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A prospective study of blood pressure and risk of cataract in men.

PURPOSE: Cataract is the leading cause of blindness worldwide. Blood pressure has been identified as a risk factor in some, but not all, previous studies. We aimed to test prospectively the hypothesis that high blood pressure increases risk of age-related cataract. METHODS: Participants in the Physicians' Health Study of 22,071 men aged 40 to 84 years in 1982 completed annual questionnaires that provided medical history including self-reported blood pressure, treatment for hypertension, and cataract. Over 12 years, 1392 cataracts were confirmed by medical record review among 17,762 physicians with complete data and no reported cataract at baseline. We used proportional hazards regression models to examine relations of systolic blood pressure (SBP), diastolic blood pressure (DBP), hypertension, as well as antihypertensive medications with cataract, after control for potential confounding factors. RESULTS: In models adjusting for age and randomized treatment assignment, there was a significant relationship of SBP, but not DBP, hypertension, or antihypertensive medications (each p > or = 0.23) with incident cataract. Estimates were attenuated after adjusting for multiple potential confounders, although the relationship of SBP with incident cataract remained significant. The multivariate adjusted rate ratio (95% confidence interval) of cataract for SBP > or = 150 versus < 120 mm Hg was 1.31 (1.04-1.66), p for trend = 0.04. For DBP > or = 90 versus < 70 mm Hg, the estimate was 1.11 (0.84-1.45), p for trend = 0.33. CONCLUSIONS: Overall, these data suggest that the relationship of blood pressure with cataract is not strong, and is subject to confounding by other risk factors. The modest magnitude of the association with SBP and lack of significant relationships with DBP and hypertension may suggest a non-causal relationship of blood pressure with cataract.

Adult↗

Relationships between hormonal status and cataract in french postmenopausal women: the POLA study.

PURPOSE: Prevalence rate of cataract is higher in women than in men. Sex hormones have been hypothesized to be linked with this gender difference. Our aim is to study the relationships between hormonal status and cataract in postmenopausal women. METHODS: The Pathologies Oculaires Liées à l'Age (POLA) study is a population-based study on age-related eye diseases and their risk factors, in 2584 residents of Sète (France). Cataract classification was based on a standardized lens examination, according to Lens Opacities Classification System III. Biological measurements were performed from fasting blood samples. We conducted a cross-sectional study in the female participants (n=1451) aged over 60 years. RESULTS: No association of hormone replacement therapy (HRT) with any type of cataract was found, but an increased risk of cataract surgery was observed in women with a long duration of hormone therapy >/=5 years) (multivariate-adjusted odds ratio (OR)=3.80; 95% CI: 1.45-9.94). Globally, the risk for cataract (any type) was not associated with a long duration of HRT use (OR=1.06; 95% CI: 0.64-1.74). After multivariate adjustment, oophorectomy was associated with a reduced risk of cataract (OR=0.60; 95% CI=0.38-0.94). In the multivariate model, no association was found between estradiol, total testosterone or sex-hormone-binding globulin and cataract. However, high levels of dehydroepiandrosterone sulfate (DHEAS) were associated with a reduced risk of cataract (OR=0.79; 95% CI: 0.63-0.99). CONCLUSION: HRT use was not associated with cataract. A reduced risk of cataract was found in oophorectomized women and in women with high DHEAS levels.

Aged↗

High levels of plasma C-reactive protein and future risk of age-related cataract.

PURPOSE: Chronic intraocular inflammation, with or without systemic inflammation, is associated with increased risk of cataract. Whether systemic inflammation alone is associated with cataract is unknown. This study examined the association between plasma C-reactive protein (CRP), a marker of systemic inflammation, and risk of cataract. METHODS: In the Physicians' Health Study, we recently analyzed plasma CRP levels in baseline blood specimens from 543 men who later developed cardiovascular disease, and 543 who did not. These data provided a cost-efficient means to explore whether baseline plasma CRP is associated with future risk of age-related cataract. After excluding 252 men with prior diagnosis of cataract or missing data, we followed the remaining 834 men defined by baseline CRP level for 11 years for incident cataract. We used proportional hazards regression models, stratified by cardiovascular disease status. RESULTS: Baseline CRP was significantly higher among men who later developed cataract than levels among those who remained free of cataract, P = 0.02 (median 1.53 versus 1.23 mg/L). In a multivariable model adjusted for cardiovascular disease, randomized aspirin and beta carotene assignments, age, diabetes, cigarette smoking, alcohol consumption, body mass index, exercise, and parental history of myocardial infarction, the levels of CRP remained significantly associated with development of cataract (P = 0.001); but the association was less significant in a model using log CRP levels (P = 0.038). In exploratory analyses of a threshold effect, the excess risk was significant only among men with levels at or above the 97.5th centile (6.17 mg/L); compared to those with lower levels, the relative risk in these men was 3.00 (95% confidence interval, 1.53 to 5.91; P = 0.002). Relative risks associated with CRP levels at or above versus below the 85th, 90th, and 95th percentiles were not significant (relative risks 1.29, 1.50, and 1.77, respectively). CONCLUSIONS: Overall, our results suggest that elevated levels of CRP are associated with future risk of cataract in these apparently healthy men. This early report raises the possibility that systemic inflammation may play a role in the pathogenesis of age-related cataract.

