Association of ambient air pollution with age-related macular degeneration and retinal thickness in UK Biobank

Association of exposure to ultraviolet radiation and warm-season ozone air pollution with incident age-related macular degeneration: A nationwide cohort study in China

BACKGROUND

As the leading cause of blindness, age-related macular degeneration (AMD) performs an adverse impact on human health and disability. AMD have been reported to be associated with environmental factors; however, the association between ultraviolet (UV) radiation, warm-season ambient ozone pollution, and incident AMD remains unclear.

METHODS

In this study, 19,707 participants without AMD at baseline were included from a nationwide longitudinal cohort in China. UV radiation and warm-season ozone exposure were evaluated through satellite-based models. Incident AMD was diagnosed via ophthalmological fundus images. Cox proportional hazard regression models were employed to explore the association of UV radiation and warm-season ozone with incident AMD, and the hazard ratios (HRs) and 95 % confidence intervals (CIs) were reported.

RESULTS

During 312,935 person-month of follow-up, 3774 participants developed to AMD. High exposure to both UV radiation and warm-season ozone was associated with increasing risk of incident AMD, with HRs and 95 % CIs of 1.32 (1.23, 1.41) and 1.20 (1.11, 1.29) in two-exposure models, respectively. Moreover, negative interaction between UV radiation and warm-season ozone was identified, and it was found that exposure to high UV radiation and low ozone presented the highest hazard for AMD. Subgroup analyses showed that the UV-AMD association was stronger in southern China, while the ozone-AMD association was greater in northern China and rural areas.

CONCLUSION

Our study provides the first epidemiological evidence that both UV radiation and warm-season ozone would elevate the risk of incident AMD, and the hazard of higher UV radiation may be attenuated by exposure to ozone. Strategies for decreasing AMD burden should jointly consider environmental exposures and geographic locations.

Retinal toxicity of heavy metals and its involvement in retinal pathology

The objective of the present review is to discuss epidemiological evidence demonstrating the association between toxic metal (Cd, Pb, Hg, As, Sn, Ti, Tl) exposure and retinal pathology, along with the potential underlying molecular mechanisms. Epidemiological studies demonstrate that Cd, and to a lesser extent Pb exposure, are associated with age-related macular degeneration (AMD), while the existing evidence on the levels of these metals in patients with diabetic retinopathy is scarce. Epidemiological data on the association between other toxic metals and metalloids including mercury (Hg) and arsenic (As), are limited. Clinical reports and laboratory in vivo studies have shown structural alterations in different layers of retina following metal exposure. Examination of retina samples demonstrate that toxic metals can accumulate in the retina, and the rate of accumulation appears to increase with age. Experimental studies in vivo and in vitro studies in APRE-19 and D407 cells demonstrate that toxic metal exposure may cause retinal damage through oxidative stress, apoptosis, DNA damage, mitochondrial dysfunction, endoplasmic reticulum stress, impaired retinogenesis, and retinal inflammation. However, further epidemiological as well as laboratory studies are required for understanding the underlying molecular mechanisms and identifying of the potential therapeutic targets and estimation of the dose-response effects.

Association between ambient air pollution and age-related macular degeneration: a meta-analysis

BACKGROUND

Several epidemiological studies have investigated the association between ambient air pollution and age-related macular degeneration (AMD). However, a consensus has not yet been reached. Our meta-analysis aimed to clarify this association.

METHODS

Databases, including PubMed, EMBASE, and Web of Science, were searched for relevant studies from 01 January 2000 to 30 January 2024. English-language, peer-reviewed studies using cross-sectional, prospective, or retrospective cohorts and case-control studies exploring this relationship were included. Two authors independently extracted data and assessed study quality. A random-effects model was used to calculate pooled covariate-adjusted odds ratios. Heterogeneity across studies was also tested.

RESULTS

We identified 358 relevant studies, of which eight were included in the meta-analysis. Four studies evaluated the association between particulate matter less than 2.5 μm in diameter (PM2.5) and AMD, and three studies explored the relationship between nitrogen dioxide (NO2) or ozone (O3) and AMD. The pooled odds ratios were 1.16 (95% confidence interval [CI]: 1.11-1.21), 1.17 (95% CI: 1.09-1.25), and 1.06 (95% CI: 1.05-1.07), respectively.

CONCLUSION

Current evidence suggests a concomitant positive but not causal relationship between PM2.5, NO2, or O3 and AMD risk.

Lessons From The Glaucoma Foundation Think Tank 2023: A Patient-Centric Approach to Glaucoma

PRCIS

The main takeaways also included that BIG DATA repositories and AI are important combinatory tools to foster novel strategies to prevent and stabilize glaucoma and, in the future, recover vision loss from the disease.

PURPOSE

To summarize the main topics discussed during the 28th Annual Glaucoma Foundation Think Tank Meeting "A Patient-Centric Approach to Glaucoma" held in New York on June 9 and 10, 2023.

METHODS

The highlights of the sessions on BIG DATA, genetics, modifiable lifestyle risk factors, female sex hormones, and neuroprotection in the field of primary open angle glaucoma (POAG) were summarized.

