Iris color and incident cataract and cataract surgery: the Blue Mountains Eye Study

PURPOSE: To assess whether an association exists between iris color and the incidence of cataract and cataract surgery. DESIGN: Population-based cohort study. METHODS: The Blue Mountains Eye Study examined 3654 predominantly Caucasian participants aged 49+ years during 1992-1994, and then 2335 survivors (75.1%) after 5 years. Iris color was determined by comparison with four standard photographs. Slit-lamp and retro-illumination lens photographs were graded for presence and severity of cortical, nuclear, or posterior subcapsular cataract. Incident cataract surgery was recorded by history and from the photographs. RESULTS: Participants with dark brown iris color had an increased incidence of nuclear cataract, odds ratio (OR) 1.8, 95% confidence interval (CI) 1.2 to 2.8, and cataract surgery (OR, 2.5; CI, 1.4-4.2) in multivariate models, compared with participants with blue iris color. CONCLUSION: Incidence data from this study support previous cross-sectional findings linking dark brown iris color with age-related cataract.     

Relation of ocular trauma to cortical, nuclear, and posterior subcapsular cataracts: the Beaver Dam Eye Study

BACKGROUND: The consequences of minor ocular trauma in the general population are unclear. The relation of self reported ocular trauma to cortical, nuclear, and posterior subcapsular cataracts is described in a defined population. METHODS: Population based, cross sectional study involving all people aged 43 to 86 years, living in Beaver Dam, Wisconsin (n=4926). Ocular trauma was ascertained by interview and cataract was graded from lens photographs. The relation of ocular trauma to cortical, nuclear, and posterior subcapsular cataracts was examined. RESULTS: People with a history of ocular trauma were more likely to have cortical (odds ratio (OR): 1.5; 95% confidence interval (CI): 1.0 to 2.2) and posterior subcapsular (OR: 1.7; 95% CI: 1.0 to 3.1) cataracts, compared to people without a history of trauma. These associations were stronger for people with previous trauma caused by a blunt object (OR: 3.3; 95% CI: 1.6 to 6.9 for cortical cataract, and OR: 4.1; 95% CI: 1.5 to 10.8 for posterior subcapsular cataracts). However, in analyses comparing the frequencies of cataract between traumatised and non-traumatised eyes among people with unilateral ocular trauma, the ocular trauma association for cortical cataract was no longer present, although the association for posterior subcapsular cataract persisted (OR: 2.4; 95% CI: 0.8 to 7.8). CONCLUSION: The data provide evidence of a possible association between self reported ocular trauma and posterior subcapsular 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.     

Cardiovascular disease,vascular risk factors and the incidence of cataract and cataract surgery: The Blue Mountains Eye Study

PURPOSE To assess whether an association exists between cardiovascular disease, vascular risk factors and incident cataract and cataract surgery. METHODS The Blue Mountains Eye Study examined 3654 participants =49 years of age during 1992–4, then 2335 survivors (75.1%) after five years. Trained interviewers administered a vascular history questionnaire; height, weight and blood pressure were measured. Lens photographs from both examinations were graded for presence of cortical, nuclear or posterior subcapsular cataract. RESULTS Obesity (body mass index =30kg/m 2 ) was significantly associated with increased incidence of both cortical [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.2–2.2] and posterior subcapsular cataract (OR 2.1, CI 1.2–3.7). Hypertensive participants using medication and aged less than 65 years at baseline had a higher incidence of posterior subcapsular cataract (OR 3.4, 95% CI 1.3–8.4) than normotensive subjects. A history of angina was associated with higher cataract surgery incidence (OR 2.1, 95% CI 1.3–3.5). CONCLUSIONS These longitudinal data provide some evidence supporting a relationship between cardiovascular disease, vascular risk factors and incident cataract and cataract surgery. The findings confirm a number of associations previously documented in cross-sectional data.     

Plasma antioxidant vitamins and carotenoids and age-related cataract.

