Racial differences in lens opacity incidence and progression: the Salisbury Eye Evaluation (SEE) study

Diversity in enrollment to clinical trials for cataract medicine and surgery: meta-analysis

PURPOSE

To investigate sex, racial, and ethnic disparities in patient enrollment across cataract trials registered in the United States.

SETTING

Participants enrolled in high-quality (reduced risk of bias), U.S.-registered (on ClinicalTrials.gov ), cataract-related randomized controlled trials (RCTs). RCTs must be completed, have used double or greater masking, and have published results through the registry or a scholarly journal.

DESIGN

Cross-sectional database study.

METHODS

Trial (study sponsor country, study site location, trial initiation year, study phase, and study masking) and demographic data (sex, race, and ethnicity according to U.S. reporting guidelines) were collected. The Global Burden of Disease database provided sex-based cataract disease burdens. Pooled participation-to-prevalence ratios (PPRs) with 95% CIs were calculated for female sex, with values between 0.8 and 1.2 constituting sufficient study enrollment. Kruskal-Wallis tests (α = 0.05) with subsequent post hoc comparisons were used to evaluate demographic representations stratified by trial characteristics.

RESULTS

From 864 records, 100 clinical trials (N = 67 874) were identified, of which 97 (N = 67 697) reported sex demographics with a pooled female PPR of 0.89 (95% CI, 0.85-0.94). Of the 67 697 total participants, the absolute female enrollment was 19 062 (28.16%). Ethnicity and race were reported in 9 (N = 1792) and 26 trials (N = 23 181), respectively. Among trials that reported race, most were White (N = 19 574; 84.44%).

CONCLUSIONS

High-quality, U.S.-registered, cataract trials enrolled acceptable proportions of women. However, the absolute number of female and racialized participants was low. Race and ethnicity were underreported. Disparity trends predominately held across secondary variables. To promote generalizability, future trials should pursue equitable demographic enrollment.

Cataract Phacoemulsification in People with Dementia: Characterization and Outcomes

PURPOSE

To characterize cataract surgery in people with dementia (PWD) using a cataract surgery outcomes database.

METHODS

Demographics, medical and ocular history, surgical characteristics, and postoperative measures were analyzed for differences between PWD and non-PWD cohorts. Patient-level data were analyzed with Fisher's Exact Test, and eye-level data were analyzed with logistic regression using generalized estimating equations to account for correlation of eyes from the same individual.

RESULTS

507 eyes from 296 PWD were identified using appropriate ICD codes and cross-referenced to a cataract surgery outcomes database containing 12,949 eyes from 7,853 patients who underwent cataract phacoemulsification at a single center between January 2014 and October 2019. PWD were older (p < .001), had shorter duration cataract surgeries (p = .006), and were more likely to have mature cataract (p = .017). The rate of general anesthesia was higher in PWD (p = .005). There were no differences in complication rates between PWD and non-PWD cohorts. Both preoperative best corrected LogMAR distance visual acuity (CDVA) (p < .001) and postoperative CDVA (p < .001) were worse in PWD. CDVA significantly improved in both groups (p < .001); however, the average magnitude of improvement in CDVA was not significantly different between groups (p = .169).

CONCLUSIONS

PWD present for cataract surgery at a later age and were more likely to have mature cataracts and general anesthesia, but did not have higher rates of complication, and showed significant improvement in CDVA following surgery. These findings should be encouraging to PWD undergoing counseling for cataract surgery, and for the potential for improved function in PWD.

The Impact of Social Determinants of Health on Vision Loss From Cataracts and Cataract Surgery Utilization in the United States-A National Health Interview Survey Analysis

PURPOSE

To investigate the association of social determinants of health (SDOH) factors and cataract-related outcomes disparities.

DESIGN

Cross-sectional, with a nationally representative sample.

METHODS

We used publicly available data from the 2008, 2016, and 2017 National Health Interview Survey data sets. Outcome measures included self-reported prevalence for ever been diagnosed with cataract, vision loss secondary to cataracts, and the likelihood of undergoing cataract surgery. Survey-weighted, multivariable logistic regression models, adjusted for age, race and ethnicity, and other relevant covariates, were used to examine the association between SDOH factors and cataract-related outcomes.