RESULTS

The researchers discussed the importance of BIG DATA repositories available at national and international levels for POAG research, including the United Kingdom Biobank. Combining genotyped large cohorts worldwide, facilitated by artificial intelligence (AI) and machine-learning approaches, led to the milestone discovery of 312 genome-wide significant disease loci for POAG. While these loci could be combined into a polygenic risk score with clinical utility, Think Tank meeting participants also provided analytical epidemiological evidence that behavioral risk factors modify POAG polygenetic risk, citing specific examples related to caffeine and alcohol use. The impact of female sex hormones on POAG pathophysiology was discussed, as was neuroprotection and the potential use of AI to help mitigate specific challenges faced in clinical trials and speed approval of neuroprotective agents.

CONCLUSIONS

The experts agreed on the importance of genetics in defining individual POAG risk and highlighted the additional crucial role of lifestyle, gender, blood pressure, and vascular risk factors. The main takeaways also included that BIG DATA repositories and AI are important combinatory tools to foster novel strategies to prevent and stabilize glaucoma and, in the future, recover vision loss from the disease.

Association of long-term ozone air pollution and age-related macular degeneration in older Chinese population

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of legal blindness. It remains unclear whether and to what extent the ambient ozone pollution could increase the risk of AMD.

METHODS

A nationwide cross-sectional survey was conducted in 129 major cities in 27 of 31 provincial regions across China from 2018 to 2021. Data in relation to demographics, residential address, and medical histories were collected. The exposure-response relationship between ozone exposure and AMD was explored using the restricted cubic splines. A piecewise logistic regression model was used to examine the magnitudes of the association, after adjusting demographic, social-economic and co-pollutants. Residential ozone exposures were estimated using a satellite-based model.

RESULTS

A total of 624,167 middle-aged and older participants were included in the final analyses, the overall prevalence of AMD was 16.76 %. The risk of AMD was consistently increasing with higher warm-season ozone concentration, and the risk became much larger after the cut-off of 110 μg/m3 (approximately 50 ppb). Every 10 μg/m3 increment in warm-season ozone concentration, the adjusted odds ratio (OR) for AMD were 1.15 (1.13, 1.16) and 1.66 (1.63, 1.69) when the warm-season ozone concentration was below or above 110 μg/m3, respectively.

CONCLUSION

This large-scale nationwide study provides the first epidemiological evidence demonstrating significant associations between long-term residential ozone exposure and AMD prevalence. Based on our findings, in conjunction with WHO global air quality guidelines, we suggest that a warm-season ozone of 110 μg/m3 should be adopted for middle-aged and older populations to reduce the risk of AMD. Ongoing efforts to reduce ozone exposure in communities through improved air quality regulations and public education are essential for the improvement of public health.

Air Pollution and Chronic Eye Disease in Adults: A Scoping Review

PURPOSE

We conducted a scoping review of studies examining ambient air pollution as a risk factor for chronic eye disease influencing the lens, retina, and intraocular pressure in adults.

METHODS

Terms related to air pollution and eye disease outcomes were used to search for publications on Embase, Web of Science Core Collection, Global Health, PubMed, and the Cochrane Central Register of Controlled Trials from January 1, 2010, through April 11, 2022.

RESULTS

We identified 27 articles, focusing on the following non-mutually exclusive outcomes: cataract (n = 9), presbyopia (n = 1), retinal vein occlusion or central retinal arteriolar and venular equivalents (n = 5), intraocular pressure (IOP) (n = 3), glaucoma (n = 5), age-related macular degeneration (AMD) (n = 5), diabetic retinopathy (n = 2), and measures of retinal morphology (n = 3). Study designs included cross-sectional (n = 16), case-control (n = 4), and longitudinal (n = 7). Air pollutants were measured in 50% and 95% of the studies on lens and retina or IOP, respectively, and these exposures were assigned to geographic locations. Most research was conducted in global regions with high exposure to air pollution. Consistent associations suggested a possibly increased risk of cataract and retina-associated chronic eye disease with increasing exposure to particulate matter (PM2.5-PM10), NO2, NOx, and SO2. Associations with O3 were less consistent.

CONCLUSIONS

Accumulating research suggests air pollution may be a modifiable risk factor for chronic eye diseases of the lens and retina. The number of studies on each specific lens- or retina-related outcome is limited. Guidelines regarding the role of air pollution in chronic eye disease do not exist.

Nighttime Outdoor Artificial Light and Risk of Age-Related Macular Degeneration

Importance

Light pollution's impact on human health is increasingly recognized, but its link to exudative age-related macular degeneration (EAMD) remains unclear.

Objective

To investigate the association between exposure to outdoor artificial light at night (OALAN) and the risk of incident EAMD.

Design, Setting, and Participants

In this nationwide population-based case-control study, all individuals 50 years or older with newly diagnosed EAMD between January 1, 2010, and December 31, 2011, were identified with reference to the Korean National Health Insurance Service registration program database for rare and intractable diseases. Birth year- and sex-matched controls (with no EAMD diagnosis until 2020) were selected at a 1:30 ratio. Data were acquired from May 1 to December 31, 2021, and analyzed from June 1 to November 30, 2022.

Exposures

Mean levels of OALAN at participants' residential addresses during 2008 and 2009 were estimated using time-varying satellite data for a composite view of persistent nighttime illumination at an approximate scale of 1 km2.

Main Outcomes and Measures

The hazard ratios (HRs) and 95% CIs of the association between residential OALAN and risk of incident EAMD were determined based on maximum likelihood estimation after adjusting for sociodemographic characteristics, comorbidities, and area-level risk factors (ie, nighttime traffic noise and particulate matter of aerodynamic diameter ≤10 μm in each participant's administrative district of residence).

