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1.  EPHA2 Polymorphisms and Age-Related Cataract in India 
PLoS ONE  2012;7(3):e33001.
We investigated whether previously reported single nucleotide polymorphisms (SNPs) of EPHA2 in European studies are associated with cataract in India.
We carried out a population-based genetic association study. We enumerated randomly sampled villages in two areas of north and south India to identify people aged 40 and over. Participants attended a clinical examination including lens photography and provided a blood sample for genotyping. Lens images were graded by the Lens Opacification Classification System (LOCS III). Cataract was defined as a LOCS III grade of nuclear ≥4, cortical ≥3, posterior sub-capsular (PSC) ≥2, or dense opacities or aphakia/pseudophakia in either eye. We genotyped SNPs rs3754334, rs7543472 and rs11260867 on genomic DNA extracted from peripheral blood leukocytes using TaqMan assays in an ABI 7900 real-time PCR. We used logistic regression with robust standard errors to examine the association between cataract and the EPHA2 SNPs, adjusting for age, sex and location.
7418 participants had data on at least one of the SNPs investigated. Genotype frequencies of controls were in Hardy-Weinberg Equilibrium (p>0.05). There was no association of rs3754334 with cataract or type of cataract. Minor allele homozygous genotypes of rs7543472 and rs11260867 compared to the major homozygote genotype were associated with cortical cataract, Odds ratio (OR) = 1.8, 95% Confidence Interval (CI) (1.1, 3.1) p = 0.03 and 2.9 (1.2, 7.1) p = 0.01 respectively, and with PSC cataract, OR = 1.5 (1.1, 2.2) p = 0.02 and 1.8 (0.9, 3.6) p = 0.07 respectively. There was no consistent association of SNPs with nuclear cataract or a combined variable of any type of cataract including operated cataract.
Our results in the Indian population agree with previous studies of the association of EPHA2 variants with cortical cataracts. We report new findings for the association with PSC which is particularly prevalent in Indians.
PMCID: PMC3297613  PMID: 22412971
2.  Risk factors for age related cataract in a rural population of southern India: the Aravind Comprehensive Eye Study 
Aim: To determine risk factors for lens opacities and age related cataract in an older rural population of southern India.
Methods: A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence ⩾3.0 and/or cortical cataract ⩾3.0 and/or PSC ⩾2.0.
Results: Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors—increasing age and illiteracy—were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94).
Conclusions: Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.
PMCID: PMC1772282  PMID: 15258010
age related cataract; India; Aravind Comprehensive Eye Study
3.  Inverse Association of Vitamin C with Cataract in Older People in India 
Ophthalmology  2011;118(10):1958-1965.e2.
To examine the association between vitamin C and cataract in the Indian setting.
Population-based cross-sectional analytic study.
A total of 5638 people aged ≥60 years.
Enumeration of randomly sampled villages in 2 areas of north and south India to identify people aged ≥60 years. Participants were interviewed for socioeconomic and lifestyle factors (tobacco, alcohol, household cooking fuel, work, and diet); attended a clinical examination, including lens photography; and provided a blood sample for antioxidant analysis. Plasma vitamin C was measured using an enzyme-based assay in plasma stabilized with metaphosphoric acid, and other antioxidants were measured by reverse-phase high-pressure liquid chromatography.
Main Outcome Measures
Cataract and type of cataract were graded from digital lens images using the Lens Opacity Classification System III (LOCS III), and cataract was classified from the grade in the worse eye of ≥4 for nuclear cataract, ≥3 for cortical cataract, and ≥2 for posterior subcapsular cataract (PSC). Any cataract was defined as any unoperated or operated cataract.
Of 7518 enumerated people, 5638 (75%) provided data on vitamin C, antioxidants, and potential confounders. Vitamin C was inversely associated with cataract (adjusted odds ratio [OR] for highest to lowest quartile = 0.61; 95% confidence interval (CI), 0.51–0.74; P=1.1×10−6). Inclusion of other antioxidants in the model (lutein, zeaxanthin, retinol, β-carotene, and α-tocopherol) made only a small attenuation to the result (OR 0.68; 95% CI, 0.57–0.82; P < 0.0001). Similar results were seen with vitamin C by type of cataract: nuclear cataract (adjusted OR 0.66; CI, 0.54–0.80; P < 0.0001), cortical cataract (adjusted OR 0.70; CI, 0.54–0.90; P < 0.002), and PSC (adjusted OR 0.58; CI, 0.45–0.74; P < 0.00003). Lutein, zeaxanthin, and retinol were significantly inversely associated with cataract, but the associations were weaker and not consistently observed by type of cataract. Inverse associations were also observed for dietary vitamin C and cataract.
