The epidemiology of cataract in Australia

PURPOSE: To describe the prevalence and risk factors for cataract in an Australian population aged 40 years and older. METHODS: Participants were recruited by a household census and stratified, random cluster sampling to represent residents of Victoria, Australia, aged 40 years and older. The following information was collected: initial visual acuity and best-corrected visual acuity, demographic details, health history, dietary intake of antioxidants, lifetime ocular ultraviolet B exposure, and clinical eye examination, including lens photography. Cortical opacities were measured in sixteenths. Cortical cataract was defined as opacity greater than or equal to 4/16 of pupil circumference. Nuclear opacities were graded according to the Wilmer cataract grading scheme, and cataract was defined as greater than or equal to nuclear standard 2.0 of four standards. The height and width of any posterior subcapsular opacity was measured and recorded. Posterior subcapsular cataract was defined as posterior subcapsular opacity greater than or equal to 1 mm2. The worse eye was selected for analysis. Backward stepwise logistic regression was used to quantify independent risk factors for cataract. RESULTS: A total of 3,271 (83% of eligible) of the urban residents, 403 (90% of eligible) nursing home residents, and 1,473 (92% of eligible) rural residents participated. The urban residents ranged in age from 40 to 98 years (mean, 59 years), and 1,511 (46%) were men. The nursing home residents ranged in age from 46 to 101 years (mean, 82 years), and 85 (21%) were men. The rural residents ranged in age from 40 to 103 years (mean, 60 years), and 701 (47.5%) were men. The overall weighted rate of cortical cataract was 11.3% (95% confidence limits, 9.68%, 13.0%) excluding cataract surgery and 12.1% (95% confidence limits, 10.5%, 13.8%) including cataract surgery. The risk factors for cortical cataract that remained in the multivariate logistic regression model were age, female gender, diabetes duration greater than 5 years, gout duration greater than 10 years, arthritis diagnosis, myopia, use of oral beta-blockers, and increased average annual ocular ultraviolet B exposure. Overall, 12.6% (95% confidence limits, 9.61%, 15.7%) of Victorians aged 40 years and older had nuclear cataract including previous cataract surgery, and 11.6% (95% confidence limits, 8.61%, 14.7%) had nuclear cataract excluding previous cataract surgery. In the urban and rural cohorts, age, female gender, rural residence, brown irides, diabetes diagnosed 5 or more years earlier, myopia, age-related maculopathy, having smoked for greater than 30 years, and an interaction between ocular ultraviolet B exposure and vitamin E were all risk factors for nuclear cataract. The rate of posterior subcapsular cataract excluding previous cataract surgery was 4.08% (95% confidence limits, 3.01%, 5.14%), whereas the overall rate of posterior subcapsular cataract including previous cataract surgery was 4.93% (95% confidence limits, 3.68%, 6.17%) . The independent risk factors for posterior subcapsular cataract in the urban and rural cohorts that remained were age in years, rural location, use of thiazide diuretics, vitamin E intake, and myopia. CONCLUSIONS: The expected increase in the prevalence of cataract with the aging of the population highlights the need to plan appropriate medical services and public health interventions for primary and secondary prevention. Many of the identified risk factors for cataract in the population have the potential for being modified through public health interventions.     

Refractive associations with cataract: the Blue Mountains Eye Study.

PURPOSE: To assess the relationship between myopia and age-related cataract in a defined older population. METHODS: A cross-sectional study of 3654 people aged 49 to 97 years was conducted in the Blue Mountains near Sydney, Australia, from 1992 through 1994. General medical, eye, and refractive history and information about confounders were collected by questionnaire. Participants had a detailed determination of refraction, and the spherical equivalent refraction of each eye was calculated. The Wisconsin Cataract Grading System was used in masked grading of slit lamp and retroillumination lens photographs, to assess presence and severity of nuclear, cortical, and posterior subcapsular (PSC) cataract. Data from both eyes were analyzed by the generalized estimating equation method, adjusting for cataract risk factors. RESULTS: Included in the analysis were 7308 eyes. A history of wearing distance glasses, excluding eyes with current hyperopic refraction, was used as a proxy for myopia. Subjects who had worn distance glasses were more likely to have nuclear cataract (odds ratio [OR] 1.3; confidence interval [CI] 1.0-2.1). After stratification by age at first wearing distance glasses, this relationship remained only for people who first wore distance glasses after age 40 years (OR 1.3; CI 1.0-1.8), which suggested a myopic refractive shift from developing nuclear opacity and was supported by the weak association found between current myopic refraction and nuclear cataract (OR 1.3; CI 1.0-1.6). Eyes with onset of myopia before age 20 years had the greatest PSC cataract risk (OR 3.9; CI 2.0-7.9). This was supported by the finding of an association between current myopic refraction and PSC cataract (OR 2.5; CI 1.6-4.1). PSC cataract was inversely associated with hyperopia (OR 0.6; CI 0.4-0.9). Refraction-related increasing odds were found between PSC cataract and myopia: low myopia (OR 2.1; CI 1.4-3.5), moderate myopia (OR 3.1; CI 1.6-5.7), and high myopia (OR 5.5; CI 2.8-10.9). High myopia was associated with PSC, cortical, and late nuclear cataract. CONCLUSIONS: Early-onset myopia (before age 20 years) may be a strong and independent risk factor for PSC cataract. The findings suggest the possibility of a dose response between levels of myopia and PSC cataract. Nuclear cataract was associated with presumed acquired myopia, whereas high myopia was associated with all three types of cataract.     