Results

A total of 126 418 participants were included in the analysis (mean [SD] age, 66.0 [7.9] years; 78 244 men [61.9%]). Of these, 4078 were patients with newly diagnosed EAMD and 122 340 were EAMD-free matched controls. In fully adjusted models, an IQR (55.8 nW/cm2/sr) increase in OALAN level was associated with an HR of 1.67 (95% CI, 1.56-1.78) for incident EAMD. The exposure-response curve demonstrated a nonlinear, concave upward slope becoming more pronounced at higher levels of light exposure (ie, at approximately 110 nW/cm2/sr). In a subgroup analysis, an IQR increase in OALAN was associated with increased risk of incident EAMD in urban areas (HR, 1.46 [95% CI, 1.33-1.61]) but not in rural areas (HR, 1.01 [95% CI, 0.84-1.22]).

Conclusions and Relevance

In this nationwide population-based case-control study, higher levels of residential OALAN were associated with an increased risk of incident EAMD. Future studies with more detailed information on exposure, individual adaptive behaviors, and potential mediators are warranted.

Acute and continuous exposure of airborne fine particulate matter (PM2.5): diverse outer blood-retinal barrier damages and disease susceptibilities

BACKGROUND

The association between air pollution and retinal diseases such as age-related macular degeneration (AMD) has been demonstrated, but the pathogenic correlation is unknown. Damage to the outer blood-retinal barrier (oBRB), which consists of the retinal pigment epithelium (RPE) and choriocapillaris, is crucial in the development of fundus diseases.

OBJECTIVES

To describe the effects of airborne fine particulate matter (PM2.5) on the oBRB and disease susceptibilities.

METHODS

A PM2.5-exposed mice model was established through the administration of eye drops containing PM2.5. Optical coherence tomography angiography, transmission electron microscope, RPE immunofluorescence staining and Western blotting were applied to study the oBRB changes. A co-culture model of ARPE-19 cells with stretching vascular endothelial cells was established to identify the role of choroidal vasodilatation in PM2.5-associated RPE damage.

RESULTS

Acute exposure to PM2.5 resulted in choroidal vasodilatation, RPE tight junctions impairment, and ultimately an increased risk of retinal edema in mice. These manifestations are very similar to the pachychoroid disease represented by central serous chorioretinopathy (CSC). After continuous PM2.5 exposure, the damage to the RPE was gradually repaired, but AMD-related early retinal degenerative changes appeared under continuous choroidal inflammation.

CONCLUSION

This study reveals oBRB pathological changes under different exposure durations, providing a valuable reference for the prevention of PM2.5-related fundus diseases and public health policy formulation.

Indenopyrene and Blue-Light Co-Exposure Impairs the Tightly Controlled Activation of Xenobiotic Metabolism in Retinal Pigment Epithelial Cells: A Mechanism for Synergistic Toxicity

High energy visible (HEV) blue light is an increasing source of concern for visual health. Polycyclic aromatic hydrocarbons (PAH), a group of compounds found in high concentrations in smokers and polluted environments, accumulate in the retinal pigment epithelium (RPE). HEV absorption by indeno [1,2,3-cd]pyrene (IcdP), a common PAH, synergizes their toxicities and promotes degenerative changes in RPE cells comparable to the ones observed in age-related macular degeneration. In this study, we decipher the processes underlying IcdP and HEV synergic toxicity in human RPE cells. We found that IcdP-HEV toxicity is caused by the loss of the tight coupling between the two metabolic phases ensuring IcdP efficient detoxification. Indeed, IcdP/HEV co-exposure induces an overactivation of key actors in phase I metabolism. IcdP/HEV interaction is also associated with a downregulation of proteins involved in phase II. Our data thus indicate that phase II is hindered in response to co-exposure and that it is insufficient to sustain the enhanced phase I induction. This is reflected by an accelerated production of endogenous reactive oxygen species (ROS) and an increased accumulation of IcdP-related bulky DNA damage. Our work raises the prospect that lifestyle and environmental pollution may be significant modulators of HEV toxicity in the retina.

Long-Term Exposure to Ambient PM2.5 and Age-Related Cataracts among Chinese Middle-Aged and Older Adults: Evidence from Two National Cohort Studies

Cataract is one key cause of visual disability and blindness. Ambient particulate matter is more likely to increase cataract risk due to eye continuous exposure to the environment. However, less is known about whether long-term exposure to particulate matter 2.5 (PM2.5) is related to age-related cataracts. We conducted a population-based study among 22,298 adults from two multicenter cohort studies [China Family Panel Studies (CFPS) and Chinese Longitudinal Healthy Longevity Survey (CLHLS)]. The associations between PM2.5 and age-related cataracts were analyzed by Cox proportional hazard regression models, which were also stratified according to demographic characteristics. The restricted cubic spline (RCS) model was used to explore the dose-response relationships between PM2.5 and age-related cataracts. The population attributable fraction (PAF) was calculated to assess the burden of age-related cataracts that can be attributed to PM2.5. In the final analysis, 1897 participants reported age-related cataracts during follow-up. Long-term exposure to PM2.5 was associated with age-related cataracts, with HRs of 1.165 (1.130, 1.201), 1.138 (1.103, 1.173), and 1.091 (1.057, 1.126) for per 10 μg/m3 increase at one-, two-, and three-year before the end of follow-up, respectively. Furthermore, associations between PM2.5 and age-related cataracts were also demonstrated in RCS models. The PAF of age-related cataracts to PM2.5 in the total participants was 24.63%. Our research found that long-term exposure to PM2.5 may increase the risk of age-related cataracts, and age-related cataracts should be considered as an important public health issue due to air pollution.

