India is a signatory to the World Health Organization resolution on Vision 2020: The right to
sight. Efforts of all stakeholders have resulted in increased number of cataract surgeries performed in India,
but the impact of these efforts on the elimination of avoidable blindness is unknown.
Projection of performance of cataract surgery over the next 15 years to determine whether India is
likely to eliminate cataract blindness by 2020.
Materials and Methods:
Data from three national level blindness surveys in India over three decades, and
projected age-specific population till 2020 from US Census Bureau were used to develop a model to predict
the magnitude of cataract blindness and impact of Vision 2020: the right to sight initiatives.
Using age-specific data for those aged 50+ years it was observed that prevalence of blindness at
different age cohorts (above 50 years) reduced over three decades with a peak in 1989. Projections show that
among those aged 50+ years, the quantum of cataract surgery would double (3.38 million in 2001 to 7.63
million in 2020) and cataract surgical rate would increase from 24025/million 50+ in 2001 to 27817/million 50+
in 2020. Though the prevalence of cataract blindness would decrease, the absolute number of cataract blind
would increase from 7.75 million in 2001 to 8.25 million in 2020 due to a substantial increase in the population
above 50 years in India over this period.
Considering existing prevalence and projected incidence of cataract blindness over the period
2001-2020, visual outcomes after cataract surgery and sight restoration rate, elimination of cataract blindness
may not be achieved by 2020 in India.
Blindness; cataract; the right to sight; vision 2020
Aim: To determine sex inequalities in cataract blindness and surgical services in south India
Methods: Details of lens status and cataract surgery were recorded for subjects aged 50 years and older identified through cluster sampling as part of population based cross sectional assessments of cataract blindness and surgical outcomes in three districts of south India.
Results: Females were less likely to be operated on for cataract (adjusted OR 0.71, 95% CI: 0.57 to 0.87) although the cataract blindness burden was higher for females (p<0.001). Literacy of the subject was a major predictor for being operated on for cataract. Achieving equal surgical coverage between sexes will have resulted in an additional 25.3% reduction of cataract blindness.
Conclusions: Eye care programmes in this population need to be sensitised to the substantial reduction in blindness possible by achieving equal surgical coverage between sexes.
sex differences; cataract blindness; surgical coverage; India
To describe the incidence and risk factors of vision reducing cataract in skin smear positive lepromatous patients.
Prospective longitudinal cohort study: 212 newly diagnosed lepromatous patients were followed during the two years of treatment with multidrug therapy and for a further five years, with biannual ocular examinations. Incidence of vision reducing (⩽6/18) cataract was calculated as the number of patients with cataract per person year of cataract‐free follow up among those who did not have cataract at baseline.
Cataract was present in 27 (11%) of lepromatous patients at diagnosis. Forty nine patients (2.87%/person year (95% confidence interval (CI), 2.17% to 3.80%)) developed cataract during a total follow up period of 1704 person years; 45 of these were ⩾41 years old and were followed for a total of 638 person years with an incident rate of 0.070 (95% CI, 0.0523 to 0.094). Stepwise multiple regression confirmed the association of age (per decade) (hazard ratio (HR) = 2.50 (95% CI, 1.82 to 2.78), p<0.001), clofazimine crystals on the cornea (HR = 49.92 (5.48 to 454.82), p = 0.001), grade 2 deformity in all limbs (HR = 3.17 (1.12 to 8.97), p = 0.029), and uveal inflammation (HR = 3.52 (1.42 to 8.67), p = 0.006). No significant association was found with oral steroids.
Cataract develops at the rate of 7%/person year in lepromatous patients over 40 years of age. It is associated with increasing age, subclinical intraocular inflammation, and grade 2 deformity.
incidence; cataract; risk factors; lepromatous leprosy
Background/aim: Paediatric cataract is a major cause of childhood blindness. Several genes associated with congenital and paediatric cataracts have been identified. The aim was to determine the incidence of cataract in a population, the proportion of hereditary cataracts, the mode of inheritance, and the clinical presentation.
Methods: The Royal Children's Hospital and the Royal Victorian Eye and Ear Hospital have a referral base for almost all paediatric patients with cataracts in south eastern Australia. The database contains cases seen over the past 25 years. The medical histories of these patients were reviewed.