RESULTS

A total of 81,551 participants were included, who were predominantly between 18 and 44 years of age (49.6%), female (51.7%), and White (74.8%). Multivariable regression models with age as a covariate showed that individuals who were not working were more likely to report having cataracts than those who were working (P < .001). Those who needed but could not afford medical care in the past year were more likely to report vision loss secondary to cataracts than their counterparts (P < .001). Uninsured participants were less likely to report undergoing cataract surgery than those with private insurance (P = .03). Individuals with higher income (poverty-income ratio: 1.00-2.99 vs <1.00) were more likely to report undergoing cataract surgery (P = .04).

CONCLUSIONS

Several SDOH factors were associated with disparities in rates of cataract-related outcomes. These findings highlight the importance of ophthalmologists screening for social risks in patients with cataract, as these social factors are important barriers for access to care.

Five-year change in refractive error and its risk factors: results from the Gutenberg Health Study

BACKGROUND/AIMS

To examine the 5-year change in refractive error in phakic eyes and its risk factors in the general population.

METHODS

The Gutenberg Health Study (GHS) is a population-based cohort study including 15 010 participants from Germany aged 35-74 years at baseline examination (2007-2012). After 5 years, a follow-up examination was carried out (83% participation). 5-year change of spherical equivalent (SE) was computed as difference between follow-up and baseline objective refraction. Linear and logistic regression analysis were conducted analysing potential risk factors. Only phakic eyes at follow-up examination were included.

RESULTS

Right eyes of 10 175 subjects were included. An age-related shift of refractive error was identified, namely -0.12 D for age 35-44 years, 0.25 D for age 45-54 years, 0.25 D for age 55-64 years and 0.12 D for age 65-74 years during the 5-year follow-up. Smokers had a hyperopic shift (OR=1.31; p<0.001), while baseline SE (OR=0.89 per dioptre; p<0.001) and female sex (OR=1.49; p<0.001) were linked with a myopic shift. Education, occupation and other cardiovascular parameters were not associated with change in refractive error.

CONCLUSIONS

The GHS demonstrates a parabolic shift in refractive error with a myopic shift at age 35-44 years, followed by a hyperopic shift at age 45-64 years which decreases at higher age. Smoking is associated with a hyperopic shift whereas female sex and myopic baseline SE is associated with a myopic shift. Educational level and occupation were not linked to a change in refractive error at age 35-74 years.

Study of the Natural Crystalline Lens Characteristics Using Dual-Energy Computed Tomography

There is a paucity of radiologic literature regarding age-related cataract, and little is known about any differences in the imaging appearance of the natural crystalline lens on computed tomography (CT) exams among different demographic groups. In this retrospective review of 198 eyes in 103 adults who underwent dual-energy computed tomography (DECT) exams of the head, regions of interest spanning 3−5 mm were placed over the center of the lens, and the x-ray attenuation of each lens was recorded in Hounsfield Units (HU) at 3 energy levels: 40 keV, 70 keV, and 190 keV. Generalized estimating equations (GEEs) were used to assess the association of clinical or demographic data with lens attenuation. The mean HU values were significantly lower for the older vs. younger group at 40 keV (GEE p-value = 0.022), but there was no significant difference at higher energy levels (p > 0.05). Mean HU values were significantly higher for females vs. males and non-whites vs. non-Hispanic whites at all 3 energy levels in bivariate and multivariable analyses (all p-value < 0.05). There was no significant association between lens attenuation and either diabetes or smoking status. The crystalline lens of females and non-whites had higher attenuation on DECT which may suggest higher density or increased concentration of materials like calcium and increased potential for cataract formation. Given the large scope of cataracts as a cause of visual impairment and the racial disparities that exist in its detection and treatment, further investigation into the role of opportunistic imaging to detect cataract formation is warranted.

Mendelian randomization study reveals a population-specific putative causal effect of type 2 diabetes in risk of cataract

BACKGROUND

The epidemiological association between type 2 diabetes and cataract has been well established. However, it remains unclear whether the two diseases share a genetic basis, and if so, whether this reflects a putative causal relationship.