Emerging roles of air pollution and meteorological factors in autoimmune eye diseases

Autoimmune eye diseases (AEDs), a collection of autoimmune inflammatory ocular conditions resulting from the dysregulation of immune system at the ocular level, can target both intraocular and periorbital structures leading to severe visual deficit and blindness globally. The roles of air pollution and meteorological factors in the initiation and progression of AEDs have been increasingly attractive, among which the systemic and local mechanisms are both involved in. Exposure to excessive air pollution and extreme meteorological conditions including PM2.5/PM0.1, environmental tobacco smoke, insufficient sunshine, and high temperature, etc., can disturb Th17/Treg balance, regulate macrophage polarization, activate neutrophils, induce systemic inflammation and oxidative stress, decrease retinal blood flow, promote tissue fibrosis, activate sympathetic nervous system, adversely affect nutrients synthetization, as well as induce heat stress, therefore may together deteriorate AEDs. The crosstalk among inflammation, oxidative stress and dysregulated immune system appeared to be prominent. In the present review, we will concern and summarize the potential mechanisms underlying linkages of air pollution and meteorological factors to ocular autoimmune and inflammatory responses. Moreover, we concentrate on the specific roles of air pollutants and meteorological factors in several major AEDs including uveitis, Graves' ophthalmopathy (GO), ocular allergic disease (OAD), glaucoma, diabetic retinopathy (DR), etc.

A Review of Ambient Air Pollution as a Risk Factor for Posterior Segment Ocular Diseases

PURPOSE

To review the most recent evidence on the association of ambient air pollution with posterior segment ocular diseases.

METHODS

A search of the most recently published medical literature was performed in PubMed and Google Scholar on 10 December 2022. Articles published between 2018 and December 2022 were included in this rapid review. Studies that evaluated the association between ambient air pollutants (nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂), ozone (O₃), particulate matters (PM_s), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), benzene), and ocular posterior segment diseases (glaucoma, age-related macular degeneration (AMD), and retinal vascular diseases) were included.

RESULTS

Nineteen research articles met the inclusion criteria. Significant associations were found between PM_2.5 and glaucoma, including primary open angle, primary angle closure, and normal tension glaucoma. An increased risk of AMD was linked to increased exposure to PM_2.5, NO₂, and CO. Single studies suggested that increased exposure to PM_2.5 and PM₁₀ is associated with diabetic retinopathy; THC and NMHC increased the risk of retinal vein occlusion; and CO, NO₂, and PM₁₀ are linked to an increased risk of central retinal artery occlusion.

CONCLUSIONS

There is increasing evidence that toxic air pollutants have an impact on posterior segment ocular diseases, hence determining it as a potential modifiable risk factor for visual impairment.

Particulate Matter Elevates Ocular Inflammation and Endoplasmic Reticulum Stress in Human Retinal Pigmented Epithelium Cells

Because of their exposure to air, eyes can come into contact with air pollutants such as particulate matter (PM), which may cause severe ocular pathologies. Prolonged ocular PM exposure may increase inflammation and endoplasmic reticulum stress in the retina. Herein, we investigated whether PM exposure induces ocular inflammation and endoplasmic reticulum (ER) stress-related cellular responses in human retinal epithelium-19 (ARPE-19) cells. To understand how PM promotes ocular inflammation, we monitored the activation of the mitogen-activated protein kinase (MAPK)/nuclear factor kappa beta (NFκB) axis and the expression of key inflammatory mRNAs. We also measured the upregulation of signature components for the ER-related unfolded protein response (UPR) pathways, as well as intracellular calcium ([Ca²⁺]_i) levels, as readouts for ER stress induction following PM exposure. Ocular PM exposure significantly elevated the expression of multiple cytokine mRNAs and increased phosphorylation levels of NFκB-MAPK axis in a PM dose-dependent manner. Moreover, incubation with PM significantly increased [Ca²⁺]_i levels and the expression of UPR-related proteins, which indicated ER stress resulting from cell hypoxia, and upregulation of hypoxic adaptation mechanisms such as the ER-associated UPR pathways. Our study demonstrated that ocular PM exposure increased inflammation in ARPE-19 cells, by activating the MAPK/NFκB axis and cytokine mRNA expression, while also inducing ER stress and stress adaptation responses. These findings may provide helpful insight into clinical and non-clinical research examining the role of PM exposure in ocular pathophysiology and delineating its underlying molecular mechanisms.

How Ophthalmologists Can Decarbonize Eye Care: A Review of Existing Sustainability Strategies and Steps Ophthalmologists Can Take

TOPIC

Understanding approaches to sustainability in cataract surgery and their risks and benefits CLINICAL RELEVANCE: In the United States, healthcare is responsible for approximately 8.5% of greenhouse gas (GHG), and cataract surgery is one of the most commonly performed surgical procedures. Ophthalmologists can contribute to reducing GHG emissions, which lead to a steadily increasing list of health concerns ranging from trauma to food instability.

