Influence of tobacco use on cataract development

Environmental exposures to cadmium and lead as potential causes of eye diseases

Humans are exposed to cadmium and lead in various regions of the world daily due to industrial development and climate change. Increasing numbers of preclinical and clinical studies indicate that heavy metals, such as cadmium and lead, play a role in the pathogenesis of eye diseases. Excessive exposure to heavy metals such as cadmium and lead can increase the risk of impaired vision. Therefore, it is essential to better characterize the role of these non-essential metals in disease etiology and progression. This article discusses the potential role of cadmium and lead in the development of age-related eye diseases, including age-related macular degeneration, cataracts, and glaucoma. Furthermore, we discuss how cadmium and lead affect ocular cells and provide an overview of putative pathological mechanisms associated with their propensity to damage the eye.

Unveiling the Impact of Electronic Cigarettes (EC) on Health: An Evidence-Based Review of EC as an Alternative to Combustible Cigarettes

Cigarette smoking has been considered a major public health concern due to its serious impact on health. However, smokers intending to quit may find long-term abstinence challenging. When smoking an electronic cigarette (EC), users can experience a sensation and taste similar to that of smoking a combustible cigarette. Therefore, manufacturers promote these products as a viable substitute for combustible cigarettes. However, several researchers report the serious health impacts experienced by EC users. Therefore, this review aims to examine the health impacts of EC use. Based on the findings of the research papers reported in the literature, the role of EC as a smoking cessation tool is unclear. Several researchers have also reported a significant association between EC usage among non-smokers at baseline and the future initiation of combustible cigarette smoking. EC use significantly impacts user health. The nicotine that is present in EC e-liquids can elevate blood pressure, resulting in blood vessel constriction and an increase in heart rate, ultimately leading the body to an ischemic condition, resulting in myocardial infarction (MI), stroke, and increased arterial stiffness. Researchers report a higher likelihood of prediabetes among EC users; its usage was associated with higher OR of having asthma attacks and higher OR of reporting depression and has an impact on birth outcomes among pregnant women. Men using EC are more likely to report erectile dysfunction than non-users. EC also has a significant impact on oral health, which includes periodontal diseases, mucosal lesions, irritation in the mouth and throat, reduced salivary flow, and an increased risk of developing cancer. The physical injury resulting from exploding EC is another health concern. The frequently burned areas included the hands, face, genitalia, and thighs. Marketers promote EC as an alternative to combustible cigarettes and a tool for quitting smoking. However, the Food and Drug Administration has not approved them for smoking cessation. EC can have a serious impact on the health of their users; hence, the findings of this paper have several implications, including the need for regulation of the sales and marketing of these products and educating the users on the impact of these products on their health and safety.

Association of Alpha-Crystallin with Human Cortical and Nuclear Lens Lipid Membrane Increases with the Grade of Cortical and Nuclear Cataract

Eye lens α-crystallin has been shown to become increasingly membrane-bound with age and cataract formation; however, to our knowledge, no studies have investigated the membrane interactions of α-crystallin throughout the development of cataracts in separated cortical membrane (CM) and nuclear membrane (NM) from single human lenses. In this study, four pairs of human lenses from age-matched male and female donors and one pair of male lenses ranging in age from 64 to 73 years old (yo) were obtained to investigate the interactions of α-crystallin with the NM and CM throughout the progression of cortical cataract (CC) and nuclear cataract (NC) using the electron paramagnetic resonance spin-labeling method. Donor health history information (diabetes, smoker, hypertension, radiation treatment), sex, and race were included in the data analysis. The right eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 1, NC: 2), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Similarly, left eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 2, NC: 3), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Analysis of α-crystallin binding to male and female eye lens CM and NM revealed that the percentage of membrane surface occupied (MSO) by α-crystallin increases with increasing grade of CC and NC. The binding of α-crystallin resulted in decreased mobility, increased order, and increased hydrophobicity on the membrane surface in male and female eye lens CM and NM. CM mobility decreased with an increase in cataracts for both males and females, whereas the male lens NM mobility showed no significant change, while female lens NM showed increased mobility with an increase in cataract grade. Our data shows that a 68 yo female donor (long-term smoker, pre-diabetic, and hypertension; grade 3 CC) showed the largest MSO by α-crystallin in CM from both the left and right lens and had the most pronounced mobility changes relative to all other analyzed samples. The variation in cholesterol (Chol) content, size and amount of cholesterol bilayer domains (CBDs), and lipid composition in the CM and NM with age and cataract might result in a variation of membrane surface mobility, membrane surface hydrophobicity, and the interactions of α-crystallin at the surface of each CM and NM. These findings provide insight into the effect of decreased Chol content and the reduced size and amount of CBDs in the cataractous CM and NM with an increased binding of α-crystallin with increased CC and NC grade, which suggests that Chol and CBDs might be a key component in maintaining lens transparency.