METHODS

We used East Asian population-based genome-wide association studies (GWAS) summary statistics of type 2 diabetes (Ncase = 36 614, Ncontrol = 155 150) and cataract (Ncase = 24 622, Ncontrol = 187 831) to comprehensively investigate the shared genetics between the two diseases. We performed: (i) linkage disequilibrium score regression (LDSC) and heritability estimation from summary statistics (ρ-HESS) to estimate the genetic correlation and local genetic correlation pattern between type 2 diabetes and cataract; (ii) multiple Mendelian randomization (MR) analyses to infer the putative causality between type 2 diabetes and cataract; and (iii) summary-data-based Mendelian randomization (SMR) to identify candidate risk genes underling the putative causality. Moreover, to investigate the extent of the population-specific genetic effect size underlying the shared genetics between type 2 diabetes and cataract, we applied the same analytical pipeline to perform a comparative analysis on European population-based GWAS of type 2 diabetes (Ncase = 62 892, Ncontrol = 596 424) and cataract (Ncase = 5045, Ncontrol = 356 096).

RESULTS

Using East Asian population-based GWAS summary data, we observed a strong genetic correlation [rg = 0.58, 95% confidence interval (CI) = 0.33, 0.83), P-value = 5.60 × 10-6] between type 2 diabetes and cataract. Both ρ-HESS and multiple MR methods consistently showed a putative causal effect of type 2 diabetes on cataract, with estimated liability-scale MR odds ratios (ORs) at around 1.10 (95% CI = 1.06, 1.17). In contrast, no evidence supports a causal effect of cataract on type 2 diabetes. SMR analysis identified two novel genes MIR4453HG (βSMR = -0.34, 95% CI = -0.46, -0.22, P-value = 6.41 × 10-8) and KCNK17 (βSMR = -0.07, 95% CI = -0.09, -0.05, P-value = 2.49 × 10-10), whose expression levels were likely involved in the putative causality of type 2 diabetes on cataract. On the contrary, our comparative analysis on European population provided universally weak evidence on the genetic correlation and causal relationship between the two diseases.

CONCLUSIONS

Our results provided robust evidence supporting a putative causal effect of type 2 diabetes on the risk of cataract in East Asians, and revealed potential genetic heterogeneity in the shared genetics underlying type 2 diabetes and cataract between East Asians and Europeans. These findings posed new paths on guiding the prevention and early-stage diagnosis of cataract in type 2 diabetes patients.

Genotype, Age, Genetic Background, and Sex Influence Epha2-Related Cataract Development in Mice

Purpose

Age-related cataract is the leading cause of blindness worldwide. Variants in the EPHA2 gene increase the disease risk, and its knockout in mice causes cataract. We investigated whether age, sex, and genetic background, risk factors for age-related cataract, and Epha2 genotype influence Epha2-related cataract development in mice.

Methods

Cataract development was monitored in Epha2+/+, Epha2+/-, and Epha2-/- mice (Epha2Gt(KST085)Byg) on C57BL/6J and FVB:C57BL/6J (50:50) backgrounds. Cellular architecture of lenses, endoplasmic reticulum (ER) stress, and redox state were determined using histological, molecular, and analytical techniques.

Results

Epha2-/- and Epha2+/- mice on C57BL/6J background developed severe cortical cataracts by 18 and 38 weeks of age, respectively, compared to development of similar cataract significantly later in Epha2-/- mice and no cataract in Epha2+/- mice in this strain on FVB background, which was previously reported. On FVB:C57BL/6J background, Epha2-/- mice developed severe cortical cataract by 38 weeks and Epha2+/- mice exhibited mild cortical cataract up to 64 weeks of age. Progression of cataract in Epha2-/- and Epha2+/- female mice on C57BL/6J and mixed background, respectively, was slower than in matched male mice. N-cadherin and β-catenin immunolabeling showed disorganized lens fiber cells and disruption of lens architecture in Epha2-/- and Epha2+/- lenses, coinciding with development of severe cataracts. EPHA2 immunolabeling showed intracellular accumulation of the mutant EPHA2-β-galactosidase fusion protein that induced a cytoprotective ER stress response and in Epha2+/- lenses was also accompanied by glutathione redox imbalance.

Conclusions

Both, Epha2-/- and Epha2+/- mice develop age-related cortical cataract; age as a function of Epha2 genotype, sex, and genetic background influence Epha2-related cataractogenesis in mice.