METHODS

We conducted a literature review to identify the benefits and risks of sustainability interventions. We then organized these interventions into a decision tree for use by individual surgeons.

RESULTS

Identified sustainability interventions fall into the domains of advocacy and education, pharmaceuticals, process, and supplies and waste. Existing literature shows certain interventions may be safe, cost-effective, and environmentally friendly. These include dispensing medications home to patients after surgery, multi-dosing appropriate medications, training staff to properly sort medical waste, reducing the number of supplies used during surgery, and implementing immediate sequential bilateral cataract surgery where clinically appropriate. The literature was lacking on the benefits or risks for some interventions, such as switching specific single use supplies to reusables or implementing a hub-and-spoke style theatre setup. Many of the advocacy and education interventions have inadequate literature specific to ophthalmology but are likely to have minimal risks.

CONCLUSIONS

Ophthalmologists can engage in a variety of safe and effective approaches to reduce or eliminate dangerous GHG emissions associated with cataract surgery.

Joint effects of meteorological factors and PM2.5 on age-related macular degeneration: a national cross-sectional study in China

BACKGROUND

Weather conditions are a possible contributing factor to age-related macular degeneration (AMD), a leading cause of irreversible loss of vision. The present study evaluated the joint effects of meteorological factors and fine particulate matter (PM_2.5) on AMD.

METHODS

Data was extracted from a national cross-sectional survey conducted across 10 provinces in rural China. A total of 36,081 participants aged 40 and older were recruited. AMD was diagnosed clinically by slit-lamp ophthalmoscopy, fundus photography, and spectral domain optical coherence tomography (OCT). Meteorological data were calculated by European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis and were matched to participants' home addresses by latitude and longitude. Participants' individual PM_2.5 exposure concentrations were calculated by a satellite-based model at a 1-km resolution level. Multivariable-adjusted logistic regression models paired with interaction analysis were performed to investigate the joint effects of meteorological factors and PM_2.5 on AMD.

RESULTS

The prevalence of AMD in the study population was 2.6% (95% CI 2.42-2.76%). The average annual PM_2.5 level during the study period was 63.1 ± 15.3 µg/m³. A significant positive association was detected between AMD and PM_2.5 level, temperature (T), and relative humidity (RH), in both the independent and the combined effect models. For PM_2.5, compared with the lowest quartile, the odds ratios (ORs) with 95% confidence intervals (CIs) across increasing quartiles were 0.828 (0.674,1.018), 1.105 (0.799,1.528), and 2.602 (1.516,4.468). Positive associations were observed between AMD and temperature, with ORs (95% CI) of 1.625 (1.059,2.494), 1.619 (1.026,2.553), and 3.276 (1.841,5.830), across increasing quartiles. In the interaction analysis, the estimated relative excess risk due to interaction (RERI) and the attributable proportion (AP) for combined atmospheric pressure and PM_2.5 was 0.864 (0.586,1.141) and 1.180 (0.768,1.592), respectively, indicating a synergistic effect between PM_2.5 and atmospheric pressure.

CONCLUSIONS

This study is among the first to characterize the coordinated effects of meteorological factors and PM_2.5 on AMD. The findings warrant further investigation to elucidate the relationship between ambient environment and AMD.

A critical review on air pollutant exposure and age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of visual impairments and blindness worldwide in the elderly and its incidence strongly increases with ages. The etiology of AMD is complex and attributed to the genetic modifiers, environmental factors and gene-environment interactions. Recently, the impacts of air pollution on the development of eye diseases have become the new area of focus, and disordered air exposure combined with inadequate health management has caused problems for the eye health, such as dry eye, glaucoma, and retinopathy, while its specific role in the occurrence of AMD is still not well understood. In order to summarize the progress of this research field, we performed a critical review to summarize the epidemiological and mechanism evidence on the association between air pollutants exposure and AMD. This review documented that exposure to air pollutants will accelerate or worsen the morbidity and prevalence of AMD. Air pollutants exposure may change the homeostasis, interfere with the inflammatory response, and take direct action on the lipid metabolism and oxidative stress in the macula. More attention should be given to understanding the impact of ambient air pollution on AMD worldwide.

Ambient Air Pollution and Age-Related Eye Disease: A Systematic Review and Meta-Analysis

Purpose

To compare the burden of age-related eye diseases among adults exposed to higher versus lower levels of ambient air pollutants.

Methods

MEDLINE, EMBASE, and Scopus were searched for relevant articles until September 30, 2021. Inclusion criteria included studies of adults, aged 40+ years, that provided measures of association between the air pollutants (nitrogen dioxide, carbon monoxide [CO], sulfur dioxide, ozone [O3], particulate matter [PM] less than 2.5 µm in diameter [PM2.5], and PM less than 10 µm in diameter [PM10]) and the age-related eye disease outcomes of glaucoma, age-related macular degeneration (AMD), or cataract. Pooled odds ratio (OR) estimates and 95% confidence intervals (CIs) were calculated using a random-effects meta-analysis model. PROSPERO registration ID: CRD42021250078.

