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.     

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.     

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.     

Dietary macronutrient intake and five-year incident cataract: the blue mountains eye study

PURPOSE: To investigate the relationships between dietary macronutrient intake at baseline and the five-year incidence of the three main types of cataract in older people. DESIGN: Population-based cohort study. METHODS: Settings: An urban community near Sydney, Australia. STUDY POPULATION: The Blue Mountains Eye Study (BMES) examined 3,654 predominantly Caucasian participants aged 49+ years during 1992 to 1994, and then 2,335 survivors (71.5%) after five years. Of these 2,335 subjects, 1988 (85%) completed a Willett-derived food frequency questionnaire (FFQ) at baseline. OBSERVATION PROCEDURES: A 145-item FFQ was used to assess nutrient intakes and lens photography was used to assess the presence of cataract at both time points. MAIN OUTCOME MEASURES: Incidence of cortical, nuclear, and posterior subcapsular (PSC) cataract was assessed via lens photographic grading following the Wisconsin cataract grading method. RESULTS: After adjusting for multiple known cataract risk factors, higher dietary intakes of omega-3 polyunsaturated fatty acids (n-3 PUFA) were associated with a reduced incidence of nuclear cataract. The odds ratio (OR) for subjects in the highest quintile of intake compared to those in the lowest quintile was 0.58 (95% confidence interval [CI] 0.35 to 0.97), P(trend) = .027. Similarly, for PSC cataract, higher dietary intakes of protein were protective (OR 0.28; 95% CI 0.10 to 0.76), P(trend) = .015. Dietary macronutrient intake was not associated with incident cortical cataract. CONCLUSIONS: Higher dietary intakes of n-3 PUFA may decrease the five-year risk of nuclear cataract, whereas higher dietary intakes of protein may decrease risk for PSC cataract.     

The potential role of nutrition on lens pathology: a systematic review and meta-analysis

Oxidative stress is one of the main mechanisms of lens opacification, and certain nutritional antioxidants are suspected to have a protective effect. To examine the role of these nutritional antioxidants on cataract prevention, we searched major databases and reviewed current evidence regarding the protective effect of nutritive antioxidants. We included observational studies that investigate the association between one or more of the following micronutrients and cataract: vitamin A, vitamin C, vitamin E, lutein, zeaxanthin, α- and β-carotene. Two independent authors extracted data and assessed their quality. We pooled results for overall cataract incidence for all types of cataract and separately for nuclear, cortical, and posterior subcapsular cataract. We did not perform sensitivity analysis. Twenty-five studies were included in the qualitative and 24 in the quantitative part of the study, with a total of 295,821 participants over 30 years old. Results from pooled analysis showed a protective effect of antioxidants on cataract, but not all of them reached statistical significance. Statistically significant results were reached for vitamin C (odds ratio [OR] = 0.88, 95% confidence interval [CI] [0.81, 0.97]), beta-carotene (OR = 0.89, 95% CI [0.83, 0.95]), and lutein and zeaxanthin (OR = 0.92, 95% CI [0.85, 0.99]). We did not find statistically significant results for vitamin E (OR = 0.84, 95% CI [0.70, 1.01]), vitamin A (OR = 0.90, 95% CI [0.80, 1.00]), or alpha-carotene (OR = 0.92, 95% CI [0.85, 1.00]). The present study shows a relation between certain antioxidants and cataract, but further studies, especially interventional, are needed to confirm this hypothesis.     

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.     

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.     

Iris color and cataract: the Blue Mountains Eye Study

PURPOSE: To investigate the relationship between eye color and cataract. METHODS: A population-based cross-sectional study (N = 3654) was conducted near Sydney, Australia. Lens photographs were graded for cortical, nuclear, and posterior subcapsular cataract. Iris color was assessed at slit-lamp examination by comparison with four photographic standards. RESULTS: Eyes with dark brown irises were more likely to have nuclear (adjusted odds ratio, 1.59; 95% confidence interval [CI], 1.03 to 2.28) or posterior subcapsular cataract (adjusted odds ratio, 2.50; 95% CI, 1.57 to 3.98) than eyes with lighter-colored irises. CONCLUSIONS: People with dark brown eyes are at increased risk of cataract and should be encouraged to protect their eyes from direct exposure to sunlight.     