OBJECTIVE: To investigate the relationships between plasma concentrations of antioxidant vitamins and carotenoids and nuclear, cortical, and posterior subcapsular cataracts in a group of elderly men and women. DESIGN: Cross-sectional survey. PARTICIPANTS: Three hundred seventy-two men and women, aged 66 to 75 years, born and still living in Sheffield, England. METHODS: The Lens Opacities Classification System (LOCS) III was used to grade nuclear, cortical, and posterior subcapsular lens opacities. Fasting blood samples were taken to assess plasma concentrations of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin. MAIN OUTCOME MEASURES: Logistic regression analyses of the associations between plasma vitamin concentrations and cataract subtype, adjusting for age, gender, and other risk factors. RESULTS: After adjustment for age, gender, and other risk factors, risk of nuclear cataract was lowest in people with the highest plasma concentrations of alpha-carotene (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.3-0.9, P for trend 0.006) or beta-carotene (OR, 0.7; 95% CI, 0.4-1.4, P for trend 0.033). Risk of cortical cataract was lowest in people with the highest plasma concentrations of lycopene (OR, 0.4; 95% CI, 0.2-0.8, P for trend 0.003), and risk of posterior subcapsular cataract was lowest in those with higher concentrations of lutein (OR, 0.5; 95% CI, 0.2-1.0, P for trend 0.012). High plasma concentrations of vitamin C, vitamin E, or the carotenoids zeaxanthin and beta-cryptoxanthin were not associated with decreased risk. CONCLUSIONS: These findings suggest that a diet rich in carotenoids may protect against cataract development, but because they are based on observational data, they need to be confirmed in randomized controlled trials.     

Incident cataract after a five-year interval and lifestyle factors: The Beaver Dam Eye Study

CONTEXT: A population-based study to investigate risk factors for age-related eye disease was begun in 1987 in a representative American community. Incidence of cataract was subsequently evaluated. SPECIFIC OBJECTIVES: To examine the relationships of cigarette smoking, alcohol, and caffeine intakes to incidence of age-related cataracts five years later. DESIGN: Observational epidemiologic incidence study of an adult population. PARTICIPANTS AND INTERVENTION: Adults 43-84 years of age were identified during a census in 1987-1988, and examined at baseline (1988-1990) and after a five-year interval (1993-1995). MAIN OUTCOME MEASURE: Standardized protocols were used at the baseline and follow-up evaluations for exposures and for objective identification of cataracts. RESULTS: Cumulative incidence of nuclear cataract in right eyes was about 12%, cortical cataract about 8%, and posterior subcapsular cataract about 3%. In multivariable analyses of the general estimating equations type, there were significant associations between nuclear cataract and: pack-years smoked (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.01, 1.09 per 10 pack-years); and current alcohol intake (OR 1.01, 95% CI 1.00, 1.02 per 10 grams ethanol/week). Cigarette smokers were more likely to have had cataract surgery in the interval between baseline and follow-up examinations. CONCLUSIONS: Cigarette smoking and alcohol consumption were associated with modestly increased risks of incident nuclear cataract over a five-year interval.     

Five-year incidence of cataract in older persons with diabetes and pre-diabetes

PURPOSE: To investigate longitudinal associations between diabetes and the 5-year incidence of cataract and cataract surgery. (A population-based, cohort study of 2335 persons with baseline ages 49 years or older resident in the Blue Mountains region, west of Sydney, Australia). METHODS: Baseline information on diabetes history was collected during an interviewer-administered questionnaire. Impaired Fasting Glucose (IFG) was defined as venous plasma glucose between 6.0 and 7.0 mmol/L and newly diagnosed diabetes as plasma glucose >7.0 mmol/L, using fasting blood glucose measurements taken at baseline. Retroillumination lens photographs from the baseline and 5-year follow-up examinations were graded for presence of cortical, posterior subcapsular (PSC) and nuclear cataract. RESULTS: We found a 2-fold higher 5-year incidence of cortical cataract in participants with IFG, multivariate adjusted odds ratio (OR) 2.2, 95% confidence interval (CI) 1.1-4.1. Incident PSC cataract was more frequent among persons with diabetes, but this association was statistically significant only for those with newly diagnosed diabetes, multivariate adjusted OR 4.5 (CI 1.5-13.0). There were no statistically significant associations found between incident nuclear cataract or cataract surgery and either diabetes or IFG. CONCLUSIONS: These epidemiological data suggest that IFG, a pre-diabetic condition, may be a risk factor for the development of cortical cataract.     

