smoking to patients may help reduce the burden of disease caused by POAG. Therefore, the aim of this review is to summarize the current evidence regarding the effect of smoking in the pathogenesis of glaucoma and its incidence, progression as well as the benefits of smoking cessation.

RECENT FINDINGS

While the association between glaucoma development and smoking history is controversial, in the last decade, several recent studies have helped to identify possible effects of smoking, especially heavy smoking, in regard to glaucomatous progression. Smoking cessation may possibly be protective against glaucoma progression.

SUMMARY

Smoking may play a role in glaucoma progression and long-term smoking cessation may be associated with lower glaucoma progression. The dose-response relationship between smoking and glaucoma as well as therapeutic potential of smoking cessation needs to be further validated with both preclinical and rigorous clinical studies.

Smoking and progressive retinal nerve fibre layer thinning in glaucoma

BACKGROUND/AIMS

To investigate the relationship between smoking and smoking intensity, and the rate of retinal nerve fibre layer (RNFL) thinning in patients with primary open angle glaucoma (POAG).

METHODS

In this longitudinal study, patients with POAG who had at least 3 years of follow-up with a minimum of 5 visits of optical coherence tomography (OCT) were enrolled. The smoking intensity was calculated as the pack-year at the baseline OCT. Univariable and multivariable linear mixed models were used to determine the effect of each parameter on the rates of RNFL thinning over time. Non-linear least-squares estimation with piecewise regression model was used to investigate the cut-off point for the relationship between circumpapillary RNFL thinning and smoking intensity.

RESULTS

A total of 466 eyes of 314 patients were included over the mean (95% CI) follow-up of 6.6 (6.4 to 6.7) years. Of the 314 patients, 121 (39%) had reported any history of smoking. Greater smoking intensity was associated with faster RNFL thinning (-0.06 (95% CI -0.11 to 0.00) µm/year per 10 pack-year higher; p=0.031) after adjusted for confounding factors. RNFL thinning became significantly faster when smoking intensity was >8 pack-year.

CONCLUSIONS

Smoking intensity is associated with faster rates of RNFL thinning. Evaluation of smoking intensity might add information to the assessment of risk of glaucoma progression. Future studies are required to explore if withdrawing smoking as a modifiable risk factor can decrease progression in patients with glaucoma.

Association Between Alcohol Consumption Patterns and Glaucoma in Japan

PRCIS

In this case-control study of the Japanese population, including 3207 glaucoma cases, alcohol consumption patterns such as frequency and quantity showed a positive association with glaucoma prevalence.

PURPOSE

To examine the association between alcohol consumption patterns and glaucoma.

SUBJECTS AND METHODS

This case-control study evaluated 3207 cases with glaucoma and 3207 matched controls. Patients over 40 years of age were included from 1,693,611 patients admitted to 34 hospitals in Japan. Detailed alcohol consumption patterns (drinking frequency, average daily drinks, and total lifetime drinks) were obtained, as well as various confounding factors, including smoking history and lifestyle-related comorbidities. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% CIs for glaucoma prevalence.

RESULTS

Drinking frequency showed an association with glaucoma for "a few days/week" (OR, 1.19; 95% CI, 1.03-1.38) and "almost every day/week" (OR, 1.40; 95% CI, 1.18-1.66). Average daily drinks showed an association for ">0-2 drinks/day" (OR, 1.16; 95% CI, 1.03-1.32). Total lifetime drinks showed an association for ">60-90 drink-year" (OR, 1.23; 95% CI, 1.01-1.49) and ">90 drink-year" (OR, 1.23; 95% CI, 1.05-1.44). As alcohol consumption levels differed considerably between men and women, additional analyses were conducted separately for men and women. Among men, drinking frequency of "a few days/week" and "almost every day/week," average daily drinks of ">0-2 drinks/day" and ">2-4 drinks/day," and total lifetime drinks of ">60-90 drink-year" and ">90 drink-year" had an association with glaucoma. Conversely, among women, neither drinking frequency, average daily drinks, nor total lifetime drinks were associated.

CONCLUSIONS

Both the frequency and quantity of alcohol consumption were associated with glaucoma. Further research on gender differences is warranted.

