Cigarette smoking and primary open angle glaucoma: a systematic review

Association of Smoking Patterns with Vision-Related Disability According to Glaucoma Subtypes

OBJECTIVE

The relationship between smoking and onset of glaucoma has been inconsistent. However, there is a gap in understanding whether tobacco smoking is linked to a worse visual impairment in different glaucoma subtypes. The objective of this study was to examine the association between smoking behavior and vision-related disability in people who have different glaucoma subtypes.

METHODS

A total of 283 people with primary open-angle glaucoma (POAG), primary angle closure glaucoma (PACG), normal tension glaucoma (NTG), and pseudo-exfoliative (PEX) were included in this cross-sectional study. The recruitment of study participants was organized in one of two tertiary centers for eye diseases in Belgrade, Serbia, during their regular eye checks. Information about the duration and quantity of smoking was self-reported. Vision-related impairment was quantified using a validated Glaucoma Quality of Life-15 (GQL-15) questionnaire.

RESULTS

A series of multiple linear regression models adjusted for age, gender, severity of glaucoma, lifestyle, and mobility, intraocular pressure level, visual parameters, previous and current therapy, and chronic illnesses suggested that a higher quantity of cigarettes smoked per day was associated with poorer vision-related quality of life only among people with NTG subtypes. This association was absent when smoking duration was tested in the adjusted linear regression model.

CONCLUSION

A higher number of cigarettes smoked daily was associated with poorer vision-related impairment among people who have NTG, but not other glaucoma subtypes. It is recommended that ophthalmologists and other health-care professionals work to improve their patients' understanding of harmful effects of tobacco smoke and quit smoking.

Nicotine acute impact on RNFL: a comparative analysis of smoking cessation aids including nicotine gum and electronic cigarettes

PURPOSE

To investigate the immediate impact of nicotine consumption on Retinal Nerve Fiber Layer (RNFL) thickness in healthy young individuals, comparing nicotine gum and electronic cigarette (vaping) as delivery methods.

MATERIALS AND METHODS

Twenty participants underwent RNFL measurements at baseline, 30, and 60 minutes after consuming 4 mg of nicotine, based on product labeling and specifications. Measurements were obtained using optical coherence tomography (OCT) (Topcon 3D OCT-1 Maestro System). Nicotine was delivered through either nicotine gum or vaping.

RESULTS

Both nicotine gum and vaping led to a statistically significant increase in RNFL thickness, with no significant difference between the two methods. The analysis revealed that area, time, and visit factors significantly affected RNFL scores. Stratification by smoking type (tobacco, vaping, dual) demonstrated significant effects for area, time, and visit factors, with an interaction effect among these factors.

CONCLUSIONS

The findings highlight the acute impact of nicotine intake on RNFL thickness in young healthy smokers. Researchers and clinicians should account for recent nicotine exposure when evaluating RNFL thickness, particularly within the first hour post-smoking. The observed significant effects warrant further research, especially in older or health-compromised populations, to improve clinical protocols and diagnostic evaluations across different demographics.

Former smoking as a risk factor for visual field progression in exfoliation glaucoma patients in Sweden

PURPOSE

The present study aimed to identify whether former smoking was a risk factor for visual field progression in exfoliation glaucoma patients.

METHODS

Prospective nonrandomised cohort study. The study included patients diagnosed with exfoliation glaucoma. All included patients were followed for three years (± three months) with reliable visual fields. At least five reliable visual fields needed to be included in the study. Exfoliation glaucoma was defined using the European Glaucoma Society Guidelines. The visual fields were tested using the 24-2 test strategy of the Humphrey Field Analyzer. Smoking was assessed through questionnaires. Outcomes: Visual field progression. Three different approaches were used: difference in mean deviation (MD), rate of progression (ROP), and guided progression analysis (GPA).

RESULTS

In total, n = 113 patients were included; among them, n = 57 were smokers. Smoking was a significant predictor for visual field progression in the three models (MD/ROP/GPA) studied (p = 0.01/p = 0.001/p ≤ 0.001), even adjusting for intraocular pressure (IOP). Other predictors were included in the MD model: IOP at diagnosis (p = 0.04) and selective laser trabeculoplasty (SLT) treatment (p = 0.01). Other predictors were in the ROP model: Visual field index (p = 0.005), number of medications (p = 0.001) and SLT treatment (p = 0.001). The number of medications was another predictor in the GPA model (p = 0.002).

CONCLUSIONS

Former smoking induced visual field deterioration in all models studied. Smoking status should be considered when establishing the glaucoma diagnosis. Increased glaucoma care should be provided to former smokers to slow the progression of the disease.

Retinal nerve fiber layer and ganglion cell complex thickness in diabetic smokers without diabetic retinopathy

PURPOSE

To compare the thickness of the retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC-IPL) in smoker and nonsmoker diabetics without diabetic retinopathy.

MATERIALS AND METHODS

Patients with diabetes were divided into two groups according to their smoking status: Group 1 consisted of 38 smoker diabetics who had chronically smoked more than 20 cigarettes per day for more than five years; Group 2 consisted of 38 nonsmoker diabetics. After a detailed ophthalmologic examination, the mean and regional (superior, supratemporal, inferior, inferotemporal, temporal, nasal, superonasal, and inferonasal) RNFL and GC-IPL thicknesses were measured with spectral-domain optic coherence tomography (SD-OCT) and compared between groups.