We found a strong association with vitamin C and cataract in a vitamin C–depleted population.
Financial Disclosure(s)
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
PMCID: PMC3185206  PMID: 21705085
4.  Prevalence of Visually Significant Cataract and Factors Associated with Unmet Need for Cataract Surgery: Los Angeles Latino Eye Study 
Ophthalmology  2009;116(12):2327-2335.
To estimate in a United States (U.S.) Latino population the prevalence of visually significant cataract, and to report predisposing, enabling, need, and health behavior characteristics associated with the unmet need for cataract surgery (UNCS).
Population-based, cross-sectional study.
6142 Latinos 40 years and older from 6 census tracts in Los Angeles County, California.
Participants completed an in-home interview and a comprehensive eye examination which included assessment of lens opacification, using the slit lamp-based Lens Opacities Classification System II (LOCS II), and best-corrected visual acuity (BCVA). Visually significant cataract was defined by: any LOCS II grading ≥2, BCVA <20/40, cataract as the primary cause of vision impairment, and self-reported vision of fair or worse. Because cataract surgery is not needed in all persons, participants with a visually significant cataract or prior cataract surgery in at least one eye composed the at-risk cohort needing cataract surgery. UNCS was defined as any person in the at-risk cohort who had at least one eye with a visually significant cataract. Univariate and stepwise logistic regression analyses were used to identify predisposing, enabling, need, and health behavior characteristics associated with UNCS.
Main Outcome Measure
Prevalence of visually significant cataract, and odds ratios for factors associated with UNCS.
Of 6142 participants who completed the interview and clinical examination, 118 (1.92%) had visually significant cataract in at least one eye. Of the 344 participants who have needed cataract surgery, 118 (29.9%) had UNCS. Independent factors associated with UNCS included health behavior - having last eye exam ≥5 years ago compared to <1 year ago (odds ratio; 95% confidence interval [OR], 3.76; 1.71-8.25)- and enabling factors - being uninsured (OR, 2.79; 1.30- 5.19), income less than $20,000 (OR, 2.60; 1.40-5.56), and self-reported barriers to eye care (OR 2.41; 1.14-5.13).
Latinos in our study had a substantial unmet need for cataract surgery. As Latinos with specific health behavior and enabling characteristics were more likely to have UNCS, interventions aimed at modifying these characteristics may be beneficial in reducing the unmet need and thus reducing the burden of visual impairment related to cataract in the U.S.
PMCID: PMC2787839  PMID: 19815276
5.  Risk factors for nuclear, cortical and posterior subcapsular cataracts in the Chinese population of Singapore: the Tanjong Pagar Survey 
The British Journal of Ophthalmology  2003;87(9):1112-1120.
Aim: To describe risk factors for nuclear, cortical, and posterior subcapsular (PSC) cataracts in Chinese Singaporeans.
Methods: A population based cross sectional study was carried out on ethnic Chinese men and women aged 40–81 years. A stratified, clustered, disproportionate (more weights to older people), random sampling procedure was used to initially select 2000 Chinese names of those aged 40–79 years from the 1996 electoral register in the Tanjong Pagar district in Singapore. Eligible subjects (n = 1717) were invited for a standardised ocular examination and interview at a centralised clinic, following which an abbreviated examination was conducted for non-respondents in their homes. Cataract was graded clinically using to the Lens Opacity Classification System (LOCS) III system. The main outcome measures were adjusted odds ratio for risk factors for specific cataract types (nuclear, cortical and PSC), any cataract and cataract surgery, examined in multiple logistic regression models.
Results: Out of the 1232 (71.8%) examined, 1206 (70.2%) provided lens data for this analysis. Increasing age was associated with all cataract types, any cataract, and cataract surgery. There was no significant sex difference in presence of any cataract, specific cataract types or cataract surgery. After controlling for age, sex, and other factors, diabetes was associated with cortical cataract (3.1; 95% CI: 1.6 to 6.1), PSC cataract (2.2; 95% CI 1.2 to 4.1), any cataract (2.0; 95% CI: 0.9 to 4.5), and cataract surgery (2.3; 95% CI: 1.3 to 4.1). Lower body mass index was associated with cortical cataract (1.8; 95% CI: 1.1 to 2.9; lowest versus highest quintile) and any cataract (2.3; 95% CI: 1.3 to 4.0). Current cigarette smoking was associated with nuclear cataract (1.7, 95% CI: 1.0 to 2.9; more than 10 cigarettes per day versus none). A non-professional occupation was associated with nuclear cataract (2.9; 95% CI: 1.5 to 5.8; for production or machine operators and 2.6; 95% CI: 1.2 to 5.5; for labourers or agricultural workers, both versus professionals). Lower education was associated with nuclear cataract (2.3; 95% CI: 1.0 to 5.2, none versus tertiary), while lower household income was associated with PSC cataract (4.7, 95% CI: 1.1 to 20.0; income S$4000).