Systemic and Ocular Comorbidities of Black, Hispanic, and White Women with Cataracts

Background: Cataracts are one of the leading causes of blindness in the world and disproportionately affect the elderly people and women. Sex- and race-related differences in cataract formation are not well understood. Furthermore, race and socioeconomic factors can play a role in developing systemic diseases. Earlier studies have supported a link between certain systemic diseases and cataract formation. Our study examined race-related differences in ocular and systemic comorbidities and analyzed differences among races and insurance types for cataract surgery visual outcomes among female patients with cataracts. Materials and Methods: Data were collected retrospectively and patients were grouped by race and insurance classifications. Female patients at a large tertiary center with an International Classification of Disease, 9th Edition (ICD-9) or ICD-10 cataract diagnosis or cataract extraction procedure code between January 2013 and June 2018 were included. A total of 909 female patients were included in the study. Frequency of systemic and ocular comorbidities was analyzed. Demographic factors were also compared among races. Finally, characteristics of cataract surgery patients, such as age at surgery, preoperative best-corrected visual acuity (BCVA), and visual outcomes among races and insurance types were analyzed. Results: There are differences among races for frequency of smoking, hemoglobin A1c, hypertension, and diabetes mellitus in female patients with cataracts and differences among races and insurance types for preoperative BCVA for patients who underwent cataract surgery (p < 0.001 for all). Conclusions: Female minority and non-minority patients with cataracts have a high frequency of systemic and ocular comorbidities at our county hospital. Patients with no insurance and white and Hispanic patients had worse preoperative BCVA.

FACTORS ASSOCIATED WITH PREVALENT LENS OPACITIES IN CHINESE AMERICAN ADULTS: THE CHINESE AMERICAN EYE STUDY

PURPOSE

To identify risk factors associated with lens opacities in Chinese Americans.

METHODS

A cross-sectional population-based study of 4,582 Chinese Americans ≥50 years residing in Monterey Park, California. Participants completed a comprehensive clinical examination with lens assessment using the Lens Opacities Classification System II, with lens opacities defined by a grade ≥2 in either eye. Participants were considered to have nuclear-only, cortical-only, or posterior subcapsular (PSC)-only if that was the only type of opacity present in both eyes.

RESULTS

Cortical-only opacity was associated with older age, diabetes mellitus (OR 1.5, 95%CI 1.1-2.1), and family history of cataracts (OR 1.5, 95%CI 1.2-1.9). Nuclear-only opacity was associated with older age, diabetes mellitus (OR 1.4, 95%CI 1.1-1.9), greater waist-to-hip ratio (OR 1.2, 95%CI 1.1-1.4), and high-density lipoprotein (OR 1.1, 95%CI 1.02-1.2). Mixed-type opacities were associated with older age, greater waist-to-hip ratio (OR 1.3, 95%CI 1.1-1.6), and higher HbA1 c (OR 1.3, 95%CI 1.1-1.4). Taller height (OR 0.7, 95%CI 0.6-0.8), greater weight (OR 0.98, 95%CI 0.97-0.99), and higher diastolic pressure (OR 0.98, 95%CI 0.96-0.99) were protective.

CONCLUSION

CHES identified a strong, dose-response association between age and all types of prevalent lens opacities, which suggests an increasing cataract burden in Chinese Americans based on aging populations. CHES results demonstrate general consistency with previous population-based studies in regard to more sedentary lifestyle exposures (e.g., Westernized lifestyle) and prevalent cortical-only, nuclear-only, and mixed-type opacities, yet also identified further sedentary lifestyle exposures associated with prevalent lens opacities. Improved glycemic control and a more active lifestyle that minimizes factors contributing to metabolic syndrome may help reduce the burden of vision loss associated with lens opacities.