Epidemiology of pterygium in Victoria, Australia

AIM: To describe the prevalence of and risk factors for pterygium in a population based sample of residents of the Australian state of Victoria who were aged 40 years and older. METHODS: The strata comprised nine randomly selected clusters from the Melbourne statistical division, 14 nursing homes randomly selected from the nursing homes within a 5 kilometre radius of the nine Melbourne clusters, and four randomly selected clusters from rural Victoria. Pterygium was measured in millimetres from the tip to the middle of the base. During an interview, people were queried about previous ocular surgery, including surgical removal of pterygium, and their lifetime exposure to sunlight. RESULTS: 5147 people participated. They ranged in age from 40 to 101 years and 2850 (55.4%) were female. Only one person in the Melbourne cohort reported previous pterygium surgery, and seven rural residents reported previous surgery; this information was unavailable for the nursing home residents. Pterygium was present upon clinical examination in 39 (1.2%) of the 3229 Melbourne residents who had the clinical examination, six (1. 7%) of the nursing home residents, and 96 (6.7%) of the rural residents. The overall weighted population rate in the population was 2.83% (95% CL 2.35, 3.31). The independent risk factors for pterygium were found to be age (OR=1.23, 95% CL=1.06, 1.44), male sex (OR=2.02, 95% CL=1.35, 3.03), rural residence (OR=5.28, 95% CL=3. 56, 7.84), and lifetime ocular sun exposure (OR=1.63, 95% CL=1.18, 2. 25). The attributable risk of sunlight and pterygium was 43.6% (95% CL=42.7, 44.6). The result was the same when ocular UV-B exposure was substituted in the model for broad band sun exposure. CONCLUSION: Pterygium is a significant public health problem in rural areas, primarily as a result of ocular sun exposure.     

Risk factors for nuclear,cortical and posterior subcapsular cataracts in the Chinese population of Singapore: the Tanjong Pagar Survey

AIM: To describe risk factors for nuclear, cortical, and posterior subcapsular (PSC) cataracts in Chinese Singaporeans. METHODS: A population based cross sectional study was carried out on ethnic Chinese men and women aged 40-81 years. A stratified, clustered, disproportionate (more weights to older people), random sampling procedure was used to initially select 2000 Chinese names of those aged 40-79 years from the 1996 electoral register in the Tanjong Pagar district in Singapore. Eligible subjects (n = 1717) were invited for a standardised ocular examination and interview at a centralised clinic, following which an abbreviated examination was conducted for non-respondents in their homes. Cataract was graded clinically using to the Lens Opacity Classification System (LOCS) III system. The main outcome measures were adjusted odds ratio for risk factors for specific cataract types (nuclear, cortical and PSC), any cataract and cataract surgery, examined in multiple logistic regression models. RESULTS: Out of the 1232 (71.8%) examined, 1206 (70.2%) provided lens data for this analysis. Increasing age was associated with all cataract types, any cataract, and cataract surgery. There was no significant sex difference in presence of any cataract, specific cataract types or cataract surgery. After controlling for age, sex, and other factors, diabetes was associated with cortical cataract (3.1; 95% CI: 1.6 to 6.1), PSC cataract (2.2; 95% CI 1.2 to 4.1), any cataract (2.0; 95% CI: 0.9 to 4.5), and cataract surgery (2.3; 95% CI: 1.3 to 4.1). Lower body mass index was associated with cortical cataract (1.8; 95% CI: 1.1 to 2.9; lowest versus highest quintile) and any cataract (2.3; 95% CI: 1.3 to 4.0). Current cigarette smoking was associated with nuclear cataract (1.7, 95% CI: 1.0 to 2.9; more than 10 cigarettes per day versus none). A non-professional occupation was associated with nuclear cataract (2.9; 95% CI: 1.5 to 5.8; for production or machine operators and 2.6; 95% CI: 1.2 to 5.5; for labourers or agricultural workers, both versus professionals). Lower education was associated with nuclear cataract (2.3; 95% CI: 1.0 to 5.2, none versus tertiary), while lower household income was associated with PSC cataract (4.7, 95% CI: 1.1 to 20.0; income S$4000). CONCLUSIONS: Age related cataracts are associated with a variety of risk factors among Chinese people in Singapore, similar to those reported in European, Indian, and African derived populations. These data support common aetiological mechanisms for age related cataracts, irrespective of ethnic origin.     