Adult↗

Trends in cataract surgery and postoperative endophthalmitis in Western Australia (1980-1998): the Endophthalmitis Population Study of Western Australia.

OBJECTIVES: Postoperative endophthalmitis results from an intraocular infection and usually occurs following cataract surgery. It has significant morbidity and causes severe visual impairment or blindness of the eye. The aim of this study was to assess the trends in the incidence rates of cataract surgery and postoperative endophthalmitis in Western Australia for the period 1980-1998. METHODS: The Western Australian Record Linkage Project was used to link the morbidity records for all patients treated for cataract surgery in Western Australia in 1980-1998. Patient records were selected using the international classification for diagnosis and procedure codes pertaining to cataract surgery and postoperative endophthalmitis. All cases of postoperative endophthalmitis were validated by case-note review. The separate databases of the Royal Perth Hospital microbiology and anaesthetic departments as well as the vitreo-retinal surgeon logbooks were used to cross-validate the hospital morbidity database. Trends in the incidence rates of cataract surgery and postoperative endophthalmitis were assessed by Poisson regression. RESULTS: There were 94,653 cataract procedures performed for 63,007 patients in Western Australia during the 19-year period. The majority (88%) of cataract procedures performed were in patients aged 60 years or older. Postoperative endophthalmitis developed in 188 patients, with serious visual impairment occurring in 70.6% of patients for whom visual acuity data was available at presentation. The incidence rate of cataract surgery increased more than three-fold from 1981 (102 per 100,000 person years) to 1998 (345 per 100,000 person years), mainly due to the increase in extracapsular cataract extraction during the 1980s and phacoemulsification extraction from 1990 onwards. In contrast, the average annual incidence rate of postoperative endophthalmitis remained relatively unchanged at around 2 per 1000 cataract procedures over the same period. CONCLUSION: Cataract surgery is becoming more prevalent in the elderly as the life expectancy of the population increases. There has been a dramatic shift in surgical practice during the last 30 years with small-incision phacoemulsification being the predominant method of intervention used since 1990. Despite changes in surgical practice the incidence rate of postoperative endophthalmitis has remained the same.

Aged↗

Use of inhaled corticosteroids and the risk of cataracts.

BACKGROUND: The use of systemic corticosteroids is a risk factor for the development of posterior subcapsular cataracts, but the association between inhaled corticosteroids and cataracts is uncertain. METHODS: We conducted a population-based, cross-sectional study of vision and common eye diseases in an urban area of the Blue Mountains, near Sydney, Australia. We recruited 3654 people 49 to 97 years of age; the participation rate was 82 percent. We collected information by questionnaire on potential risk factors for cataracts, including the current or prior use of inhaled corticosteroids (beclomethasone or budesonide). Photographs of the subjects' lenses were graded, without information on the subjects, to determine the presence and severity of cortical, nuclear, and posterior subcapsular cataracts. RESULTS: Three hundred seventy subjects reported using inhaled corticosteroids, 164 currently and 206 previously. Among these subjects, after adjustment for age and sex, there was a higher prevalence of nuclear cataracts (relative prevalence, 1.5; 95 percent confidence interval, 1.2 to 1.9) and posterior subcapsular cataracts (relative prevalence, 1.9; 95 percent confidence interval, 1.3 to 2.8) than among the subjects with no inhaled-corticosteroid use, but the prevalence of cortical cataracts was not significantly higher (relative prevalence, 1.1; 95 percent confidence interval, 0.9 to 1.3). Higher cumulative lifetime doses of beclomethasone were associated with higher risks of posterior subcapsular cataracts (P for trend <0.001); the highest prevalence (27 percent) was found in subjects whose lifetime dose was over 2000 mg (relative prevalence, 5.5). Adjusting for the use of systemic corticosteroids and other potential confounders had little effect on the magnitude of the associations. The associations with posterior subcapsular cataracts, but not those with nuclear cataracts, were less marked when the analyses were restricted to subjects who had never used systemic corticosteroids. CONCLUSIONS: The use of inhaled corticosteroids is associated with the development of posterior subcapsular and nuclear cataracts.