Effect of a Lens Protein in Low-Temperature Culture of Novel Immortalized Human Lens Epithelial Cells (iHLEC-NY2)

The prevalence of nuclear cataracts was observed to be significantly higher among residents of tropical and subtropical regions compared to those of temperate and subarctic regions. We hypothesized that elevated environmental temperatures may pose a risk of nuclear cataract development. The results of our in silico simulation revealed that in temperate and tropical regions, the human lens temperature ranges from 35.0 °C to 37.5 °C depending on the environmental temperature. The medium temperature changes during the replacement regularly in the cell culture experiment were carefully monitored using a sensor connected to a thermometer and showed a decrease of 1.9 °C, 3.0 °C, 1.7 °C, and 0.1 °C, after 5 min when setting the temperature of the heat plate device at 35.0 °C, 37.5 °C, 40.0 °C, and 42.5 °C, respectively. In the newly created immortalized human lens epithelial cell line clone NY2 (iHLEC-NY2), the amounts of RNA synthesis of αA crystallin, protein expression, and amyloid β (Aβ)1-40 secreted into the medium were increased at the culture temperature of 37.5 °C compared to 35.0 °C. In short-term culture experiments, the secretion of Aβ1-40 observed in cataracts was increased at 37.5 °C compared to 35.0 °C, suggesting that the long-term exposure to a high-temperature environment may increase the risk of cataracts.

Philadelphia Telemedicine Glaucoma Detection and Follow-Up Study: Cataract Classifications Following Eye Screening

Background: Cataracts are a major cause of visual impairment and blindness in the United States and worldwide. Introduction: Risk factors for cataracts include age over 40 years, smoking, diabetes, low socioeconomic status, female sex, steroid use, ocular trauma, genetic factors, and exposure to ultraviolet-B light. Community-based telemedicine vision screenings can be an efficient method for detecting cataracts in underserved populations. The Philadelphia Telemedicine Glaucoma Detection and Follow-Up Study reports the prevalence and risk factors for cataracts in individuals screened and examined for glaucoma and other eye diseases. Materials and Methods: A total of 906 high-risk individuals were screened for glaucoma using telemedicine in seven primary care practices and four Federally Qualified Health Centers in Philadelphia. Participants with suspicious nerves or other abnormalities on fundus photographs, unreadable images, and ocular hypertension returned for an eye examination with an ophthalmologist at the same community location. Results: Of the participants screened through telemedicine, 347 (38.3%) completed a follow-up eye examination by an ophthalmologist. Of these, 267 (76.9%) were diagnosed with cataracts, of which 38 (14.2%) had visually significant cataracts. Participants who were diagnosed with visually significant cataract were more likely to be older (p < 0.001), have diabetes (p = 0.003), and worse visual acuity (p < 0.001). Discussion: Our study successfully detected and confirmed cataracts in a targeted, underserved urban population at high risk for eye disease. Conclusions: Telemedicine programs offer an opportunity to identify and refer individuals who would benefit from continuous follow-up eye care and treatment to improve visual function and quality of life.

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.

Absolute and estimated values of macular pigment optical density in young and aged Asian participants with or without age-related macular degeneration

Background

Lutein and zeaxanthin are suggested micronutrient supplements to prevent the progression of age-related macular degeneration (AMD), a leading cause of blindness worldwide. To monitor the levels of lutein/zeaxanthin in the macula, macular pigment optical density (MPOD) is measured. A commercially available device (MPSII®, Elektron Technology, Switzerland), using technology based on heterochromatic flicker photometry, can measure both absolute and estimated values of MPOD. However, whether the estimated value is applicable to Asian individuals and/or AMD patients remains to be determined.

Methods

The absolute and estimated values of MPOD were measured using the MPSII® device in 77 participants with a best-corrected visual acuity (BCVA) > 0.099 (logMAR score).

Results

The studied eyes included 17 young (20–29 years) healthy, 26 aged (>50 years) healthy, 18 aged and AMD-fellow, and 16 aged AMD eyes. The mean BCVA among the groups were not significantly different. Both absolute and estimated values were measurable in all eyes of young healthy group. However, absolute values were measurable in only 57.7%, 66.7%, and 43.8%, of the aged healthy, AMD-fellow, and AMD groups, respectively, and 56.7% of the eyes included in the 3 aged groups. In contrast, the estimated value was measurable in 84.6%, 88.9% and 93.8% of the groups, respectively, and 88.3% of eyes in the pooled aged group. The estimated value was correlated with absolute value in individuals from all groups by Spearman’s correlation coefficient analyses (young healthy: R² = 0.885, P = 0.0001; aged healthy: R² = 0.765, P = 0.001; AMD-fellow: R² = 0.851, P = 0.0001; and AMD: R² = 0.860, P = 0.013). Using the estimated value, significantly lower MPOD values were found in aged AMD-related eyes, which included both AMD-fellow and AMD eyes, compared with aged healthy eyes by Student’s t-test (P = 0.02).