Incidence and progression of cataract in the Melbourne Visual Impairment Project

PURPOSE: To determine the 5-year incidence and progression of cataract and cataract surgery in the Melbourne Visual Impairment Project. DESIGN: Prospective cohort study. methods: Demographic information including race, sex, age, and education level was collected at baseline. Cortical cataract was defined as 4/16 or greater opacity; progression was defined as a more than 2/16 increase. Nuclear cataract was defined as Wilmer standard grade 2 or higher; progression was defined as more than 0.5 increase. Posterior subcapsular (PSC) cataract was defined as opacity 1 mm(2) or greater; progression was defined as greater than 1 mm(2) increase. results: Of the 3040 participants eligible to attend follow-up examinations, 2594 (85% of those eligible) participated. The mean age of participants at follow-up was 62.5 years, and 55% were female. The percentage of patients who had at least one lens extracted over 5 years increased from 0.5% of those aged 40 to 49 years at baseline to 35.7% of those aged 80 years or more at baseline. The overall incidence of the three types of cataract was as follows: cortical 7.7% (95% confidence limits [CL] = 5.8-9.8), nuclear 16.4% (95% CL = 12.1-20.8), and PSC 7% (95% CL = 5.3-8.7). The overall progression of cataract was cortical 14.3% (95% CL = 10.2-18.3), nuclear 19.3% (95% CL = 15.9-22.7), and PSC 20% (95% CL = 8.7-31.1). The incidence and progression rates increased significantly by age, but the rates were not significantly different by sex. CONCLUSION: These cataract incidence data confirm the public health importance of cataract in Australia. The data also support the need to plan both primary prevention program and adequate surgical services to meet the anticipated increase in demand with the aging population.     

Prevalence and associations of cataract in a rural Chinese adult population: the Handan Eye Study

Background

Cataract remains the leading cause of blindness and visual impairment in the world and in China. However, data on the prevalence of cataract based on standardized lens grading protocols from mainland China are limited. This paper estimated the age- and gender-specific prevalence and risk factor for cataract

Methods

In a population-based Chinese sample, participants underwent a comprehensive ophthalmic examination, including assessment of cortical, nuclear, posterior subcapsular (PSC) and mixed lens opacities from slit-lamp grading using the Lens Opacities Classification System III.

Results

Of the 7,557 eligible subjects, 6,830 took part in the study (90.4?% response rate), and 6,544 participants (95.8?%, mean age 52.0?±?11.8 years) had lens data for analyses. The prevalence of any cataract surgery in at least one eye was 0.8?% (95?% confidence interval [CI], 0.62, 1.06), with similar rates between men and women. The overall prevalence of any cataract or cataract surgery was 20.8?% (95?% CI, 19.8, 21.8), higher in women than in men after adjusting for age (23.6?% vs 17.6?%; OR: 1.78; 95?% CI: 1.54–2.07). When distinct lens opacity was categorized in each eye as cortical, nuclear, PSC or mixed, based on one randomly selected eye, cortical cataract was the most common distinct subtype (12.3?%), followed by mixed (3.2?%), nuclear (1.7?%), and PSC (0.2?%) cataract. The prevalence of all lens opacities increased with age (P?<?0.001). After excluding other causes for visual impairment, the proportion of people with best corrected visual acuity <20/60 was 21?% among those with PSC, and 12?% among those with mixed opacities in the better-seeing eye. In multivariable logistic regression models, myopia was associated with all cataract types, while higher fasting plasma glucose and diabetes were only associated with PSC cataract.