Administration, Inhalation↗

Alterations in lens protein tyrosine phosphorylation and phosphatidylinositol 3-kinase signaling during selenite cataract formation.

PURPOSE: Protein tyrosine phosphorylation is an important event in the cell signal transduction process. Phosphatidylinositol-3 kinase (PI-3K) is an intracellular signal mediator and plays a key role in many cellular functions. In this study we have examined the changes in lens protein tyrosine phosphorylation and its impact on phosphatidylinositol 3-kinase (PI-3K) signaling during selenite cataract development. METHODS: Cataract was induced in 10 days old rat pups by a single sub-cutaneous injection of sodium selenite (30 microM/Kg body weight) and lenses were collected at different stages of cataract development. Immunoprecipitation and Western immunoblotting were employed to determine protein tyrosine phosphorylation, PI-3K activity and protein in lens cell extracts. Tyrosine kinase activity in lens membrane preparations was assayed in the presence of a synthetic substrate peptide and [32P]ATP. RESULTS: Protein tyrosine phosphorylation in the lens was disrupted before the onset of cataract. A decrease in tyrosine phosphorylation of lens proteins was observed within 2-3 days of selenite injection (pre-cataract stage). The effect was much more prominent with the progression of cataract. The decrease in protein tyrosine phosphorylation correlated with the decrease in tyrosine kinase activity associated with the lens membrane fraction. Stimulation of normal rat lenses in organ culture with insulin and IGF-1 caused an increase in the phosphorylation of proteins, whose tyrosine phosphorylation status appeared to be diminished during cataract development. Insulin and IGF-1 also stimulated rat lens PI-3K activity. While there was no change in total PI-3K activity during the onset of cataract, the activity of PI-3K associated with tyrosine phosphorylated proteins decreased markedly in pre-cataract lenses. Further, the ability of IGF-1 to stimulate PI-3K activity was significantly reduced in lens epithelial cells treated with selenium. CONCLUSIONS: These studies show that signaling events involving the protein tyrosine phosphorylation process and activation of PI-3K are altered during selenite cataract formation and implicate defects in signal transduction mechanisms as contributing factors in the development of cataract.

Animals↗

Plasma fibrinogen and other cardiovascular disease risk factors and cataract.

PURPOSE: To determine whether associations exist between cataract and established cardiovascular risk factors (other than smoking) - hypertension, body mass index, serum lipids and plasma fibrinogen. METHODS: The Blue Mountains Eye Study is a large (n=3654) population-based cross-sectional study conducted among people aged 49-97 years residing in the Blue Mountains, a region west of Sydney, Australia. Risk factor data were collected using standardised clinical procedures. Lens photographs were taken and graded for presence and severity of cortical, nuclear, and posterior subcapsular cataracts. RESULTS: Cortical cataract was associated with a history of myocardial infarction, higher plasma fibrinogen, and higher serum cholesterol. Nuclear cataract was associated with a higher platelet count but hypertension was associated with lower prevalence of nuclear cataract. Posterior subcapsular cataract was associated with higher plasma fibrinogen and lower body mass index. Some of these associations appeared to be stronger in women than in men: fibrinogen and cortical cataract and body mass index and posterior subcapsular cataract. CONCLUSIONS: Several risk factors for cardiovascular disease are associated with presence of cataract, perhaps explaining the observation in several studies that people with cataract have increased mortality rates. The possibility of strong associations between plasma fibrinogen and cataract merits further epidemiological and laboratory research.

Aged↗

Cataract in type 2 diabetes mellitus in Isfahan, Iran: incidence and risk factors.