RESULTS

The mean age was 54.7 ± 10.5 and 51.2 ± 9.7 years in the smoker and nonsmoker groups, respectively (p = 0.14). Gender, duration of diabetes, and the mean axial length were similar between groups (p:0.43, p:0.54, p: 0.52, respectively). Mean RNFL thickness was 89.1 ± 8.0 µm in the smoker group and 93.4 ± 7.0 µm in the nonsmoker group, and it was significantly thinner in the smoker group (p = 0.01). The temporal RNFL thickness in the smoker group was thinner than in the nonsmoker group (p = 0.02). There was no difference in superior, inferior, and nasal RNFL thicknesses between the groups (p = 0.31, p = 0.12, p = 0.39, respectively). The mean macular GC-IPL thickness of the smoker and nonsmoker groups was 78.53 ± 15.74 µm and 83.08 ± 5.85 µm, respectively (p = 0.09). Superior, superonasal, inferonasal, inferior, inferotemporal, and superotemporal quadrant GC-IPL thicknesses were similar between the groups (p = 0.07, p = 0.60, p = 0.55, p = 0.77, p = 0.71, p = 0.08, respectively). The groups showed no difference in minimum GC-IPL thickness (p = 0.43). There was a significant negative correlation between smoking exposure and mean, inferior quadrant RNFL thicknesses in the smoker group (p = 0.04, r= -0.32, and p = 0.01, r= -0.39, respectively).

CONCLUSION

Mean RNFL thickness was significantly thinner in smoker diabetics. Although not statistically significant, especially mean, superior, and superotemporal GC-IPL was thinner in smoker diabetics. The results suggest a potential association between the coexistence of diabetes and smoking with alterations in RNFL and GC-IPL thickness.

Background polygenic risk modulates the association between glaucoma and cardiopulmonary diseases and measures: an analysis from the UK Biobank

AIMS

To assess whether associations of cardiopulmonary conditions and markers with glaucoma differ by background genetic risk for primary open angle glaucoma (POAG).

METHODS

We constructed a POAG polygenic risk score (PRS) using genome-wide association study summary statistics from a large cross-ancestry meta-analysis. History of glaucoma (including self-report and codes for POAG, 'other glaucoma' or unspecified glaucoma), history of common cardiopulmonary conditions and cardiopulmonary measures were assessed in the UK Biobank. Stratifying by PRS decile 1 (lowest risk) versus decile 10 (highest risk), separate multivariable models were estimated to assess the associations of cardiopulmonary diseases or factors with glaucoma, adjusting for age, sex, smoking and medication use. A Bonferroni correction was used to adjust p values for multiple comparisons.

RESULTS

Individuals in POAG PRS decile 1 (417 cases, 44 458 controls; mean age 56.8 years) and decile 10 (2135 cases, 42 413 controls; mean age 56.7 years) were included. Within decile 1, glaucoma cases had significantly higher glycated haemoglobin (38.5 vs 35.9 mmol/mol) and higher prevalence of diabetes (17.5% vs 6.5%), dyslipidaemia (31.2% vs 18.3%) and chronic kidney disease (CKD) (6.7% vs 2.0%) than controls (adjusted p<0.0013 for each). Within decile 10, glaucoma was associated with higher prevalence of dyslipidaemia (27.7% vs 17.3%, p=6.9E-05). The magnitude of association between glaucoma and diabetes, CKD and glycated haemoglobin differed between deciles 1 and 10 (contrast test p value for difference <0.05).

CONCLUSION

The relations between systemic conditions and glaucoma vary by underlying genetic predisposition to POAG, with larger associations among those who developed glaucoma despite low genetic risk.

Smoking Cessation May Reduce Risk of Visual Field Progression in Heavy Smokers

PRCIS

The earlier a person quits smoking the more likely is the optic nerve be spared from damage.

PURPOSE

To investigate the effect of smoking cessation on visual field (VF) progression in glaucoma.

METHODS

Primary open angle glaucoma patients with a minimum of 3 years follow-up and 5 VFs were included. Linear mixed models were used to investigate the effects of smoking on the rates of 24-2 VF mean deviation loss after adjusting for confounding factors. Cox proportional hazard regression was used to identify whether different levels of smoking intensity were associated with VF progression with respect to different duration of quitting.

RESULTS

Five hundred eleven eyes of 354 patients were included over the mean follow-up of 12.4 years. Mean baseline age (95% confidence interval) was 62.3 (61.2, 63.4) years. One hundred forty nine (42.1%) patients were smokers. In a multivariable model, smoking intensity was associated with faster VF loss (-0.06, 95% confidence interval (-0.10, -0.01) dB/year per 10 pack-years, P =0.01) among smokers. Heavy smokers (≥20 pack-years) who had quit ˂25 years prior had significantly greater odds of VF progression compared with never smokers (odds ratio=2.49 (1.01, 6.08); P =0.046). There was no significant difference in odds of VF progression in heavy smokers who had quit smoking more than 25 years compared with never smokers ( P =0.43). A significantly higher proportion of VF progression was found in heavy smokers who quit < 25 years compared with heavy smokers who quit ≥25 years by Kaplan-Meier analysis ( P =<0.001).

CONCLUSIONS

After ≥25 years of smoking cessation, the risk of VF progression in former heavy smokers becomes similar to never smokers. Long-term smoking cessation may be associated with lower VF progression in glaucoma patients.

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.

Nonocular Influencing Factors for Primary Glaucoma: An Umbrella Review of Meta-Analysis

INTRODUCTION

Glaucoma is the main cause of irreversible blindness worldwide. Still, little is known about nonocular risk factors. We use an umbrella review to examine the meta-analytic evidence of the correlation between nonocular factors and glaucoma.

METHOD

We searched PubMed and Embase databases up to July 24, 2020. Eligible meta-analyses (MAs) included cohort, case-control, and randomized controlled study designs. Two authors independently extracted the data and evaluated the methodological quality of the MAs. AMSTAR 2 was used to assess the methodological quality of each included MA.

