Mixed lens opacities and subsequent mortality

Self-reported cataract surgery and 10-year all-cause and cause-specific mortality: findings from the National Health and Nutrition Examination Survey

PURPOSE

To investigate the association of self-reported cataract surgery with all-cause and cause-specific mortality using a large-scale population-based sample.

METHODS

Data from the 1999-2008 cycles of the National Health and Nutrition Examination Survey were used. A self-reported history of cataract surgery was considered a surrogate for the presence of clinically significant cataract surgery. Mortality data were ascertained from National Death Index records. Hazard ratios (HRs) and 95% confidence intervals (CIs) for survival were estimated using Cox proportional hazards regression models.

RESULTS

A total of 14 918 participants were included in the analysis. During a median follow-up of 10.8 (Interquartile range, IQR, 8.25-13.7) years, 3966 (19.1%) participants died. Participants with self-reported cataract surgery were more likely to die from all causes and specific causes (vascular disease, cancer, accident, Alzheimer's disease, respiratory disease, renal disease and others) compared with those without (all Ps <0.05). The association between self-reported cataract surgery and all-cause mortality remained significant after multiple adjustments (HR=1.13; 95% CI 1.01 to 1.26). For cause-specific mortality, multivariable Cox models showed that self-reported cataract surgery predicted a 36% higher risk of vascular-related mortality (HR=1.36; 95% CI 1.01 to 1.82). The association with other specific causes of mortality did not reach statistical significance after multiple adjustments.

CONCLUSIONS

This study found significant associations of self-reported cataract surgery with all-cause and vascular mortalities. Our findings provide potential insights into the pathogenic pathways underlying cataract.

Association between Age-related Cataract and Mortality in Sweden: A Long-term Population-based Follow-up Study

PURPOSE

To assess the relationship of age-related cataract with all-cause mortality in a Swedish population.

METHODS

Cox regression analyses were performed in a cohort of 746 residents 65-74 years of age, examined in a population survey in the rural district of Tierp, Sweden, 1984-86. To expand the sample size, 1,071 people were recruited by means of glaucoma case records established at the Eye Department in Tierp from 1978 to 2007. In this way, the cohort comprised 1,817 subjects, representing nearly 27,000 person-years at risk. The presence of cataract was determined based on retroillumination with lens opacities evident on slit-lamp examination. Information on deaths was obtained from the local population register.

RESULTS

By the conclusion of the study in April 2020, 1,633 deaths had been reported. Of these cases, 694 were affected by lens opacities or had history of cataract surgery at baseline. In multivariate analysis, including cataract, age, sex, smoking habits, cancer, diabetes, hypertension and ischemic heart disease, no association was found between cataract and mortality (hazard ratio 0.99; 95% confidence interval 0.90-1.10). Adjustment for participation in the population survey had no effect on the estimate.

CONCLUSION

In this long-term follow-up study of subjects 65-74-years-old in Sweden, cataract was not associated with all-cause mortality.

Age-related cataract and 10-year mortality: the Liwan Eye Study

PURPOSE

To explore the association between age-related cataract and 10-year mortality in an adult population in urban China.

METHODS

A total of 1405 participants aged 50 years or older were examined at baseline in the Guangzhou Liwan Eye Study. All participants were invited to attend a 10-year follow-up visit. Cataract cases were defined as either having visible lens opacity confirmed with direct ophthalmoscope under pupil dilation or previous history of cataract surgery. Visual impairment (VI) was defined as a visual acuity of 20/40 or worse in the better-seeing eye with habitual correction if worn. Body mass index (BMI) was based on anthropometric data. A brief questionnaire regarding family income, educational attainment and medical history of systemic disease was administered. Mortality rates were compared using the log-rank test and Cox proportional hazards regression models.

RESULTS

Among 1405 participants examined at baseline, 957 participants (68.1%) had visible lens opacity or history of cataract surgery. After 10 years, 320 (22.8%) participants died. The 10-year mortality rate was significantly higher in participants with cataract than in those without (30.1% versus 7.14%, log-rank p < 0.05). After adjusting for age, gender, family income, educational attainment, BMI, history of diabetes and hypertension and presence of VI, presence of cataract predicted a nearly threefold increase in the risk of mortality (HR, 2.99; 95% CI, 1.89-4.71).

CONCLUSIONS

Our findings that age-related cataract is a predictor for poorer survival compared to those without may imply that cataract is a biomarker of ageing and frailty.

Association of Mortality with Ocular Diseases and Visual Impairment in the Age-Related Eye Disease Study 2: Age-Related Eye Disease Study 2 Report Number 13

PURPOSE

To evaluate the association of mortality with visual acuity (VA) impairment, age-related macular degeneration (AMD), and cataract surgery.

DESIGN

Cohort study.

PARTICIPANTS

Participants with at least intermediate AMD enrolled in a randomized controlled clinical trial of lutein/zeaxanthin and/or omega-3 fatty acids, the Age-Related Eye Disease Study 2 (AREDS2), for treatment of AMD and cataract.

METHODS

Baseline and annual eye examinations included best-corrected visual acuity (BCVA) assessments, slit-lamp examinations, and stereoscopic fundus photographs that were centrally graded for development of late AMD (central geographic atrophy or neovascular AMD) or pseudophakia. Cause-specific mortality was determined on the basis of the International Classification of Diseases 9th or 10th Revision codes. Risk of all-cause and cause-specific mortality was assessed with Cox proportional hazards models adjusted for age, sex, AMD severity, VA, history of cataract surgery, and assigned AREDS2 study treatment. Analyses included baseline covariates: race, education, smoking status, diabetes, and cardiovascular disease.

RESULTS

During follow-up (median 5 years), 368 (9%) of the 4203 AREDS2 participants died. Participants with neovascular AMD in 1 eye at baseline had a statistically significant increased risk for mortality compared with participants with no or few drusen (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.21-2.01; P < 0.001). Poorer survival was associated with bilateral cataract surgery before enrollment compared with baseline bilateral phakia (HR, 1.63; 95% CI, 1.29-2.07; P < 0.001) and with BCVA of less than 20/40 compared with participants with 20/40 or better (HR, 1.56; 95% CI, 1.06-2.30; P = 0.024), adjusted for age, sex, and statistically significant covariates. Participants who received antivascular endothelial growth factor therapies for neovascular AMD had decreased mortality compared with those who did not (HR, 0.71; 95% CI, 0.57-0.88; P = 0.002). The association between all-cause mortality and AREDS2 treatment whether assessing the main or individual treatment effect was not significantly different (omega-3 fatty acids main effect HR, 1.18; 95% CI, 0.96-1.45; P = 0.12; lutein/zeaxanthin main effect HR, 1.04; 95% CI, 0.85-1.28; P = 0.71).

CONCLUSIONS

In AREDS2, the presence of late AMD, bilateral cataract surgery, and VA less than 20/40 was associated with decreased survival. However, oral supplementation with omega-3 fatty acids, lutein plus zeaxanthin, zinc, or beta-carotene had no statistically significant impact on mortality.

Oxidative Stress Intensity in Lens and Aqueous Depending on Age-Related Cataract Type and Brunescense

Purpose

Cataract formation represents a serious problem in the elderly, and has a large impact on healthcare budget. The oxidative stress form and intensity might determine the cataract type and pigmentation, making efforts in the cataract prevention challenge more complex.

Methods

This is a retrospective cross-sectional review of 80 samples of aqueous humor and lens corticonuclear blocks. Aqueous samples were analyzed by the method of antioxidant activity estimation (%iMDA), while lipid peroxides (LP) and total sulfhydryl groups (TSH) were determined in lenses.

Results

Mixed and brunescent cataracts have statistically significant lower values of antioxidative %iMDA and TSH (p<0.001 for both parameters) and higher values of lipid peroxidation (p<0.001). No correlation between LP and TSH with maturity of cortical cataract was found, but there was a significant correlation with the %iMDA (p<0.05).

Conclusions

The role of the oxidative stress in cataractogenesis could not be the same for all cataract types. High level of lipid peroxides in pigmented cataracts may point to the different nature of pigment source than proteins solely, whereas lipid peroxidation and SH groups consumption in cortical cataractogenesis might be of less importance.