Results

A total of eight studies were included in the review. Consistent evidence for an association was found between PM2.5 and glaucoma, with four of four studies reporting a positive association. The pooled OR for each 10-µg/m3 increase of PM2.5 on glaucoma was 1.18 (95% CI, 0.95-1.47). Consistent evidence was also found for O3 and cataract, with three of three studies reporting an inverse association. Two of two studies reported a null association between PM2.5 and cataract, while one of one studies reported a positive association between PM10 and cataract. One of one studies reported a positive relationship between CO and AMD. Other relationships were less consistent between studies.

Conclusions

Current evidence suggests there may be an association between some air pollutants and cataract, AMD, and glaucoma.

Fine particulate matter measured by satellites predicts the risk of age-related macular degeneration in a longitudinal cohort study

Although studies have revealed that ambient particulate matter (PM) has detrimental effects on the ocular surface, there have been limited reports detailing the effect of ambient PM on the posterior segment of the eye. A large-scale longitudinal cohort study evaluating the association between fine PM, especially PM2.5, and the retina could elucidate the risk of ambient pollutants for retinal diseases. We investigated the association between PM2.5 and the development of age-related macular degeneration (AMD). We conducted a population-based cohort study of 4,284,128 participants in Taiwan between 2001 and 2011. PM2.5 was continuously measured by satellites and subsequently assigned to each geographic district along with its postcode. A time-dependent Cox proportional-hazard model was used to assess the overall effects of average PM2.5. We used distributed lag non-linear models to evaluate the dose-response relationship between PM2.5 and AMD development. The annual mean of PM2.5 exposure was 34.23 ± 7.17 μg/m3. The PM2.5 concentrations were highest in spring, followed by those in winter, autumn, and summer. Twelve thousand ninety-five new AMD cases were reported during the study period. After adjusting for covariates, the AMD risk increased by 19% (95% confidence interval 1.13-1.25) for a 10 μg/m3 PM2.5 increase. The present study demonstrated that chronic exposure to PM2.5 increases the risk of AMD. Almost half of the Taiwanese live in a polluted area where the PM2.5 levels are higher than the World Health Organization recommended air quality guideline of 10 μg/m3 had a 1.4-fold risk, which significantly increases concern about their visual health and social burden.

Air Quality, Pollution and Sustainability Trends in South Asia: A Population-Based Study

Introduction: Worsening air quality and pollution lead to numerous environmental health and sustainability issues in the South Asia region. This study analyzes India, Nepal, Bangladesh, Pakistan, Sri Lanka, and Nepal for air quality data trends and sustainability indicators. Methodology: By using a population-based study design, six South Asian countries were analyzed using a step-wise approach. Data were obtained from government websites and publicly available repositories for region dynamics and key variables. Results: Between 1990 and 2020, air quality data indicated the highest rise in CO₂ emissions in India (578.5 to 2441.8 million tons) (MT), Bangladesh, Nepal, and Pakistan. Greenhouse gas emissions, from 1990 to 2018, nearly tripled in India (1990.4 to 3346.6 MT of CO₂-equivalents), Nepal (20.6 to 54.6 MT of CO₂-equivalents), and Pakistan, and doubled in Bangladesh. Methane emissions rose the highest in Pakistan (70.4 to 151 MT of CO₂-equivalents), followed by Nepal (17 to 31 MT of CO₂-equivalents) and India (524.8 to 669.3 MT of CO₂-equivalents). Nitrous oxide nearly doubled in Bangladesh (16.5 to 29.3 MT of CO₂-equivalents), India (141.6 to 256.9 MT of CO₂-equivalents), Nepal (17 to 31 MT of CO₂-equivalents), and more than doubled in Pakistan (27 to 61 MT of CO₂-equivalents). On noting particulate matter 2,5 annual exposure, India saw the highest rise from 81.3 µg/m³ (in 1990) to 90.9 µg/m³ (2017), whereas trends were steady in Pakistan (60.34 to 58.3 µg/m³). The highest rise was noted in Nepal (87.6 to 99.7 µg/m³) until 2017. During the coronavirus disease 19 pandemic, the pre-and post-pandemic changes between 2018 and 2021 indicated the highest PM_2.5 concentration in Bangladesh (76.9 µg/m³), followed by Pakistan (66.8 µg/m³), India (58.1 µg/m³), Nepal (46 µg/m³) and Sri Lanka (17.4 µg/m³). Overall, South Asian countries contribute to the worst air quality and sustainability trends regions worldwide. Conclusions: Air pollution is prevalent across a majority of South Asia countries. Owing to unsustainable industrial practices, pollution trends have risen to hazardous levels. Economic, environmental, and human health impacts have manifested and require urgent, concerted efforts by governing bodies in the region.

Dust Storms Increase the Risk of Age-Related Macular Degeneration

The main purpose of this study was to examine the association between dust storms (DSs) and age-related macular degeneration (AMD) using a 5 year representative national dataset with one million participants, according to information on DS, meteorology, and air pollution in Taiwan. There were 18,855 AMD outpatient cases and 1080 AMD inpatient cases during 2008–2012. A Poisson time-series model was used for the analysis. The results show that AMD cases are significantly associated with exposure to dust storm events. Average daily numbers of wet and dry AMD outpatient cases increased from 6.03 and 4.26 on no-event days to 8.25 and 6.67, 2 days after DSs. Average daily numbers of wet and dry AMD inpatient cases increased from 0.26 and 0.33 on no-event days to 0.58 and 0.75, 1 day after DSs. Both genders and different age groups are all affected by the occurrence of DSs, especially 1 and 2 days after DS events. Women are at a higher risk of outpatient visits and hospitalizations for relatively severe wet AMD. Although AMD highly correlated with age, this study also found that dry AMD outpatient visits in people under the age of 50 were also found to be significantly associated with DS events. In order to protect the health of eyes and avoid AMD, one should reduce or avoid outdoor activities when DS events occur.