Towards modifying the genetic predisposition for glaucoma: An overview of the contribution and interaction of genetic and environmental factors

Glaucoma, the leading cause of irreversible blindness worldwide, is a complex human disease, with both genetic and environmental determinants. The availability of large-scale, population-based cohorts and biobanks, combining genotyping and detailed phenotyping, has greatly accelerated research into the aetiology of glaucoma in recent years. Hypothesis-free genome-wide association studies have furthered our understanding of the complex genetic architecture underpinning the disease, while epidemiological studies have provided advances in the identification and characterisation of environmental risk factors. It is increasingly recognised that the combined effects of genetic and environmental factors may confer a disease risk that reflects a departure from the simple additive effect of the two. These gene-environment interactions have been implicated in a host of complex human diseases, including glaucoma, and have several important diagnostic and therapeutic implications for future clinical practice. Importantly, the ability to modify the risk associated with a particular genetic makeup promises to lead to personalised recommendations for glaucoma prevention, as well as novel treatment approaches in years to come. Here we provide an overview of genetic and environmental risk factors for glaucoma, as well as reviewing the evidence and discussing the implications of gene-environment interactions for the disease.

Prevalence of Primary Open-Angle Glaucoma and its Relationship with Smoking in the Population of the Azar Cohort: A Cross-Sectional Study

PURPOSE

The purpose is to determine the prevalence of primary open-angle glaucoma (POAG) and study the relationship of smoking and other potential risk factors with POAG.

METHODS

This is a cross-sectional study based on the Azar cohort databases (including the eye cohort study) in Iran, including 11,208 participants aged 35-70 years. According to the questionnaire, participants were divided into five groups in terms of smoking. Ophthalmologic examinations were performed in two steps. The first step was performed by an optometrist, and all referred participants underwent a complete ophthalmological examination in the second step, then after POAG cases were diagnosed using Criteria of the International Society of Geographic and Epidemiological Ophthalmology.

RESULTS

Of the participants, 4992 (44.5%) were male and 6216 (55.5%) were female, with a mean age of 50.1 ± 9.27 years. The prevalence of POAG in our study population was 1%, which included 58 (1.2%) males and 58 (0.9%) females. There was no significant difference between the two groups in terms of the prevalence of different smoking categories in both genders. There was a statistically significant difference between the two groups in both genders in terms of diabetes mellitus (DM) after adjusting for age and there was a statistically significant difference between the two groups in the male population in terms of triglycerides ≥150 mg/dl.

CONCLUSION

Findings of this study indicated that there is no association between cigarette smoking in different doses and a history of smoking with POAG. Other factors, such as aging and underlying diseases, including DM and hypertriglyceridemia, have a statistically significant association with POAG.

Asian Race and Primary Open-Angle Glaucoma: Where Do We Stand?

Primary open-angle glaucoma (POAG) is an optic neuropathy characterized by irreversible retinal ganglion cell damage and visual field loss. The global POAG prevalence is estimated to be 3.05%, and near term is expected to significantly rise, especially within aging Asian populations. Primary angle-closure glaucoma disproportionately affects Asians, with up to four times greater prevalence of normal-tension glaucoma reported compared with high-tension glaucoma. Estimates for overall POAG prevalence in Asian populations vary, with Chinese and Indian populations representing the majority of future cases. Structural characteristics associated with glaucoma progression including the optic nerve head, retina, and cornea are distinct in Asians, serving as intermediates between African and European descent populations. Patterns in IOP suggest some similarities between races, with a significant inverse relationship between age and IOP only in Asian populations. Genetic differences have been suggested to play a role in these differences, however, a clear genetic pattern is yet to be established. POAG pathogenesis differs between Asians and other ethnicities, and it may differ within the broad classification of the Asian race. Greater awareness and further research are needed to improve treatment plans and outcomes for the increasingly high prevalence of normal tension glaucoma within aging Asian populations.

The anterior scleral thickness in eyes with primary open-angle glaucoma

Purpose

To investigate the anterior scleral thickness (AST) and its associations with Schlemm’s canal (SC) area, trabecular meshwork (TM) thickness and length, and scleral spur (SS) length in healthy and primary open-angle glaucoma (POAG) groups.

Methods

Thirty-five eyes of 35 healthy subjects and 23 eyes of 23 patients with POAG were included. The AST, SC area, TM thickness and length, and SS length were measured using swept-source optical coherence tomography. AST was measured at 0 mm (AST0), 1 mm (AST1), 2 mm (AST2), and 3 mm (AST3) from SS. Associations between AST and SC area, TM thickness and length, and SS length were also estimated.