Whales, lifespan, phospholipids, and cataracts

This study addresses the question: why do rats get cataracts at 2 years, dogs at 8 years, and whales do not develop cataracts for 200 years? Whale lens lipid phase transitions were compared with the phase transitions of other species that were recalculated. The major phospholipids of the whale lens were sphingolipids, mostly dihydrosphingomyelins with an average molar cholesterol/phospholipid ratio of 10. There was a linear correlation between the percentage of lens sphingolipid and lens lipid hydrocarbon chain order until about 60% sphingolipid. The percentage of lens sphingolipid correlated with the lens lipid phase transition temperature. The lifespan of the bowhead whale was the longest of the species measured and the percentage of whale lens sphingolipid fit well in the correlation between the percentage of lens sphingolipid and lifespan for many species. In conclusion, bowhead whale lens membranes have a high sphingolipid content that confers resistance to oxidation, allowing these lenses to stay clear relatively longer than many other species. The strong correlation between sphingolipid and lifespan may form a basis for future studies, which are needed because correlations do not infer cause. One could hope that if human lenses could be made to have a lipid composition similar to whales, like the bowhead, humans would not develop age-related cataracts for over 100 years.

Blindness, cataract surgery and mortality in Ethiopia

PURPOSE

To examine the relationships between blindness, the intervention of cataract surgery and all-cause mortality in a rural Ethiopian population.

DESIGN

Population-based, interventional prospective study.

METHODS

Community-based detection methods identified blind Ethiopian persons from two selected kebeles in Amhara region, Ethiopia. Data from 1201 blind patients were collected-628 cataract-blind and 573 blind from other conditions. Free cataract surgery was provided for consenting, cataract-blind patients. Follow-up surveys were conducted after 12 months (±1 month)-the main outcome measure for this report is all-cause mortality at 1 year.

RESULTS

During the follow-up period, 110 persons died from the selected population (mortality 9.2%), which consisted of those cataract-blind patients who received cataract surgery (N=461), cataract-blind patients who did not receive surgery (N=167) and all non-cataract-blind patients (N=573). Of the 461 patients who received cataract surgery, 44 patients died (9.5%). Of the 740 patients who did not receive surgery, 66 died (8.9%)-28 patients from the cohort of cataract-blind patients who did not receive surgery (16.8%) and 38 patients from the cohort of non-cataract blind (6.6%). Subgroup analysis revealed significantly increased odds of mortality for cataract-blind patients over 75 years of age who did not receive surgery and for unmarried patients of all age groups.

CONCLUSIONS

In this population, mortality risk was significantly elevated for older cataract-blind patients when compared with non-cataract-blind patients-an elevation of risk that was not noted in an age-matched cohort of cataract-blind patients who underwent cataract surgery as early as 1-year follow-up.

Impact of Visual Impairment and Eye diseases on Mortality: the Singapore Malay Eye Study (SiMES)

We investigated the relationship of visual impairment (VI) and age-related eye diseases with mortality in a prospective, population-based cohort study of 3,280 Malay adults aged 40–80 years between 2004–2006. Participants underwent a full ophthalmic examination and standardized lens and fundus photographic grading. Visual acuity was measured using logMAR chart. VI was defined as presenting (PVA) and best-corrected (BCVA) visual acuity worse than 0.30 logMAR in the better-seeing eye. Participants were linked with mortality records until 2012. During follow-up (median 7.24 years), 398 (12.2%) persons died. In Cox proportional-hazards models adjusting for relevant factors, participants with VI (PVA) had higher all-cause mortality (hazard ratio[HR], 1.57; 95% confidence interval[CI], 1.25–1.96) and cardiovascular (CVD) mortality (HR 1.75; 95% CI, 1.24–2.49) than participants without. Diabetic retinopathy (DR) was associated with increased all-cause (HR 1.70; 95% CI, 1.25–2.36) and CVD mortality (HR 1.57; 95% CI, 1.05–2.43). Retinal vein occlusion (RVO) was associated with increased CVD mortality (HR 3.14; 95% CI, 1.26–7.73). No significant associations were observed between cataract, glaucoma and age-related macular degeneration with mortality. We conclude that persons with VI were more likely to die than persons without. DR and RVO are markers of CVD mortality.

Neurocardiovascular instability may modulate end-organ damage: A review of this hypothesis investigating the eye and manifestations of NCVI

Neurocardiovascular instability (NCVI) represents age-related changes in blood pressure and heart rate behaviour. It has been associated with increased leukoaraiosis in the brain and also conditions which are likely to be are related to cerebral end-organ damage, such as stroke and falls. The eye is a 'window' into the brain and cardiovascular (CV) system, changes in retinal microvasculature being independently predictive of cardiovascular events. The eye is highly vascular, having two circulatory systems and as such the ideal target end-organ to investigate NCVI and early end-organ damage. The retinal and choroidal circulations of the eye would be vulnerable to NCVI if ocular vasoregulation becomes impaired with age, particularly given the high metabolic activity of the retina. The choroid is predominantly extrinsically regulated by the autonomic nervous system. In patients with NCVI, autonomic dysfunction is more common and thus impairment of the tightly regulated ocular microcirculation may indeed be compromised. We review the evidence for the hypothesis that NCVI may modulate end-organ cardiovascular pathology and that the eye is the ideal target organ to monitor this.

Longitudinal relationships among visual acuity, daily functional status, and mortality: the Salisbury Eye Evaluation Study

IMPORTANCE

Determination of the mechanisms by which visual loss increases mortality risk is important for developing interventional strategies.

OBJECTIVE

To evaluate the direct and indirect effects of loss of visual acuity (VA) on mortality risk through functional status changes among aging adults.

DESIGN, SETTING, AND PARTICIPANTS

Prospective longitudinal study of a population-based sample of 2520 noninstitutionalized adults aged 65 to 84 years from September 16, 1993, through July 26, 2003, in the greater Salisbury area of Maryland. Participants underwent reassessment 2, 6, and 8 years after baseline. Mortality status was ascertained from linkage with the National Death Index through 2009.

EXPOSURES

Results of VA testing and self-reported functional status based on activities of daily living (ADL) and instrumental ADL (IADL).

MAIN OUTCOMES AND MEASURE

Mortality.

RESULTS

Worse VA levels at baseline were associated with an increased the risk for mortality (hazard ratio [HR], 1.16 [95% CI, 1.04-1.28]; P < .01) through their effect on lower IADL levels at baseline. Declines in VA over time were associated with increased mortality risk (HR, 1.78 [95% CI, 1.27-2.51]; P < .001) by way of decreasing IADL levels over time. Participants experiencing the mean linear decline in VA of 1 letter on the Early Treatment Diabetic Retinopathy Study acuity chart per year are expected to have a 16% increase in mortality risk during the 8-year study exclusively through associated declines in IADL levels.

CONCLUSIONS AND RELEVANCE

In this longitudinal study of older adults, VA loss adversely affected IADL levels, which subsequently increased the risk for mortality. Prevention of disabling ocular conditions, treatment of correctable visual impairment, and interventions designed to prevent the effect of visual impairment on IADL declines may all reduce mortality risk in aging adults.

Age-related cataract, cataract surgery and subsequent mortality: a systematic review and meta-analysis

PURPOSE

Changes in lens may reflect the status of systemic health of human beings but the supporting evidences are not well summarized yet. We aimed to determine the relationship of age-related cataract, cataract surgery and long-term mortality by pooling the results of published population-based studies.

METHODS

We searched PubMed and Embase from their inception till March, 2014 for population-based studies reporting the associations of any subtypes of age-related cataract, cataract surgery with all-cause mortality. We pooled the effect estimates (hazards ratios [HRs]) under a random effects model.

RESULTS

Totally, we identified 10 unique population-based studies including 39,659 individuals at baseline reporting the associations of any subtypes of cataract with all-cause mortality from 6 countries. The presence of any cataract including cataract surgery was significantly associated with a higher risk of death (pooled HR: 1.43, 95% CI, 1.21, 2.02; P<0.001; I(2) = 64.2%). In the meta-analysis of 9 study findings, adults with nuclear cataract were at higher risks of mortality (pooled HR: 1.55, 95% CI, 1.17, 2.05; P = 0.002; I(2) = 89.2%). In the meta-analysis of 8 study findings, cortical cataract was associated with higher risks of mortality (pooled HR: 1.26, 95% CI, 1.12, 1.42; P<0.001, I(2) = 29.7%). In the meta-analysis of 6 study findings, PSC cataract was associated with higher risks of mortality (pooled HR: 1.37, 95% CI, 1.04, 1.80; P = 0.03; I(2) = 67.3%). The association between cataract surgery and mortality was marginally non-significant by pooling 8 study findings (pooled HR: 1.27, 95% CI, 0.97, 1.66; P = 0.08; I(2)= 76.6%).

CONCLUSIONS

All subtypes of age-related cataract were associated with an increased mortality with nuclear cataract having the strongest association among the 3 cataract subtypes. However, cataract surgery was not significantly related to mortality. These findings indicated that changes in lens may serve as markers for ageing and systemic health in general population.

Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of lenses has been lacking. Among the general lay public, misconceptions on eye-sun protection have been identified. For example, sun protection is mainly ascribed to sunglasses, but less so to clear lenses. Skin malignancies in the periorbital region are frequent, but usual topical skin protection does not include the lids. Recent research utilized exact dosimetry and demonstrated relevant differences in UV burden to the eye and skin at a given ambient irradiation. Chronic UV effects on the cornea and lens are cumulative, so effective UV protection of the eyes is important for all age groups and should be used systematically. Protection of children's eyes is especially important, because UV transmittance is higher at a very young age, allowing higher levels of UV radiation to reach the crystalline lens and even the retina. Sunglasses as well as clear lenses (plano and prescription) effectively reduce transmittance of UV radiation. However, an important share of the UV burden to the eye is explained by back reflection of radiation from lenses to the eye. UV radiation incident from an angle of 135°-150° behind a lens wearer is reflected from the back side of lenses. The usual antireflective coatings considerably increase reflection of UV radiation. To provide reliable labeling of the protective potential of lenses, an eye-sun protection factor (E-SPF®) has been developed. It integrates UV transmission as well as UV reflectance of lenses. The E-SPF® compares well with established skin-sun protection factors and provides clear messages to eye health care providers and to lay consumers.

Cataract, visual impairment and long-term mortality in a rural cohort in India: the Andhra Pradesh Eye Disease Study

BACKGROUND

A large-scale prevalence survey of blindness and visual impairment (The Andhra Pradesh Eye Diseases Study [APEDS1]) was conducted between 1996-2000 on 10,293 individuals of all ages in three rural and one urban clusters in Andhra Pradesh, Southern India. More than a decade later (June 2009-March 2010), APEDS1 participants in rural clusters were traced (termed APEDS2) to determine ocular risk factors for mortality in this longitudinal cohort.

METHODS AND FINDINGS

Mortality hazard ratio (HR) analysis was performed for those aged >30 years at APEDS1, using Cox proportional hazard regression models to identify associations between ocular exposures and risk of mortality. Blindness and visual impairment (VI) were defined using Indian definitions. 799/4,188 (19.1%) participants had died and 308 (7.3%) had migrated. Mortality was higher in males than females (p<0.001). In multivariable analysis, after adjusting for age, gender, diabetes, hypertension, body mass index, smoking and education status the mortality HR was 1.9 (95% CI: 1.5-2.5) for blindness; 1.4 (95% CI: 1.2-1.7) for VI; 1.8 (95% CI: 1.4-2.3) for pure nuclear cataract, 1.5 (95% CI: 1.1-2.1) for pure cortical cataract; 1.96 (95% CI: 1.6-2.4) for mixed cataract, 2.0 (95% CI: 1.4-2.9) for history of cataract surgery, and 1.58 (95% CI: 1.3-1.9) for any cataract. When all these factors were included in the model, the HRs were attenuated, being 1.5 (95% CI: 1.1-2.0) for blindness and 1.2 (95% CI: 0.9-1.5) for VI. For lens type, the HRs were as follows: pure nuclear cataract, 1.6 (95% CI: 1.3-2.1); pure cortical cataract, 1.5 (95% CI: 1.1-2.1); mixed cataract, 1.8 (95% CI: 1.4-2.2), and history of previous cataract surgery, 1.8 (95% CI: 1.3-2.6).

CONCLUSIONS

All types of cataract, history of cataract surgery and VI had an increased risk of mortality that further suggests that these could be potential markers of ageing.

Assessment of candidate ocular biomarkers of ageing in a South African adult population: relationship with chronological age and systemic biomarkers

Certain anatomic and functional parameters of the eye change with increasing chronological age. They may, therefore, serve as potential biomarkers of ageing. We investigated associations between four such ocular parameters (lens density, retinal vessel calibre, corneal endothelial cells and retinal nerve fibre layer thickness) and two 'cellular' biomarkers of ageing (leukocyte telomere length and CDKN2A expression), with frailty (a clinical correlate of biological ageing) in a population of South African adults. All ocular parameters revealed an association with either telomere length or CDKN2A expression. However, lens density was most strongly correlated with age, increased CDKN2A expression, and with frailty (p=0.05 and 0.03, respectively). Narrow retinal arteriolar diameter, associated with increased chronological age, was also associated with increased CDK2NA expression (0.42 vs. 0.31, p=0.02) but not with frailty. Ocular parameters may aid in determining biological age, warranting investigation in longitudinal studies.

The eye as a model of ageing in translational research--molecular, epigenetic and clinical aspects

The eye and visual system are valuable in many areas of translational research such as stem cell therapy, transplantation research and gene therapy. Changes in many ocular tissues can be measured directly, easily and objectively in vivo (e.g. lens transparency; retinal blood vessel calibre; corneal endothelial cell counts) and so the eye may also be a uniquely useful site as a model of ageing. This review details cellular, molecular and epigenetic mechanisms related to ageing within the eye, and describes ocular parameters that can be directly measured clinically and which might be of value in ageing research as the translational "window to the rest of the body". The eye is likely to provide a valuable model for validating biomarkers of ageing at molecular, epigenetic, cellular and clinical levels. A research agenda to definitively establish the relationship between biomarkers of ageing and ocular parameters is proposed.

Increased mortality risk among the visually impaired: the roles of mental well-being and preventive care practices

PURPOSE

Mechanisms by which visual impairment (VI) increases mortality risk are poorly understood. We estimated the direct and indirect effects of self-rated VI on risk of mortality through mental well-being and preventive care practice mechanisms.

METHODS

Using complete data from 12,987 adult participants of the 2000 Medical Expenditure Panel Survey with mortality linkage through 2006, we undertook structural equation modeling using two latent variables representing mental well-being and poor preventive care to examine multiple effect pathways of self-rated VI on all-cause mortality. Generalized linear structural equation modeling was used to simultaneously estimate pathways including the latent variables and Cox regression model, with adjustment for controls and the complex sample survey design.

RESULTS

VI increased the risk of mortality directly after adjusting for mental well-being and other covariates (hazard ratio [HR] = 1.25 [95% confidence interval: 1.01, 1.55]). Poor preventive care practices were unrelated to VI and to mortality. Mental well-being decreased mortality risk (HR = 0.68 [0.64, 0.74], P < 0.001). VI adversely affected mental well-being (β = -0.54 [-0.65, -0.43]; P < 0.001). VI also increased mortality risk indirectly through mental well-being (HR = 1.23 [1.16, 1.30]). The total effect of VI on mortality including its influence through mental well-being was HR 1.53 [1.24, 1.90]. Similar but slightly stronger patterns of association were found when examining cardiovascular disease-related mortality, but not cancer-related mortality.

CONCLUSIONS

VI increases the risk of mortality directly and indirectly through its adverse impact on mental well-being. Prevention of disabling ocular conditions remains a public health priority along with more aggressive diagnosis and treatment of depression and other mental health conditions in those living with VI.

Evaluation of retrobulbar blood flow in patients with age-related cataract; color Doppler ultrasonographic findings

Objectives

Cataracts are the most common cause of blindness worldwide, with cataract surgery being the most common ophthalmic procedure. To our best knowledge, this is the first case-control study with a large number of participants to evaluate ocular blood flow in patients with cataracts.

Materials and methods

Color Doppler and duplex sonography of the orbital vessels was performed in 224 eyes of 112 patients with known bilateral age-related cataracts and in 76 eyes of 38 healthy age- and sex-matched volunteers.

Results

The mean ± (standard deviation [SD]) of peak systolic velocity (PSV) of the ophthalmic artery in patients with cataracts (34.59 ± 22.49 cm/second) was significantly different to that in controls (52.11 ± 14.01 cm/second) (P < 0.001). The mean ± SD PSV of the central retinal artery in patients with cataracts (15.31 ± 4.93 cm/second) was significantly different to that in controls (9.61 ± 5.64 cm/second) (P < 0.001).

Conclusion

The mean PSV and resistive index (RI) of the ophthalmic and central retinal arteries were lower in cataract patients when compared with normal subjects. This suggests that ocular hypoperfusion and changes in ocular hemodynamic may have a role in the formation of age-related cataracts.

Prevalence and causes of visual impairment among Saudi adults attending primary health care centers in northern Saudi Arabia

BACKGROUND AND OBJECTIVES

Few studies have been conducted in Saudi Arabia to estimate the prevalence of visual impairment and its causes. The objective of this study was to estimate the prevalence of visual impairment, and identify its causes and associated factors among the adult population attending primary health care (PHC) centers in Aljouf province, in northern Saudi Arabia.