Conclusions

Absolute, in contrast to estimated, value was measurable in a limited number of aged participants; however, it was correlated with estimated value both in young and aged Asian populations with or without AMD. These results may inform future clinical studies investigating the measurement of MPOD in understanding the role of macular pigments in the pathogenesis of AMD.

Cataracts

An estimated 95 million people worldwide are affected by cataract. Cataract still remains the leading cause of blindness in middle-income and low-income countries. With the advancement of surgical technology and techniques, cataract surgery has evolved to small-incisional surgery with rapid visual recovery, good visual outcomes, and minimal complications in most patients. With the development of advanced technology in intraocular lenses, the combined treatment of cataract and astigmatism or presbyopia, or both, is possible. Paediatric cataracts have a different pathogenesis, surgical concerns, and postoperative clinical course from those of age-related cataracts, and the visual outcome is multifactorial and dependent on postoperative visual rehabilitation. New developments in cataract surgery will continue to improve the visual, anatomical, and patient-reported outcomes. Future work should focus on promoting the accessibility and quality of cataract surgery in developing countries.

Association between polymorphisms of OGG1, EPHA2 and age-related cataract risk: a meta-analysis

Background

Evidences have identified the correlation of 8-oxoguanine DNA glycosylase-1 (OGG1) and eph-receptor tyrosine kinase-type A2 (EPHA2) polymorphisms in age-related cataract (ARC) risk. However, the results were not consistent. The objective of this study was to examine the role of these two gene polymorphisms in ARC susceptibility.

Methods

Eligible case–control studies published between January 2000 and 2015 were searched and retrieved in the electronic databases. The odds ratio with 95 % confidence interval (CI) was employed to calculate the strength of the relationship.

Results

We totally screened out six articles, including 5971 cataract patients and 4189 matched controls. Three variants were contained (OGG1 rs1052133; EPHA2 rs7543472 and rs11260867). For OGG1 rs1052133, we detected a significant correlation between OGG1 polymorphism and ARC risk under the heterogenous model (CG vs. CC: OR = 1.34, 95 % CI = 1.06–1.70, P = 0.01) and dominant model (GG+CG vs. CC: OR = 1.45, 95 % CI = 1.16–1.81, P = 0.001), especially in patients with cortical cataract of subgroup analysis by phenotypes (P < 0.05). For EPHA2 rs7543472 and rs11260867, we did not find a positive association between these two mutations and ARC susceptibility in total cases. Subgroup analysis by phenotypes of cataract showed that only in cortical cataract, genotypes of rs7543472 under the allele model, homogenous model and recessive model; genotypes of rs11260867 under the heterogenous model and dominant model were associated with ARC risk.

Conclusions

OGG1 rs1052133 (CG and CG+GG genotypes) might be risk factor for ARC, particularly in cortical cataract risk. EPHA2 rs7543472 (T allele and TT genotype) and rs11260867 (CG and GG+CG genotypes) might be associated with cortical cataract.

Different amounts of alcohol consumption and cataract: a meta-analysis

PURPOSE

To evaluate the association between different amounts of alcohol consumption and the risk of age-related cataract.

METHODS

We searched PubMed and Embase from their inception until May 2014 for case-control or cohort studies with data on alcohol consumption and age-related cataract. Heavy alcohol consumption was defined as more than two standard drinks per day, which is equal to a daily intake of 20 g of alcohol or 140 g per week. Moderate consumption was defined as less than 20 g of alcohol per day but more than never any. We performed separate meta-analyses for the associations of moderate or heavy alcohol consumption with age-related cataract under a random-effects model, respectively.

RESULTS

Five case-control and five cohort studies were identified through comprehensive literature search. In the meta-analysis of 10 studies, the associations between moderate alcohol consumption and age-related cataract were marginally nonsignificant (pooled relative risk, 0.88; 95% confidence interval, 0.74 to 1.05; I = 82.1%), whereas heavy alcohol consumption was associated with an increased risk of age-related cataract (pooled relative risk, 1.26; 95% confidence interval, 1.06 to 1.50; I = 58.9%). The association between heavy alcohol consumption and cataract was stronger in case-control than in cohort studies. Adjusting for smoking as a potential confounder attenuated the association between heavy alcohol consumption and cataract.