Conclusions

Cataract affects 20?% of the population aged 30 years and older living in rural China, with cortical cataract the most common subtype. Risk factors for cataract include myopia and diabetes.     

Female reproductive factors and eye disease in a rural South Indian population: the Aravind Comprehensive Eye Survey

PURPOSE: To determine the potential associations of female reproductive factors with age-related cataract, open-angle glaucoma, macular degeneration, and myopia in an older population of rural south India. METHODS: This was a population-based, cross-sectional study of older adults in rural south India identified through a cluster sampling technique. Histories relating to female reproductive factors were ascertained through a questionnaire administered by trained workers. Detailed ocular examinations including automated perimetry were performed on all participants at a base hospital to arrive at a diagnosis of ocular morbidity. RESULTS: The study achieved a high response rate (93.0%), with examinations performed on 5150 of the eligible 5539 persons aged 40 years or more. Age at menarche was available for 2797 (98.6%) of the women and age at natural menopause for 1841 (98.0%) of 1878 women who were postmenopausal. The mean age at menarche was 14.8 +/- 1.8 years, and the mean age at menopause was 43.4 +/- 3.9 years. The mean duration of endogenous estrogen exposure was 28.4 +/- 4.3 years. The median number of pregnancies was 4 (mean, 4.3 +/- 2.6; range, 0-16). Older age at menarche (>or=14 years) was associated with reduced risk for age-related cataract and myopia, and greater risk for macular degeneration. Neither age at menopause nor duration of endogenous estrogen exposure was associated with any of the ocular diseases studied. Parity was not associated with any of the ocular diseases studied in a multivariate model. CONCLUSIONS: Female reproductive factors do not appear to influence age-related cataract, open-angle glaucoma, macular degeneration or myopia significantly in rural south India.     

Prevalence of cataract type in relation to axial length in subjects with high myopia and emmetropia in an Indian population

PURPOSE: To compare the prevalence of different types and densities of age-related cataract in subjects with high myopia and emmetropia in an Indian urban clinic-based population. DESIGN: Prospective, observational, clinic-based case-control study. METHODS: An observational case-control study of 800 healthy eyes was undertaken at Iladevi Cataract & IOL Research Center, Ahmedabad, India. Subjects with high myopia (axial length [AXL], > or = 26.0 mm; n = 400 eyes) and those with emmetropia (AXL, 21.0 to 23.99 mm) were examined (n = 400 eyes). The type of cataract was categorized as: nuclear, cortical, or posterior subcapsular cataract (PSC). Nuclear density was measured based on the Emery and Little classification. RESULTS: In all the age groups (40 years of age or more), nuclear cataract was encountered more often in subjects with high myopia (odds ratio, 3.8; 95% confidence interval, 2.9 to 5.2; P < .001); PSC and mixed cataracts were encountered frequently in subjects with emmetropia (P < .001). Prevalence of nuclear cataract was higher in subjects with high myopia with increasing AXL when compared with other types of cataract (P < .001). In all the age groups, the nuclear density was significantly higher than grade 3 in subjects with high myopia when compared with those with emmetropia (P < .001 in those younger than 70 years; P = .003 in those older than 70 years). CONCLUSIONS: Nuclear cataract was associated strongly with high axial myopia. The density of the cataract was higher in the high myopia group. No association was observed between PSC or cortical cataract and high axial myopia.     

Risk factors for age related cataract in a rural population of southern India: the Aravind Comprehensive Eye Study

AIM: To determine risk factors for lens opacities and age related cataract in an older rural population of southern India. METHODS: A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence >/=3.0 and/or cortical cataract >/=3.0 and/or PSC >/=2.0. RESULTS: Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors-increasing age and illiteracy-were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94). CONCLUSIONS: Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.     