The Association of Ambient Air Pollution With Cataract Surgery in UK Biobank Participants: Prospective Cohort Study

Purpose

Air pollution is associated with chronic diseases of later life. Cataract is the most common cause of blindess globally. It is biologically plausible that cataract risk is increased by pollution exposure. Therefore, the relationship between air pollution and incident cataract surgery was examined.

Methods

This was a prospective, observational study involving 433,727 UK Biobank participants. Ambient air pollution measures included particulates, nitrogen dioxide (NO2) and nitrogen oxides (NOx). Outdoor air pollution was estimated based on land use regression models. Participants undergoing cataract surgery in either eye were ascertained via data linkage to the National Health Service procedure statistics. Those undergoing cataract surgery within 1 year of baseline assessment and those reporting cataract at baseline were excluded. Cox proportional hazards models were used to examine the associations between air pollutants and incident cataract surgery, adjusting for sociodemographic and lifestyle factors.

Results

There were 16,307 incident cases of cataract surgery. Higher exposure to PM2.5 was associated with a 5% increased risk of incident cataract surgery (per interquartile range [IQR] increase). Compared to the lowest quartile, participants with exposures to PM2.5, NO2, and NOx in the highest quartile were 14%, 11%, and 9% more likely to undergo cataract surgery, respectively. A continuous exposure-response relationship was observed, with the likelihood of undergoing cataract surgery being progressively higher with greater levels of PM2.5, NO2, and NOx (P for trend P < 0.001).

Conclusions

Although the results of our study showed a 5% increased risk of future cataract surgery following an exposure to PM2.5, NO2, and NOx, the effect estimates were relatively small. Further research is required to determine if the associations identified are causal.

The association between long-term exposure to ambient fine particulate matter and glaucoma: A nation-wide epidemiological study among Chinese adults

BACKGROUND

A growing body of evidence has confirmed the association between fine particulate matter (PM_2.5) and ocular diseases, but little is known on the effect of long-term PM_2.5 exposure on glaucoma.

METHODS

A national cross-sectional study of the Rural Epidemiology for Glaucoma was conducted in 10 provinces of China, and 33,701 adults aged 40 years or more were included. A satellite-based model at 1-km resolution level was used to estimate PM_2.5 concentrations which were assigned to each participant according to geocoded home addresses. Logistic regression model was performed to investigate associations of long-term PM_2.5 exposure with glaucoma and its subtypes.

RESULTS

Estimated PM_2.5 concentrations ranged from 28.0 to 96.4 μg/m³. For each 10 μg/m³ increment in PM_2.5, the adjusted odds ratios (ORs) were 1.07 (95% CI: 1.00-1.15) and 1.14 (95% CI: 1.02-1.26) for glaucoma and primary angle-closure glaucoma (PACG), respectively. A positive but non-significant association (OR = 1.05, 95% CI: 0.92-1.18) was detected between long-term exposure to PM_2.5 and odds of primary open-angle glaucoma. The middle aged residents and non-smokers were more sensitive to the adverse effects of PM_2.5.

CONCLUSIONS

Long-term PM_2.5 exposure was associated with glaucoma and PACG in Chinese adults, which provided new insights on adverse ophthalmic effect of PM_2.5.

The Protective Effect of Topical Spermidine on Dry Eye Disease with Retinal Damage Induced by Diesel Particulate Matter2.5

Air pollutants, especially ambient fine particulate matter2.5, may contribute to various ocular surface disorders, including dry eye disease, keratitis and conjunctivitis. A natural polyamine spermidine has a protective effect on the retina and optic nerve; however, no study has been conducted on the application of spermidine in particulate matter2.5-induced dry eye disease. In the present study, we investigated the effect of spermidine eye drops in topically exposed particulate matter2.5-induced dry eye models of Sprague-Dawley rats, by hematological, biochemical and histological evaluation. Spermidine eye drops attenuated the particulate matter2.5 exposure-induced reduction of tear secretion and corneal epithelial damage. Furthermore, spermidine protected against conjunctival goblet cell loss and retinal ganglion cell loss induced by particulate matter2.5. Additionally, spermidine markedly prevented particulate matter2.5-induced infiltration of cluster of differentiation3⁺ and cluster of differentiation4⁺ T lymphocytes and F4/80⁺ macrophages on lacrimal gland. Moreover, over expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 and interleukin-17 in the lacrimal gland and cornea. Meanwhile, the levels of serum total cholesterol and low-density lipoprotein cholesterol were markedly increased by topical exposure to particulate matter2.5, but this change in the lipid profile was decreased by spermidine. Taken together, spermidine may have protective effects against particulate matter2.5-induced dry eye symptoms via stabilization of the tear film and suppression of inflammation and may in part contribute to improving retinal function and lipid metabolism disorder.