DESIGN AND SETTING

A cross-sectional study during the year 2005 in PHC centers in Aljouf province in northern Saudi Arabia.

PATIENTS AND METHODS

A sample of 620 Saudi adults, of age 18 years and older, from the catchment area of the Aljouf PHC centers, were randomly selected through a multistage random sampling technique. Data were collected using a questionnaire about socioeconomic and related information and a visual acuity test was performed using the Snellen chart (E). Diagnosis was established according to World Health Organization (WHO) criteria. Visual impairment was categorized into blindness for a visual acuity of less than 3/60 (20/400, 0.05) in the better eye with the best correction and low vision for a best corrected visual acuity of less than 6/18 (20/60, 0.3) but not less than 3/60 (20/400, 0.05) in the better eye. Regression analysis was used to identify the predictors of visual impairment.

RESULTS

Of 617 adult Saudis interviewed and examined, 269 (43.6%) were females. The mean (SD) age was 38.6 (16.2) years. The overall prevalence of visual impairment was 13.9% (95% CI: 11.4%-16.9%). The main medical causes of visual impairments were refractive errors (36.0%) followed by cataract (29.1%) and diabetic retinopathy (20.9%), and the least leading cause was glaucoma (5.8%). The most prominent determinants of visual impairment were age (P<.05), sex (P<.001), and a history of previous eye injury (P<.05).

CONCLUSION

Prevalence of visual impairment in the study population from the Aljouf area is high. It is recommended that regular checks of visual acuity be conducted for all Saudis of age 50+ years, who attend the PHC centers.

Vision and hearing impairments are associated with depressive--anxiety syndrome in Italian elderly

OBJECTIVE

The aim of this study was to evaluate the association between vision and hearing impairment and depressive-anxiety syndrome in a large population participating in the Faenza Project, Northern Italy.

METHOD

The study population consisted of 7389 participants not affected by dementia, 4408 (59.7%), of whom were women, mean age ± standard deviation (±SD) 71.9 (±7.7) years. Information about previous or current psychiatric symptoms, including sleeping and eating habits, non-verbal language and ability in activity of daily living was used to investigate depressive and anxiety syndrome. A semi-structured interview was administered to survey the presence of sensory impairment. Logistic regression analyses were used to evaluate the association between sensory impairment and depressive-anxiety syndrome estimating Odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

The prevalence of vision and hearing impairment was 1.4% and 0.2%, respectively, with an increasing trend in people aged 75+ years (p < 0.001). The prevalence of depressive syndrome was higher among vision-impaired participants (20.2% vs. 9.3%, p < 0.001), especially women (22.9%) and persons aged 75+ years (22.1%). The prevalence of anxiety syndrome was higher in the hearing-impaired group (25.0% vs. 11.0%, p = 0.09). Vision-impaired participants, especially women and participants aged 75+ years had have a twofold higher probability to have depressive syndrome (OR = 2.03, 95% CI = 1.21-3.38), and hearing-impaired individuals showed an increased probability of presenting anxiety syndrome (OR = 2.71, 95% CI = 0.86-8.55), although these results were not statistically significant.

CONCLUSION

This study's findings suggest that sensory impairment in older adults can increase their probability of experiencing depressive and anxiety syndrome. Correction of these deficits could improve the quality of life in this population.

Non-standard vision measures predict mortality in elders: the Smith-Kettlewell Institute (SKI) study

PURPOSE

To determine which vision tests predict mortality within 10 years in a community-based elderly sample.

METHODS

Nine hundred residents of Marin County, California 58 to 101 years of age (mean 75 years at baseline), underwent a battery of tests, including high contrast acuity, low contrast acuity, low contrast/low luminance acuity, acuity in glare, contrast sensitivity, color vision, stereopsis, standard and attentional fields. The association between the vision tests and mortality within 10 years of baseline was assessed with Cox Proportional Hazards models controlling for age, sex, education level, depression, cognitive status and self-reported medical conditions.

RESULTS

Forty-three percent of the sample died within 10 years of baseline. When controlling for mortality-related covariates, impairment in any of the vision measures was associated with increased risk of death. However, non-standard vision measures (ie, impairment in low contrast/low luminance acuity, standard field integrity and the impact of the attentional task on field integrity) were more highly associated with mortality than standard high contrast acuity.

CONCLUSIONS

In agreement with other studies, we find that visual impairment is a significant predictor of death. However, the strongest relationship was found for measures other than high contrast acuity. These results suggest that non-standard vision measures may be more sensitive indicators of generalized aging in the most elderly.

Lipids and the ocular lens

The unusually high levels of saturation and thus order contribute to the uniqueness of human lens membranes. In addition, and unlike in most biomembranes, most of the lens lipids are associated with proteins, thus reducing their mobility. The major phospholipid of the human lens is dihydrosphingomyelin. Found in significant quantities only in primate lenses, particularly human ones, this lipid is so extremely stable that it was reported to be the only lipid remaining in a frozen mammoth 40,000 years after its death. Unusually high levels of cholesterol add peculiarity to the composition of lens membranes. Beyond the lateral segregation of lipids into dynamic domains known as rafts, the high abundance of cholesterol in the human lens leads to the formation of patches of pure cholesterol. Changes in human lens lipid composition with age and disease as well as differences among species are greater than those observed for any other biomembrane. The relationships among lens membrane composition, structure, and lipid conformation reviewed in this article are unique to the mammalian lens and offer exciting insights into lens membrane function. This review focuses on findings reported over the last two decades that demonstrate the uniqueness of mammalian lens membranes regarding their morphology and composition. Because the membranes of human lenses do undergo the most dramatic changes with age and cataractogenesis, the final sections of this review address our current knowledge of the unusual composition and organization of adult human lens membranes with and without opacification. Finally, the questions that still remain to be answered are presented.

Eye disease and the older diabetic

Elderly diabetic persons are 1.5 times more likely than age-matched nondiabetic persons to develop vision loss and blindness. Annually, between 12,000 and 24,000 diabetic patients in the United States become legally blind because of complications caused by diabetic retinopathy. Even more diabetic persons experience vision loss caused by comorbid ocular and periocular conditions such as dry eye syndrome, cataracts, macular degeneration, and glaucoma. This article discusses the synergy between these conditions and diabetes. Standards of care that slow the progression of vision loss and exciting new research on new strategies of care that may reverse vision loss are presented.

Circadian photoreception: ageing and the eye's important role in systemic health

AIM

To analyse how age-related losses in crystalline lens transmittance and pupillary area affect circadian photoreception and compare the circadian performance of phakic and pseudophakic individuals of the same age.

METHODS

The spectral sensitivity of circadian photoreception peaks in the blue part of the spectrum at approximately 460 nm. Photosensitive retinal ganglion cells send unconscious information about environmental illumination to non-visual brain centres including the human body's master biological clock in the suprachiasmatic nuclei. This information permits human physiology to be optimised and aligned with geophysical day-night cycles using neural and hormonal messengers including melatonin. Age-related transmittance spectra of crystalline lenses and photopic pupil diameter are used with the spectral sensitivity of melatonin suppression and the transmittance spectra of intraocular lenses (IOLs) to analyse how ageing and IOL chromophores affect circadian photoreception.

RESULTS

Ageing increases crystalline lens light absorption and decreases pupil area resulting in progressive loss of circadian photoreception. A 10-year-old child has circadian photoreception 10-fold greater than a 95-year-old phakic adult. A 45-year-old adult retains only half the circadian photoreception of early youth. Pseudophakia improves circadian photoreception at all ages, particularly with UV-only blocking IOLs which transmit blue wavelengths optimal for non-visual photoreception.

CONCLUSIONS

Non-visual retinal ganglion photoreceptor responses to bright, properly timed light exposures help assure effective circadian photoentrainment and optimal diurnal physiological processes. Circadian photoreception can persist in visually blind individuals if retinal ganglion cell photoreceptors and their suprachiasmatic connections are intact. Retinal illumination decreases with ageing due to pupillary miosis and reduced crystalline lens light transmission especially of short wavelengths. Inadequate environmental light and/or ganglion photoreception can cause circadian disruption, increasing the risk of insomnia, depression, numerous systemic disorders and possibly early mortality. Artificial lighting is dimmer and less blue-weighted than natural daylight, contributing to age-related losses in unconscious circadian photoreception. Optimal intraocular lens design should consider the spectral requirements of both conscious and unconscious retinal photoreception.

Reported visual impairment and risk of suicide: the 1986-1996 national health interview surveys

OBJECTIVE

To examine the relationship between reported visual impairment and suicide mortality.