Age-related cataract - Prevalence, epidemiological pattern and emerging risk factors in a cross-sectional study from Central India

Purpose

To study the epidemiological pattern, prevalence, types, and correlates of age-related cataracts in a tertiary care center in central India.

Methods

This hospital-based single-center cross-sectional study was conducted on 2,621 patients diagnosed with cataracts for 3 years. Data pertaining to demography, socio-economic profile, cataract grading, cataract types, and associated risk factors were evaluated. Statistical analysis using unadjusted odds ratio (OR) and multivariate logistic regression was performed, with P-value <0.05 considered significant with the power of the study being 95%.

Results

The commonest age group affected was 60-79 years, closely followed by the 40-59 years age group. The prevalence of nuclear sclerosis (NS), cortical (CC), and posterior subcapsular cataract (PSC) was found to be 65.2% (3,418), 24.6% (1,289), and 43.4% (2,276), respectively. Among mixed cataracts, (NS + PSC) had the highest prevalence of 39.8%. Smokers were found to have 1.17 times higher odds of developing NS than non-smokers. Diabetics had 1.12 times higher odds of developing NS cataracts and 1.04 times higher odds of developing CC. Patients with hypertension showed 1.27 times higher odds of developing NS and 1.32 times higher odds of developing CC.

Conclusion

The prevalence of cataracts in the pre-senile age group (<60 years) was found to have increased significantly (35.7%). A higher prevalence of PSC (43.4%) was found in studied subjects, as compared to the data of previous studies. Smoking, diabetes, and hypertension were found to have a positive association with a higher prevalence of cataracts.

Changing Trends in the Disease Burden of Cataract and Forecasted Trends in China and Globally from 1990 to 2030

Aim

To explore the trends in the prevalence and disease burden of cataract from 1990 to 2019, evaluate attributable risk factors, and predict trends over the next decade in China and globally.

Methods

Data was obtained from Global Burden of Disease Study 2019. We calculated the age-standardized prevalence rate (ASR) and annual percentage change (EAPC) to show the trends of cataract in China and different regions. We calculated and reported the proportion of disability adjusted life years (DALYs) attributable to risk factors by sex in China and different regions. Then, the Bayesian age-period-cohort (BAPC) analysis model was also used to predict the prevalence trends from 2020 to 2030 in China and globally.

Results

The ASR increased from 867.09 in 1990 to 991.56 in 2019 per 100,000 with an EAPC of 0.88 in China. The age-standardized DALY rate of females was higher than males. DALY rates were correlated to household air pollution from solid fuels, tobacco, high fasting plasma glucose and high body-mass index. The projective model indicates that the ASR for cataracts will rise to 1101.35×10⁶ for male and 1616.63×10⁶ for female by 2030.

Conclusion

The trends from 1990 to 2030 suggested that the burden of cataract remains high in China. Maintaining good lifestyle habits such as switching to clean energy, reducing cigar intake, controlling blood glucose and weight can reduce the risk of cataracts. As aging increases, China should pay more attention to cataract-induced low vision and blindness and develop public policies to reduce the disease burden.

Effects of Type 2 Diabetes Mellitus and Smoking on Changes in Corneal Endothelial Morphology and Cell Density

PURPOSE

The purpose of this study was to compare the corneal endothelial morphology and cell density of diabetic smokers and nonsmokers with 50 to 70 age-matched healthy subjects and to determine whether smoking increases the effects of type 2 diabetes mellitus (DM) on these corneal parameters.

METHODS

This prospective cohort study included 200 patients who were assigned to 4 groups, including smokers with type 2 DM (group 1), nonsmokers with type 2 DM (group 2), healthy smokers (group 3), and healthy nonsmokers (control group, group 4). Noncontact specular microscopy was used to measure central endothelial cell density (ECD), coefficient of variation of cell area, percentage of hexagonal cells, and central corneal pachymetry (CCT).