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.     

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.     

Plasma homocysteine is elevated in patients with exfoliation syndrome

PURPOSE: To compare plasma homocysteine concentrations among patients with exfoliation syndrome, exfoliative glaucoma, normal-tension glaucoma, and normal control subjects without vascular or inflammatory ocular disease or glaucoma. DESIGN: Cross-sectional study. METHODS: We tested 25 patients with exfoliation syndrome, 50 with exfoliative glaucoma, 25 with normal-tension glaucoma, and 24 control subjects. Fasting plasma homocysteine concentrations were measured by fluorescence polarization immunoassay. Patients using vitamin supplements or medications known to alter serum homocysteine were excluded. RESULTS: Homocysteine levels were higher in both exfoliatin groups compared with controls (exfoliation syndrome: P =.003; exfoliative glaucoma: P =.009); levels in normal-tension glaucoma were higher than but not significantly different from those in controls (P =.2). Hyperhomocysteinemia was present in 16 of 25 (64%) exfoliation syndrome patients, 28 of 50 (56%) exfoliative glaucoma patients, 13 of 25 (52%) normal-tension glaucoma patients, and 7 of 24 (29.2%) controls (P =.005). Multiple logistic regression analyses comparing exfoliation syndrome and exfoliative glaucoma patients with controls indicated that elevated plasma homocysteine concentration was a significant risk factor for exfoliation syndrome, in both those patients (odds ratios per 1.0 micromol/l increase in plasma homocysteine concentrations = 1.47; 95% confidence interval [CI] = 1.08-2.0) and in exfoliative glaucoma patients (odds ratio = 1.3; 95% CI = 1.07-1.6). Although exfoliative glaucoma and normal-tension glaucoma patients were not significantly different with respect to hyperhomocysteinemia, logistic regression modeling of exfoliative glaucoma vs normal-tension glaucoma patients showed that an increased homocysteine concentration was a significant risk factor for exfoliation syndrome in the presence of glaucoma (odds ratio per 1.0 micromol/l increase in homocysteine = 1.2, 95% CI = 1.0-1.4). These relationships were not affected by adjustment for potential confounding due to sex, history of hypertension, or other factors. RESULTS: Elevated plasma homocysteine, a risk factor for cardiovascular disease, is more common in exfoliation syndrome and exfoliative glaucoma patients than healthy controls. Patients with exfoliation syndrome may benefit from measurement of homocysteine levels.     

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.     

Update on a long-term, prospective study of capsulotomy and retinal detachment rates after cataract surgery

PURPOSE: To evaluate the retinal detachment risks and neodymium:YAG (Nd:YAG) capsulotomy rates associated with different cataract approaches and intraocular lens (IOL) styles in a long-term,prospective clinical study. SETTING: Clinical practice of 1 ophthalmologist, Fort Collins, Colorado, USA. METHODS: Prospectively studied were surgical approach, date, and complications; IOL type; axial length; patient age and sex; Nd:YAG capsulotomy and date; and retinal detachment and date. RESULTS: Phacoemulsification had a lower risk of retinal detachment than intracapsular cataract extraction (ICCE) (0.4% versus 5.4%; P <.001) and extracapsular cataract extraction (ECCE) (0.4% versus 1.6%; P =. 002). Although retinal detachment was significantly associated with Nd:YAG for ECCE (3.1% versus 1.0%; P =.01), no patient in the phacoemulsification group had a retinal detachment after an Nd:YAG treatment. Retinal detachment was strongly associated with axial length of 24.0 mm and greater (P <.001), age of 60 years or less if axial length was 24.0 mm or greater (for ECCE, P =.001; for phacoemulsification, P =.01) and sex; that is, male (for ECCE, P =. 04; for phacoemulsification, P =.02). Regarding IOL styles the Surgidev B20/20 (P <.001) and AcrySof MA60 (P <.001) had significantly lower Nd:YAG rates, while the Cilco UPB 320 GS had a significantly higher Nd:YAG rate (P <.001). CONCLUSIONS: Cataract surgical approach and IOL style significantly affect Nd:YAG and retinal detachment rates. Being a man, being 60 years or younger, and especially having an axial length of 24.0 mm or greater were associated with detachment. Some Nd:YAG approaches may not put the patient at increased risk for retinal detachment.     