Associations of cataract with antioxidant enzymes and other risk factors: the French Age-Related Eye Diseases (POLA) Prospective Study

PURPOSE: To determine the association of potential risk factors, including antioxidant enzymes, with the incidence of cataract. DESIGN: Cohort study. PARTICIPANTS: At baseline, the Age-Related Eye Diseases (Pathologies Oculaires Liées à l'Age, POLA) Study included 2584 residents of Sète (southern France) aged 60 years or older. From September 1998 to May 2000, a 3-year follow-up examination was performed on 1947 of the 2436 surviving participants (79.9%). METHODS: Cataract classification was based on a standardized lens examination at the slit lamp, according to Lens Opacities Classification System III. Biologic measurements were performed at baseline from fasting blood samples. MAIN OUTCOME MEASURES: At baseline and follow-up, the presence of cataract was defined as: NC or nuclear opalescence (NO) > or = 4 for nuclear cataract, C > or = 4 for cortical cataract, and P > or = 2 for posterior cataract (PSC) opacities, using opacity grades corrected for interobserver variability. Incidence rates were assessed separately for right and left eyes and for each type of cataract. RESULTS: In the multivariate model, the incidence of cortical cataract was increased in subjects with high red blood cell superoxide dismutase activity (odds ratio [OR] 4.2 [1.5-12.1], P = 0.007). The incidence of PSC cataract was increased in subjects with a high level of plasma glutathione peroxidase (OR 1.8 [1.0-3.3], P = 0.05). In addition to age, gender, and opacities at baseline, significant risk factors for incident cataract were: long-duration diabetes (OR 5.8, P = 0.001 for cortical cataract) and lifetime heavy smoking (OR 2.9, P = 0.006 for PSC cataract). CONCLUSIONS: Consistent with the baseline analysis, the results of this prospective study suggest that antioxidant enzymes might be implicated in the etiology of cataract.     

Cataract and age-related maculopathy: the Blue Mountains Eye Study

PURPOSE. To assess the relationship between different types of cataract or past cataract surgery and late or early age-related maculopathy (ARM) in an older population. METHODS. A population-based survey examined 3,654 people aged =49 years, 82% of permanent residents of an area near Sydney, Australia. Participants had a detailed eye examination, including standardised dilated lens and stereo macular photographs. Presence of cataract and ARM was diagnosed from masked photographic grading using the Wisconsin Cataract and Age-related Maculopathy Grading Systems. Generalized Estimating Equation (GEE) and logistic regression models were used in the statistical analysis. RESULTS. Higher prevalence was found for both late and early ARM in eyes with cataract or a past history of cataract surgery. However, after adjusting for age, sex and other ARM risk factors, no consistent association was found between presence of cortical, nuclear or posterior subcapsular (PSC) cataract or past history of cataract surgery and either late or early ARM. In the GEE model, the only statistically significant association found was between PSC and late ARM. Non-significant increased odds were found for late ARM in eyes with cortical cataract. However, detailed analyses of cortical cataract location failed to show a relationship. CONCLUSIONS. The co-existence of cataract and ARM was almost entirely explained by the age-related increase in prevalence of both conditions. We found no evidence of a consistent relationship between cortical, nuclear or PSC cataract or history of past cataract surgery and either late or early ARM, after adjusting for age and other potential ARM risk factors. The possibility of a relationship between PSC and late ARM or between cortical cataract and any ARM was not excluded. Long-term follow up data from this population will be useful.     

Serum lipids and age-related lens opacities: a longitudinal investigation: the Framingham Studies

OBJECTIVE: To investigate whether serum lipid/lipoprotein levels are independent risk factors for nuclear, cortical, or posterior subcapsular (PSC) cataracts. DESIGN: Case-control study nested in a cohort study. PARTICIPANTS AND METHODS: Eye examinations were conducted on surviving members of the Framingham Offspring Heart Study cohort from 1989 to 1991 (Framingham Offspring Eye Study) to determine cataract case-control status. Data from the Framingham Offspring Heart Study, including fasting serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride measurements collected first in 1971, again approximately 8 years later, and approximately every 4 years thereafter were used to examine associations between lipid levels (mean levels across examinations and slope of measurements over time) and the presence of specific cataract types. The multistage analyses included 1869 persons aged 45 years and older. MAIN OUTCOME MEASURES: A standardized grading system was used to grade cortical, nuclear, and PSC cataracts. RESULTS: The median age of participants was 55 years; 49% were males. In multivariable logistic regression models adjusted for potential confounders, fasting hypertriglyceridemia (>/=250 mg/dl) was associated with an increased risk of PSC cataract in men (P = 0.02). High-density lipoprotein cholesterol levels 相似文献   

A case-control study on risk factors for nuclear, cortical and posterior subcapsular cataract: The Casteldaccia Eye Study