Results: 421 patients with paediatric cataract were identified, which gives an estimated incidence of 2.2 per 10 000 births. Of the 342 affected individuals with a negative family history, 50% were diagnosed during the first year of life, and 56/342 (16%) were associated with a recognised systemic disease or syndrome. Unilateral cataract was identified in 178/342 (52%) of sporadic cases. 79 children (from 54 nuclear families) had a positive family history. Of these 54 families, 45 were recruited for clinical examination and DNA collection. Ten nuclear families were subsequently found to be related, resulting in four larger pedigrees. Thus, 39 families have been studied. The mode of inheritance was autosomal dominant in 30 families, X linked in four, autosomal recessive in two, and uncertain in three. In total, 178 affected family members were examined; of these 8% presented with unilateral cataracts and 43% were diagnosed within the first year of life.
Conclusions: In the paediatric cataract population examined, approximately half of the patients were diagnosed in the first year of life. More than 18% had a positive family history of cataracts. Of patients with hereditary cataracts 8% presented with unilateral involvement. Identification of the genes that cause paediatric and congenital cataract should help clarify the aetiology of some sporadic and unilateral cataracts.
cataracts; paediatric cataracts; congenital cataracts; hereditary cataracts
An earlier case control investigation has indicated a strong relationship between dehydrational crises and risk of presenile cataract. A second methodologically distinct case control study of risk factors in cataract has been carried out in a population very different in terms of environmental and sociocultural characteristics from the population investigated in the earlier study in Central India. The results strongly confirm the findings from the first study and indicate that an estimated 38% of blinding cataract may be attributable to repeated dehydrational crises resulting from severe life threatening diarrhoeal disease and/or heatstroke. The risk of blinding cataract was strongly related to level of exposure to dehydrational crises in a consistent and dose dependent manner, thus indicating a causal association. The findings are discussed in relation to possible sources of bias in the study, confounding in the data, and the steps that were taken to minimise their undesirable effects.
In prospective studies of incident cataract, a person may have developed two or all three of cortical, nuclear sclerotic and posterior subscapsular cataract at the time when clinically significant cataract is apparent. One can compare the impact of risk factors on different types of cataract with methods of competing risk survival analysis that account for tied events.
We studied risk factors for incident cataract among 20,599 participants in the Physicians’ Health Study; 1,923 of whom developed cataract that reduced visual acuity over a median follow-up of 13.0 years. Among incident cases, 45% had two types of cataract and an additional 12% had all three. Proportional hazards models, adjusted for tied failures through use of generalized estimating equations, provided comparisons across different cataract types. Stratified analyses by type with age as the time scale were used to accommodate the strong but different relationships of age with occurrence of different cataract types.
Analyses found different relationships of diabetes and body mass index, but similar relationships of smoking, family history of coronary disease and multivitamin use, across different cataract types. A simplified model provided common estimates for relative risks associated with those characteristics with similar effects across cataract types.
Whereas polytomous logistic regression has proven useful for comparisons of risks across cataract types in retrospective and cross-sectional studies, this approach based on methods of survival analysis has greater flexibility in prospective studies with variable follow-up and frequently tied event times for different cataract types.
To estimate the burden of blindness and visual impairment due to cataract in Egbedore Local Government Area of Osun State, Nigeria.
Materials and Methods:
Twenty clusters of 60 individuals who were 50 years or older were selected by systematic random sampling from the entire community. A total of 1,183 persons were examined.
The age- and sex-adjusted prevalence of bilateral cataract-related blindness (visual acuity (VA) < 3/60) in people of 50 years and older was 2.0% (95% confidence interval (CI): 1.6–2.4%). The Cataract Surgical Coverage (CSC) (persons) was 12.1% and Couching Coverage (persons) was 11.8%. The age- and sex-adjusted prevalence of bilateral operable cataract (VA < 6/60) in people of 50 years and older was 2.7% (95% CI: 2.3–3.1%). In this last group, the cataract intervention (surgery + couching) coverage was 22.2%. The proportion of patients who could not attain 6/60 vision after surgery were 12.5, 87.5, and 92.9%, respectively, for patients who underwent intraocular lens (IOL) implantation, cataract surgery without IOL implantation and those who underwent couching. “Lack of awareness” (30.4%), “no need for surgery” (17.6%), cost (14.6%), fear (10.2%), “waiting for cataract to mature” (8.8%), AND “surgical services not available” (5.8%) were reasons why individuals with operable cataract did not undergo cataract surgery.