RESULTS

This umbrella review contains 22 MAs with 22 unique nonocular factors in total. We identified 11 factors that increase the risk of glaucoma: hyperlipidemia, nocturnal dip in blood pressure, infection with Helicobacter pylori, myopia, obstructive sleep apnea syndrome, corneal properties, diabetes, hypertension, hypothyroidism, migraine, and plasma homocysteine. We identified 3 factors that reduce the risk of glaucoma: dietary intake of vitamin A, dietary intake of vitamin C, and short-term statin use. We identified 8 factors that had no association with glaucoma: dietary intake of vitamin B, dietary intake of vitamin E, cigarette smoking, Alzheimer's disease, serum folic acid, serum vitamin B6, serum vitamin B12, and serum vitamin D.

CONCLUSIONS

In this umbrella review of MAs, evidence was found for associations of various nonocular factors with glaucoma to different degrees. However, risk factors were only mildly associated, suggesting low impact of systemic risk factors. Additional higher quality studies are needed to provide robust evidence.

The effect of smoking on corneal densitometry and endothelial cell morphology

PURPOSE

We investigated corneal endothelial morphology and corneal densitometry in smokers and compared our results with findings observed in non-smokers.

MATERIALS AND METHODS

This cross-sectional observational study included 100 participants (50 smokers, 50 non-smokers) aged 18-80 years in whom corneal endothelial morphology was analysed using a non-contact Tomey EM-4000 specular microscope (Tomey Corporation, Japan). The Pentacam HR system was used to measure corneal densitometry spatially in three concentric zones (from the centre to the periphery) and at three different corneal depths (from the anterior to the posterior aspects). Endothelial morphology findings and corneal densitometry values were recorded in all participants, and these results were compared between smokers and non-smokers.

RESULTS

Endothelial morphology and corneal densitometry analysis showed significantly lower endothelial cell counts (Num) in smokers (228 cells/mm² vs. 246 cells/mm², p = 0.02) in addition to increased maximum cell area (Max) values (986.5 µm² vs. 935 µm², p = 0.04). We observed no statistically significant intergroup difference in corneal densitometry values (p > 0.05 for each zone); however, we observed a moderately positive correlation between densitometry values in the 6-10 mm concentric zone and between the all total corneal zones and number of pack-years in smokers.

CONCLUSIONS

Our study highlights that among the morphometric corneal endothelial variables analysed in this study, only the Num value was significantly correlated with smoking. We observed no statistically significant intergroup difference in corneal densitometry values in this study; however, a positive correlation was observed between the number of pack-years and corneal densitometry findings. Therefore, as the pack-years increase, the increase in corneal densitometry values may indicate a decrease in corneal clarity, considering the possible contribution of secondary factors such as age.

Comparison between provocative test-based and long-term intraocular pressure parameters in patients with stable open-angle glaucoma

PURPOSE

To compare provocative test-based and long-term intraocular pressure variation parameters in patients with stable open-angle glaucoma.

METHODS

A prospective observational study was carried out in which stable open-angle glaucoma patients (⩾3 years of follow-up without any changes on current medical regimen) were consecutively enrolled. All patients were submitted to a water-drinking test. Long-term intraocular pressure parameters were obtained from isolated intraocular pressure measurements from each visit (⩾5 visits). We investigated the correlation and agreement between the following water-drinking test and long-term intraocular pressure parameters: mean, peak, and fluctuation. In addition, the percentage of eyes with significant intraocular pressure peaks during the water-drinking test (defined as a difference ⩾25% between water-drinking test intraocular pressure peak and mean long-term intraocular pressure) was assessed.

RESULTS

Sixty-three eyes from 63 open-angle glaucoma patients (mean age, 60.7 ± 11.8 years) were included. Mean and water-drinking test intraocular pressure peak correlated significantly with mean (r = 0.67) and maximum long-term intraocular pressure (r = 0.52), respectively (p < 0.01). The correlation between water-drinking test intraocular pressure fluctuation and long-term intraocular pressure fluctuation was not significant (p = 0.45). Limits of agreement from Bland-Altman plots exceeded the maximum allowed difference between methods (3 mm Hg) for all the intraocular pressure parameters analyzed, suggesting poor agreement between water-drinking test-derived and long-term intraocular pressure values. Overall, significant water-drinking test intraocular pressure peaks were observed in 39.7% of these eyes with stable open-angle glaucoma.

CONCLUSION

Although some water-drinking test-based and long-term intraocular pressure parameters correlate significantly, water-drinking test results may not reflect the long-term intraocular pressure profile of stable open-angle glaucoma patients, as their agreement is poor. Many of these patients may experience significant water-drinking test intraocular pressure peaks, despite long-standing stable disease and unchanged medical regimen.

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.

Factors Associated With Long-term Intraocular Pressure Fluctuation in Primary Angle Closure Disease: The CUHK PACG Longitudinal (CUPAL) Study

PURPOSE

To determine the demographic, ocular, and systemic factors associated with long-term intraocular pressure (IOP) fluctuation in primary angle closure disease (PACD).

METHODS

This prospective cohort study included 422 PACD eyes from 269 Chinese patients, including 274 primary angle closure glaucoma (PACG) eyes and 152 primary angle closure/primary angle closure suspect (PAC/PACS) eyes. Long-term IOP fluctuation defined as the SD of all IOP measurements over 2 years (at least 5 measurements in total). Chinese patients with PACD were recruited and followed up 3 monthly. Eyes with IOP-lowering surgery or lens extraction performed within the 2-year study period were excluded. Patient demographics, received treatments, ocular biometry, retinal nerve fiber layer thickness, and systemic factors (eg, hypertension, smoking) were evaluated. Generalized estimating equations adjusting for inter-eye correlation were used to determine the associations.