PURPOSE: To investigate risk factors for nuclear, cortical and posterior subcapsular age-related cataract. METHODS: A case-control study was carried out on subjects aged 40 years and older, living in Casteldaccia, Sicily. Twenty-seven potential risk factors were investigated. Nuclear, cortical and posterior subcapsular opacities of the lens were classified according to the Lens Opacities Classification System II. Subjects with advanced lens opacities represented the cases, while an identical number of subjects without or with early cataract, matched for sex and age, were recruited as controls from within the same population. RESULTS: Univariate analysis showed that myopia and iris atrophy were significantly associated with nuclear cataract. Iris atrophy, use of corticosteroids, pseudoexfoliation syndrome and familial occurrence of cataract were positively correlated with cortical cataract. Myopia, iris atrophy, use of corticosteroids and familial occurrence of cataract presented an association with posterior subcapsular cataract. After multivariate analysis, the variables that remained significantly associated were myopia and iris atrophy for nuclear cataract; iris atrophy, pseudoexfoliation syndrome and familial occurrence of cataract for cortical cataract; and myopia, iris atrophy and familial occurrence of cataract for posterior subcapsular cataract. CONCLUSION: In addition to well known risk factors such as myopia or use of corticosteroids, the Casteldaccia case-control study shows that iris atrophy represents a previously unrecognized risk factor for each of the three types of cataract.     

Refractive errors and incident cataracts: the Beaver Dam Eye Study

PURPOSE: To describe the relation between refractive errors and incident age-related cataracts in a predominantly white US population. METHODS: All persons aged 43 to 84 years of age in Beaver Dam, Wisconsin, were invited for a baseline examination from 1988 through 1990 and a follow-up examination 5 years later from 1993 through 1995. At both examinations, participants had refraction and photographic assessment of cataract, according to a standardized protocol. Myopia was defined as a spherical equivalent of -1.0 diopters (D) or less, hyperopia as +1.0 D or more. The relations between refractive errors at baseline and cataract at baseline (prevalent cataract), 5-year incident cataract, and incident cataract surgery were analyzed by using generalized estimating equations. RESULTS: When age and gender were controlled for, myopia was related to prevalent nuclear cataract (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.23-2.27), but not to cortical and posterior subcapsular cataracts. Myopia was not related to 5-year incident nuclear, cortical, and posterior subcapsular cataracts, but was related to incident cataract surgery (OR 1.89; CI 1.18-3.04). Hyperopia was related to incident nuclear (OR 1.56; CI 1.25-1.95) and possibly cortical (OR 1.25; CI 0.96-1.63) cataracts, but not to posterior subcapsular cataract or cataract surgery. After further adjustment for diabetes, smoking, and education, the association between myopia and incident cataract surgery was attenuated (OR 1.60; CI 0.96-2.64), but the associations between hyperopia and incident nuclear and cortical cataracts were unchanged. CONCLUSIONS: These data support the cross-sectional association between myopia and nuclear cataract seen in other population-based studies, but provide no evidence of a relationship between myopia and 5-year incident cataract. Hyperopia may be related weakly to incident nuclear and cortical cataract.     

Cataract in the 21st Century: lessons from previous epidemiologic research

Background: Cataract surgery is currently the most commonly performed ophthalmic procedure in Australia. The purpose of this paper is to review Australian data on cataract prevalence and risk factors and to project potential future demand for cataract services. Methods: Age‐ and gender‐specific cataract prevalence data from the Melbourne Visual Impairment Project (VIP) and the Blue Mountains Eye Study (BMES) were applied to population estimates from the Australian Bureau of Statistics. Published cataract risk factor data from the two studies were reviewed. Results: Although the projected number of cataracts varies substantially based on the definition used, the relative number of cataracts will double over the next 50 years due to the aging of the population. Risk factors for cortical cataract identified in both the VIP and the BMES included female gender, sunlight exposure and myopia. Concord‐ ant findings for nuclear cataract included female gender, brown irides, cigarette smoking and myopia. The only risk factor for posterior subcapsular cataract (PSC) that was identified in both studies was myopia. Some of the discrepant findings between the two studies included alcohol intake, diabetes and medication use. Discussion: These data suggest that supply and demand for cataract surgery must be considered and managed to maintain the current level of cataract surgery delivery as the number of people with cataract increases at a proportionately greater rate than the total population. The supply of cataract surgical services could be increased through an increase in the number of ophthalmologists, an increase in the efficiency with which cataract surgical services are delivered, or improved technology. The demand for cataract surgery could be decreased through the implementation of effective primary prevention strategies, although successful strategies are currently unknown and/or untested. Given our current state of knowledge about cataract, it seems most feasible immediately to alter the health service delivery side of the equation to reduce the public health burden of cataract.     