BACKGROUND: Evidence on the incidence of and risk factors for cataract in type 2 diabetes mellitus is scarce and mainly derived from studies in developed countries. Locally derived evidence is required for planning a well co-ordinated approach to this public health problem in developing countries. OBJECTIVE: The objective of the present study was to estimate the incidence of and risk factors for the development of cataract in type 2 (insulin-treated and non-insulin-treated) diabetes using routinely collected data from a clinical information system at Isfahan Endocrinology and Metabolism Research Center, Iran. METHOD: During the mean (standard deviation (SD)) follow-up period of 3.6 (2.7) (range 1-11) years, 3888 diabetic patients (1348 male and 2540 female) from Isfahan Endocrinology and Metabolism Research Center outpatient clinics have been examined. The mean (SD) age of the participants was 52.0 (10.5) years with a mean (SD) duration of diabetes of 12.6 (7.5) years at initial registration. RESULTS: Among the 3888 patients who were free of cataract at initial registration with at least one follow-up visit between 1992 and 2004, the incidence of cataract was 33.1 (95% confidence interval (CI): 30.2, 36.1) (64.8 (95% CI: 57.7, 72.0) in males and 17.9 (95% CI: 15.2, 20.5) in females per 1000 person-years based on 14012 person-years of follow-up. The age-adjusted incidence rate of cataract was 20% greater among insulin-treated than non-insulin-treated type 2 diabetes mellitus clinic attenders and it increased with age. Using a Cox's Proportional Hazards Model for insulin and non-insulin-treated type 2 diabetes separately, age, age at diagnosis of diabetes, duration of diabetes, and smoking were significant predictors of cataract for insulin and non-insulin-treated type 2 diabetes patients. When all variables were entered in the model, fasting blood glucose and insulin treatment were significant predictors of cataract. In the insulin-treated group, fasting blood glucose was a significant predictor of cataract. Systolic and diastolic blood pressure, gender, HbA(1), proteinuria, body mass index, cholesterol, triglyceride and creatinine had no significant independent association with cataract when other covariates were considered. CONCLUSION: These data suggest that cataract in this population of Iranian type 2 diabetic patients is common. With an estimated incidence of 33.1 per 1000 person-years of observation after mean 3.6 years' follow-up, diabetic cataract clearly poses a formidable health threat to Iranian diabetic patients. The results of this study highlight the need for regular eye examination in people with diabetes.

Age Distribution↗

Older drivers and cataract: driving habits and crash risk.

BACKGROUND: Cataract is a leading cause of vision impairment in older adults, affecting almost half of those over age 75 years. Driving is a highly visual task and, as with other age groups, older adults rely on the personal automobile for travel. The purpose of this study was to examine the role of cataract in driving. METHODS: Older adults (aged 55-85 years) with cataract (n = 279) and those without cataract (n = 105) who were legally licensed to drive were recruited from eye clinics to participate in a driving habits interview to assess driving status, exposure, difficulty, and "space" (the distance of driving excursions from home base). Crash data over the prior 5 years were procured from state records. Visual functional tests documented the severity of vision impairment. RESULTS: Compared to those without cataract, older drivers with cataract were approximately two times more likely to report reductions in days driven and number of destinations per week, driving slower than the general traffic flow, and preferring someone else to drive. Those with cataract were five times more likely to have received advice about limiting their driving. Those with cataract were four times more likely to report difficulty with challenging driving situations, and those reporting driving difficulty were two times more likely to reduce their driving exposure. Drivers with cataract were 2.5 times more likely to have a history of at-fault crash involvement in the prior 5 years (adjusted for miles driven/week and days driven/week). These associations remained even after adjustments for the confounding effects of advanced age, impaired general health, mental status deficit, or depression. CONCLUSIONS: Older drivers with cataract experience a restriction in their driving mobility and a decrease in their safety on the road. These findings serve as a baseline for our ongoing study evaluating whether improvements in vision following cataract surgery expand driving mobility and improve driver safety.

Accidents, Traffic↗

Epidemiologic associations with nuclear, cortical, and posterior subcapsular cataracts.