RESULTS

Eyes with PACG had significantly higher IOP fluctuation than PAC/PACS (2.4±1.2 versus 2.1±0.9 mm Hg; P=0.04). In the multivariate analysis with PACG eyes, higher baseline IOP (P<0.001), greater number of IOP-lowering medications (P<0.001), previous trabeculectomy (P=0.002), and current smoking (P=0.03) were significantly associated with larger IOP fluctuation, whereas diabetes mellitus was associated with lower IOP fluctuation (P=0.03). Among PAC/PACS eyes, younger age group (P<0.001), male sex (P=0.002), and higher baseline IOP (P<0.001) were significantly associated with larger IOP fluctuation.

CONCLUSIONS

PACG eyes have greater IOP fluctuation than PAC/PACS eyes. Certain demographic, ocular, and systemic factors are associated with IOP fluctuation in PACD eyes.

Lifestyles guide and glaucoma (II). Diet, supplements, drugs, sleep, pregnancy, and systemic hypertension

PURPOSE

To establish evidence based guidelines to advise patients on the relationship between habits, diet, certain circumstances, diseases and glaucoma.

METHODS

Review of all published articles on glaucoma and sports or other activities. The papers were classified according to the level of scientific evidence based on the Oxford Centre for Evidence-based Medicine classification.

RESULTS

The evidence on the relationship between diet or supplements and the incidence or progression of glaucoma is insufficient to make a general recommendation for glaucoma patients. Although some studies on normal tension glaucoma suggest that Gingko biloba could reduce glaucoma progression, the results do not allow a general recommendation for all these patients. Similarly, the evidence on the usefulness of vitamin supplements is not conclusive. The studies on smoking do not clearly demonstrate the relationship between this habit and incidence of glaucoma. Marihuana is not a useful treatment for glaucoma. Although the results on the relationship between sleep apnoea and glaucoma are heterogeneous, it is recommended that patients with moderate to intense apnoea are tested for glaucoma. Pregnancy does not influence the course of the disease, but several hypotensive drugs may be harmful for the foetus. Nocturnal systemic hypotension is a risk factor for glaucoma progression.

CONCLUSIONS

Certain habits, circumstances, or diseases may have an influence on the onset or progression of glaucoma. It is important to have adequate information about the scientific evidence in the publications in order to properly advise patients.

Cigarette smoking and glaucoma in the United States population

PurposeTo evaluate the association between cigarette smoking and glaucoma in the United States population.Patients and methodsUS civilian, non-institutionalized population from 2005 to 2008 administrations of the National Health and Nutrition Examination Survey that were ≥40 years of age with visual fields and optic disc photographs were included. Diagnosis of glaucoma was based on the Rotterdam criteria. Logistic regression modeling was performed to assess the association between glaucoma and smoking history, while controlling for age, gender, ethnicity, household income, alcohol consumption, diabetes, and hypertension.ResultsIn 3864 participants, 212 (5.5%) had glaucoma (corresponds to a population weighted glaucoma prevalence of 3.7% in a total of 83 570 127 subjects). Population weighted proportion of current smokers was 20.6% and ex-smokers was 28.3%. Participants with glaucoma were older (63.0±11.6 vs 56.1±11.2, P=0.002), likely to be male (57.1% vs 49.2%, P=0.03), to be Black (36.3% vs 20.7%, P<0.001), and to have diabetes (18.9% vs 12.4%, P=0.006) and hypertension (50.5% vs 39.7%, P=0.003). Current smokers had a lower odds of glaucoma compared to non-smokers (OR=0.61, 95% CI=0.41-0.88, P=0.009), and ex-smokers (OR=0.46, 95% CI=0.28-0.76, P=0.002). The effect estimates were similar in adjusted models, but not statistically significant. Among smokers, greater pack/day of smoking history was associated with statistically significantly higher odds of glaucoma (OR=1.70, 95% CI=1.08-2.67, P=0.02).ConclusionsAmong cigarette smokers, heavy smoking defined by greater number of pack of cigarettes smoked per day is associated with higher odds of glaucoma. Health care providers should include this association when counseling patients on their smoking habit.

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

IMPORTANCE

There is limited literature on lifestyle and health factors related to primary open-angle glaucoma amongst Asians.

BACKGROUND

This study evaluated the association of primary open-angle glaucoma with smoking, health and ocular factors amongst Chinese Singaporeans.

DESIGN

Case-control study.

PARTICIPANTS

The study used 711 primary open-angle glaucoma patients from a Singapore hospital and 2788 population-based controls.

METHODS

Subjects underwent clinical examination and completed a questionnaire with details on family history of glaucoma, comorbidities, smoking and alcohol consumption. Glaucoma cases were subclassified as normal or high-tension glaucoma according to their untreated intraocular pressures.

MAIN OUTCOME MEASURES

The association of various health and lifestyle factors, with normal-tension and high-tension glaucoma was evaluated.

RESULTS

Using multiple logistic regression, primary open-angle glaucoma was associated with older age (odds ratio 1.12 per year older; 95% confidence interval 1.10-1.15; P < 0.001), family history of glaucoma (odds ratio 7.86; 95% confidence interval 4.48-13.79; P < 0.001), higher intraocular pressure (odds ratio 1.75 per 1 mmHg; 95% confidence interval 1.64-1.87; P < 0.001) and thinner central corneal thickness (odds ratio 1.01; 95% confidence interval 1.01-1.02; P < 0.001). Myopes were more likely to have primary open-angle glaucoma (P < 0.001). A current smoking habit was protective against normal-tension glaucoma (odds ratio 0.30; 95% confidence interval 0.10-0.92; P = 0.035).