Lutein and zeaxanthin and the risk of cataract: the Melbourne visual impairment project

PURPOSE: To evaluate the association of cortical, nuclear, or posterior subcapsular (PSC) cataract with dietary intake of lutein-zeaxanthin (LZ) in a population-based sample. METHODS: For the study, 3271 (83% of the eligible residents) permanent residents aged > or =40 years were recruited in 1992 to 1994 via a cluster random sampling. In 1997 to 1999, 2594 (79%) attended the follow-up examination including lens photography, a life-style questionnaire, and a food-frequency questionnaire (FFQ). Cases were those with cortical opacity > or =4/16, nuclear opacity grade > or =2.0, or PSC opacity > or =1 mm2. Logistic regression was used to calculate the odds ratios for cataract by daily LZ intake, or its quintile indicator with the lowest quintile as the baseline category, controlling for energy-adjusted fat intake and variables previously found to be associated with the cataract outcomes. RESULTS: Of the 2322 participants who attended the follow-up survey and completed the FFQ, 1841 (79%), 1955 (84%), and 1950 (84%) were included in the analyses of cortical, nuclear, and PSC cataract, respectively. There were 182 (9.9%), 387 (19.8%), and 177 (9.1%) cases for cortical, nuclear, and PSC cataract, respectively. Cortical and PSC cataract were not significantly associated with LZ intake. For nuclear cataract the odds ratios were 0.67 (0.46-0.96) and 0.60 (0.40-0.90) for every 1-mg increase in crude and energy-adjusted daily LZ intake, respectively. The odds ratios (95% CI) for those in the top quintile of crude LZ intake was 0.58 (0.37-0.92; P = 0.023 for trend), and it was 0.64 (0.40-1.03) for energy adjusted LZ intake (P = 0.018 for trend). CONCLUSIONS: This study found an inverse association between high dietary LZ intake and prevalence of nuclear cataract.     

Incidence and progression of lens opacities in the Barbados Eye Studies

OBJECTIVE: To provide 4-year cumulative incidence and progression rates of age-related lens opacities in a population > or =40 years of age, which is mainly of African origin. DESIGN: Cohort study that reexamined surviving members of the population-based Barbados Eye Study 4 years after baseline. PARTICIPANTS: Three thousand four hundred twenty-seven members of the Barbados Eye Study cohort (85% of those eligible). MAIN OUTCOME MEASURES: The Lens Opacities Classification System II (LOCS II) was used at the slit lamp. Cumulative incidence was defined as the development of any nuclear, cortical or posterior subcapsular (PSC) opacities (LOCS II scores > or =2) among persons without that opacity type at baseline. Cumulative progression was defined by at least two-step increases in scores among persons with preexisting lens opacities. RESULTS: The incidence of cortical opacities was about five times greater in black than white participants (age-gender adjusted relative risk = 4.7; 95% confidence interval: 1.9-11.4). In the black population, the 4-year incidence rates were 22.2% (20.4%-24.0%) for any cortical, 9.2% (8.2%-10.4%) for any nuclear, and 3.3% (2.7%-4.0%) for any PSC opacities; rates increased greatly with age. Four-year progression rates were 12.5% for cortical, 3.6% for nuclear, and 23.0% for PSC opacities, without consistent pattern by age. Women had a greater risk of cortical and nuclear opacities (P<0.05) than men and greater progression of nuclear opacities. The presence of PSC opacities at baseline seemed to at least double the incidence and progression rates of other opacities. In persons initially opacity free, single cortical opacities were the predominant type to develop at followup. Visual acuity loss frequently accompanied incident opacities. CONCLUSIONS: This longitudinal study provides new population-based data on the natural history of lens opacities. Incidence and progression of opacities, especially of cortical opacities, were high. After 4 years of followup, 1 in 4 to 5 participants developed cortical opacities, 1 in 11 developed nuclear opacities, and 1 in 30 developed PSC opacities. The information obtained attests to the public health impact of age-related cataract, as well as its extent, in this and similar black populations.     