RESULTS

According to the ECD and CCT values ( P < 0.001 and P = 0.013, respectively), a significant difference was observed between the groups. The mean ECD was lowest in diabetic smokers (1917 ± 399 cells/mm 2 ). Healthy smokers and diabetic smokers had significantly lower ECD compared with the control group ( P = 0.03 and P < 0.001, respectively). Healthy smokers and diabetic smokers had significantly lower ECD compared with diabetic nonsmokers ( P = 0.012 and P < 0.001, respectively). The cornea was significantly thicker in the diabetic smokers than in the control group ( P = 0.013).

CONCLUSIONS

The coexistence of DM and smoking causes a significant decrease in ECD and an increase in CCT. Cigarette smoking is more harmful to corneal endothelial cells than DM alone.

Relationship between cooking fuel and lens opacities in South India: a 15-year prospective cohort study

PURPOSE

Unclean cooking fuels such as wood and kerosene have been associated with cataract in cross-sectional studies. This study sought to determine whether exposure to unclean cooking fuels was associated with subsequent cataract progression.

DESIGN

Prospective cohort study.

METHODS

This is a secondary observational analysis of the community-based Antioxidants in Prevention of Cataracts trial (ClinicalTrials.gov ID NCT01664819). The exposure of interest was cooking fuel type, measured at baseline. Main outcome measures were baseline cataract severity and self-reported cataract surgery at a 15-year visit.

RESULTS

Baseline and 15-year follow-up data were available for 798 and 579 participants, respectively. Wood or kerosene was used by 711/798 (89.1%) baseline participants, including 539/579 (93.1%) participants with complete follow-up. Cooking fuel type was not associated with cataract severity at baseline (p=0.443). Out of 8,334 person-years of follow up, 90 cataract surgeries were observed over 15 years (1.08 surgeries per 100 person-years; 95%CI 0.87-1.32). Use of wood or kerosene was not associated with 15-year incidence of cataract surgery relative to individuals using propane (adjusted p=0.154). Cataract surgery was more common in older individuals (HR 1.1 per year, 95%CI 1.1-1.2, p<0.001), those with baseline myopia (HR 2.1, 95%CI 1.2-3.5, p=0.009) and women (HR 3.5, 95%CI 1.2 to 10.1, p=0.019).

CONCLUSIONS

This study found no association between unclean cooking fuels and cataract progression over a 15-year period. No other modifiable risk factors were associated with incident self-reported cataract surgery.

Ergonomic lighting considerations for the home office workplace

BACKGROUND: The COVID-19 pandemic has resulted in a large increase in the use of the home office environment. Compared to traditional commercial offices, home offices typically have more variable lighting conditions that can affect the worker’s performance and well-being. OBJECTIVE: To review and discuss various lighting sources and their ergonomic impacts on the population of office employees now working from home. Specifically addressing the impacts of electronic light from screens, daylight, and task lighting’s impact on health and well-being in the frame of the COVID-19 pandemic. METHODS: Over 75 ergonomic and lighting literature publications covering various work environments were reviewed, with a focus on the health effects of screen light, daylight, and task light. RESULTS: Resulting from the literature review, design recommendations regarding the safety and health of home office lighting conditions are discussed. CONCLUSION: As COVID-19 continues to encourage remote working, individuals will be exposed to daylight and screen light in different ways compared to a traditional office environment. The impact of these different lighting conditions should be further studied to understand best design and well-being practices.

The Adverse Effects of Air Pollution on the Eye: A Review

Air pollution is inevitably the result of human civilization, industrialization, and globalization. It is composed of a mixture of gases and particles at harmful levels. Particulate matter (PM), nitrogen oxides (NOx), and carbon dioxides (CO₂) are mainly generated from vehicle emissions and fuel consumption and are the main materials causing outdoor air pollution. Exposure to polluted outdoor air has been proven to be harmful to human eyes. On the other hand, indoor air pollution from environmental tobacco smoking, heating, cooking, or poor indoor ventilation is also related to several eye diseases, including conjunctivitis, glaucoma, cataracts, and age-related macular degeneration (AMD). In the past 30 years, no updated review has provided an overview of the impact of air pollution on the eye. We reviewed reports on air pollution and eye diseases in the last three decades in the PubMed database, Medline databases, and Google Scholar and discussed the effect of various outdoor and indoor pollutants on human eyes.