Over 600 operable cataracts exist in this region of Nigeria. There is an urgent need for an effective, affordable, and accessible cataract outreach program. Sustained efforts have to be made to increase the number of IOL surgeries, by making IOL surgery available locally at an affordable cost, if not completely free.
Barriers; Cataract Blindness; Nigeria; Prevalence; Surgery
AIMS—A population based cross sectional survey was conducted to determine the magnitude of cataract blindness and the barriers to uptake of cataract services in a rural community of northern Nigeria.
METHODS—1461 people out of 1924 registered eligible people were examined. The study population was chosen by two stage cluster random sampling. In the first sampling stage 15 villages were randomly chosen while in the final stage 170 people who were 40 years and over were selected in each village. Each selected person had visual acuity recorded for both eyes. Those with vision of less than 3/60 in the better eye were assessed for cataract. People with cataract were asked why they had not sought medical attention.
RESULTS—A blindness prevalence of 8.2% (95% CI 5.8%-10.5%) was found among the sampled population. Cataract was responsible for 44.2% of the blindness. Thus, a cataract blindness prevalence of 3.6% was found. The cataract surgical coverage (people) was 4.0% and the couching coverage (people) was 18%. The main barrier to seeking cataract surgery was cost of the service (61%).
CONCLUSION—Some regions of the world still have high burden of cataract blindness that needs attention. Such areas need an effective free cataract outreach programme.
Corneal diseases represent the second leading cause of blindness in most developing world countries. Worldwide, major investments in public health infrastructure and primary eye care services have built a strong foundation for preventing future corneal blindness. However, there are an estimated 4.9 million bilaterally corneal blind persons worldwide who could potentially have their sight restored through corneal transplantation. Traditionally, barriers to increased corneal transplantation have been daunting, with limited tissue availability and lack of trained corneal surgeons making widespread keratoplasty services cost prohibitive and logistically unfeasible. The ascendancy of cataract surgical rates and more robust eye care infrastructure of several Asian and African countries now provide a solid base from which to dramatically expand corneal transplantation rates. India emerges as a clear global priority as it has the world's largest corneal blind population and strong infrastructural readiness to rapidly scale its keratoplasty numbers. Technological modernization of the eye bank infrastructure must follow suit. Two key factors are the development of professional eye bank managers and the establishment of Hospital Cornea Recovery Programs. Recent adaptation of these modern eye banking models in India have led to corresponding high growth rates in the procurement of transplantable tissues, improved utilization rates, operating efficiency realization, and increased financial sustainability. The widespread adaptation of lamellar keratoplasty techniques also holds promise to improve corneal transplant success rates. The global ophthalmic community is now poised to scale up widespread access to corneal transplantation to meet the needs of the millions who are currently blind.
Avoidable blindness; cataract surgical rate; corneal blindness; eye care services
Cataract is known to be more common in India than it is in the industrialised world, but there is little evidence to show whether people emigrating from India will continue to have a high incidence of the disease. Data have been collected from the outpatient clinics of a hospital in Leicester, England, that suggest that for people aged over 45 the demand incidence of cataract is more than five times higher in people of Indian descent than it is in the indigenous population. As well as measuring the demand incidence of cataract in Leicester's two main racial groups the data are used to investigate other risk factors. For both communities the demand incidence of cataract is significantly higher in women than in men, and it is significantly higher in people of Indian descent who emigrated directly from India than in those who emigrated from East Africa. Religious subgroups within the immigrant community also show small differences in their demand incidence. The possibility that these differences are linked to diet is considered.
Aim: To determine risk factors for lens opacities and age related cataract in an older rural population of southern India.
Methods: A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence ⩾3.0 and/or cortical cataract ⩾3.0 and/or PSC ⩾2.0.
Results: Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors—increasing age and illiteracy—were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94).