Results

AST0 (728.84 ± 99.33 vs. 657.39 ± 67.02 μm, p < 0.001), AST1 (537.79 ± 79.55 vs. 506.83 ± 57.37 μm, p = 0.038), AST3 (571.09 ± 79.15 vs. 532.13 ± 59.84 μm, p = 0.009), SC area (6304.26 ± 1238.72 vs. 4755.64 ± 1122.71 μm2, p < 0.001), TM thickness (107.21 ± 31.26 vs. 94.51 ± 24.18 μm, p = 0.035), TM length (736.20 ± 141.85 vs. 656.43 ± 127.03 μm, p = 0.004), and SS length (219.89 ± 50.29 vs. 174.54 ± 35.58 μm, p < 0.001) were significantly greater in healthy group than in POAG group. In addition, SC area, TM thickness, and SS length were significantly and positively associated with AST0 in the healthy group, whereas no similar associations were observed in the POAG group.

Conclusions

Compared with the healthy group, AST was significantly thinner in the POAG group, which also had smaller SC and TM dimensions. Moreover, the SC area, TM thickness, and SS length were significantly and positively associated with AST in the healthy group. Thus, AST might play an important role in maintaining TM and SC morphology and further in the pathogenesis of POAG.

Alcohol, intraocular pressure and open-angle glaucoma: A systematic review and meta-analysis

Topic

This systematic review and meta-analysis summarizes the existing evidence for the association of alcohol use with intraocular pressure (IOP) and open-angle glaucoma (OAG).

Clinical Relevance

Understanding and quantifying these associations may aid clinical guidelines or treatment strategies and shed light on disease pathogenesis. The role of alcohol, a modifiable factor, in determining IOP and OAG risk also may be of interest from an individual or public health perspective.

Methods

The study protocol was preregistered in the Open Science Framework Registries (https://osf.io/z7yeg). Eligible articles (as of May 14, 2021) from 3 databases (PubMed, Embase, Scopus) were independently screened and quality assessed by 2 reviewers. All case-control, cross-sectional, and cohort studies reporting a quantitative effect estimate and 95% confidence interval (CI) for the association between alcohol use and either IOP or OAG were included. The evidence for the associations with both IOP and OAG was qualitatively summarized. Effect estimates for the association with OAG were pooled using random effects meta-analysis. Studies not meeting formal inclusion criteria for systematic review, but with pertinent results, were also appraised and discussed. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

Results

Thirty-four studies were included in the systematic review. Evidence from 10 studies reporting an association with IOP suggests that habitual alcohol use is associated with higher IOP and prevalence of ocular hypertension (IOP > 21 mmHg), although absolute effect sizes were small. Eleven of 26 studies, comprising 173 058 participants, that tested for an association with OAG met inclusion criteria for meta-analysis. Pooled effect estimates indicated a positive association between any use of alcohol and OAG (1.18; 95% confidence interval [CI], 1.02–1.36; P = 0.03; I² = 40.5%), with similar estimates for both prevalent and incident OAG. The overall GRADE certainty of evidence was very low.

Conclusions

Although this meta-analysis suggests a harmful association between alcohol use and OAG, our results should be interpreted cautiously given the weakness and heterogeneity of the underlying evidence base, the small absolute effect size, and the borderline statistical significance. Nonetheless, these findings may be clinically relevant, and future research should focus on improving the quality of evidence.

Research advance in optic disc tilt and rotation in high myopia and its implications for glaucoma and visual field defects

High myopia is of worldwide concern due to its high prevalence, and myopia is an independent risk factor for glaucoma. The purpose of this paper is to review the mechanism and clinical manifestations of optic disc tilt and rotation in high myopia and its relationship with glaucoma, to provide clues for monitoring fundus changes in high myopia and the early diagnosis of high myopia with glaucoma.

Non-drug interventions in glaucoma: Putative roles for lifestyle, diet and nutritional supplements

Glaucoma is a major ocular neurodegenerative disease characterized by progressive retinal ganglion cells degeneration and sight loss. Current treatment options have been limited to reducing intraocular pressure (IOP), known as the leading risk factor for this disease; however, glaucoma can develop even with low or normal IOP and progress despite controlling IOP values. Lifestyle, dietary habits, and supplementation may influence some of the risk factors and pathophysiological mechanisms underlying glaucoma development and progression; thus, the role of this complementary and alternative medicine in glaucoma has received great interest from both patients and ophthalmologists. We provide a summary of the current evidence concerning the relationship between lifestyle, dietary habits, and effects of supplements on the incidence and progression of glaucoma and their targets and associated mechanisms. The data suggest the existence of a therapeutic potential that needs to be further explored with both preclinical and rigorous clinical studies.

Agreement of Optic Nerve Head Evaluation of Primary Open-Angle Glaucoma Between General Ophthalmologists and Glaucoma Specialists

Purpose

To investigate the agreement of optic nerve head evaluations and initial diagnoses of primary open-angle glaucoma (POAG) by general ophthalmologists and glaucoma specialists in Shanghai, China.