Nicotine Use Disorder in Older Adults

Nicotine is one of the most abused substances worldwide. Just as in adolescence and adulthood, tobacco use is also problematic in the elderly. Older people are more vulnerable to smoking consequences because of the additive effects of smoke. Cardiovascular diseases are the most common health problems associated with smoking; however, other systems are also affected, including the respiratory, nervous, integumentary, and many other systems. Smoking cessation is a difficult task especially in the elderly; therefore, physicians should encourage older patients to quit with every patient-physician encounter by offering counseling and replacement therapy.

Redox chemistry of lens crystallins: A system of cysteines

The nuclear region of the lens is metabolically quiescent, but it is far from inert chemically. Without cellular renewal and with decades of environmental exposures, the lens proteome, lipidome, and metabolome change. The lens crystallins have evolved exquisite mechanisms for resisting, slowing, adapting to, and perhaps even harnessing the effects of these cumulative chemical modifications to minimize the amount of light-scattering aggregation in the lens over a lifetime. Redox chemistry is a major factor in these damages and mitigating adaptations, and as such, it is likely to be a key component of any successful therapeutic strategy for preserving or rescuing lens transparency, and perhaps flexibility, during aging. Protein redox chemistry is typically mediated by Cys residues. This review will therefore focus primarily on the Cys-rich γ-crystallins of the human lens, taking care to extend these findings to the β- and α-crystallins where pertinent.

Connexin Gap Junctions and Hemichannels in Modulating Lens Redox Homeostasis and Oxidative Stress in Cataractogenesis

The lens is continuously exposed to oxidative stress insults, such as ultraviolet radiation and other oxidative factors, during the aging process. The lens possesses powerful oxidative stress defense systems to maintain its redox homeostasis, one of which employs connexin channels. Connexins are a family of proteins that form: (1) Hemichannels that mediate the communication between the intracellular and extracellular environments, and (2) gap junction channels that mediate cell-cell communication between adjacent cells. The avascular lens transports nutrition and metabolites through an extensive network of connexin channels, which allows the passage of small molecules, including antioxidants and oxidized wastes. Oxidative stress-induced post-translational modifications of connexins, in turn, regulates gap junction and hemichannel permeability. Recent evidence suggests that dysfunction of connexins gap junction channels and hemichannels may induce cataract formation through impaired redox homeostasis. Here, we review the recent advances in the knowledge of connexin channels in lens redox homeostasis and their response to cataract-related oxidative stress by discussing two major aspects: (1) The role of lens connexins and channels in oxidative stress and cataractogenesis, and (2) the impact and underlying mechanism of oxidative stress in regulating connexin channels.

Incidence, Incident Causes, and Risk Factors of Visual Impairment and Blindness in a Rural Population in India: 15-Year Follow-up of the Andhra Pradesh Eye Disease Study

PURPOSE

To report 15-year incidence rate of visual loss (blindness and visual impairment [VI]), causes, and risk factors for participants in Andhra Pradesh Eye Disease Study III (APEDS III).

DESIGN

Population-based cohort study.

METHODS

From 2012 to 2016, all rural participants were interviewed and underwent a comprehensive eye examination, including dilated fundus examination and imaging. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were measured using a standard logarithm of Minimum Angle of Resolution chart at 3 meters. World Health Organization (WHO) and United States of America (USA) categories of VI and blindness were used. Incident visual loss was defined as the development of or worsening of visual loss of one or more categories.

RESULTS

In APEDS I, 7,771 rural participants were examined using stratified, random-cluster systematic sampling; in APEDS III, 5,395 participants (69.4% of rural or 52.4% of total participants) were re-examined. Using WHO categories, the crude incidence rate of any visual loss based on PVA and BCVA were 14.6 (95% confidence interval [CI]:13.6-15.7) and 6.3 (95% CI: 6.1-6.4) per 100 person-years, respectively. Using USA criteria, the values were 22.6 (95% CI: 22.3-23.0) and 10.6 (95% CI: 10.3-10.8) per 100 person-years, respectively. More than 90% of visual loss was attributable to cataract and uncorrected refractive error. Using WHO categories, significant independent risk factors for the incident visual loss were increasing age, female gender, illiteracy, past or current smoker, and current use of alcohol. Using the USA definition, an additional risk factor was lower level of education.

CONCLUSIONS

The high incidence likely reflects poor access to eye care in this population, which needs to be taken into account when planning eye care programs.

Age-related cataract and 10-year mortality: the Liwan Eye Study

PURPOSE

To explore the association between age-related cataract and 10-year mortality in an adult population in urban China.