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.     

Myopia and incident cataract and cataract surgery: the blue mountains eye study

PURPOSE: To assess whether an association exists between myopia and incident cataract and cataract surgery in an older population-based cohort study. METHODS: The Blue Mountains Eye Study examined 3654 participants aged 49 years or more during 1992 to 1994 and then 2334 (75.1%) of the survivors after 5 years. A history of using eyeglasses for clear distance vision was obtained. Objective refraction was performed with an autorefractor, followed by subjective refraction with a logarithm of minimum angle of resolution (logMAR) chart. Emmetropia was defined as a spherical equivalent refraction between +1 D and -1 D, hyperopia as more than +1 D, and myopia as less than -1 D. Slit lamp and retroillumination lens photographs were graded for presence of cortical, nuclear, or posterior subcapsular cataract, according to the Wisconsin Cataract Grading System. Generalized estimating equation models analyzed data by eye. RESULTS: There was a statistically significant association between high myopia (-6 D or less) and incident nuclear cataract (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.5-7.4). Incident posterior subcapsular cataract was associated with any myopia (OR 2.1, 95% CI 1.0-4.8), moderate to high myopia (-3.5 D or less, OR 4.4, 95% CI 1.7-11.5), and use of distance glasses before age 20 (OR 3.0, 95% CI 1.0-9.3), after adjustment for multiple potential confounders, including severity of nuclear opacity. Incident cataract surgery was significantly associated with any myopia (OR 2.1, 95% CI 1.1-4.2) as well as moderate (-3.5 to more than -6D; OR 2.9, 1.2-7.3) and high myopia (OR 3.4, 95% CI 1.0-11.3). CONCLUSIONS: These epidemiologic data provide some evidence of an association between myopia and incident cataract and cataract surgery, after adjustment for multiple confounders and severity of nuclear opacity. These data support other cross-sectional and longitudinal population-based findings.     

Fasting blood glucose levels and the long‐term incidence and progression of cataract – the Blue Mountains Eye Study

Purpose: To assess the associations between fasting blood glucose and the long‐term incidence and progression of cataract. Methods: A total of 3654 persons aged 49+ years were examined at baseline with fasting blood glucose measured, and 2454 re‐examined after 5 and/or 10 years. Lens photographs from each visit were used to assess cataract incidence and progression. Associations between baseline fasting blood glucose and incidence and progression of cortical, nuclear and posterior subcapsular (PSC) cataract were assessed using discrete logistic regression and change‐point models. Results: After adjusting for potential confounders, baseline fasting blood glucose was associated with the 10‐year incidence of cortical cataract with a threshold at blood glucose level of 6.0 mm (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.25–2.57 for fasting glucose ≥6.0 mm compared to fasting glucose <6.0 mm). Each 1.0 mm increase in fasting glucose was also associated with higher 5‐year progression of PSC (OR 1.25, 95% CI: 1.15–1.35), 10‐year progression of cortical (OR 1.14, 95% CI: 1.01–1.27) and nuclear (OR 1.20, 95% CI: 1.01–1.43) cataract, with no thresholds detected. Conclusions: In this primarily nondiabetic older population, baseline fasting blood glucose was associated with the long‐term incidence of cortical cataract and long‐term progression of all three cataract subtypes.     