Conclusions: Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.
age related cataract; India; Aravind Comprehensive Eye Study
AIMS: To estimate the risk of retinal detachment (RD) following cataract extraction in Denmark, and to compare the risk with that following cataract extraction in the USA, and with that in a sample of Danish patients who did not have ocular surgery. METHODS: A sample was created from the administrative Danish Hospital Register and included 19,252 patients who underwent first eye cataract surgery between 1985 and 1987, and who were 50 years of age or older. The patients were then followed for 4-6 years using the register data. The design and definition of events were identical to the US National Study of Cataract Outcomes. RESULTS: In Denmark a 4 year cumulative risk of hospitalisation for RD of 0.93% (95% confidence interval (CI) 0.71-1.16) was observed following an extracapsular cataract extraction with a lens implant. A similar cumulative risk of RD was reported from the US study. Thus, no difference in outcomes concerning risk of RD was shown between Denmark and the USA. In a multivariate analysis younger age, male sex, and intracapsular cataract extraction were all associated with higher risk of postoperative RD. A reference group of 7636 people not undergoing any ocular surgery was created and the incidence of RD in this group was calculated. During the sixth year following cataract surgery, the incidence of RD in the cataract group was still 7.5 (95% CI 1.6-22.0) times higher than that observed in the reference group.
Some large population-based studies have reported a dose-related increased risk of cataracts and glaucoma associated with use of inhaled corticosteroids (ICS) in patients with asthma or chronic obstructive pulmonary disease (COPD). We evaluated the association between use of ICS-containing products, specifically fluticasone propionate/salmeterol fixed-dose combination (FSC), and incidence of cataracts and glaucoma among patients with COPD in a large electronic medical record database in the United Kingdom.
We identified a cohort of patients aged 45 years and over with COPD in the General Practice Research Database (GPRD) between 2003 and 2006. Cases of incident cataracts or glaucoma were defined based on diagnosis and procedure codes and matched to controls from the risk set to estimate odds ratios (OR) and 95% confidence intervals (CI). The association with FSC or ICS exposure was modeled using conditional logistic regression. Medication exposure was assessed with respect to recency, duration, and number of prescriptions prior to the index date. Average daily dose was defined as none, low (1–250 mcg), medium (251–500 mcg), high (501–1000 mcg), or very high (1001+ mcg) using fluticasone propionate (FP) equivalents.
We identified 2941 incident cataract cases and 327 incident glaucoma cases in the COPD cohort (n = 53,191). FSC or ICS prescriptions were not associated with risk of incident cataracts or glaucoma for any exposure category, after adjusting for confounders. We observed a lack of a dose response in all analyses, where low dose was the reference group. The odds of cataracts associated with FSC dose were medium OR: 1.1 (95% CI: 0.9–1.4); high OR: 1.2 (95% CI: 0.9–1.5); and very high OR: 1.2 (95% CI: 0.9–1.7). The odds of glaucoma associated with FSC dose: medium OR: 1.0 (95% CI: 0.5–2.1); high OR: 1.0 (95% CI: 0.5–2.0); and very high OR: 1.0 (95% CI: 0.4–2.8).
FSC or other ICS exposure was not associated with an increased odds of cataracts or glaucoma, nor was a dose–response relationship observed in this population-based nested case-control study of COPD patients in the United Kingdom.
inhaled corticosteroids; fluticasone propionate/salmeterol; cataracts; glaucoma; risk
Sunlight exposure has been found to be associated with the development of age-related cataract. Use of some medications has been related to the development of sensitization to sun exposure.
To examine the relationship of use of sun-sensitizing medication on cumulative incidence of age-related cataract.
Population-based longitudinal cohort study.
Adults in the Midwestern community of Beaver Dam, Wisconsin, who were seen at baseline and three follow-up visits each five years apart.
Sun exposure was estimated from residential history that permitted calculation of Wisconsin sun years (WISY) at the baseline examination. Medication history was reported at each examination. Cataract presence was determined by standardized lens photographs that were taken at each examination and graded according to standard protocols.
Main Outcome Measure
Cumulative incidence of age-related cataract.
There were no significant effects of WISY exposure or use of sun-sensitizing medications on cumulative incidence of any type of age-related cataract while controlling for age and gender. However, there was a significant interaction term combining WISY and use of any sun-sensitizing medication on cortical cataract (P=.04) such that risk of cataract is significantly higher for persons in both risk groups: taking sun-sensitizing medication and higher sun exposure. Further controlling for diabetes status, history of heavy drinking and hat or sunglasses use did not alter the relationships.
These data suggest that use of sun-sensitizing medications interacts with sun exposure to influence the risk of cortical cataract, a common age-related cataract. If confirmed, this finding may have important implications for medication use.
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.
mortality; women; cataract; London
To investigate potential risk factors associated with incident nuclear, cortical, and posterior subcapsular (PSC) cataracts and cataract surgery in participants in the Age-Related Eye Disease Study (AREDS).