Conclusions: Age related cataracts are associated with a variety of risk factors among Chinese people in Singapore, similar to those reported in European, Indian, and African derived populations. These data support common aetiological mechanisms for age related cataracts, irrespective of ethnic origin.
PMCID: PMC1771847  PMID: 12928278
cataracts; Chinese; Singapore
6.  Comparison of age-specific cataract prevalence in two population-based surveys 6 years apart 
BMC Ophthalmology  2006;6:17.
In this study, we aimed to compare age-specific cortical, nuclear and posterior subcapsular (PSC) cataract prevalence in two surveys 6 years apart.
The Blue Mountains Eye Study examined 3654 participants (82.4% of those eligible) in cross-section I (1992–4) and 3509 participants (75.1% of survivors and 85.2% of newly eligible) in cross-section II (1997–2000, 66.5% overlap with cross-section I). Cataract was assessed from lens photographs following the Wisconsin Cataract Grading System. Cortical cataract was defined if cortical opacity comprised ≥ 5% of lens area. Nuclear cataract was defined if nuclear opacity ≥ Wisconsin standard 4. PSC was defined if any present. Any cataract was defined to include persons who had previous cataract surgery. Weighted kappa for inter-grader reliability was 0.82, 0.55 and 0.82 for cortical, nuclear and PSC cataract, respectively. We assessed age-specific prevalence using an interval of 5 years, so that participants within each age group were independent between the two surveys.
Age and gender distributions were similar between the two populations. The age-specific prevalence of cortical (23.8% in 1st, 23.7% in 2nd) and PSC cataract (6.3%, 6.0%) was similar. The prevalence of nuclear cataract increased slightly from 18.7% to 23.9%. After age standardization, the similar prevalence of cortical (23.8%, 23.5%) and PSC cataract (6.3%, 5.9%), and the increased prevalence of nuclear cataract (18.7%, 24.2%) remained.
In two surveys of two population-based samples with similar age and gender distributions, we found a relatively stable cortical and PSC cataract prevalence over a 6-year period. The increased prevalence of nuclear cataract deserves further study.
PMCID: PMC1524813  PMID: 16623958
7.  The influence of cortical, nuclear, subcortical posterior, and mixed cataract on the results of microperimetry 
Eye  2011;25(10):1317-1321.
Microperimetry is a useful instrument for evaluating sensitivity threshold due to retinal pathologies. The aim of the study is to assess the impact of different forms of cataract on microperimetry results.
In a prospective design, patients were recruited for cataract surgery at the Department of Ophthalmology, Medical University of Vienna. Exclusion criteria were any other ophthalmic disease except cataract, that is, macular pathology. Using the Lens Opacities Classification System III classification, patients were classified into four groups: nuclear, cortical, subcapsular posterior, and mixed cataract. Then patients underwent microperimetry: results were analyzed for magnitude of retinal sensitivity loss and correlated to the forms and density of the cataract.
Mean density of cataract was LOCS 3.2–3.5 in the four groups. Differences were not statistically significant. The best-corrected visual acuity (BCVA) was LogMAR 0.5±0.13 in nuclear, LogMAR 0.49±0.21 in cortical, and LogMAR 0.58±0.12 in mixed cataract patients, and significantly worse in patients with subcapsular posterior cataract (LogMAR 0.64±0.12). Microperimetry shows a mean sensitivity of 11.4–12.6 dB without significant group differences. The BCVA is correlated with microperimetry in patients with nuclear and cortical cataract. Density of cataract is highly correlated with microperimetry results in all groups.
The present study shows a good correlation of microperimetry results with the BCVA of patients with nuclear and cortical cataract. In patients with subcapsular posterior cataract, microperimetry results were better than estimated by BCVA. Density of cataract is highly correlated with macular sensitivity. A reduction of 1 dB in microperimetry per 1 posterior capsule opacification score increase can be estimated for these patients.
PMCID: PMC3194310  PMID: 21738231
microperimetry; retinal sensitivity; cataract; density of cataract; PCO score; best corrected visual acuity
8.  Effect of Cataract Type and Severity on Visual Acuity and Contrast Sensitivity 
To determine the effect of cataract type and severity in eyes with pure types of age-related lens opacities on visual acuity (VA) and contrast sensitivity in the presence and absence of glare conditions.