METHODS

A total of 1405 participants aged 50 years or older were examined at baseline in the Guangzhou Liwan Eye Study. All participants were invited to attend a 10-year follow-up visit. Cataract cases were defined as either having visible lens opacity confirmed with direct ophthalmoscope under pupil dilation or previous history of cataract surgery. Visual impairment (VI) was defined as a visual acuity of 20/40 or worse in the better-seeing eye with habitual correction if worn. Body mass index (BMI) was based on anthropometric data. A brief questionnaire regarding family income, educational attainment and medical history of systemic disease was administered. Mortality rates were compared using the log-rank test and Cox proportional hazards regression models.

RESULTS

Among 1405 participants examined at baseline, 957 participants (68.1%) had visible lens opacity or history of cataract surgery. After 10 years, 320 (22.8%) participants died. The 10-year mortality rate was significantly higher in participants with cataract than in those without (30.1% versus 7.14%, log-rank p < 0.05). After adjusting for age, gender, family income, educational attainment, BMI, history of diabetes and hypertension and presence of VI, presence of cataract predicted a nearly threefold increase in the risk of mortality (HR, 2.99; 95% CI, 1.89-4.71).

CONCLUSIONS

Our findings that age-related cataract is a predictor for poorer survival compared to those without may imply that cataract is a biomarker of ageing and frailty.

Association of cataract and sun exposure in geographically diverse populations of India: The CASE study. First Report of the ICMR-EYE SEE Study Group

Purpose

To determine the prevalence of cataract and its association with sun exposure and other environmental risk factors in three different geographically diverse populations of India.

Design

Population based cross sectional study during 2010–2016

Participants

People aged ≥ 40 years residing in randomly sampled villages were enumerated (12021) and 9735 (81%) underwent ophthalmic evaluation from plains, hilly and coastal regions (3595, 3231, 2909 respectively)

Methods

A detailed questionnaire-based interview about outdoor activity in present, past and remote past, usage of sun protective measures, exposure to smoke, and detailed ophthalmic examination including assessment of uncorrected and best corrected visual acuity, measurement of intraocular pressure, slit lamp examination, lens opacities categorization using LOCS III and posterior segment evaluation was done. Lifetime effective sun exposure was calculated using Melbourne formula and expressed as quintiles. These were supplemented with physical environmental measurements.

Main outcome measures

Lifetime sun exposure hours, smoking, indoor kitchen smoke exposure and their association with cataract and subtypes. Prevalence of cataract calculated based on lens opacities or evidence of cataract surgery.

Results

Cataract was identified in 3231 (33.3%) participants. Prevalence of cataract in males (32.3%) and females (34.1%) was similar. Nuclear cataract was the commonest sub-type identified in 94.7% of affected eyes. Sun exposure had a significant association with cataract with odds ratio (OR) increasing from 1.6 (95% Confidence Intervals [CI]: 1.4, 1.9) in 3^rd quintile, to 2.6 (CI: 2.2, 3.1) in 4^th quintile and 9.4 (CI: 7.9, 11.2) in 5^th quintile (p<0.0001). Cataract also showed a significant association with smoking (OR: 1.4, CI: 1.2, 1.6) and indoor kitchen smoke exposure (OR: 1.2, CI: 1.0–1.4). Nuclear cataract showed a positive association with increasing sun exposure in 3^rd (β coefficient 0.5, CI:0.2–0.7), 4^th (β: 0.9, CI: 0.7–1.1) and 5^th (β: 2.1, CI:1.8–2.4) quintiles of sun exposure, smoking (β: 0.4, CI: 0.2–0.6) and indoor kitchen smoke exposure (β: 0.3, CI: 01–0.5) while cortical cataract showed a positive association with sun exposure only in 5^th quintile (β: 2.6, CI:1.0–4.2). Posterior subcapsular cataract was not associated with any of the risk factors.

Conclusion

Cataract is associated with increasing level of sun exposure, smoking and exposure to indoor kitchen smoke.

Estimation of superoxide dismutase levels in saliva and gingival crevicular fluid among smokers and non-smokers in periodontitis patients - An Observational Study

Background:

Smoking, which is an important risk factor for periodontitis, induces oxidative stress in the body and causes an imbalance between reactive oxygen species (ROS) and antioxidants, such as superoxide dismutase (SOD). The present study was done to quantify and compare the level of SOD enzyme levels in gingival crevicular fluid (GCF) and saliva among smokers and nonsmokers.