Clinic-based prospective cohort study.
Persons (N=4425), aged 60 to 80 years of age enrolled in a controlled clinical trial of antioxidant vitamins and minerals, AREDS, for age-related macular degeneration (AMD) and cataract.
Lens photographs were graded centrally for nuclear, cortical, and PSC opacities using the AREDS System for Classifying Cataracts. Type-specific incident cataracts were defined as an increase in cataract grade from none or mild at baseline to a grade of moderate at follow-up, with also a grade of at least moderate at the final visit, or cataract surgery. Cox regression analyses were used to assess baseline risk factors associated with type specific opacities and cataract surgery.
Main Outcome Measures
Moderate cataract was defined as a grade of ≥4.0 for nuclear opacity, ≥10% involvement within the full visible lens for cortical opacity, and ≥5% involvement of the central 5 mm circle of the lens for PSC opacity. These were graded on baseline and annual lens photographs.
A clinic-based cohort of 4425 persons aged 55–80 years at baseline was followed for an average of 9.8 ± 2.4 years. The following associations were found: increasing age with increased risk of all types of cataract and cataract surgery; males with increased risk of PSC and decreased risk of cortical cataracts; non-whites with increased risk of cortical cataract; hyperopia with decreased risk of PSC, nuclear cataract, and cataract surgery; Centrum use with decreased risk of nuclear cataract; diabetes with increased risk of cortical, PSC cataract, and cataract surgery; higher educational level with decreased risk of cortical cataract; and smoking with increased risk of cortical cataract and cataract surgery. Estrogen replacement therapy in female participants increased the risk of cataract surgery.
Our findings are largely consistent with the results of previous studies, providing further evidence for possible modifiable risk factors for age-related cataract.
Data on the prevalence and causes of blindness and visual impairment in Polynesians are not readily available nor are they population based. This survey was designed to obtain an accurate estimate of blindness and its causes in Tonga. A sample of 4056 persons, aged 20 years and over, was selected by stratified cluster sampling. Participants received a screening, visual acuity examination, and, if visually impaired, were referred for detailed ophthalmic examination to determine the cause. The prevalence of bilateral blindness in the study population was 0.47% and all affected were aged over 50 years. It is estimated that the national prevalence of bilateral blindness, adjusted for the sample weight applied in the selection procedure, is 0.56% (95% confidence interval 0-1.13). Monocular blindness was three times more frequent. Cataract was responsible for 68.4% of bilateral and 30.3% of monocular blindness. Risk factors for life time experience of cataract included age and diabetes (self-reported). Neither smoking nor the presence of pterygium were independently associated with cataract. Increasing years of education were protective against cataract for women, but not men. Corneal opacity from infection or trauma, and diabetes were responsible for most of the remaining visual impairment. While these results do not represent a significant public health problem by world standards they do provide a basis for planning blindness prevention programmes in the region.
Cataract is among the major causes of vision impairment and blindness worldwide. Epidemiological studies support the role of antioxidants in the etiology of cataract, but the evidence for one specific antioxidant over another is inconsistent. Few studies have examined the association of cataract with fruit and vegetable intake with inconclusive results. In the present study, the relationship between cataract and fruit and vegetable intake and dietary and blood levels of carotenoids, vitamins C and E were examined in a Spanish Mediterranean population.
The present work is an analysis of data from 599 elderly ( ≥ 65 years) participants from the Spanish segment of the EUREYE study. This is a European multi-center cross-sectional population-based study. Cataract was diagnosed using a slit-lamp examination and defined as any lens opacity in either eye or evidence of its removal (cataract extraction). Energy-adjusted intake of fruit and vegetables and antioxidant vitamins was estimated using a semi-quantitative food frequency questionnaire. Plasma concentrations of vitamin C were analyzed by a colorimetric method and carotenoids and α-tocopherol by a HPLC method. The associations between cataract and quartiles of fruit and vegetable intake and plasma antioxidants were investigated using logistic regression models.
Of the 599 elderly recruited, 433 (73%) had cataract or cataract extraction, 54% were women and 46% were men. After adjustments, increasing quartiles of combined fruit and vegetable intake were associated with decreasing reduction of odds of cataract or cataract extraction, (P for trend = 0.008). Increasing quartiles of dietary intakes from 107 mg/d of vitamin C showed a significant decreasing association with prevalence of cataract or cataract extraction (P for trend = 0.047). For vitamin E, a protective association was found from intakes from 8 mg/d, but no linear trend was observed across quartiles of intake (P for trend = 0.944).