Sixty patients with senile cataracts aged 40 years or older with no other ocular pathologies were evaluated for VA and contrast sensitivity with and without glare. Lens opacities were classified according to the Lens Opacities Classification System (LOCS) III. VA was measured using the Snellen chart. Contrast sensitivity was measured with the Vector Vision CSV-1000E chart in the presence and absence of glare by calculating the area under log contrast sensitivity (log CS) function (AULCSF).
Cataracts were posterior subcapsular in 26 eyes, cortical in 19 eyes and nuclear in 15 eyes. VA significantly decreased with increasing cataract severity and there was significant loss of contrast sensitivity at all spatial frequencies with increasing cataract severity. AULCSF significantly decreased with increasing cataract severity in the presence and absence of glare conditions. Contrast sensitivity was significantly reduced at high spatial frequency (18 cpd) in cortical cataracts in the presence of glare in day light and at low spatial frequency (3 cpd) in night light.
Increased cataract severity is strongly associated with a decrease in both VA and AULCSF. Contrast sensitivity scores may offer additional information over standard VA tests in patients with early age-related cataracts.
PMCID: PMC3306069  PMID: 22454703
Contrast Sensitivity; Glare Sensitivity; Visual Acuity; Age-Related Cataract
9.  The need for cataract surgery: projections based on lens opacity, visual acuity, and personal concern 
AIM—To assess the projected needs for cataract surgery by lens opacity, visual acuity, and patient concern.
METHODS—Data were collected as part of the Melbourne Visual Impairment Project, a population based study of age related eye disease in a representative sample of Melbourne residents aged 40 and over. Participants were recruited by a household census and invited to attend a local screening centre. At the study sites, the following data were collected: presenting and best corrected visual acuity, visual fields, intraocular pressure, satisfaction with current vision, personal health history and habits, and a standardised eye examination and photography of the lens and fundus. Lens photographs were graded twice and adjudicated to document lens opacities. Cataract was defined as nuclear greater than or equal to standard 2, 4/16 or greater cortical opacity, or any posterior subcapsular opacities.
RESULTS—3271 (83% response) people living in their own homes were examined. The participants ranged in age from 40 to 98 years and 1511 (46.2%) were men. Previous cataract surgery had been performed in 107 (3.4%) of the participants. The overall prevalence of any type of cataract that had not been surgically corrected was 18%. If the presence of cataract as defined was considered the sole criterion for cataract surgery with no reference to visual acuity, there would be 309 cataract operations per 1000 people aged 40 and over (96 eyes of people who were not satisfied with their vision, 210 eyes of people who were satisfied with their vision, and three previous cataract operations). At a visual acuity criterion of less than 6/12 (the vision required to legally drive a car), 48 cataract operations per 1000 would occur and people would be twice as likely to report dissatisfaction with their vision.
CONCLUSIONS—Estimates of the need for cataract surgery vary dramatically by level of lens opacity, visual acuity, and patient concern. These data should be useful for the planning of health services.

 Keywords: cataract surgery; visual acuity; patient satisfaction
PMCID: PMC1722775  PMID: 10209437
10.  Pseudoexfoliation in south India 
The British Journal of Ophthalmology  2003;87(11):1321-1323.
Aim: To study the profile of pseudoexfoliation in a population based study.
Method: 2850 consecutive subjects aged 40 years or older from a population based survey in a rural area of southern India underwent complete ophthalmic evaluation including history, visual acuity testing, refraction, slit lamp examination, applanation tonometry, gonioscopy, and dilated examination of the lens (including LOCS II grading of cataract), fundus, and optic disc. Patients with pseudoexfoliation syndrome were identified and their data were analysed with respect to age, sex, intraocular pressure, gonioscopic grading, cataract, and optic neuropathy.
Results: 108 subjects had pseudoexfoliation syndrome (3.8 %). There was a significant increase in prevalence with age but no sex predilection. The condition was unilateral in 53 cases (49.1%) and bilateral in 55 cases (50.9%). 18 cases with pseudoexfoliation (16.7%) had high intraocular pressure (>21 mm Hg), 16 cases (14.8%) had occludable angles, and 14 cases (13%) had pseudoexfoliation glaucoma. There was a significantly higher prevalence of cataract among people with pseudoexfoliation compared to those without pseudoexfoliation (p = 0.014).
Conclusion: The prevalence of pseudoexfoliation syndrome in the rural population of south India was 3.8%. Raised intraocular pressure was seen in 16.7% of people with pseudoexfoliation and glaucoma was present in 13%.