Data from the 1971-1972 National Health and Nutrition Examination Survey were used to examine the associations between specific cataract types and age, race, sex, number of years spent in school, diabetes, systolic blood pressure, urban versus rural residence, and average daily ultraviolet spectrum B (UV-B) radiation counts at the site of examination. Separate comparisons were made of persons with no lens changes (n = 1,299) and persons with cortical (n = 55), nuclear (n = 104), and posterior subcapsular cataracts (n = 18). Persons with more than one type of cataract were excluded from the analysis. Cortical cataracts were associated with age (relative risk (RR) = 11.4 for age 70 years vs. age 50 years), race (RR = 3.5 for blacks vs. whites), sex (RR = 3.0 for women vs. men), educational achievement (RR = 1.8 for less than nine years of schooling vs. college), and UV-B count (RR = 3.6 for 6.0 X 10(3) counts vs. (2.6 X 10(3) counts). Nuclear cataracts were associated with age (RR = 38.6 for age 70 years vs. age 50 years), race (RR = 1.8 for black vs. white), and residence (RR = 1.6 for rural vs. urban). Posterior subcapsular cataracts were associated with diabetes (RR = 6.6 for diabetes present vs. diabetes absent) and systolic blood pressure (RR = 2.2 for 160 mmHg vs. 120 mmHg). Cortical cataracts were more common in women and more often found in locations with increased UV-B radiation counts than either nuclear or posterior subcapsular cataracts. In diabetics, the risk of posterior subcapsular cataracts was greater than the risk of nuclear cataracts (p less than 0.05) and also appeared to be greater than the risk of cortical cataracts (p = 0.06).

Age Factors↗

Autosomal dominant congenital nuclear cataracts in strain 13/N guinea pigs.

Bilateral cataracts observed in the eyes of a 13/N guinea pig and one of her two offspring led to studies to determine the nature of this cataract and its possible heritability. The cataract was determined to be of the nuclear type, was congenital, and apparently transmitted by a single autosomal dominant gene. The cataractous condition of the mother had no effect on the percentage of litters containing stillborns. The cataractous condition of the offspring had no effect on their viability in utero, i.e., there was no greater incidence of stillborns among cataractous than among non-cataractous offspring. The birthweights of the cataractous animals were lower, but not significantly, than those of their non-cataractous littermates; however, the survivability to weaning of the cataractous offspring was reduced significantly when compared to their non-cataractous siblings.

Animals↗

Lenticular rubidium uptake in hypertensive 'cataract-prone' salt-sensitive rats.

We have previously reported a high incidence of cataract formation in adult hypertensive salt-sensitive rats, suggesting that hypertension may be an important cataractogenic risk factor. Weanling salt-sensitive rats that eventually developed cataracts showed a marked increase in the pressor response to a high-sodium diet compared to salt-sensitive rats that did not develop cataracts. A lens and aqueous fluid electrolyte imbalance occurred in all adult salt-sensitive rats examined, but was greater in the salt-sensitive rats that developed cataracts, suggesting an alteration in lens and/or ciliary ion transport in cataracts associated with hypertension. In the present study, lens 86Rb uptake was measured in adult hypertensive salt-sensitive rats prior to cataract formation. 'Cataract-prone' salt-sensitive hypertensive rats (increased pressor response to a high sodium diet given at weanling age), salt-sensitive hypertensive rats unlikely to develop cataracts and control salt-resistant rats were studied at the age of 16 weeks. Total and ouabain-insensitive lens 86Rb uptake were measured for the determination of ouabain-sensitive uptake, an index of Na+,K+-ATPase activity. Lens ouabain-sensitive 86Rb uptake was low in adult hypertensive cataract-prone salt-sensitive rats before cataract formation compared with values in control resistant rats. Intermediate values were observed in hypertensive salt-sensitive rats unlikely to develop cataracts. These data suggest that altered ion transport may play a pivotal role in cataractogenesis associated with this model of hypertension. The data are also consistent with the concept of a generalized defect in epithelial ion transport, at least in salt-sensitive hypertension.

Animals↗

Classification and protein distribution in a series of intracapsular cataracts.

The crystallin profiles of the cortices and nuclei of intracapsular cataractous lenses were studied by high pressure liquid chromatography (HPLC), polyacrylamide gel electrophoresis (PAGE), and dot blotting. The complete personal and medical history of 381 patients and the Cooperative Cataract Research Group (CCRG) classification of each were obtained. Few statistically significant associations between patient personal history and cataract types were found. Protein profiles of selected cataracts which had specifically located opacities (i.e., nuclear only, cortical only, etc.) were studied in detail. Sodium dodecyl sulphate-PAGE revealed few differences in lens-soluble proteins between cataractous and normal cortices or nuclei. By HPLC, the proteins of cataractous cortices and their nuclei differed very little from age-matched controls. The cortical proteins of nuclear cataracts appeared normal. However, two major alterations of proteins were observed in the nuclei of dense nuclear cataracts. Increased high molecular weight protein and increased components with molecular weights < 20,000 Da were found in cataractous nuclei as compared with normal age-matched control lens nuclei. Dot blot (immunological) analyses identified the crystallins of normal lenses that eluted from the HPLC column more efficiently than those of cataractous lenses. Cortical protein HPLC samples had the most specificity. Nuclear protein HPLC samples of older normal and cataractous lenses had little if any alpha crystallin specificity in the void volume peak. A relation between the presence of opacities and changes in molecular weight distribution of crystallins was found in the opaque nuclei but not in the opaque cortices.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Total lactate dehydrogenase and its isoenzyme pattern in lens, aqueous humour, and serum in cases of senile cataract.