Methods

This multicenter, cross-sectional study involved the outpatients from the general ophthalmology departments of four top eye hospitals in Shanghai. The participants underwent ocular examinations, including intraocular pressure, fundus photography, corneal thickness, refractometry, visual acuity, visual field and gonioscopy. General ophthalmologists and glaucoma specialists performed the diagnoses and classified them as non-glaucoma, POAG suspects, and POAG. The consistency of initial diagnosis between general ophthalmologists and glaucoma specialists was measured using the weighted kappa coefficient. Logistic regression analysis was used to detect the risk factors for the reliability of POAG diagnosis.

Results

In 922 participants, the initial diagnosis rates of POAG and non-glaucoma were much higher in the glaucoma specialist group than in the general ophthalmologist group, while the initial diagnosis rates of POAG suspects were higher in the general ophthalmologist group. The weighted kappa coefficient between the two groups was 0.831±0.027 (95% confidence interval, 0.779–0.884). Logistic regression analysis of the risk factors for the reliability of POAG diagnosis showed that the independent risk factors were intraocular pressure (OR 8.363, 95% CI: 4.27–16.37) and vertical cup-to-disc ratio (OR 3.459, 95% CI: 1.54–7.76).

Conclusion

The diagnosis consistency between the general ophthalmologists and the glaucoma specialists was similar among outpatients in the area of Shanghai. However, general ophthalmologists tended to classify the indefinite subjects as POAG suspects, and their accuracy in diagnosing POAG was low. By paying more attention to the risk factors of POAG diagnosis, general ophthalmologists could improve the diagnosis accuracy.

Alcohol consumption is associated with glaucoma severity regardless of ALDH2 polymorphism

The present study investigated the effect of aldehyde dehydrogenase2 (ALDH2) rs671 polymorphism and alcohol consumption on the severity of primary open-angle glaucoma (POAG). The questionnaire for alcohol consumption pattern and targeted genotyping for ALDH2 rs671 polymorphism was performed from 445 Korean POAG patients. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were measured and compared according to alcohol consumption and ALDH2 rs671 genotype. Heavy drinking group eyes had thinner RNFL thickness than did abstinence group eyes (65.0 ± 10.9 vs. 70.9 ± 11.5 µm, P = 0.023). Both mild (65.8 ± 9.6 µm) and heavy (63.8 ± 8.4 µm) drinking group eyes had significantly thinner macular GCIPL thickness than did abstinence group eyes (68.1 ± 8.2 µm, P = 0.003). However, ALDH2 rs671 polymorphism did not show any significant association with RNFL or GCIPL thickness. Alcohol consumption was significantly associated with GCIPL thinning (β = –0.446, P = 0.035) after adjustment for multiple confounding factors. As excessive alcohol consumption was significantly associated with thinner GCIPL thickness while ALDH2 polymorphism had no significant effect on RNFL or GCIPL thickness, glaucoma patients should avoid excessive alcohol consumption regardless of ALDH2 polymorphism.

Factors affecting the diagnostic performance of circumpapillary retinal nerve fibre layer measurement in glaucoma

BACKGROUND/AIMS

To identify factors that influence the diagnostic performance of circumpapillary retinal nerve fibre layer (RNFL) thickness measurements in the detection of primary open-angle glaucoma (POAG).

METHODS

1592 eyes from 1076 healthy controls and 758 eyes from 502 patients with POAG underwent optical coherence tomography (OCT) imaging to assess RNFL parameters. Visual field (VF) mean deviation (MD) from standard automated perimetry was used to indicate severity in subjects with glaucoma.

RESULTS

RNFL thickness significantly decreased with age (ρ=-0.10 to -0.16, p<0.001) and increased with spherical equivalent (SE) refractive error (ρ=0.23-0.29, p<0.001) in healthy and glaucoma groups but showed a significant reduction with SE (ρ=-0.20, p<0.001) in the temporal RNFL of healthy subjects. RNFL measurements significantly decreased with VF MD (ρ=0.08-0.53, p<0.05) in subjects with POAG. When healthy subjects and subjects with glaucoma were matched to subgroups within a factor, significant differences in area under the curve (AUC) between subgroups were only found with SE AUCs increased significantly with disease severity, particularly in the global, inferior and superior measurements (p<0.001). Overall, the diagnostic performance of the inferior and global RNFL measurements were found to be more resilient to different factors.

CONCLUSION

Diagnostic accuracy in glaucoma was influenced by SE but could be mitigated by using controls with similar refractive characteristics. Increasing disease severity led to significantly better diagnostic accuracy. These factors should be considered when using OCT for glaucoma diagnosis in practice.