CONCLUSIONS AND RELEVANCE

Older age, family history of glaucoma, higher intraocular pressure, thinner central corneal thickness and myopia were significantly associated with primary open-angle glaucoma amongst Chinese Singaporeans.

Nicotine promotes blood retinal barrier damage in a model of human diabetic macular edema

More than 1 billion world's population actively smokes tobacco containing the bioactive component nicotine (NT). The biological role of this molecule is mediated through the activation of nicotinic cholinergic receptors, widely distributed in various human tissues including retinal pigmented epithelium. The long-term assumption of NT contributes to several diseases development such as diabetic retinopathy. The major complication of this pathology is the diabetic macular edema (DME), characterized by macular area thinning and blood-retinal barrier (BRB) breakdown. Retinal hyperglycemic/hypoxic microenvironment represents one of the main factors favoring DME progression by eliciting the hypoxia-inducible factors (HIFs) expression. The latter induce new vessels formation by stimulating cellular secretion of vascular endothelial growth factor (VEGF). The etiology of DME is multifactorial, but little is known about the risk factors linked to cigarette smoking, in particular to nicotine's contribution. In the present study, we have investigated the NT role in a model, in vitro, of DME, by evaluating its effect on outer BRB permeability and HIFs/VEGF expression following exposure to hyperglycemic/hypoxic insult. Our results have demonstrated that this compound alters outer BRB integrity exposed to high glucose and low oxygen pressure microenvironment by upregulating HIF-1α/HIF-2α, VEGF expression and ERK1/2 phosphorylation. These data have suggested that NT may play a negative role in active smokers affected by DME.

Effect of Active and Passive Smoking on Retinal Nerve Fibre Layer and Ganglion Cell Complex

Aim. To evaluate the possible structural and functional changes in the retinal nerve fibre layer (RNFL) and the ganglion cell complex (GCC) of chronic smokers and compare them with those of passive healthy smokers using spectral domain optical coherence tomography (SD-OCT) and pattern electroretinogram (PERG). Materials and Methods. We include 80 active chronic smokers and 80 age- and sex-matched healthy passive smokers. After a full ophthalmological examination, SD-OCT and PERG were tested for all participants. Urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio (CCR). Results. Inferior and superior quadrants of RNFL were thinner in group I, but nasal and temporal quadrants did not show significant difference between the groups. There were no significant differences of GCC values between the two groups. There was no significant difference of PERG-P50 amplitude and latency; however, PERG-N95 showed significant difference between the two groups. Multiple regression analyses demonstrated that the number of cigarettes/day, urinary cotinine, and PERG-N95 amplitude are the most important determinants for both superior and inferior RNFL thicknesses. Conclusion. RNFL thickness decreases in chronic, healthy, heavy cigarette smokers, and this thinning is related to the number of cigarettes/day, urinary cotinine, and PERG-N95 latency and amplitude.

The association between cigarette smoking and primary open-angle glaucoma: a systematic review

Glaucoma is one of the most common causes of irreversible blindness, globally. Findings from the Blue Mountain Eye Study suggest a moderate positive association between smoking and increased IOP (a significant risk factor for glaucoma). The previous two reviews investigating the association between smoking and primary open-angle glaucoma (POAG) show inconsistent findings and do not include recent studies investigating the dose-response effect of smoking. The current study aims to conduct an up-to-date, comprehensive evaluation of the existing literature. Identification of relevant existing literature was performed by an online search in MEDLINE for studies published from 1st January 1946 to 5th February 2015. The MESH headings (keywords) included "open-angle glaucoma" and "cigarette" or "smoking" or "tobacco". Two independent reviewers assessed the eligibility of each report based on predefined inclusion criteria. Odds ratios and 95 % confidence intervals (95 % CIs) were obtained from studies, for the change in risk of glaucoma due to both past and current smoking. Of the 26 abstracts reviewed, 17 papers were included in the final analysis. Nine of these were case-control studies, five cohort studies and three cross-sectional in design. Six of the case-control studies found a positive association between smoking and POAG, unlike the remaining studies. However, two relatively recent, large studies (including one prospective cohort study) investigating the effect of smoking dose have found a significant increase in risk of POAG in very heavy smokers. There is limited evidence for a causal association between tobacco smoking and POAG. The evidence for a link between current smoking and POAG appears stronger than that of past smoking, but recent studies suggest that heavy smoking may increase the risk of POAG. Future studies must further investigate the possible positive association between heavy smoking and POAG by stratifying participants by pack years and age.

Cigarette Smoke Extract Causes Injury in Primary Retinal Ganglion Cells via Apoptosis and Autophagy

AIMS

To investigate whether tobacco smoke directly injures retinal ganglion cells (RGCs) and to evaluate the mechanisms of cell death.

METHODS

Primary rat RGCs were harvested from 3- or 4-day-old newborn rats and exposed to cigarette smoke extract (CSE). Cell viability was determined by adenosine 5'-triphosphate (ATP) assay. Apoptosis was evaluated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) and real-time reverse transcription polymerase chain reaction (RT-PCR) for Bcl-2 family. Autophagy was also assessed by Western immunoblots for light chain (LC) 3B.