METHODS

From 1986 through 1996, annual cross-sectional multistage area probability surveys of the US civilian noninstitutionalized population living at addressed dwellings were conducted by the National Center for Health Statistics. We performed mortality linkage through 2002 with the National Death Index of 137,479 adults 18 years and older. The relationships between reported visual impairment and suicide were examined using structural equation modeling.

RESULTS

The mean duration of follow-up was 11.0 years, and 200 suicide deaths were identified. After controlling for survey design, age, sex, race, marital status, number of nonocular health conditions, and self-rated health, the direct effect of visual impairment on death from suicide was elevated but not significant (hazard ratio, 1.50; 95% confidence interval, 0.90-2.49). The approximate indirect effect of visual impairment on death from suicide via poorer self-rated health (1.05; 1.02-1.08) or number of nonocular health conditions (1.12; 1.01-1.24) was significant. The total effect of visual impairment on death from suicide was elevated but not significant (1.64; 0.99-2.72).

CONCLUSIONS

Visual impairment may be associated with an increased risk of suicide through its effect on poor health. This suggests that improved treatment of visual impairment and factors causing poor health may potentially reduce suicide risk.

Visual Acuity and Mortality in a Chinese Population

OBJECTIVE

To examine the relationship between visual acuity and mortality in a Chinese population.

DESIGN

Population-based cohort study.

PARTICIPANTS

Chinese persons in Singapore ages 40 to 79 years at baseline examination.

METHODS

The Tanjong Pagar Study in Singapore examined 1232 persons (response rate, 71.8%) at the baseline examination in 1997 and 1998. Participants had measurements of presenting and best-corrected visual acuity (VA) using standardized protocols. Mortality data were obtained from the National Death Registry, which linked subjects who had died since the baseline examination. Cause of death was determined from the International Classification of Diseases 9 codes. Analysis was performed on 1225 (99.4%) participants with VA data.

MAIN OUTCOME MEASURE

All-cause mortality.

RESULTS

By December 31, 2004 (median follow-up, 6.8 years), 126 persons had died. Participants with presenting VA in the better eye worse than 20/40 (logarithm of the minimum angle of resolution [logMAR] score, 0.3) had a significantly higher mortality rate (hazard ratio [HR], 2.9; 95% confidence interval [CI], 1.4-6.3, adjusting for age, gender, hypertension, diabetes, smoking, heart attack, stroke, and income) as compared with participants with VA of 20/20 (logMAR, 0.0). Associations were similar for best-corrected VA in the better eye (HR, 2.7; 95% CI, 1.4-5.5). Among clinic participants with logMAR VA measurements, each 1-line difference in presenting VA (logMAR gain, 0.10) was associated with a 4-fold increased risk of mortality (HR, 4.4; 95% CI, 1.9-10.2).

CONCLUSIONS

In this Chinese population in Singapore, visual impairment was associated independently with an increased risk of mortality.

Epidemiology of cataract: accomplishments over 25 years and future directions

The purpose of this review is to highlight the advances made by epidemiologic research into cataract. Considerable progress has been made in characterizing phenotypes, determining the prevalence and incidence in various population groups, and understanding risk factors for cataract. Cataract surgery research has documented functional improvements following surgery and has identified aspects of surgery delivery that could be made. Cataract is an independent marker of early mortality, providing a possible system for studying the aging process. Promising future work in cataract epidemiology is highlighted. Despite the availability of cataract surgery, cataract is still the leading cause of blindness worldwide. From a public health standpoint, research that can identify ways to delay onset or progression, or achieve the holy grail of prevention of cataract, should remain a leading priority.

Retrobulbar blood flow in patients with cataract

OBJECTIVE

To investigate retrobulbar haemodynamics in patients with cataract.

SUBJECTS AND METHODS

Colour Doppler imaging of the ophthalmic artery was carried out on the eye scheduled for surgery in 30 patients with cataract and in one randomly selected eye of 100 healthy controls. The peak systolic velocity, mean velocity, end diastolic velocity and resistivity index in the ophthalmic artery were computed and adjusted for the influence of age and mean arterial pressure. Cataract type was recorded and lens opacity was measured with an opacity lensmeter. Odds ratio (OR) for cataract was analysed in a logistic regression model, depending on the adjusted blood-flow parameters, age and smoking status.

RESULTS

The mean (SD) age was 45.5 (17.7) and 67.6 (5.8) years in controls and patients with cataract, respectively (p<0.001). The female to male ratio was 54:46 and 13:17, respectively (p = 0.41). Significant predictors of cataract in a forward stepwise logistic regression analysis were age (OR = 1.194; 95% confidence interval (CI) = 1.103 to 1.292; p<0.001), smoking status (OR = 14.119; 95% CI = 2.753 to 72.398; p = 0.002) and mean blood-flow velocity in the ophthalmic artery (OR = 0.731; 95% CI = 0.607 to 0.881; p = 0.001). Adjusted mean velocity was significantly lower in patients with cataract, even when only age-matched (age >55 years) non-smokers (31 controls, 19 patients with cataract) were considered (p = 0.003). Lens opacity and the type of cataract had no influence on the present findings.

CONCLUSION

High mean velocity in the ophthalmic artery may be associated with a reduced risk of cataract.

Associations between Elevated Intraocular Pressure and Glaucoma, Use of Glaucoma Medications, and 5-Year Incident Cataract

PURPOSE

To examine incident relationships between elevated intraocular pressure (IOP), open-angle glaucoma (OAG), and use of glaucoma medications with 5-year incident cataract.

DESIGN

Population-based cohort study.

PARTICIPANTS

The Australian Blue Mountains Eye Study examined 3654 participants > or =50 years old at baseline (82.4% response; 1992-1994); 2335 eligible participants were reexamined after 5 years (75.1% response; 1997-1999).

METHODS

A detailed medical and ocular history, including current medications, was taken, and a comprehensive eye examination, including applanation tonometry, automated perimetry, and lens photography, was performed at each examination. The Wisconsin system was used to grade lens photographs in assessing incident nuclear, cortical, and posterior subcapsular cataract (PSC). Data from both eyes were assessed using generalized estimating equation analyses.

MAIN OUTCOME MEASURES

Elevated IOP was defined as > or =21 mmHg. Open-angle glaucoma was diagnosed from typical glaucomatous field loss with matching optic disc cupping, without reference to IOP. Subjects without OAG or secondary or angle-closure glaucoma with IOP > 21 mmHg in either eye were classified as having ocular hypertension (OH), as were non-OAG subjects with IOP < 22 mmHg using glaucoma medications. Wisconsin levels 4 to 5 were graded as nuclear cataract, at least 5% lens involvement was graded as cortical cataract, and any PSC defined its presence.

RESULTS

The 5-year incidence of nuclear cataract was 23.4% (592/2532), or 23.1% (574/2486) after excluding subjects using glaucoma medication. A marginally significant association was found for elevated IOP or OH at baseline and incident nuclear cataract (odds ratio [OR], 1.93 [95% confidence interval (CI), 0.97-3.89], and OR, 1.83 [95% CI, 0.96-3.48], respectively) in subjects not using glaucoma medications, after multivariate adjustment. Age- and gender-adjusted analyses showed similar but statistically significant associations. The association between elevated IOP or OH and nuclear cataract was significant in multivariate analyses (OR, 2.07 [95% CI, 1.04-3.12], and OR, 1.78 [95% CI, 1.05-3.01], respectively). Use of glaucoma medications was associated with nonsignificantly increased adjusted odds for incident nuclear cataract (OR, 1.90 [95% CI, 0.92-3.92]). No associations, however, were found with incident cortical cataract or PSC.

CONCLUSIONS

Elevated IOP may increase the risk of nuclear cataract, but not that of other types. The use of glaucoma medications could magnify this risk.

Aggregation of lens crystallins in an in vivo hyperbaric oxygen guinea pig model of nuclear cataract: dynamic light-scattering and HPLC analysis

PURPOSE

The role of oxygen in the formation of lens high-molecular-weight (HMW) protein aggregates during the development of human nuclear cataract is not well understood. The purpose of this study was to investigate lens crystallin aggregate formation in hyperbaric oxygen (HBO)-treated guinea pigs by using in vivo and in vitro

METHODS

methods. Guinea pigs were treated three times weekly for 7 months with HBO, and lens crystallin aggregation was investigated in vivo with the use of dynamic light-scattering (DLS) and in vitro by HPLC analysis of water-insoluble (WI) proteins. DLS measurements were made every 0.1 mm across the 4.5- to 5.0-mm optical axis of the guinea pig lens.