Ocular conditions and dry eye due to traditional and new forms of smoking: A review

Addiction to cigarette smoking has high prevalence rates recorded worldwide. Smoking has been linked to several life-threatening systemic conditions such as cancer, heart attack and stroke, in addition to a range of ocular pathologies. In recent years, electronic cigarettes (EC) have emerged as alternatives to smoking. ECs are nicotine delivery devices which produce an aerosol by heating, rather than combusting, a liquid which contains nicotine, flavours and preservatives. This review focuses on the association of traditional and new forms of smoking with dry eye disease, contact lens wear and four other common ocular diseases: cataract, age-related macular degeneration, glaucoma and Graves' ophthalmopathy. It is concluded that smoking and vaping appear as a risk factor for the aforementioned ocular conditions. An evidence-based, clear link between cigarette smoking, or EC vaping and ocular problems is yet to be discovered.

Glaucoma in myopia: diagnostic dilemmas

Myopic eyes have an increased risk of glaucoma. However, glaucomatous changes in a myopic eye are often difficult to detect. Classic structural and functional investigations to diagnose glaucoma may be confounded by myopia. Here, we identify some of the common pitfalls in interpreting these structural parameters, and the possible solutions that could be taken to overcome them. For instance, in myopic eyes, we discuss the limitations and potential sources of error when using neuroretinal rim parameters, and retinal nerve fibre layer and ganglion cell-inner plexiform layer thickness measurements. In addition, we also review new developments and potential adjuncts in structural imaging such as the assessment of the retinal nerve fibre layer texture, and the examination of the microcirculation of the optic nerve head using optical coherence tomography angiography. For the functional assessment of glaucoma, we discuss perimetric strategies that may aid in detecting characteristic visual field defects in myopic glaucoma. Ultimately, the evaluation of glaucoma in myopia requires a multimodal approach, to allow correlation between structural and functional assessments. This review provides overview on how to navigate this diagnostic dilemma.

Relationship of lifestyle, exercise, and nutrition with glaucoma

PURPOSE OF REVIEW

Although reducing the intraocular pressure (IOP) through medications, laser or surgery remains the primary means of glaucoma treatment, there is increasing evidence during the last decade that environmentally modifiable factors may help to prevent glaucoma or its progression through different mechanisms that may or may not involve lowering IOP. Additionally, patients are increasingly interested in maintaining a healthy lifestyle and taking an active role in the management of their disease. Therefore, the aim of this review is to summarize the current evidence regarding environmentally modifiable factors such as lifestyle, exercise, and nutrition in the pathogenesis of glaucoma.

RECENT FINDINGS

In the last decade, large population-based studies have helped to identify possible environmentally modifiable protective and risk factors with regard to glaucomatous disease. Smoking cessation; moderate aerobic exercise; recommended weight; and a balanced diet including green leafy vegetables, omega fatty-acids, and moderate intake of hot tea and coffee have been reported to be possibly protective against developing glaucoma or its progression.

SUMMARY

Modifiable environmental factors such as lifestyle, exercise, and nutrition may play a role in glaucoma pathogenesis. Large prospective studies with long-term follow-up should be encouraged to corroborate these findings, which may guide future treatments for our patients, some of which may not be limited to IOP reduction.

Risks of all-cause mortality and major kidney events in patients with new-onset primary open-angle glaucoma: a nationwide long-term cohort study in Taiwan

OBJECTIVE

Cardiovascular risk factors are associated with primary open-angle glaucoma (POAG) in the general population. However, long-term mortality and major kidney events in patients with new-onset POAG remain unclear.

METHODS

Using the Taiwan National Health Insurance Research Database between 1997 and 2011, 15 185 patients with a new diagnosis of POAG were enrolled and propensity score matched (1:1) with 15 185 patients without ocular disorders (WODs). All-cause mortality and major kidney events were analysed by a multivariate Cox proportional hazards regression model and a competing risk regression model.

RESULTS

The risk of all-cause mortality was significantly higher in patients with new-onset POAG than in those WODs (adjusted HR (aHR) 2.11, 95% CI 1.76 to 2.54; p<0.001). Patients with POAG had higher risks of acute renal failure (ARF) (competing risk aHR 2.58, 95% CI 1.88 to 3.55; p<0.001) and end-stage renal disease (ESRD) (competing risk aHR 4.84, 95% CI 3.02 to 7.77; p<0.001) than those WODs.

CONCLUSIONS

Our data demonstrate that POAG is a risk of all-cause mortality, ARF and ESRD, thus needing to notice mortality and major kidney events in patients with new-onset POAG.