Lens, aqueous humour and serum LDH and its isoenzyme pattern were estimated in 50 patients with senile cataract; 10 each with immature senile cortical cataract, mature senile cortical cataract, hypermature senile cortical cataract, immature senile nuclear cataract and mature senile nuclear cataract. The gradual decrease in total LDH and activity in the lens with advancement of cataract was maximum in hypermature senile cortical cataract. Aqueous LDH and its isoenzyme pattern remained unaltered with the maturity of cataract, and serum LDH and its isoenzyme pattern were found to be within normal limits. The lens LDH activity was found to be not related to the serum and aqueous humour LDH activity, but LDH3 isoenzyme showed declining trend, whereas LDH5 isoenzyme increased with the maturity of cataract. The present study concluded that significant decrease in lens LDH did not bear any relationship to LDH in serum and aqueous humour in cases of senile cataract.

Aged↗

Juvenile cataract with autosomal recessive inheritance. A study from the Aland Islands, Finland.

Juvenile (including congenital and infantile) cataract occurs commonly as part of a more generalized or systematic condition, or as a component of a syndrome. Isolated juvenile cataract is a relatively rare disorder and the mode of inheritance is often autosomal dominant. Autosomal recessive transmission of isolated juvenile cataract is rare. The present paper is a report of 15 cases of juvenile cataract on the Aland Islands (Finland) with about 23,000 inhabitants. Twelve belong to 7 sibships of two different pedigrees and 3 cases are sporadic, of which we have found no genealogical connections in the last 6-10 generations to the two cataracta pedigrees. One of the sporadic cases presented an operated cleft palate and a chromosomal anomaly. In another sporadic case the mother probably had been infected with rubella during early gestation. In the third sporadic case the cataract was combined with partial aniridia, but he has several genealogical connections to one of the cataract pedigrees. Consanguinity between the parents was detected in 5 of the 7 sibships, in some even on various ancestral levels. Apart from the cataracts, all patients were healthy, with normal intellect, behavior, hearing, growth and development. They were neurologically intact and there were no ocular lesions apart from cataract. In the Alandic familial cases the cataracts appear to be an autosomal recessive trait. A family branch originating from southwestern Sweden and south Norway showed transmission of the cataract in three successive generations. The possibility of quasi-dominant inheritance is discussed against the background that autosomal recessive juvenile cataract may not be so rare as the small number of recorded cases would suggest.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Some blood plasma constituents correlate with human cataract.

AIMS: To look for differences between matched pairs of patients and controls in concentrations of various plasma constituents which might indicate dysfunctions associated with cataract. METHOD: One thousand patients were taken from the cataract waiting list of a specialist eye hospital. For each patient a matched control of the same sex and half-decade of age but without cataract was taken from the patient list of the family doctor of the patient; the control was the next alphabetically after the patient on the doctor's list. The patients and controls were visited in their homes by a team of nurses who performed venepunctures and collected information for a questionnaire. Eye examinations were performed by a team of ophthalmologists. RESULTS: Significant differences were found between the cataract and control groups in 10 of the 18 examined plasma constituents. A constellation of three--bilirubin, alkaline phosphatase, and gamma glutamyl transpeptidase--was significantly higher in the cataract group, suggesting subclinical liver dysfunction as a risk factor. Steroid treatment and diabetes increased cataract risk. Endogenous basal plasma cortisol levels were raised in the cataract group, irrespective of steroid use and diabetic status. Alkaline phosphatase, calcium, glucose, and sodium were all raised in the cataract group. Given the raised total protein and albumin also found in the cataract group, the lower albumin/(total protein-albumin) ratio (an approximation for albumin/globulin ratio) may imply an increase in globulin, suggestive of possible (chronic) infection. Total cholesterol was lower in the cataract group. CONCLUSION: Human cataract in older age groups seems to be due to an accumulation of risk factors, even if individual mean concentrations are well within normal limits but, of course, differing significantly from the corresponding means in the control population.