RESULTS

The average apparent diameter of proteins in the nucleus (the central region) of lenses of HBO-treated animals was nearly twice that of the control animals (P < 0.001). Size distribution analysis conducted at one selected point in the nucleus and cortex (the outer periphery of the lens) after dividing the proteins into small-diameter and large-diameter groups, showed in the O2-treated nucleus a threefold increase in intensity (P < 0.001) and a doubling in apparent size (P = 0.03) of large-diameter aggregate proteins, compared with the same control group. No significant changes in apparent protein diameter were detected in the O2-treated cortex, compared with the control. The average diameter of protein aggregates at the single selected location in the O2-treated nucleus was estimated to be 150 nm, a size capable of scattering light and similar to the size of aggregates found in human nuclear cataracts. HPLC analysis indicated that one half of the experimental nuclear WI protein fraction (that had been dissolved in guanidine) consisted of disulfide cross-linked 150- to 1000-kDa aggregates, not present in the control. HPLC-isolated aggregates contained alphaA-, beta-, gamma-, and zeta-crystallins, but not alphaB-crystallin, which is devoid of -SH groups and thus does not participate in disulfide cross-linking. All zeta-crystallin present in the nuclear WI fraction appeared to be there as a result of disulfide cross-linking.

CONCLUSIONS

The results indicate that molecular oxygen in vivo can induce the cross-linking of guinea pig lens nuclear crystallins into large disulfide-bonded aggregates capable of scattering light. A similar process may be involved in the formation of human nuclear cataract.

MMP-9 microsatellite polymorphism and susceptibility to exudative form of age-related macular degeneration

PURPOSE

To assess if a polymorphism (PM) of the microsatellite (CA(13-27)) in the promoter region of Matrix Metalloproteinase 9 (MMP-9) was associated with the exudative form of age-related macular degeneration (AMD) and to its risk factors.

METHODS

In 107 patients with AMD (AMD Group) and 223 age- and gender-matched controls (Control Group) with cataract, demographic, clinical data, and MMP-9 PM have been compared.

RESULTS

The comparison of allelic frequencies showed a different pattern of CA repeats between AMD and Control Group (P < 0.00005), in particular the prevalence of longer microsatellites (> or = 22 CA repeats) was higher in AMD than in Control Group (O.R. 2.49, 95% CI 1.71-3.37, P < 0.001). Analyses of genetic frequencies gave similar results. Logistic regression confirmed that 22 or more CA repeats are associated to AMD. The only association between MMP-9 PM and other risk factors for AMD was with BMI (Spearman's R = 0.298, P < 0.00005): all patients with both microsatellites > or = 22 CA repeats were overweight or obese (chi2 test P < 0.0005, compared to other genotypes).

CONCLUSIONS

Longer microsatellites in the promoter of MMP-9 are associated to the exudative form of AMD and to body mass index, a well-known risk factor for the disease.

Age-related maculopathy: A risk indicator for poorer survival in women

PURPOSE

To examine patient survival in age-related maculopathy in a 14-year follow-up study.

DESIGN

Population-based 14-year cohort study.

PARTICIPANTS

Nine hundred forty-six residents, aged 60 to 80 years, living in the Osterbro district of Copenhagen, Denmark, participated in the first examination conducted from 1986 to 1988. These participants were followed until death or until May 1, 2002, whichever came first.

METHODS

Participants underwent an extensive ophthalmologic examination at Rigshospitalet, the National University Hospital of Copenhagen. Standardized protocols for physical examination, blood samples, and data from the National Central Person Register, the National Death Register, and the National Patient Register were used.

MAIN OUTCOME MEASURES

Mortality and age-related maculopathy.

RESULTS

By May 1, 2002, 60.9% (577 of 946) of the participants of the baseline study cohort had died. The adjusted 14-year cumulative mortality hazard ratio for subjects with early and late age-related maculopathy at baseline was 1.26 (95% confidence interval [CI], 1.06-1.51). We identified a strong correlation between mortality and age-related maculopathy among women (relative risk, 1.59; 95% CI, 1.23-2.07) but not among men.

CONCLUSIONS

When adjusting for survival-related factors, age-related maculopathy is a significant risk indicator for poorer survival in women and may be a marker of underlying serious systemic factors or aging processes specific to women.

Lens lipids and maximum lifespan

Unlike in most organs, the lipid composition of lenses varies dramatically among species and with age. The focus of this study is to assess how these changes relate to lifespan. Studies on cataract suggest that the lens may serve as a window into the processes leading to accelerated mortality. As a first step toward elucidating cellular processes in the lens that may serve as markers for accelerated mortality, we examined the correlation between species-dependent and age-related lens lipid compositional differences and maximum life span. We included data from camels, which, even in old age, rarely develop cataracts although they live under adverse conditions. Camel lens lipids were mainly composed of sphingolipids (77%) and phosphatidylcholines (23%). Bovine lens lipid composition was comparable to a previous study, and both bovine lens sphingolipids, phosphatidylcholines and camel lens phosphatidylcholines content fit well (within the 95% confidence limits) in the curve obtained by plotting maximum life spans of other species with sphingolipids and phosphatidylcholines. Lifespan was directly related to lens sphingolipid content and indirectly related to lens phosphatidylcholine content. The camel lens sphingolipid value was significantly above the curve for other species. Except for the camel lens nucleus, lipid order and sphingolipid content were linearly related, p < 0.005 with a slope of 0.85+/-0.07, and intercept of 6.9+/-3.8. Lipid phase transition temperature and sphingolipid content were also linearly related, p = 0.01 with a slope of 0.20+/-0.07, and intercept of 21.7+/-5.3. Our data support the hypothesis that humans have adapted so that their lens membranes have a high sphingolipid content that confers resistance to oxidation, allowing these membranes to stay clear for a relatively longer time than is the case in many other species. Age-related changes in human lens lipid composition may serve as a marker for oxidative stress and may reflect systemic oxidative insult, providing a window into the health of an individual.

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

AIM

To describe the distribution of cataract subtypes present before surgery among a defined population of older, bilaterally pseudophakic individuals.

METHODS

This was a cohort study of bilaterally pseudophakic individuals participating in the Salisbury Eye Evaluation (SEE), and their locally resident siblings. Subjects underwent slit lamp and retroillumination photography and grading using the Wilmer Cataract Grading System. For all individuals determined to be bilaterally pseudophakic, an attempt was made to determine for each eye the type(s) of cataract present before surgery, based on previous SEE photographs (for SEE participants) and/or medical records obtained from the operating ophthalmologist (for both SEE participants and their siblings).

RESULTS

The mean age of 223 participants providing data in this study was 78.7 (SD 5.2) years, 19.3% of subjects were black and 60.1% female. The most common surgically removed cataract subtype in this population was pure nuclear (43.5%), followed by nuclear combined with posterior subcapsular cataract (PSC) (20.6%), and nuclear combined with cortical (13.9%); less common types were pure cortical (4.9%), pure PSC (4.5%), and PSC combined with cortical (2.7%). Factors such as sex and source of lens data (study photograph versus clinical record) did not significantly affect the distribution of lens opacity types, while PSC was significantly (p = 0.01) more common among younger people and nuclear cataract was significantly (p = 0.001) more common among white compared to black people.

CONCLUSION

Epidemiological studies have suggested that the different subtypes of cataract are associated with different risk factors. As studies begin to identify new prevention strategies for cataract, it would appear likely that different strategies will be efficacious against different types of cataract. In this setting, it will be helpful to know which cataract types are most frequently associated with surgery. Among this older, majority white population, nuclear cataract showed a clear predominance among individuals having undergone surgery in both eyes. This may be contrasted with both clinic and population based studies of younger people, which have generally found PSC cataract to predominate.

Is poor life expectancy a predictive factor in the progression of primary open angle glaucoma?

AIM

To investigate the disease progression and final visual outcome of glaucoma patients with poor life expectancy, compared to matched patients with a longer life expectancy.

METHOD

Visual fields at diagnosis and at the last ophthalmic appointment before death were analysed for glaucoma patients referred between 1991 and 1995, and deceased before the end of 2001. These patients were matched to the patients living beyond 2001. Functional vision was also assessed, and classified as better than the NHS partial sighted criteria.

RESULTS

A total of 61 deceased patients were identified, resulting in 40 matched pairs. In all, 6.5% of the patients with poor life expectancy progressed from functional vision to beyond partial sighted criteria, and none of the matched patients progressed to this extent. At final assessment an association between poor life expectancy and progression beyond functional vision was found existing (P = 0.02), with a lesser association at diagnosis (P = 0.06). Visual field scores of the matched pairs who had test results available for both initial and final assessment (n = 23 pairs) showed no statistically significant difference between the two groups at diagnosis (P = 0.52); However, a significant difference at final the assessment did exist (P = 0.042). No difference between the initial (off medication) intraocular pressures (IOPs) was found (P = 0.82). At the final assessment a significant difference existed (P = 0.025), with the surviving group having a higher final mean pressure (15.9 mmHg, SD 2.8, vs 18.3 mmHg, SD 4.9).