RESULTS

When the primary RGCs were exposed to CSE for 2 h, cell viability decreased in a dose-dependent manner, as measured by ATP assay. In the presence of 0.05% CSE, the RGC viability was 77.68% ± 7.60% compared to the control cells; in the presence of 1.0% CSE, viability was 47.48% ± 2.56% of the control cells. As determined by TUNEL, CSE increased the apoptotic RGCs in a dose-dependent manner. In the presence of 0.05% CSE, the apoptosis was 26.55% ± 1.97% of the control cells; in the presence of 2.5% CSE, it was 41.07% ± 3.75% of the control cells. When apoptosis was evaluated using real-time RT-PCR, exposure to 0.05% CSE resulted in significantly increased expression of Bad, Bax, Bcl-2, and Bcl-XL mRNA. When autophagy was assessed by Western immunoblots, exposure to 0.05% CSE significantly increased the expression of LC3B II.

CONCLUSIONS

Our data suggest that CSE directly injures primary RGCs, and both cell death mechanisms of apoptosis and autophagy seem to be related to this CSE-induced RGC damage.

Epidemiology and clinical characteristics of patients with glaucoma: An analysis of hospital data between 2003 and 2012

PURPOSE

To assess demographic and clinical characteristics of glaucoma patients in an Ophthalmologic Hospital of Jinan, China from 2003 to 2012.

MATERIALS AND METHODS

Medical charts of patients with primary open-angle glaucoma (POAG), primary angle closure glaucoma (PACG), and secondary glaucoma (SG) were reviewed. The main outcome measures of patients with glaucoma included basic demographic data (age at presentation, gender, and residence), clinical characteristics (admission date, intraocular pressure, and naked vision), and previous history (injury, cardiovascular disease, diabetes mellitus, hypertension, smoking, and alcohol consumption).

RESULTS

Data from 1458 glaucoma patients were reviewed, of which PACG and SG patients accounted for 45.40% and 47.19%, respectively. The average age of all patients with glaucoma increased from 56.05 years in 2003 to 57.83 years in 2012, and the proportion of patients from rural areas rose from 46.43% to 59.13% during 10-year period. Female gender, cardiovascular disease, and hypertension were associated with PACG. POAG was related to smoking and alcohol consumption. There was positive correlation between SG and history of injury and diabetes mellitus.

CONCLUSION

PACG and SG are the major types of glaucoma. Gender, injury, diabetes mellitus, cardiovascular disease, hypertension, smoking, and alcohol consumption were associated with different types of glaucoma.

Comparison of Risk Factor Profiles for Primary Open-Angle Glaucoma Subtypes Defined by Pattern of Visual Field Loss: A Prospective Study

PURPOSE

We explored whether risk factor associations differed by primary open-angle glaucoma (POAG) subtypes defined by visual field (VF) loss pattern (i.e., paracentral or peripheral).

METHODS

We included 77,157 women in the Nurses' Health Study (NHS) and 42,773 men in the Health Professionals Follow-up Study (HPFS 1986-2010), and incident medical record confirmed cases of paracentral (n = 440) and peripheral (n = 865) POAG subtypes. We evaluated African heritage, glaucoma family history, body mass index (BMI), mean arterial blood pressure, diabetes mellitus, physical activity, smoking, caffeine intake, and alcohol intake. We used competing risk Cox regression analyses modeling age as the metameter and stratified by age, cohort, and event type. We sequentially identified factors with the least significant differences in associations with POAG subtypes ("stepwise down" approach with P for heterogeneity [P-het] < 0.10 as threshold).

RESULTS

Body mass index was more inversely associated with the POAG paracentral VF loss subtype than the peripheral VF loss subtype (per 10 kg/m2; hazard ratio [HR] = 0.67 [95% confidence interval (CI): 0.52, 0.86] versus HR = 0.93 [95% CI: 0.78, 1.10]; P-het = 0.03) as was smoking (per 10 pack-years; HR = 0.92 [95% CI: 0.87, 0.98] versus HR = 0.98 [95% CI: 0.94, 1.01]; P-het = 0.09). These findings were robust in sensitivity analyses using a "stepwise up" approach (identify factors that showed the most significant differences). Nonheterogeneous (P-het > 0.10) adverse associations with both POAG subtypes were observed with glaucoma family history, diabetes, African heritage, greater caffeine intake, and higher mean arterial pressure.

CONCLUSIONS

These data indicate that POAG with early paracentral VF loss has distinct as well as common determinants compared with POAG with peripheral VF loss.

Bupropion use and risk of open-angle glaucoma among enrollees in a large U.S. managed care network

OBJECTIVE

Tumor Necrosis Factor (TNF) mediates retinal ganglion cell death in glaucoma. Anti-TNF drugs are neuroprotective in an animal model of glaucoma. It is unclear whether medications with anti-TNF properties such as bupropion have an impact on the risk of developing open-angle glaucoma (OAG) in humans. The purpose of this study is to determine whether bupropion use alters the risk of developing OAG.

METHODS

Claims data for beneficiaries age ≥35 years with no pre-existing OAG enrolled in a large nationwide U.S. managed care network continuously for ≥4 years between 2001-2011 was analyzed to identify patients who had been newly-diagnosed with OAG. The amount of bupropion use as captured from outpatient pharmacy claims over a four-year period was also quantified for each beneficiary. Multivariable Cox regression modeling assessed the impact of bupropion and other antidepressant medications on the risk of developing OAG with adjustment for sociodemographic characteristics of the enrollees along with medical and ocular comorbidities.

RESULTS

Of 638,481 eligible enrollees, 15,292 (2.4%) developed OAG. After adjustment for confounding factors including use of other antidepressant medication classes, each additional month of bupropion use was associated with a 0.6% reduced risk of OAG (HR = 0.994, (95% CI: 0.989-0.998), p = 0.007). Compared to nonusers, those with 24-48 months of bupropion use had a 21% reduced hazard (HR=0.79, (CI: 0.65-0.94), p = 0.0099) of OAG. This association did not differ among persons taking bupropion for depression or for other reasons (p-interaction = 0.82). There was no significant association between use of tricyclic antidepressants (HR = 1.000, (CI: 0.997-1.004), p = 0.95) or selective serotonin reuptake inhibitors (HR = 0.999, (CI: 0.997-1.001), p = 0.39) and development of OAG.