Statin use and the long-term risk of incident cataract: the Blue Mountains Eye Study

PURPOSE: To assess the association between statin use and long-term incident cataract. DESIGN: Population-based cohort study. METHODS: Of 3,654 baseline (1992 to 1994) elderly participants in the Blue Mountains Eye Study (BMES), 2,335 (75% of survivors) were reexamined after five years (1997 to 1999) and 1,952 (76% of survivors) after 10 years (2002 to 2004). Lens photographs were taken and graded using the Wisconsin Cataract Grading System. History, physical examination, and fasting blood samples provided data on possible risk factors. Discrete linear logistic models were used to assess the risk of cataract. RESULTS: After controlling for age, gender, and other factors, statin use was protective for any cataract (hazard ratio [HR] 0.52; 95% confidence interval [CI] 0.29-0.93), but was not significantly associated with incident nuclear (HR 0.66; CI 0.35 to 1.25), cortical (HR 0.76; CI 0.44 to 1.33), or posterior subcapsular (PSC) cataract (HR 1.47; CI 0.70 to 3.08). CONCLUSIONS: Statin use was found to reduce by 50% the risk of cataract development, principally nuclear or cortical cataract subtypes.     

Cataract surgery and subtype in a defined, older population: the SEECAT Project

AIM: To describe the distribution of cataract subtypes present before surgery among a defined population of older, bilaterally pseudophakic individuals. METHODS: This was a cohort study of bilaterally pseudophakic individuals participating in the Salisbury Eye Evaluation (SEE), and their locally resident siblings. Subjects underwent slit lamp and retroillumination photography and grading using the Wilmer Cataract Grading System. For all individuals determined to be bilaterally pseudophakic, an attempt was made to determine for each eye the type(s) of cataract present before surgery, based on previous SEE photographs (for SEE participants) and/or medical records obtained from the operating ophthalmologist (for both SEE participants and their siblings). RESULTS: The mean age of 223 participants providing data in this study was 78.7 (SD 5.2) years, 19.3% of subjects were black and 60.1% female. The most common surgically removed cataract subtype in this population was pure nuclear (43.5%), followed by nuclear combined with posterior subcapsular cataract (PSC) (20.6%), and nuclear combined with cortical (13.9%); less common types were pure cortical (4.9%), pure PSC (4.5%), and PSC combined with cortical (2.7%). Factors such as sex and source of lens data (study photograph versus clinical record) did not significantly affect the distribution of lens opacity types, while PSC was significantly (p = 0.01) more common among younger people and nuclear cataract was significantly (p = 0.001) more common among white compared to black people. CONCLUSION: Epidemiological studies have suggested that the different subtypes of cataract are associated with different risk factors. As studies begin to identify new prevention strategies for cataract, it would appear likely that different strategies will be efficacious against different types of cataract. In this setting, it will be helpful to know which cataract types are most frequently associated with surgery. Among this older, majority white population, nuclear cataract showed a clear predominance among individuals having undergone surgery in both eyes. This may be contrasted with both clinic and population based studies of younger people, which have generally found PSC cataract to predominate.     

Nuclear sclerotic cataract in young patients in Taiwan

PURPOSE: To document the clinical features of discrete nuclear sclerosis in young patients. SETTING: Chang-Gung Memorial Hospital, Taoyuan, Taiwan, Republic of China. METHODS: The medical records of all patients younger than 45 years with nuclear sclerosis who had cataract surgery at 1 hospital were retrospectively reviewed. Patients with congenital cataract, ocular trauma, ocular disease in addition to myopia, and systemic disease associated with cataract were excluded. The patients' age, sex, bilateral lens status, axial length, original and preoperative refractive status, and preoperative and postoperative best corrected visual acuities (BCVAs) were recorded. RESULTS: Fifty-five eyes of 35 patients aged 32 to 45 years met the study criteria. Nuclear sclerotic cataract was bilateral in 20 patients. The mean age at surgery was 40.64 years +/- 3.63 (SD). The mean refraction before the development of cataract was -7.80 +/- 3.57 diopters (D) and the mean preoperative refraction, -17.40 +/- 6.05 D. The mean axial length was 28.09 +/- 2.31 mm. The postoperative BCVA was 20/22 or better in 53 eyes (96.4%). CONCLUSIONS; In patients younger than 45 years with cataract in Taiwan, nuclear sclerosis was not a rare cause of visual loss and axial myopia was strongly associated with the formation of nuclear sclerosis. Bilateral sclerosis was observed in most cases. Patients with an axial length greater than 27.0 mm had the greatest risk. Surgical treatment was therapeutic.