CONCLUSION

Patients with poor life expectancy progressed more than the matched surviving patients, when measured from an initially similar position, despite better IOP control.

Overall adherence to the dietary guidelines for americans is associated with reduced prevalence of early age-related nuclear lens opacities in women

Few studies have examined the efficacy of the Dietary Guidelines for Americans in the prevention of age-related chronic disease, such as age-related cataract. We examined whether adherence to the Guidelines was associated with a lower prevalence of age-related nuclear lens opacities in women. Eye exams were conducted in 479 Nurses' Health Study participants aged 52 to 73 y without previously diagnosed cataract or diabetes living in the Boston, MA area. Four FFQs, collected during a 9- to 11-y period before evaluation of lens status, were used to define diet quality according to the following: 1) daily number of servings of fruits, vegetables, and whole grains; 2) Recommended Foods Score (RFS); and 3) Healthy Eating Index (HEI). Nuclear opacities were defined as scores >/= 2.5 using the Lens Opacification Classification System III. After adjusting for age, smoking, and other risk factors, women in the highest quartile category of HEI scores were significantly less likely to have nuclear opacities than those in the lowest category [odds ratio (OR) = 0.47; 95% CI: 0.26-0.84]. This association appeared to be stronger among nonusers of supplemental vitamin C (OR = 0.23; 95% CI: 0.10-0.52). Decreased prevalence odds of nuclear opacities were also observed with high intake of fruit (OR = 0.58; 95% CI: 0.32-1.05) and whole grains (OR = 0.64; 95% CI: 0.36-1.15). These results suggest that overall compliance with the Dietary Guidelines, as measured by the HEI, protects against nuclear opacities.

Incidence and Progression of Lens Opacities

BACKGROUND

Hormone replacement therapy (HRT) is associated in cross-sectional studies with a decreased prevalence of lens opacities. We explored the associations of HRT and reproductive factors with the incidence and progression of lens opacities over a 2-year period.

METHODS

Data were derived from 1458 women ages 65 years and older from the Salisbury Eye Evaluation population-based prospective cohort study in Salisbury, MD, 1993-1997.

RESULTS

HRT was not associated with incident nuclear, cortical, or posterior subcapsular opacities, or with progression of nuclear or cortical opacification. Women who had an early menopause had a higher risk of nuclear progression, whereas those who had a later menopause had a lower risk (linear trend P = 0.013). Other variables related to reproduction, such as oral contraceptive use, age at menarche, number of births, and history of hysterectomy, were not associated with any of the outcomes.

CONCLUSIONS

These data suggest no evidence of protection against the incidence or progression of lens opacities with HRT.

Associations of mortality with ocular disorders and an intervention of high-dose antioxidants and zinc in the Age-Related Eye Disease Study: AREDS Report No. 13

OBJECTIVE

To assess the association of ocular disorders and high doses of antioxidants or zinc with mortality in the Age-Related Eye Disease Study (AREDS).

METHODS

Baseline fundus and lens photographs were used to grade the macular and lens status of AREDS participants. Participants were randomly assigned to receive oral supplements of high-dose antioxidants, zinc, antioxidants plus zinc, or placebo. Risk of all-cause and cause-specific mortality was assessed using adjusted Cox proportional hazards models.

RESULTS

During median follow-up of 6.5 years, 534 (11%) of 4753 AREDS participants died. In fully adjusted models, participants with advanced age-related macular degeneration (AMD) compared with participants with few, if any, drusen had increased mortality (relative risk [RR], 1.41; 95% confidence interval [CI], 1.08-1.86). Advanced AMD was associated with cardiovascular deaths. Compared with participants having good acuity in both eyes, those with visual acuity worse than 20/40 in 1 eye had increased mortality (RR, 1.36; 95% CI, 1.12-1.65). Nuclear opacity (RR, 1.40; 95% CI, 1.12-1.75) and cataract surgery (RR, 1.55; 95% CI, 1.18-2.05) were associated with increased all-cause mortality and with cancer deaths. Participants randomly assigned to receive zinc had lower mortality than those not taking zinc (RR, 0.73; 95% CI, 0.61-0.89).

CONCLUSIONS

The decreased survival of AREDS participants with AMD and cataract suggests that these conditions may reflect systemic rather than only local processes. The improved survival in individuals randomly assigned to receive zinc requires further study.

The environment and the eye

The use of the 'environment' has become extended to include population changes, the 'domestic' environment, and cultural factors, in addition to physical influences such as global warming and ultraviolet radiation (UVR). The likely effects of each of these classes of agents on the eye and rates of blindness are illustrated by reference mainly to cataract and trachoma--two of the commonest causes of the world blindness.Trachoma infection and its blinding consequences could be eventually eliminated by environmental measures and changes in behaviour. While the threat of increased incidence of blindness from cataract due to ozone depletion and greater solar UVR has receded, global warming may become a factor in the early onset and rapid progression of cataract. Although we continue to need research into the physical and biological causes of cataract, elimination of world blindness will only be achieved when we understand the conceptual and cultural environments which are inhibiting the acceptance of cataract surgery.

Association between lens opacities and mortality in the Priverno Eye Study

BACKGROUND

Lens opacities are associated with a higher risk of death, although there are some discrepancies regarding the specific types of cataract representing risk. The purpose of the present study was to further investigate the relationships between different types of lens opacity and patient survival.

METHODS

In 1987, 860 residents of Priverno, Italy, aged 45-69 years underwent an ophthalmologic examination. Based on patient histories and the findings of the slit-lamp examination, each of the 860 patients was classified according to the type of opacity (pure cortical, pure nuclear, pure posterior subcapsular, mixed, and surgical aphakia). The survivors of the original cohort were re-examined in 1994. Death and survival rates were computed by the Kaplan-Meier method. Associations between mortality and significant factors were included in a stepwise Cox proportional-hazards regression model.

RESULTS

Forty-four members of the original cohort had died during the 7-year follow-up. Age-adjusted survival curves based on Kaplan-Meier estimates showed significantly lower survival in those whose baseline examinations had revealed pure nuclear opacity (log rank test: P=0.020) and aphakia (log rank test: P<0.001). When adjusted for other mortality risk factors (age, sex, diabetes, cardiovascular diseases), the hazard ratio was 4.32 for pure nuclear opacity (95% CI 1.13-16.4) and 18.3 for aphakia (95% CI 3.21-104.0).

CONCLUSIONS

The analysis of the Priverno data seems to confirm an association between lower survival and cataracts, particularly those confined to the lens nucleus and those that had already prompted surgery.

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 > or = 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 > or = 30 kg/m2) 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.

Glaucoma and survival: the National Health Interview Survey 1986-1994

OBJECTIVE

Associations between glaucoma and survival have not been studied extensively, in part, because of the relatively low prevalence of this condition. This study examines associations between self-reported glaucoma and mortality in a nationally representative sample of U.S. adults.

DESIGN

Annual cross-sectional multistage area probability survey of the U.S. civilian noninstitutionalized population living at addressed dwellings.

PARTICIPANTS

Mortality linkage with >96% of participants from the 1986 to 1994 National Health Interview Survey was performed by the National Center for Health Statistics through 1997. Complete data were available on 116796 adults >or=018 years old.

METHODS

Adults within randomly selected households were administered a chronic conditions list that included questions about glaucoma and visual impairment. Proxy information on these conditions was obtained when household members were unavailable for interview. Statistical methods included Cox regression models with adjustments for covariates, as well as for the complex sample survey design.

MAIN OUTCOME MEASURE

All-cause mortality and cardiovascular and cancer mortality.

RESULTS

A total of 1559 (1.3%) glaucoma cases were reported. Nearly 19% of participants with reported glaucoma also had reported visual impairment (n = 303). Mortality linkage identified 8949 deaths; the average follow-up was 7.0 years. After controlling for survey design, gender, age, race, marital status, education level, and self-rated health, participants with reported glaucoma but without reported visual impairment were at significantly increased risk of death relative to participants without reported glaucoma, irrespective of visual impairment status (hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.19-1.53); similar associations were found for participants with reported glaucoma and visual impairment vs. participants with no reported glaucoma (HR, 1.39; 95% CI, 1.14-1.71). An increased risk of cardiovascular disease mortality was found for participants with reported glaucoma both without (HR, 1.31; 95% CI, 1.11-1.55) and with (HR, 1.53; 95% CI, 1.15-2.05) reported visual impairment. Risk of mortality due to cancer was increased only in participants with reported glaucoma but without reported visual impairment (HR, 1.57; 95% CI, 1.25-1.98); this association was stronger when the mortality analysis was restricted to cancers amenable to early screening, including breast, cervical, colon, and prostate cancer (HR, 1.99; 95% CI, 1.41-2.81).