CONCLUSION

These findings suggest bupropion use may be beneficial in reducing the risk of OAG. If prospective studies confirm the findings of this analysis, this may identify a novel therapeutic target for OAG.

Comparison of risk factors for initial central scotoma versus initial peripheral scotoma in normal-tension glaucoma

Purpose

To investigate the risk factors for initial central scotoma (ICS) compared with initial peripheral scotoma (IPS) in normal-tension glaucoma (NTG).

Methods

Fifty-six NTG patients (56 eyes) with an ICS and 103 NTG patients (103 eyes) with an IPS were included. Retrospectively, the differences were assessed between the two groups for baseline characteristics, ocular factors, systemic factors, and lifestyle factors. Also, the mean deviation of visual field was compared between the two groups.

Results

Patients from both ICS and IPS groups were of similar age, gender, family history of glaucoma, and follow-up periods. Frequency of disc hemorrhage was significantly higher among patients with ICS than in patients with IPS. Moreover, systemic risk factors such as hypotension, migraine, Raynaud's phenomenon, and snoring were more prevalent in the ICS group than in the IPS group. There were no statistical differences in lifestyle risk factors such as smoking or body mass index. Pattern standard deviation was significantly greater in the ICS group than in the IPS group, but the mean deviation was similar between the two groups.

Conclusions

NTG Patients with ICS and IPS have different profiles of risk factors and clinical characteristics. This suggests that the pattern of initial visual field loss may be useful to identify patients at higher risk of central field loss.

Nicotine accelerates diabetes-induced retinal changes

PURPOSE

To investigate the effects of nicotine on retinal alterations in early-stage diabetes in an established rodent model.

MATERIALS AND METHODS

Sprague-Dawley rats were examined using a combination of confocal scanning laser ophthalmoscopy and spectral domain optical coherence tomography to determine changes in retinal structure in response to nicotine exposure, diabetes and the combined effects of nicotine and diabetes. Diabetes was induced by a single injection of 65 mg/kg streptozotocin and nicotine injections were administered subcutaneously daily. Retinal thickness in the superior, inferior, nasal and temporal quadrants were determined based on the spectral domain optical coherence tomography (SD-OCT) volume scans (20° × 20°) centered on the optic disc. Segmentation of discrete retinal layers was performed on a subset of SD-OCT cross-sections to further examine changes in each treatment group. Survival of neurons within the ganglion cell layer (GCL) was assessed by confocal morphometric imaging.

RESULTS

The control group did not experience any significant change throughout the study. The nicotine treatment group experienced an average decrease in total retinal thickness (TRT) of 9.4 µm with the majority of the loss localized within the outer nuclear layer (ONL) as determined by segmentation analysis (p < 0.05). The diabetic group exhibited a trend toward decreased TRT while segmentation analysis of the diabetic retinopathy (DR) group revealed significant thinning within the ONL (p < 0.05). The combination of nicotine and diabetes revealed a significant increase of 8.9 µm in the TRT (p < 0.05) accompanied by a decrease in the number of GCL neurons.

CONCLUSIONS

We demonstrated significant temporal changes in retinal morphology in response to nicotine exposure, diabetes and with the combined effects of nicotine and diabetes. These findings may have implications in determining treatment strategies for diabetic patients using products containing nicotine, such as cigarettes, smokeless tobacco, electronic cigarettes or smoking cessation products.

Relation of smoking, drinking, and physical activity to changes in vision over a 20-year period: the Beaver Dam Eye Study

OBJECTIVE

To describe the relationships of lifestyle characteristics to changes in vision and incidence of visual impairment (VI) over a 20-year period in the Beaver Dam Eye Study (BDES).

DESIGN

Longitudinal, population-based cohort study.

PARTICIPANTS

A cohort of 4926 persons aged 43 to 86 years participated in the baseline examinations in 1988-1990, and 3721, 2962, 2375, and 1913 persons participated in follow-up examinations in 1993-1995, 1998-2000, 2003-2005, and 2008-2010, respectively.

METHODS

Best-corrected visual acuity (BCVA) measured by a modified Early Treatment Diabetic Retinopathy Study protocol.

MAIN OUTCOME MEASURES

Change in number of letters read correctly and incidence of VI based on BCVA in the better eye assessed at each examination over a 20-year period.

RESULTS

The 20-year cumulative incidence of VI was 5.4%. There was a mean loss of 1.6 letters between examinations, with a 20-year loss of 6.6 letters. While adjusting for age, income, and age-related macular degeneration (AMD) severity, being a current or past smoker was related to a greater change in the numbers of letters lost. Persons who had not consumed alcoholic beverages over the past year and sedentary persons had higher odds of incident VI than persons who drank occasionally or who were physically active. For example, in women with early AMD and annual household income less than $10,000, the estimated 20-year cumulative incidence of VI in those who drank occasionally and were physically active was 5.9% compared with 25.8% in women who had not consumed alcoholic beverages over the past year and were sedentary.

CONCLUSIONS

Three modifiable behaviors-smoking, drinking alcohol, and physical activity-were associated with changes in vision. Further evidence that changes in these behaviors will result in less loss of vision is needed because of the expected increase in the burden of VI due to the aging of the population.

Association of smoking with intraocular pressure in middle-aged and older Japanese residents

OBJECTIVES

To clarify whether smoking was associated with elevated intraocular pressure (IOP) and to evaluate the interrelationship among IOP, blood viscosity, and smoking.