The Protective Effect of Oral Application of Corni Fructus on the Disorders of the Cornea, Conjunctiva, Lacrimal Gland and Retina by Topical Particulate Matter 2.5

Particulate matter 2.5 (PM_2.5) may aggravate dry eye disease (DED). Corni Fructus (CF), which is fruit of Cornus officinalis Sieb. et Zucc., has been reported to have various beneficial pharmacological effects, whereas the effect of CF on the eye is still unknown. Therefore, in this study, we investigated the effect of oral administration of water extract of CF (CFW) on the eye, hematology, and biochemistry in a DED model induced by topical exposure to PM_2.5. Furthermore, the efficacy of CFW compared with cyclosporine (CsA), an anti-inflammatory agent, and lutein, the posterior eye-protective agent. Sprague-Dawley rats were topically administered 5 mg/mL PM_2.5 in both eyes four times daily for 14 days. During the same period, CFW (200 mg/kg and 400 mg/kg) and lutein (4.1 mg/kg) were orally administered once a day. All eyes of rats in the 0.05% cyclosporine A (CsA)-treated group were topically exposed to 20 μL of CsA, twice daily for 14 days. Oral administration of CFW attenuated the PM_2.5-induced reduction of tear secretion and corneal epithelial damage. In addition, CFW protected against goblet cell loss in conjunctiva and overexpression of inflammatory factors in the lacrimal gland following topical exposure to PM_2.5. Furthermore, CFW markedly prevented PM_2.5-induced ganglion cell loss and recovered the thickness of inner plexiform layer. Meanwhile, CFW treatment decreased the levels of total cholesterol and low-density lipoprotein cholesterol in serum induced by PM_2.5. Importantly, the efficacy of CFW was superior or similar to that of CsA and lutein. Taken together, oral administration of CFW may have protective effects against PM_2.5-induced DED symptoms via stabilization of the tear film and suppression of inflammation. Furthermore, CFW may in part contribute to improving retinal function and lipid metabolism disorder.

Fine Particulate Matter and Age-Related Eye Disease: The Canadian Longitudinal Study on Aging

Purpose

To determine the relationship between fine particulate matter (PM2.5) and ocular outcomes such as visual impairment and age-related eye disease.

Methods

Baseline data were used from the Canadian Longitudinal Study on Aging. The Comprehensive Cohort consisted of 30,097 adults ages 45 to 85 years. Annual mean PM2.5 levels (µg/m3) for each participant's postal code were estimated from satellite data. Ozone, sulfur dioxide, and nitrogen dioxide levels were also estimated. Binocular presenting visual acuity was measured using a visual acuity chart. Intraocular pressure (IOP) was measured in millimeters of mercury using the Reichart Ocular Response Analyzer. Participants were asked about a diagnosis of glaucoma, macular degeneration, or cataract. Logistic and linear regression models were used.

Results

The overall mean PM2.5 level was 6.5 µg/m3 (SD = 1.8). In the single pollutant models, increased PM2.5 levels (per interquartile range) were associated with visual impairment (odds ratio [OR] = 1.12; 95% confidence interval [CI], 1.02-1.24), glaucoma (OR = 1.14; 95% CI, 1.01-1.29), and visually impairing age-related macular degeneration (OR = 1.52; 95% CI, 1.10-2.09) after adjustment for sociodemographics and disease. PM2.5 had a borderline adjusted association with cataract (OR = 1.06; 95% CI, 0.99-1.14). In the multi-pollutant models, increased PM2.5 was associated with glaucoma and IOP only after adjustment for sociodemographics and disease (OR = 1.24; 95% CI, 1.05-1.46 and β = 0.24; 95% CI, 0.12-0.37).

Conclusions

Increased PM2.5 is associated with glaucoma and IOP. These associations should be confirmed using longitudinal data and potential mechanisms should be explored. If confirmed, this work may have relevance for revision of World Health Organization thresholds to protect human health.

Sulforaphane Alleviates Particulate Matter-Induced Oxidative Stress in Human Retinal Pigment Epithelial Cells

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly, and oxidative damage to retinal pigment epithelial (RPE) cells plays a major role in the pathogenesis of AMD. Exposure to high levels of atmospheric particulate matter (PM) with an aerodynamic diameter of <2.5 μm (PM2.5) causes respiratory injury, primarily due to oxidative stress. Recently, a large community-based cohort study in the UK reported a positive correlation between PM2.5 exposure and AMD. Sulforaphane (SFN), a natural isothiocyanate found in cruciferous vegetables, has known antioxidant effects. However, the protective effects of SNF in the eye, especially in the context of AMD, have not been evaluated. In the present study, we evaluated the effect of SFN against PM2.5-induced toxicity in human RPE cells (ARPE-19) and elucidated the molecular mechanism of action. Exposure to PM2.5 decreased cell viability in ARPE-19 cells in a time- and dose-dependent manner, potentially due to elevated intracellular reactive oxygen species (ROS). SFN treatment increased ARPE-19 cell viability and decreased PM2.5-induced oxidative stress in a dose-dependent manner. PM2.5-induced downregulation of serum- and glucocorticoid-inducible kinase 1 (SGK1), a cell survival factor, was recovered by SFN. PM2.5 treatment decreased the enzymatic activities of the antioxidant enzymes including superoxide dismutase and catalase, which were restored by SFN treatment. Taken together, these findings suggest that SFN effectively alleviates PM2.5-induced oxidative damage in human ARPE-19 cells via its antioxidant effects, and that SFN can potentially be used as a therapeutic agent for AMD, particularly in cases related to PM2.5 exposure.