CONCLUSIONS

Heavy alcohol consumption significantly increased the risk of age-related cataract, whereas moderate consumption may be protective for this ocular condition. Clinically, information on a patient's alcohol drinking history might be valuable to general physicians and ophthalmologists when there is a diagnosis of age-related cataract and should be collected on a routine basis in eye clinics.

The consequences for human health of stratospheric ozone depletion in association with other environmental factors

Ozone depletion, climate and human health.

Hypertension and risk of cataract: a meta-analysis

Background

Cataract is the major cause of blindness across the world. Many epidemiologic studies indicated that hypertension might play an important role in the development of cataract, while others not. We therefore conducted this meta-analysis to determine the relationship between risk of cataract and hypertension.

Methods

Retrieved studies on the association of hypertension with cataract risk were collected from PubMed, Web of Science and the Cochrane Library during June 2014 and were included into the final analysis according to the definite inclusion criteria. Odds ratio (OR) or risk ratio (RR) were pooled with 95% confidence interval (CI) to evaluate the relationship between hypertension and cataract risk. Subgroup analyses were carried out on the basis of cataract type, race and whether studies were adjusted for main components of metabolic syndrome (MS).

Results

The final meta-analysis included 25 studies (9 cohort, 5 case-control and 11 cross-sectional) from 23 articles. The pooled results showed that cataract risk in populations with hypertension significantly increased among cohort studies (RR 1.08; 95% CI: 1.05–1.12) and case-control or cross-sectional studies (OR 1.28; 95% CI: 1.12–1.45). This association was proved to be true among both Mongolians and Caucasians, and the significance was not altered by the adjustment of main components of MS. Subgroup analysis on cataract types indicated that an increased incidence of posterior subcapsular cataract (PSC) resulted among cohort studies (RR 1.22; 95% CI: 1.03–1.46) and cross-sectional/case-control studies (OR 1.23; 95% CI: 1.09–1.39). No association of hypertension with risk of nuclear cataract was found.

Conclusions

The present meta-analysis suggests that hypertension increases the risk of cataract, especially PSC. Further efforts should be made to explore the potential biological mechanisms.

Alcohol intake and the risk of age-related cataracts: a meta-analysis of prospective cohort studies

Purpose

Epidemiologic studies assessing the relationship between alcohol consumption and the risk of age-related cataracts (ARCs) led to inconsistent results. This meta-analysis was performed to fill this gap.

Methods

Eligible studies were identified via computer searches and reviewing the reference lists of these obtained articles. Pooled estimates of the relative risks (RR) and the corresponding 95% confidence Intervals (CI) were calculated using random effects models.

Results

Seven prospective cohort studies involving a total of 119,706 participants were ultimately included in this meta-analysis. Pooled results showed that there is no substantial overall increased risk of ARC due to heavy alcohol consumption. The estimated RRs comparing heavy drinkers versus non-drinkers were 1.25 (95% CI: 1.00, 1.56) for cataract sugery, 1.06 (95% CI: 0.63, 1.81) for cortical cataracts, 1.26 (95% CI: 0.93, 1.73) for nuclear cataracts, and 0.91 (95% CI: 0.32, 2.61) for posterior subcapsular cataracts (PSCs), respectively. No significant associations between moderate alcohol consumption and cataracts were observed. The pooled RRs comparing moderate drinkers versus non-drinkers were 0.90 (95% CI: 0.64, 1.26) for cataract surgery, 0.97 (95% CI: 0.75, 1.25) for cortical cataracts, 0.91 (95% CI: 0.76, 1.08) for nuclear cataracts, and 0.97 (95% CI: 0.49, 1.91) for PSCs, respectively.

Conclusions

This meta-analysis suggests that there is no substantial overall increased risk of ARC due to alcohol intake. Because of the limited number of studies, the findings from our study must be confirmed in future research via well-designed cohort or intervention studies.