METHODS

This cross-sectional study analyzed health examination data obtained between 2001 and 2004 from 1113 individuals (829 men and 284 women), ranging in age from 28 to 79 years, who had not undergone any ocular surgery or medical treatment for hypertension, ocular hypertension, and glaucoma.

RESULTS

Multiple-regression analysis showed that systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), and number of cigarettes smoked per day had a significantly positive association with IOP in men (P < 0.05). In women also, SBP, DBP, and BMI were positively related to IOP (P < 0.05). On the contrary, age had a significant negative association with IOP in both sexes (P < 0.01). Analysis of covariance and multiple logistic regression analyses showed that the adjusted mean IOP and the multivariate odds ratios for IOP increased with increasing cigarette consumption in men (P for trend = 0.01 and 0.06, respectively). Analysis of covariance found that smoking was significantly associated with both high IOP and high hematocrit in men (P for trend <0.05); however, the adjusted mean IOP values were higher in smokers than in nonsmokers, regardless of the hematocrit level.

CONCLUSIONS

The results of this study suggested that the IOP level may be substantially affected by smoking habit in middle-aged and older Japanese men.

Association analysis of cigarette smoking with onset of primary open-angle glaucoma and glaucoma-related biometric parameters

Background

To date, studies on the role played by cigarette smoking in primary open-angle glaucoma (POAG) remains controversial. The current study evaluated cigarette smoking as a risk factor of POAG and its relationships with vertical cup-to-disc ratio (VCDR), central corneal thickness (CCT) and intraocular pressure (IOP) in a Chinese cohort.

Methods

In a total of 248 unrelated individuals including 30 juvenile-onset POAG (JOAG), 92 adult-onset POAG (AOAG) and 126 sex-matched senile cataract controls, underwent comprehensive ophthalmic examination. Their smoking was obtained and documented by questionnaire. Association of cigarette smoking with POAG was performed using logistic regression controlled for age and sex. Effects of cigarette smoking on VCDR, IOP and CCT were analyzed with multiple linear regression.

Results

In either JOAG or AOAG, no association of cigarette smoking was found with disease onset (P = 0.692 and 0.925 respectively). In controls and JOAG, no significant effects of smoking were found on VCDR, IOP or CCT (all P > 0.05). Smoking was found to be correlated with decreased CCT in AOAG and combined POAG (JOAG + AOAG) (P = 0.009 and 0.003), but no association with VCDR or IOP was observed (P > 0.05).

Conclusions

Although cigarette smoking was not found to be risk factor for onset of POAG, it was correlated with CCT in AOAG, and thus might still play a role in the disease course, especially for AOAG.

The effects of nicotine on the human electroretinogram

PURPOSE

To examine the effects of nicotine on responses from the human retina measured electrophysiologically.

METHODS

Electroretinogram (ERG) responses were obtained from ten healthy, visually normal adults who were nonsmokers. Nicotine (2 and 4 mg) and a placebo were administered in the form of gum 30 minutes before testing in two separate experiments. ERG responses were collected and analyzed using a full-field ERG system. Responses were recorded from one eye of each subject using a bipolar contact-lens electrode. Intensity-response curves were obtained under both dark- and light-adapted conditions. In experiment 1, both dark- and light-adapted tests were completed sequentially. In experiment 2, only light-adapted testing was performed. Intensity-response functions were analyzed using the Naka-Rushton equation.

RESULTS

In experiment 1, compared with placebo, dark-adapted b-wave amplitude responses decreased significantly after chewing gum containing both 2 and 4 mg of nicotine. Under light-adapted conditions, the peak b-wave amplitude was significantly decreased after chewing gum containing 4 mg of nicotine. In experiment 2, light-adapted b-wave amplitudes were increased after 4 mg nicotine. Oscillatory potentials were measured but no significant effects under nicotine were observed.

CONCLUSIONS

To the knowledge of the authors, this is the first demonstration that nicotine by itself affects responses in the human retina. These data support reports of the expression of nicotinic acetylcholine receptors in rabbit and nonhuman primate retina.

Expression of myocilin mutants sensitizes cells to oxidative stress-induced apoptosis: implication for glaucoma pathogenesis

Mutations in the myocilin gene are associated with juvenile and adult-onset primary open-angle glaucoma. However, the pathogenic mechanisms of myocilin-induced glaucoma are still largely unknown. To investigate these mechanisms, we developed stably transfected HEK293 cell lines expressing wild-type or mutant (Y437H and I477N) myocilins under an inducible promoter. Expression of two mutant myocilins led to different levels of endoplasmic reticulum stress and increased apoptosis after treatment of cells with hydrogen peroxide. The Y437H mutant myocilin cell line showed the highest sensitivity to the oxidant treatment. Several antioxidant genes were down-regulated in the Y437H mutant myocilin cell line, but not in other cell lines. The Y437H mutant myocilin cell line also produced more reactive oxygen species than other cell lines examined. Consistent with the data obtained in cultured cells, the endoplasmic reticulum stress marker, 78 kDa glucose-regulated protein, was up-regulated, whereas antioxidant proteins, paraoxonase 2 and glutathione peroxidase 3, were down-regulated in the eye angle tissue of 18-month-old transgenic mice expressing Y437H myocilin mutant. In addition, a pro-apoptotic factor, CCAAT/enhancer-binding protein-homologous protein, was up-regulated in the aged transgenic mouse angle tissue. Our results suggest that expression of mutated myocilins may have a sensitization effect, which can lead to a severe phenotype in combination with oxidative stress. Mutant myocilins may confer different sensitivity to oxidative stress depending on the mutation.