Methodology:

One hundred and thirty-five individuals in the age range of 20–55 years, including 45 light smokers, 45 heavy smokers, and 45 nonsmokers (controls), were selected and the clinical parameters recorded were plaque index, probing depth, and attachment loss. Smokers were divided into light smokers (<10 cigarettes/day) and heavy smokers (>10 cigarettes/day) and into three subgroups: healthy, mild periodontitis, and moderate periodontitis. GCF and saliva samples were collected then SOD levels were analyzed using spectrophotometric assay.

Results:

The mean levels of SOD in the GCF and saliva of smokers were decreased compared to controls. Intra- and inter-group analyses showed a significant reduction in the levels of SOD in the GCF and saliva of heavy smokers compared to light smokers and the control group.

Conclusions:

There was a progressive reduction in SOD levels from healthy nonsmokers to light smokers to heavy smokers.

Risk of cataract in smokers: A meta-analysis of observational studies

OBJECTIVE

The aim of the study was to compare the risk of cataract in smokers and ex-smokers.

METHODS

A systematic search of observational studies was carried out in Medline, Embase, and Lilacs databases. Studies that have evaluated the association between cigarette smoking and any type of clinically diagnosed cataract were selected. The association estimators were extracted, adjusted at least by age, and were combined using random-effects models, by subtype of study (cohort, case control and cross sectional), subtype of cataract (nuclear, cortical, and posterior subcapsular), and exposure (current smoker or ex-smoker). Statistical heterogeneity, meta-regression analysis and publication bias were assessed.

RESULTS

A total of 13 cohort studies, 12 case-control studies, and 18 cross-sectional studies were selected. A risk of cataract was found in current smokers: cohort (OR: 1.41; 95%CI: 1.24-1.60), cases and controls (OR: 1.45; 95%CI: 1.08-1.96), and cross-sectional studies (OR: 1.21; 95%CI: 1.09-1.34); risk of nuclear cataract: cohort (OR: 1.71; 95%CI: 1.47-1.98), case-control (OR: 1.79; 95%CI: 1.43-2.25), and cross sectional studies (OR: 1.45; 95%CI: 1.27-1.65). There was no risk of cortical or posterior subcapsular cataract in ex-smokers.

CONCLUSIONS

There is a risk of cataract in smokers, particularly nuclear type. With cross-sectional studies, similar results are obtained with cohorts and cases and controls.

A comparative clinical study on the generation of nitrosative stress in cataractous lenses of smokers and non-smoker tobacco patients

AIM:

To quantify the levels of nitric oxide, inducible nitric oxide synthase, and 3-nitrotyrosine in cataractous lenses of smokers and smokers who chewed tobacco in comparison with non-smokers and non-smokers who chewed tobacco.

STUDY DESIGN:

A total of 80 cataractous lenses from smokers, non-smokers, smokers with tobacco chewing habit, and non-smokers with tobacco chewing habit were collected from the patients who had enrolled in the Department of Ophthalmology, Mahatma Gandhi Medical College & Research Institute, Puducherry.

METHODS:

Levels of nitric oxide, inducible nitric oxide synthase, and 3-nitrotyrosine were quantified using commercially available enzyme-linked immunosorbent assay kits.

RESULTS:

The mean concentrations of lens nitric oxide, inducible nitric oxide synthase, and 3-nitrotyrosine are as follows: (a) smokers-112.01, 59.57, and 88.91 µmol/L; (b) smokers who chewed tobacco-175.15, 93.95, and 128.72 µmol/L; (c) non-smokers-76.15, 40.65, and 70.20 µmol/L; and (d) non-smokers who chewed tobacco-96.56, 52.87, and 83.88 µmol/L, respectively.

CONCLUSION:

Nitric oxide, inducible nitric oxide synthase, and 3-nitrotyrosine at high levels are the major causative agents for cataractogenesis. The results of this study suggest that smoking and tobacco chewing habit generate nitrosative stress that could enhance the pathogenesis for early cataractogenesis.

Prevention of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) compromises quality of life. However, the available therapeutic options are limited. This has led to the identification of modifiable risk factors to prevent the development or alter the natural course and prognosis of AMD. The identification and modification of risk factors has the potential for greater public health impact on reducing morbidity from AMD. Likewise, identifying the imaging clues and genetic clues could serve as a guide to recognizing the propensity for progression to severe and end stages of the disease. Several attempts, both successful and unsuccessful, have been made for interventions that could delay the progression of AMD. Of these, pharmacological interventions have shown promising results. The Age-Related Eye Disease Study 1 and 2 have shown the beneficial role of antioxidants in a selected group of patients.