CONCLUSIONS

Among adults residing in the United States, reported glaucoma is associated with an increased risk of all-cause and cardiovascular disease mortality. Associations between glaucoma and cancer were inconsistent and may reflect, in part, a detection bias, in which glaucoma is more likely to be diagnosed in adults receiving health care because of other medical conditions.

Is there a direct association between age-related eye diseases and mortality? The Rotterdam Study

PURPOSE

To study mortality in subjects with age-related maculopathy (ARM), cataract, or open-angle glaucoma (OAG) in comparison with those without these disorders.

DESIGN

Population-based prospective cohort study.

PARTICIPANTS

Subjects (n = 6339) aged 55 years and older from the population-based Rotterdam Study for whom complete information on eye disease status was present.

MAIN OUTCOME MEASURES

Vital status continuously monitored from 1990 until January 1, 2000.

METHODS

The diagnosis of ARM was made according to the International Classification System. Cataract, determined on biomicroscopy, was defined as any sign of nuclear or (sub)cortical cataract, or both, in at least one eye with a visual acuity of 20/40 or less. Aphakia and pseudophakia in at least one eye were classified as operated cataract. Definite OAG was defined as a glaucomatous optic neuropathy combined with a glaucomatous visual field defect. Diagnoses were assessed at baseline. Mortality hazard ratios were computed using Cox proportional hazard regression analysis, adjusted for appropriate confounders (age, gender, smoking status, body mass index, cholesterol level, atherosclerosis, hypertension, history of cardiovascular disease, and diabetes mellitus).

RESULTS

The adjusted mortality hazard ratio for subjects with AMD (n = 104) was 0.94 (95% confidence interval [CI], 0.52-1.68), with biomicroscopic cataract (n = 951) was 0.94 (95% CI, 0.74-1.21), with surgical cataract (n = 298) was 1.20 (95% CI, 0.86-1.68), and with definite OAG (n = 44) was 0.39 (95% CI, 0.10-1.55).

CONCLUSIONS

Both ARM and cataract are predictors of shorter survival because they have risk factors that also affect mortality. When adjusted for these factors, ARM, cataract, and OAG were themselves not significantly associated with mortality.

The association between cataract and mortality among older adults

CONTEXT

Previous research has suggested that persons with cataract have an increased risk of death.

OBJECTIVE

To compare the mortality experience of patients with cataract who elect surgery, patients with cataract who do not elect surgery, and patients without cataract independent of potentially confounding risk factors.

DESIGN

Cohort study.

SETTING

Ophthalmology and optometry clinics affiliated with the Callahan Eye Foundation Hospital in Birmingham, Alabama.

PATIENTS

384 persons with and without cataract.

MAIN OUTCOME MEASURE

Mortality.

RESULTS

Of the 384 study subjects, 286 had cataract, of whom 200 elected to have cataract surgery. Patients with cataract who did and did not elect surgery had significantly higher mortality compared to those without cataract (crude mortality rate ratio (MRR) 3.9 (95% confidence interval (CI) 1.5-9.8) and 7.3 (95% CI 2.8-19.1), respectively). After adjustment for age, gender, race, education, chronic medical conditions, smoking, drinking, depression, and cognitive status, the no-surgery cataract group had an elevated mortality rate (MRR 3.2 (95% 1.2-9.0)), compared to the no-cataract group, with a borderline elevation in MR for the surgery group (MRR 2.0 (95% 0.8-5.9). Limiting the study population to non-diabetics or those without concurrent eye conditions (glaucoma, maculopathy, retinopathy) did not materially influence the adjusted MRRs although the precision of the estimates was reduced.

CONCLUSIONS

The results suggest that older persons with cataract, in particular those who decline surgery, have an increased risk of death, supporting the hypothesis that age-related cataract reflects systemic as well as localized ocular disease.

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

OBJECTIVE

To investigate whether serum lipid/lipoprotein levels are independent risk factors for nuclear, cortical, or posterior subcapsular (PSC) cataracts.

DESIGN

Case-control study nested in a cohort study.

PARTICIPANTS AND METHODS

Eye examinations were conducted on surviving members of the Framingham Offspring Heart Study cohort from 1989 to 1991 (Framingham Offspring Eye Study) to determine cataract case-control status. Data from the Framingham Offspring Heart Study, including fasting serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride measurements collected first in 1971, again approximately 8 years later, and approximately every 4 years thereafter were used to examine associations between lipid levels (mean levels across examinations and slope of measurements over time) and the presence of specific cataract types. The multistage analyses included 1869 persons aged 45 years and older.

MAIN OUTCOME MEASURES

A standardized grading system was used to grade cortical, nuclear, and PSC cataracts.

RESULTS

The median age of participants was 55 years; 49% were males. In multivariable logistic regression models adjusted for potential confounders, fasting hypertriglyceridemia (>/=250 mg/dl) was associated with an increased risk of PSC cataract in men (P = 0.02). High-density lipoprotein cholesterol levels </=35 mg/dl were associated with PSC cataract in men at a borderline level of significance (P = 0.09). No associations were noted between serum lipid/lipoprotein variables and risk of cortical or nuclear cataract.

CONCLUSIONS

These findings suggest that hypertriglyceridemia, a potentially modifiable factor, is associated with the development of PSC cataract in men.

Five year incidence of cataract surgery: the Blue Mountains Eye Study

AIMS

To assess the 5 year incidence of cataract surgery in an older population based prospective cohort.

METHODS

5 Year prospective follow up of the population based Blue Mountains Eye Study (BMES) performed in 1992. The follow up study examined 2335 survivors (75.1%) of the 3654 baseline participants. Baseline and 5 year slit lamp and retroillumination lens photographs were graded for presence of cortical, nuclear, or posterior subcapsular cataract using the Wisconsin cataract grading method and cataract surgery was documented from the history and the clinical examination.

RESULTS

An overall cataract surgery rate of 5.7% in first or both eyes was documented. The incidence was 0.3% in people aged 49-54 years at baseline, 1.7% for ages 55-64 years, 7.9% for ages 65 to 74 years, and 17.4% in people aged 75 years or older. The rate of surgery in first or both eyes was 6.0% in women and 5.2% in men, age adjusted p = 0.66. Bilateral cataract surgery was performed during follow up on 2.7% of participants, while 43.1% of unilateral phakic cases had second eye surgery. Presence of any posterior subcapsular (PSC) cataract, either alone or in combination with other cataract types, was the most likely type of cataract at baseline to be associated with incident cataract surgery. Baseline age was the most important non-ocular variable predicting incident cataract surgery.

CONCLUSIONS

This study has documented age specific rates for 5 year incident cataract surgery in an older community. The finding of relatively similar incidence rates and ocular predictors of cataract surgery to those reported by the Beaver Dam Eye Study, Wisconsin, United States, is of interest, given previous documented similarities between these two populations.

Increased mortality in women with cataract: a population based follow up of the North London Eye Study

BACKGROUND/AIMS

In diabetics, cataract is associated with higher risk of death. In non-diabetics the data are conflicting, but some indicate an association between one type of cataract (nuclear) and increased mortality. The aim of this study was to estimate and compare age and sex specific mortality for elderly people with and without cataract in a population based cohort.

METHODS

A random sample drawn from a defined population of elderly people (age 65 and older) registered with 17 general practice groups in north London formed the study cohort and were followed up for 4 years. The age and sex specific mortality from various causes was estimated and compared in those with and without cataract.

RESULTS

In non-diabetics (n=1318), cataract (lens opacity at baseline) was significantly associated with higher mortality in women. The age standardised death rate per 1000 was 39.8 and 24.8 in women with and without cataract, respectively (age adjusted hazard ratio 1.7, confidence limits 1.1 to 2.7, p=0.032). This was not the case in non-diabetic men (hazard ratio 0.9, confidence limits 0.6 to 1.5, p=0.782). The excess mortality in women with cataract was consistent for cardiovascular, respiratory, and other non-cancer causes of death. There was no association between cataract and mortality from cancer.

CONCLUSIONS

This study has shown, for the first time, that cataract is associated with higher mortality in women but not in men, among the non-diabetic population. This sex effect suggests that women may be exposed to risk factors that increase both the risk of cataract and mortality, and that men may have little or no exposure to these "sex specific" factors. Possible risk factors that warrant further investigation may be those associated with some pregnancy and childbearing experience.