Gender and cataract--the role of estrogen

There is evidence from epidemiologic data that cataract is more common in women than men. This is not solely due to a higher rate of cataract extraction in women, as is the case in the western world, but several population-based studies show that females have a higher prevalence of lens opacities, especially cortical. There is no firm evidence that lifestyle-related factors are the cause of this gender discrepancy. Focus has therefore been directed towards the role of estrogen in cataract formation. Although data on endogenous and exogenous estrogen involvement in cataractogenesis are conflicting, some studies have indicated that hormone therapy may decrease the risk of cataract and thus be protective. It has been hypothesized that the decrease in estrogen at menopause cause increased risk of cataract in women, i.e. not strictly the concentration of estrogen, but more the withdrawal effect. Estrogens are known to exert several anti-aging effects that may explain the longer lifespan in women, including metabolically beneficial effects, neuroprotection, preservation of telomeres and anti-oxidative properties. Since oxidative stress is considered important in cataractogenesis, studies have investigated the effects of estrogens on lens epithelial cells in culture or in animal models. Several investigators have found protection by physiological concentrations of 17β-estradiol against oxidative stress induced by H2O2 in cultured lens epithelial cells. Although both main types of estrogen receptors, ERα and ERβ, have been demonstrated in lens epithelium, most studies so far indicate that the estrogen-mediated protection in the lens is exerted through non-genomic, i.e. receptor-independent mechanisms, possibly through phosphorylation of extracellular signal-regulated kinase (ERK1/ERK2), a member of the mitogen-activated protein kinase (MAPK)-signaling pathway. Further studies are needed, both epidemiologic as to the role of hormone therapies, and laboratory studies regarding molecular estrogen-mediated mechanisms, in order to comprehend the role of estrogens on cataract formation.

Comparing methodologies for imputing ethnicity in an urban ophthalmology clinic

PURPOSE

To compare methodologies for imputing ethnicity in an urban ophthalmology clinic.

METHODS

Using data from 19,165 patients with self-reported ethnicity, surname, and home address, we compared the accuracy of three methodologies for imputing ethnicity: (1) a surname method based on tabulation from the 2000 US Census; (2) a geocoding method based on tract data from the 2010 US Census; and (3) a combined surname geocoding method using Bayes' theorem.

RESULTS

The combined surname geocoding model had the highest accuracy of the three methodologies, imputing black ethnicity with a sensitivity of 84% and positive predictive value (PPV) of 94%, white ethnicity with a sensitivity of 92% and PPV of 82%, Hispanic ethnicity with a sensitivity of 77% and PPV of 71%, and Asian ethnicity with a sensitivity of 83% and PPV of 79%. Overall agreement of imputed and self-reported ethnicity was fair for the surname method (κ 0.23), moderate for the geocoding method (κ 0.58), and strong for the combined method (κ 0.76).

CONCLUSION

A methodology combining surname analysis and Census tract data using Bayes' theorem to determine ethnicity is superior to other methods tested and is ideally suited for research purposes of clinical and administrative data.

Association between lutein and zeaxanthin status and the risk of cataract: a meta-analysis

The purpose of this meta-analysis was to evaluate the relationship between blood lutein and zeaxanthin concentration and the risk of age-related cataract (ARC). MEDLINE, EMBASE, ISI and Cochrane Library were searched to identify relevant studies up to April 2013. Meta-analysis was conducted to obtain pooled relative risks (RRs) for the highest-versus-lowest categories of blood lutein and zeaxanthin concentrations. One cohort study and seven cross-sectional studies were included in the meta-analysis. There were significant inverse associations between nuclear cataract and blood lutein and zeaxanthin concentrations, with the pooled RRs ranging from 0.63 (95% confidence interval (CI): 0.49, 0.77) for zeaxanthin to 0.73 (95% CI: 0.59, 0.87) for lutein. A stronger association between nuclear cataract and blood zeaxanthin might be noted for the studies conducted in the European Nations. Blood lutein and zeaxanthin were also noted to lead towards a decrease in the risk of cortical cataract and subcapsular cataract; however, these pooled RRs were not statistically significant, with the exception of a marginal association between lutein and subcapsular cataract. Our results suggest that high blood lutein and zeaxanthin are significantly associated with a decrease in the risk of nuclear cataract. However, no significant associations were found for ARC in other regions of the lens.