Diet and cataract: the Blue Mountains Eye Study

PURPOSE: To investigate relationships between a wide range of macro- and micronutrients, including antioxidant vitamins, and the three main types of cataract in older people. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Two thousand nine hundred people aged 49 to 97 years living in an urban community near Sydney, Australia. TESTING: Food frequency questionnaires and lens photography. MAIN OUTCOME MEASURE: Lens photographs were graded for presence and severity of cortical, nuclear, and posterior subcapsular cataracts. RESULTS: Higher intakes of protein, vitamin A, niacin, thiamin, and riboflavin were associated with reduced prevalence of nuclear cataract. After adjusting for multiple known cataract risk factors, the odds ratios for those in the highest intake quintile groups compared to those in the lowest intake quintiles were 0.5 (95% confidence interval [CI], 0.3-0.8) for protein, 0.5 (95% CI, 0.3-0.9) for vitamin A, 0.6 (95% CI, 0.4-0.9) for niacin, 0.6 (95% CI, 0.4-0.9) for thiamin, and 0.5 (95% CI, 0.3-0.9) for riboflavin. Intake of polyunsaturated fats was associated with reduced prevalence of cortical cataract. No nutrients were associated with posterior subcapsular cataract. CONCLUSIONS: The nucleus of the lens is particularly sensitive to nutrient deficiencies. Protein, vitamin A, niacin, thiamin, and riboflavin protected against nuclear cataract in this study.     

A dose–response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract

Background

Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. We aimed to conduct a meta-analysis of prospective cohort studies to examine the association between dietary lutein and zeaxanthin intake and risk of age-related cataract (ARC).

Methods

We systematically searched MEDLINE, EMBASE, Web of Science, and Cochrane Library databases up to March 2013. Reference lists from retrieved articles were also reviewed. The adjusted relative risks (RRs) from each study were extracted to calculate a pooled estimate with its 95 % confidence interval (CI). The dose–response relationships were assessed by using generalized least-squares trend estimation.

Results

Six prospective cohort studies were identified involving 4,416 cases and 41,999 participants. For the comparison between the highest and the lowest categories of dietary lutein and zeaxanthin intake, significant inverse association were found for nuclear cataract (RR: 0.75; 95 % CI: 0.65, 0.85), but not for cortical cataract (RR: 0.85; 95 % CI: 0.53, 1.17) and for posterior subcapsular cataract (RR: 0.77; 95 % CI: 0.40, 1.13). Dose–response analysis showed that every 300 μg/d increment in dietary lutein and zeaxanthin intake was associated with a 3 %, 1 %, or 3 % reduction in the risk of nuclear cataract (RR: 0.97; 95 % CI: 0.94, 0.99), cortical cataract (RR: 0.99; 95 % CI: 0.95, 1.02), or posterior subcapsular cataract (RR: 0.97; 95 % CI: 0.93, 1.01) respectively.

Conclusions

Dietary lutein and zeaxanthin intake is associated with a reduced risk of ARC, especially nuclear cataract in a dose–response manner, indicating a beneficial effect of lutein and zeaxanthin in ARC prevention.     

Iris color and age-related changes in lens optical density.

PURPOSE: Epidemiologic evidence indicates that dark iris color increases risk of age-related cataract. No information is currently available, however, on the effects of iris color on the lens prior to cataract development. In this study, we relate iris color to lens optical density (OD) in individuals without frank cataract. METHODS: 90 subjects with blue or green irises (light color) were compared with 87 subjects having hazel, brown, or black irises (dark color). Lens OD was measured psychophysically by comparing scotopic thresholds obtained at 410 (measuring) and 550 nm (reference). Stimuli were presented in Maxwellian view. RESULTS: The groups with light and with dark iris color did not differ significantly in smoking habits, dietary patterns, or age. Despite other similarities between the groups, lens OD was significantly (p < 0.024) higher in the group with dark irises. The higher OD of the dark iris group was due to differences in the older subjects (> 45 years, p < 0.005), rather than the younger subjects (20-45 years) who showed no differences in lens OD. CONCLUSION: Our data indicate that iris pigmentation may be directly related to age-associated increases in lens OD.     