High daily intakes of fruit and vegetables and vitamins C and E were associated with a significantly decreased of the prevalence of cataract or cataract surgery. This study reinforces the WHO recommendations on the benefits of diets rich in fruit and vegetables.
Cataract; Fruit intake; Vegetables intake; Antioxidant vitamins; WHO recommendations
Rapid assessment of avoidable blindness provides valid estimates in a short period of time to assess the magnitude and causes of avoidable blindness. The study determined magnitude and causes of avoidable blindness in India in 2007 among the 50+ population.
Methods and Findings
Sixteen randomly selected districts where blindness surveys were undertaken 7 to 10 years earlier were identified for a follow up survey. Stratified cluster sampling was used and 25 clusters (20 rural and 5 urban) were randomly picked in each district.. After a random start, 100 individuals aged 50+ were enumerated and examined sequentially in each cluster. All those with presenting vision <6/18 were dilated and examined by an ophthalmologist. 42722 individuals aged > = 50 years were enumerated, and 94.7% examined. Based on presenting vision,, 4.4% (95% Confidence Interval[CI]: 4.1,4.8) were severely visually impaired (vision<6/60 to 3/60 in the better eye) and 3.6% (95% CI: 3.3,3.9) were blind (vision<3/60 in the better eye). Prevalence of low vision (<6/18 to 6/60 in the better eye) was 16.8% (95% CI: 16.0,17.5). Prevalence of blindness and severe visual impairment (<6/60 in the better eye) was higher among rural residents (8.2%; 95% CI: 7.9,8.6) compared to urban (7.1%; 95% CI: 5.0, 9.2), among females (9.2%; 95% CI: 8.6,9.8) compared to males (6.5%; 95% CI: 6.0,7.1) and people above 70 years (20.6%; 95% CI: 19.1,22.0) compared to people aged 50–54 years (1.3%; 95% CI: 1.1,1.6). Of all blindness, 88.2% was avoidable. of which 81.9% was due to cataract and 7.1% to uncorrected refractive errors/uncorrected aphakia.
Cataract and refractive errors are major causes of blindness and low vision and control strategies should prioritize them. Most blindness and low vision burden is avoidable.
In April 2004, The Eye Disease Prevalence Research Group published a series of articles that included age-specific estimates for the prevalence of low vision and blindness in whites, African Americans, and Hispanics living in the United States. Also included were age-, sex-, and ethnic-specific incidences of the following age-related eye diseases: diabetic retinopathy, macular degeneration, cataracts, and glaucoma.
We reviewed the group's series of articles and highlighted key findings on the overall prevalence of and risk factors for age-related eye diseases, as well as opportunities to preserve and restore vision. We examined publications that show the public health impact of age-related eye diseases and the importance of projected increases in prevalence of low vision and blindness.
Approximately 1 in 28 Americans aged older than 40 years is affected by low vision or blindness. Among community-dwelling adults, the prevalence of low vision and blindness increases dramatically with age in all racial and ethnic groups. Whites have higher rates of macular degeneration than African Americans, but glaucoma is more common among older African Americans. Between 2000 and 2020, the prevalence of blindness is expected to double.
Age-related eye diseases are costly to treat, threaten the ability of older adults to live independently, and increase the risk for accidents and falls. To prevent vision loss and support rehabilitative services for people with low vision, it is imperative for the public health community to address the issue through surveillance, public education, and coordination of screening, examination, and treatment.
Background/aims: Unoperated cataract is the main challenge to blindness reduction in China. This demonstration project in Guangdong Province was designed to test various strategies to improve the cataract surgical rate.
Methods: Two strategies (reduction of the cataract surgical fee and training of country doctors in the detection of cataract blindness) were implemented in each of two counties. Both interventions were introduced in a third county.
Results: The cataract surgery rate (CSR) per million was 366 in the county where training took place, 588 where the fee was lowered, and 1140 where both interventions took place. The improvement in CSR was highly significant (p<0.001).
Conclusions: In southern China, CSR can be increased with community based measures. Sustainability for such measures will be the major future challenge.
To examine the associations of cataract and cataract surgery with early and late age-related macular degeneration (AMD) over a 20-year interval.