Adult↗

Altered lens short-circuit current in adult cataract-prone Dahl hypertensive rats.

We assessed components of lenticular short-circuit current in adult hypertensive Dahl salt-sensitive rats (DS) during chronic control (0.4% sodium) versus high (3% sodium) dietary NaCl intake begun at the age of 4 weeks until rats were studied. We also evaluated the influence of barium, a potassium channel blocker, and ouabain, a specific inhibitor of Na+, K(+)-ATPase activity, by adding them to the anterior lens surface, thus measuring barium-sensitive, ouabain-sensitive, and barium- and ouabain-in-sensitive short-circuit currents. During control NaCl intake, short-circuit current in DS and their control group, Dahl salt-resistant rats (DR), did not differ significantly. DS were subclassified into cataract-prone rats and rats unlikely to develop cataracts on the basis of their initial pressor response to the change from a normal to high NaCl diet during the first weeks of age. Although only transparent lenses were studied, total lens short-circuit current was already markedly decreased in the cataract-prone subgroup compared with DS unlikely to develop cataracts and control DR. This was in sharp contrast to the increase in short-circuit current previously reported in Sprague-Dawley rats and now observed in control DR in response to high dietary NaCl. The decrease in lens short-circuit current in cataract-prone rats was associated with lower absolute values of barium- and ouabain-sensitive short-circuit currents as well as with low barium- and ouabain-insensitive short-circuit current. Although the barium- and ouabain-sensitive components of the short-circuit current were similar in DS unlikely to develop cataracts and DR, the barium- and ouabain-insensitive component of the short-circuit current was lower in DS unlikely to develop cataracts than values in DR. Interestingly, this component of lens short-circuit current also increased in DR during chronic high NaCl, whereas the opposite change occurred in cataract-prone DS and DS unlikely to develop cataracts. Thus, the barium- and ouabain-insensitive short-circuit current may be a mechanism that protects the normal lens from developing cataracts. Possible candidates for this short-circuit current component are voltage-dependent potassium channels, calcium-activated potassium channels, or both. Our studies show altered lens short-circuit current in response to high NaCl intake in cataract-prone DS and suggest the possibility of altered lens potassium transport during sustained hypertension but before loss of lens transparency.

Animals↗

Contrast acuity in cataracts of different morphology and association to self-reported visual function.

PURPOSE: To evaluate the relationship between contrast acuity at declining contrast levels and the type and density of lens opacity in cataract. METHODS: Contrast acuity at declining contrast levels was determined with the Holladay Contrast Acuity Test, in relation to the type and density of age-related cataract in 180 patients with bilateral cataract and 20 control subjects with normal macular function. Cataracts were graded according to the Lens Opacities Classification System (LOCS) III of nuclear color (NC), nuclear opalescence (NO), cortical (C), and posterior subcapsular (P) cataract. Best-corrected visual acuity and near contrast acuity were determined in randomized order monocularly in both eyes. Visual difficulties in everyday life were evaluated, using the VF-14 questionnaire and the Cataract Symptom Score. RESULTS: The contrast-dependent effect of cataract on contrast acuity was statistically significant (P < 0.001; two-way ANOVA). In the comparison of early, intermediate, and advanced nuclear, nuclear-cortical, and posterior subcapsular cataracts (PSCs), significantly reduced contrast acuity scores were found for the PSC groups (P < 0.001). Comparison of nuclear and nuclear-cortical cataracts showed the contrast acuity scores to be comparable at all contrast levels (P > 0.05). High correlation coefficients were found between the LOCS III P score and the contrast acuity measurements (r = 0.77-0.84; P < 0.001). In contrast, the correlation coefficients of the NO, NC, and C scores were considerably lower (r = 0.45-0.66; P < 0.001). High correlation coefficients were also found between the contrast acuity measurements and self-reported functional vision. CONCLUSIONS: The statistically significant, contrast-dependent effect of cataract on contrast acuity supports the clinical relevance of recording visual acuity at low contrast levels in patients with age-related cataract. Particularly, the severity of PSC has a strong influence on the impairment of contrast acuity. Contrast acuity corresponded closely to the self-reported visual difficulties in everyday life.

Aged↗