Incidence of and risk factors for residual posterior capsule opacification after cataract surgery

PURPOSE: To evaluate the incidence of and determine the risk factors for residual posterior capsule opacification (PCO). SETTING: University of New Mexico Health Sciences Center and the Veterans Administration Medical Center, Albuquerque, New Mexico, USA. METHODS: This study evaluated 194 uneventful cataract surgeries. Immature cataracts were graded for nuclear sclerosis (NS), posterior subcapsular cataract (PSC), and anterior cortical spokes on a 1 to 4 scale. Preoperative Snellen best corrected visual acuity was converted to the logMAR scale. The posterior capsule was examined after polishing and was classified as clear or as having residual opacity. Those with residual capsule opacity were evaluated 6 weeks postoperatively for the presence of visually significant PCO. RESULTS: The incidence of residual capsule opacity was 23% (44 eyes). Seven (54%) of 13 eyes with white mature cataract had residual capsule opacity. In contrast, 37 (20%) of 181 eyes with immature cataract had residual capsule opacity (P = .01). In eyes with immature cataract, the mean preoperative logMAR acuity was +1.14 +/- 0.60 (SD) in the residual capsule opacity group and +0.73 +/- 0.46 in the clear group (P<.001). In eyes with immature cataract, the adjusted odds ratio for each increasing grade of NS was 2.3 and of PSC, 1.8 (P = .002 and P<.001, respectively). Eleven percent (5 eyes) of residual capsule opacities resulted in visually significant PCO 6 weeks postoperatively. All 5 opacities were centrally located at surgery. CONCLUSIONS: Results indicate that aggressive polishing of peripheral or adherent residual capsule opacities is not advisable as only 5 eyes with central residual capsule opacities developed visually significant PCO.     

Low-dose aspirin and risk of cataract and subtypes in a randomized trial of U.S. physicians

PURPOSE: To examine whether low-dose aspirin (325 mg on alternate days) reduces the risk of age-related cataract and subtypes. This report extends previous findings, including both subtypes and additional newly identified incident cases since the earlier report. METHODS: All 20,979 participants in the Physicians' Health Study, a randomized trial of aspirin and beta-carotene among U.S. male physicians age 40-84 in 1982, who did not report cataract at baseline were included. Average follow-up was five years. The main outcome measure was incident, age-related cataract responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report confirmed by medical record review. RESULTS: 501 age-related cataracts were diagnosed during follow-up, including 416 with nuclear sclerosis and 212 with a posterior subcapsular component; 318 cataracts progressed to surgical extraction. Overall, there were 245 cataracts in the aspirin group and 256 in the placebo group (relative risk [RR], 0.94; 95% confidence interval [CI], 0.79 to 1.13; P=0.52). Cataract extractions were 19% less frequent in the aspirin than in the placebo group (RR, 0.81; 95% CI, 0.65 to 1.01; P=0.06). In subgroup analyses of subtypes, aspirin takers had a lower risk of posterior subcapsular cataract (RR, 0.74; 95% CI, 0.57 to 0.98; P=0.03) but not nuclear sclerosis (RR, 0.96; 95% CI, 0.79 to 1.16; P=0.65) cataract. CONCLUSIONS: Overall, these randomized trial data tend to exclude a large benefit of five years of low-dose aspirin therapy on cataract development and extraction. The data are compatible with a modest benefit on cataract extraction for this duration of aspirin therapy. Subgroup analyses raise the possibility of a modest, but potentially important, protective effect of aspirin on posterior subcapsular cataract, a particularly disabling subtype.     

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.     

Discriminative power of reading tests to differentiate visual impairment caused by cataract and age-related macular degeneration