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.     

Dietary antioxidants and age-related maculopathy: the Blue Mountains Eye Study

OBJECTIVE: To assess associations between the stages of age-related maculopathy (ARM) and dietary intake of carotene, vitamin C, retinol, and zinc. DESIGN: Cross-sectional, population-based study. PARTICIPANTS: A total of 3654 subjects 49 years of age and older from a defined area, west of Sydney, Australia, participated. A total of 2900 participants (79.4%) completed accurate food records. INTERVENTION: Masked grading of stereoscopic macular photographs, detailed interviewer-administered questionnaire, and 145-item self-administered food frequency questionnaire. MAIN OUTCOME MEASURES: Late ARM and early ARM were diagnosed from photographic grading. RESULTS: The authors found no statistically significant associations between ARM and dietary intake of either carotene, zinc, or vitamins A or C, either from diet or supplements or from the combined intake from diet and supplements. Multivariate-adjusted odds ratios (95% confidence interval) were calculated comparing highest to lowest dietary intake quintiles. For late ARM, the odds ratios were carotene, 0.7 (range, 0.3-2.0); vitamin A, 1.2 (range, 0.5-3.3); vitamin C, 1.3 (range, 0.5-3.4); and zinc, 1.0 (range, 0.4-2.8). For early ARM, the odds ratios were carotene, 0.7 (range, 0.4-1.1); vitamin A, 1.2 (range, 0.7-2.0); vitamin C, 0.9 (range, 0.5-1.4); and zinc, 0.8 (range, 0.5-1.3). No significant trends were apparent. Adjustment for energy intake also showed no associations between these antioxidants and ARM. Further, no associations were found between increasing intake of foods high in antioxidant vitamins and decreasing prevalence of either late or early ARM. CONCLUSIONS: The authors found no associations between ARM and dietary antioxidants, either from diet alone or including supplements, or from selected foods, in the Blue Mountains Eye Study population.     

晶状体密度测量在年龄相关性白内障诊断中的价值探讨

目的探讨应用Pentacam系统测量晶状体密度在不同类型年龄相关性白内障诊断中的价值。方法根据LOCSⅢ将年龄相关性白内障分成核型白内障核混浊度（NO）1～5、核颜色（NC）1～5,皮质型白内障（C）1-4和后囊下型白内障（P）1～4,每级30眼。采用Pentacam系统测量晶状体密度。分析晶状体密度值与LOCSⅢ评分值和LogMAR视力的相关性。结果核型白内障眼的晶状体密度值与LOCSⅢ评分值呈线性正相关（r=0．973,r=0．822）;晶状体密度值与LogMAR视力的相关系数r=0．867。皮质型白内障眼的晶状体密度值与C分级评分值的相关系数r=0．634;晶状体密度值与中央前房深度和前房容积均呈负相关（r=-0．453;r=-0．380）。结论核型白内障的晶状体密度值与LOCSⅢ评分值有良好的一致性,可以反映晶状体混浊程度及视力损害程度。晶状体密度和前房深度的变化可用于评价皮质型白内障的进展程度。     

C677T variant in the methylentetrahydrofolate reductase gene is a genetic risk factor for primary open-angle glaucoma