Nicotine exposure exacerbates development of cataracts in a type 1 diabetic rat model

Diabetes and smoking are known risk factors for cataract development. In this study, we evaluated the effect of nicotine on the progression of cataracts in a type 1 diabetic rat model. Diabetes was induced in Sprague-Dawley rats by a single injection of 65 mg/kg streptozotocin. Daily nicotine injections were administered subcutaneously. Forty-five rats were divided into groups of diabetics with and without nicotine treatment and controls with and without nicotine treatment. Progression of lens opacity was monitored using a slit lamp biomicroscope and scores were assigned. To assess whether systemic inflammation played a role in mediating cataractogenesis, we studied serum levels of eotaxin, IL-6, and IL-4. The levels of the measured cytokines increased significantly in nicotine-treated and untreated diabetic animals versus controls and demonstrated a positive trend in the nicotine-treated diabetic rats. Our data suggest the presence of a synergistic relationship between nicotine and diabetes that accelerated cataract formation via inflammatory mediators.

Smoking as a risk factor for cystoid macular edema complicating intermediate uveitis

PURPOSE

To describe risk factors for the presence of cystoid macular edema (CME) among patients presenting with intermediate uveitis.

DESIGN

Cross-sectional study.

METHODS

SETTINGS

Single-center, academic practice.

STUDY POPULATION

Two hundred and eight patients with intermediate uveitis evaluated from July 1, 1984 through September 30, 2006.

PROCEDURES

Clinical and demographic data were entered retrospectively into a database and analyzed.

OUTCOME MEASURES

Presence of CME at presentation to our clinic; risk factors for presenting with CME.

RESULTS

Of the 208 patients, 74% had bilateral intermediate uveitis, yielding 363 affected eyes. Eighty-nine patients (43%) had CME in at least one eye at the time of presentation to our clinic. After controlling for potentially confounding variables including demographics, duration of disease, active intraocular inflammation, history of diabetes mellitus or hypertension, and presence of epiretinal membrane, actively smoking at presentation was associated with a four-fold increased risk of CME at presentation vs never smoking (odds ratio (OR), 3.90; 95% confidence interval (CI), 1.43, 10.66; P = .008). Former smoking also appeared to increase the risk of CME at presentation in the multivariate analysis, but the result was of borderline statistical significance (OR, 1.97; 95% CI, 0.99, 3.94; P = .055). After adjusting for confounding, there was a 4% increased risk of CME at presentation for each cigarette smoked per day (OR, 1.04; 95% CI, 1.01, 1.7; P = .005).

CONCLUSIONS

CME was a common structural ocular complication observed in our cohort. Current smoking was associated with a dose-dependent increased risk of having CME at the time of presentation to our clinic.

Cadmium accumulation in the human retina: effects of age, gender, and cellular toxicity

Tobacco smoking and aging are among the few factors linked to age-related macular degeneration (AMD), a major cause of blindness in the elderly. Recent studies indicate that cadmium (Cd), an environmental toxic trace metal, is approximately four-fold higher in the retinas of smokers compared to non-smokers. In this study, we determined the effects of age and gender on Cd accumulation in human retinal tissues, specifically the neural retina, retinal pigment epithelium (RPE), and choroid. Cadmium levels in cultured RPE cells or retinal tissues isolated from frozen donor eyes were measured using inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrophotometry (GF-AAS). Cadmium uptake in cultured human RPE cells (ARPE-19) was also assessed using GF-AAS. Toxic effects of cadmium were determined from cell loss (measured as a decrease in cell density) and lactate dehydrogenase release (an indicator of membrane disruption). In "young" eyes (< 55 years) Cd was highest in the retinal pigment epithelium and lowest in the neural retina. Cd was higher in all tissues in aged eyes (>or=55 years) and was significantly higher in the neural retina and RPE in older females. Cultured RPE cells exposed to Cd showed altered cell morphology, decreased cell survival, elevated ROS levels and concentration-dependent disruption of membrane integrity. We conclude that cadmium is accumulated differently in the neural retinal and RPE of older men and women. The deleterious effects of Cd on RPE cells indicate that this environmental toxin is a potentially important factor in age-related retinal disease.