PURPOSE: To determine whether preoperative reading tests can be used for differentiating visual impairments with regard to the diagnosis of cataract and age-related macular degeneration (ARMD). SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: Reading performance of patients with nuclear cataract, posterior subcapsular cataract, and ARMD were evaluated with respect to reading acuity, maximum reading speed, and critical print size; normal-sighted participants were tested as controls. A multivariate discriminant analysis of the 4 groups (100 eyes of 100 participants) was performed to evaluate how many patients could be correctly diagnosed by significant differences in the tested reading parameters. Subsequently, the nuclear cataract and posterior subcapsular cataract patients were compared with cataract patients with coexisting ARMD. RESULTS: Distance visual acuity was comparable in the nuclear cataract, posterior subcapsular cataract, and ARMD groups (P>.05). Reading acuity was significantly reduced in posterior subcapsular cataract and ARMD patients compared with nuclear cataract patients and controls (P<.0001). No significant difference in maximum reading speed was found between the nuclear cataract patients and the controls (P = .07), whereas the maximum reading speed of the posterior subcapsular cataract and ARMD patients was significantly reduced (P<.0001). In the discriminant analysis, it was possible to assign the correct diagnosis to 72% of the nuclear cataract patients, 76% of the posterior subcapsular cataract patients, 72% of the ARMD patients, and 92% of the controls. Comparing the reading performance of nuclear cataract and posterior subcapsular cataract patients and cataract patients with coexisting ARMD showed that reading performance was significantly impaired in the comorbid patients (nuclear cataract and ARMD, P<.001; posterior subcapsular cataract and ARMD, P<.05). CONCLUSION: The high discriminant accuracy shows that this standardized reading test system is a valuable diagnostic tool for evaluating functional visual impairments when distance visual acuity alone cannot elucidate the origin of functional impairment. Considering the significant discrepancies in reading performance among patients with nuclear cataract, posterior subcapsular cataract, and ARMD, reading tests may relevantly improve the clinical evaluation of patients with visual loss, even of patients with ocular comorbidity.     

Pterygium, pinguecula, and 5-year incidence of cataract

PURPOSE: To assess longitudinal associations between pterygium, pinguecula, and 5-year incident cataract. DESIGN: Population-based cohort study. METHODS: The Blue Mountains Eye Study examined 3,654 residents aged > or =49 years during 1992 to 1994 and reexamined 2,335 (75.1% of survivors) 5 years later. Slit-lamp examination recorded pterygium and pinguecula. Cataract was assessed using masked grading of lens photographs. Incidence was assessed in participants without cataract at baseline. Eye-specific data were analyzed using generalized estimating equation models, adjusting for age, sex, smoking, diabetes, and corticosteroid use. RESULTS: Pinguecula was associated with a borderline-significant, increased risk of developing cortical cataract (adjusted odds ratio, 1.3; 95% confidence interval, 1.0 to 1.7). We found no significant association between baseline pterygium and the incidence of cortical, nuclear, or posterior subcapsular cataract. CONCLUSIONS: Longitudinal data from the same study population provide weak support for cross-sectional associations between pinguecula and cortical cataract previously reported from our study.     

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.     

Lens opacities in a rural population of southern India: the Aravind Comprehensive Eye Study

OBJECTIVES: To determine the prevalence of lens opacities in an older population in rural southern India. METHODS: A cross-sectional study of 5150 persons aged 40 years and more who were selected as part of a representative sample from three southern districts of the state of Tamil Nadu in southern India. All lenses were graded and classified for opacities and other disorders by slit lamp after pupillary dilation, using the Lens Opacification Classification System (LOCS) III and standard photographs. Definite cataract was defined as either LOCS III nuclear opalescence of grade 3.0 or more and/or cortical cataract of grade 3.0 or more and/or posterior subcapsular cataract (PSC) of grade 2.0 or more. RESULTS: Definite cataract was present in one or both eyes in 2499 (47.5%) of 5150 subjects. The age-adjusted prevalence (adjusted to U.S. population estimates for 2000) of definite cataract in this population was 61.9% (95% CI, 60.6-6.3). The prevalence was significantly lower in men (P=0.0002). In those eyes with cataracts, nuclear cataract (59.7%) was most common, and cortical cataract was present in 20.0% and PSC in 24.3%. Cataract surgery had been performed in 9.4% persons, including 3.0% who had bilateral surgery for cataracts. Best corrected visual acuity was less than 6/60 in 3.7% of aphakic eyes and in 0.8% of pseudophakic eyes. CONCLUSIONS: The higher age-adjusted prevalence and relatively early onset of age-related cataract in this population suggest that the cataract-centered approach to minimizing preventable blindness, adopted by the National Program for Prevention of Blindness in India, is appropriate.