PURPOSE: To estimate the prevalence of C677T single nucleotide polymorphism in the 5,10-methylentetrahydrofolate reductase (MTHFR) gene in primary open-angle glaucoma (POAG) and pseudoexfoliation open-angle glaucoma (PEXG). DESIGN: Case-control study METHODS: MTHFR was assessed in 147 patients (76 POAG, 71 PEXG) and 71 control subjects with cataract. Associations of genotypes were assessed by Armitage's trend test and the corresponding odds ratio (OR) for allele positivity with 95% confidence interval (CI). RESULTS: We observed significant evidence of a higher prevalence of C677T in POAG (9% homozygote, 49% heterozygote, 42% wildtype, P = .01, OR = 2.38, 95% CI 1.23-4.62), but not in PEXG (9% homozygote, 41% heterozygote, 50% wildtype, P = .09, OR = 1.78, 95% CI 0.91-3.50) compared with the controls (3% homozygote, 34% heterozygote, 63% wildtype). CONCLUSIONS: The MTHFR C677T variant leading to moderate hyperhomocysteinemia may play a role in the pathogenesis of POAG acting as a genetic risk factor.     

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.     

Prevalence of lens opacity in Chinese residents of Singapore: the tanjong pagar survey

OBJECTIVE: To determine the prevalence of lens opacity among Chinese residents of Singapore. DESIGN: Population-based, cross-sectional survey. PARTICIPANTS: Chinese men and women aged 40 years or more in Singapore. METHODS: A stratified, clustered, random sampling method, with more weights given to the older age groups, was used to initially select 2000 Chinese persons aged 40 to 79 years from the 1996 electoral register in the Tanjong Pagar district in Singapore. Eligible subjects (n = 1717) were invited for a comprehensive ocular examination at a centralized clinic, after which nonrespondents were examined in their homes with portable instruments. MAIN OUTCOME MEASURES: Lens opacity, as determined clinically at the slit lamp using a modification of the Lens Opacity Classification System III. Prevalence rates were age adjusted to the 1997 Singapore census population. RESULTS: Of the 1232 persons examined (71.8%), 1206 (70.2%) provided lens data for this analysis. The age-adjusted prevalence of any cataract surgery was 5.1% (95% confidence interval [CI], 3.6, 6.5), with similar rates between men and women. The age-adjusted prevalence of specific types of lens opacity was 22.6% (95% CI, 19.8, 25.4) for any nuclear opacity, 23.9% (95% CI, 21.0, 26.8) for any cortical opacity, and 7.0% (95% CI, 5.3, 8.8) for any posterior subcapsular opacity. The overall age-adjusted prevalence of any cataract or cataract surgery was 34.7% (95% CI, 31.5, 38.0), increasing from 7.0% in those 40 to 49 years and to 94.3% in those 70 years and older (P < 0.001, test for trend for age). When the prevalence of distinct types of lens opacity in an eye was considered, the most common was mixed (age-adjusted prevalence, 11.5%, based on right eye data), followed by nuclear only (9.7%), cortical only (8.3%), and posterior subcapsular only (0.6%). For all cataract types, the prevalence was similar in men and women and was higher in persons examined at their homes than in those examined at the study clinic. CONCLUSIONS: These population-based data suggest that cataract is common among adult Chinese residents in Singapore, despite ready access to cataract surgical services. Persons accepting the offer of free eye examinations were less likely to have cataract than those who did not take up this offer.     

An association between central serous chorioretinopathy and gastroesophageal reflux disease

PURPOSE: To explore a clinically observed association between central serous chorioretinopathy (CSC) and gastroesophageal reflux disease (GERD) DESIGN: A retrospective case-control study. PARTICIPANTS AND CONTROLS: Sixty-nine consecutive patients diagnosed with CSC were compared with a control group of 55 non-CSC patients. METHODS: The records of 69 patients with CSC were retrospectively reviewed and compared with the records of 55 controls. All patients and controls were examined in a referral setting. RESULTS: Patients with CSC were significantly more likely to have GERD compared with controls (odds ratio 6.05; 95% confidence interval 2.14-17.11; P =.0003). Central serous chorioretinopathy patients were also more likely than controls to have used oral corticosteroid medications (odds ratio 16.30; 95% confidence interval 2.09-127.33; P =.0006) and antacid/antireflux medications (odds ratio 15.00; 95% confidence interval 1.91-117.58; P =.001). CONCLUSIONS: This study identifies an association between CSC and GERD. There are biochemical factors common to both diseases that support this association, giving further insight into the pathogenesis of CSC.