Longitudinal population-based study of age-related eye diseases. Participants: Beaver Dam Eye Study participants.
All persons 43-84 years of age were recruited in 1987-1988. Participants were followed up at five year intervals after the baseline examination in 1988-1990. Examinations consisted of ocular examination with lens and fundus photography, medical history, measurements of blood pressure, height, and weight. Values of risk variables were updated, and incidences of early and late AMD were calculated for each 5-year interval. Odds ratios were computed using discrete linear logistic regression modeling with generalized estimating equation methods to account for correlation between the eyes and multiple intervals.
Main Outcome Measures
After controlling for age and sex, neither cataract nor cataract surgery was associated with increased odds for developing early AMD. Further controlling for high risk gene alleles (CFH and ARMS2) and other possible risk factors did not materially affect the odds ratio (OR). However, cataract surgery was associated with incidence of late AMD (OR 1.93; 95% CI 1.28, 2.90). This OR was not materially altered by further controlling for high risk alleles (CFH Y402H, ARMS2) or for other risk factors. The OR for late AMD was higher for cataract surgery performed 5 or more years prior as compared to less than 5 years prior.
These data strongly support the past findings of an association of cataract surgery with late AMD independent of other risk factors including high risk genetic status, and suggest the importance of considering these findings when counseling patients regarding cataract surgery. These findings should provide further impetus for the search for measures to prevent or delay the development of age-related cataract.
This large, two-center, population-based study provides estimates of the prevalence of age-related macular degeneration in India.
To estimate the prevalence of early and late age-related macular degeneration (AMD) in India.
Of 7518 people aged 60 years and older identified from randomly sampled villages in North and South India, 5853 (78%) attended an eye examination including fundus photography. Fundus images were graded according to the Wisconsin Age-Related Maculopathy Grading System.
Fundus images were ungradable in 1587 people, mainly because of cataract. People 80 years of age and older were less likely to attend the eye examination and more likely to have ungradable images. For ages 60 to 79 years, the percent prevalence (95% confidence interval [CI]) were late AMD 1.2 (0.8–1.5); and early AMD: grade 1 (soft distinct drusen or pigmentary irregularities), 39.3 (37.2–41.5); grade 2 (soft distinct drusen with pigmentary irregularities or soft indistinct or reticular drusen), 6.7 (5.8–7.6); and grade 3 (soft indistinct or reticular drusen with pigmentary irregularities), 0.2 (0.1–0.4). For ages 80 and older, the respective percent prevalence was: late AMD, 2.5 (0.4–4.7); and early AMD: grade 1, 43.1(35.7–50.6); grade 2, 8.1 (4.3–12.0); and grade 3, 0.5 (0–1.5).
The prevalence of early AMD (grades 1 and 2) is similar to that observed in Western populations, but grade 3 appears to be lower. The prevalence of late AMD is comparable to that in Western populations in the age group 60 to 79 years. It is likely that the prevalence in the 80 and older age group is underestimated.
AIMS—To derive preliminary estimates for the number of adults in China suffering from glaucoma, and project the burden of visual morbidity attributable to primary and secondary glaucoma.
METHODS—Age and sex specific data from two population surveys were applied to US Census Bureau population estimates for urban and rural China. It was assumed that data from Singapore were representative of urban China, and those from Mongolia were representative of rural China.
RESULTS—It was estimated that 9.4 million people aged 40 years and older in China have glaucomatous optic neuropathy. Of this number, 5.2 million (55%) are blind in at least one eye and 1.7 million (18.1%) are blind in both eyes. Primary angle closure glaucoma (PACG) is responsible for the vast majority (91%) of bilateral glaucoma blindness in China. The number of people with the anatomical trait predisposing to PACG (an "occludable" drainage angle) is in the region of 28.2 million, and of these 9.1 million have significant angle closure, indicated by peripheral anterior synechiae or raised intraocular pressure.
CONCLUSIONS—This extrapolation of data from two east Asian countries gives an approximate number of people in China suffering from glaucoma. It is unlikely that this crude statistical model is entirely accurate. However, the authors believe the visual morbidity from glaucoma in China is considerable. PACG is probably the leading cause of glaucoma blindness in both eyes, and warrants detailed investigation of strategies for prevention.
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.
cataract; cataract surgery; Blue Mountains Eye Study