PMCID: PMC1771878  PMID: 14609823
cataract; epidemiology; glaucoma; pseudoexfoliation
American journal of ophthalmology  2010;149(5):728-34.e1-2.
To estimate the 4-year incidence and progression of lens opacities.
Population-based longitudinal study.
4,658 adult Latinos from Los Angeles County, were examined at baseline and 4-year follow-up. Examination included assessment of lens opacities using the Lens Opacities Classification System II (LOCS II). Incidences of cortical, nuclear, and posterior subcapsular opacities (with LOCS II scores ≥2) were defined as opacity development in persons without that opacity at baseline. Single and mixed opacities were defined in persons without any opacity at baseline. Incidence of all lens changes included development of at least one opacity or cataract surgery among those without any opacity at baseline. 4-year progressions were defined as increase of ≥2 in LOCS II score.
The 4-year incidence of all lens opacities was 14.2%. 4-year incidence of cataract surgery was 1.48%. The incidences were 4.1% for cortical-only, 5.8% for nuclear-only, 0.5% for PSC-only, and 2.5% for mixed. The incidences for any opacities were 7.5% for cortical, 10.2% for nuclear, and 2.5% for PSC. Incidence increased with age (P<0.0001 for all). The progressions were 8.5% for cortical, 3.7% for nuclear, and 2.9% for PSC opacities.
Our Latino population had a higher incidence of nuclear than cortical opacities, but a greater progression of cortical than nuclear opacities. Incidence and progression of PSC was low. Additional understanding of the natural history and progression of various lens opacities will give us a better understanding of how and when to screen for, monitor, and treat cataracts.
PMCID: PMC2867354  PMID: 20181327
12.  Allopurinol use and the risk of cataract formation. 
Several reports have suggested an association between chronic allopurinol ingestion and cortical and subcapsular cataract formation. To examine this possibility we identified 51 allopurinol users and compared their lenses with those of 76 patients who did not use allopurinol. The existence of lens opacities and the level of visual acuity were assessed by review of medical records or by prospective ophthalmic examinations; in both phases of the study the examiners were blinded as to the patient's use or non-use of allopurinol. Three different outcomes were considered: formation of any cataract, formation of a posterior subcapsular cataract, and formation of a cataract contributing to a corrected visual acuity of 20/30 or worse. The risk ratio for the formation of any cataract was 1.3 (95% confidence interval: 0.8, 2.0), the risk ratio for the formation of a posterior subcapsular cataract was 0.9 (0.3, 2.0), and the risk ratio for the formation of a cataract contributing to a loss of visual acuity was 1.3 (0.6, 2.9). None of these risk ratios was changed appreciably after controlling for age, sex, hypertension, or diabetes. Thus, after a mean of 6.9 years of allopurinol use, we found no evidence to confirm that allopurinol users were at higher risk of acquiring cataracts.
PMCID: PMC1041685  PMID: 2706206
13.  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.
PMCID: PMC1771515  PMID: 12543745
cataract; cataract surgery; Blue Mountains Eye Study
14.  Risk factors associated with incident cataracts and cataract surgery in the Age Related Eye Disease Study (AREDS). AREDS Report Number 32 
Ophthalmology  2011;118(11):2113-2119.
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.
PMCID: PMC3178670  PMID: 21684602
15.  Cataract progression in India 
AIMS—The study was undertaken to test the feasibility of using the LOCS III cataract grading scale in the field and to determine the rate of cataract progression over a 1 year period of time.
METHODS—For 150 subjects between the ages of 33 and 55 who attended the refraction clinic at Aravind Eye Hospital in Madurai, India, lens abnormalities were graded at the slit lamp using the LOCS III scale. One year later, 99 of the subjects were re-evaluated by the same methodology to assess the amount of lens change.
RESULTS—Interrater reliability was high. A change of 0.5 or more in lens colour, cortical, nuclear, or posterior subcapsular cataract was observed in at least one eye of 54% of the subjects.
CONCLUSION—The LOCS III grading scale is a feasible method for measuring lens changes in the field with the slit lamp. Cataract progression in India is rapid enough to permit intervention studies to be performed with relatively small numbers of subjects over a short period of time (that is, 600 subjects for 2 years).

PMCID: PMC1722012  PMID: 9486033
16.  Cataract subtype risk factors identified from the Korea National Health and Nutrition Examination survey 2008–2010 
BMC Ophthalmology  2014;14:4.
To assess the socio-demographic and health-related risk factors associated with cataract subtypes in Korea.
A total of 11,591 participants (aged ≥40 years) were selected from the Korean National Health and Nutrition Examination Survey between 2008 and 2010. The Korean Ophthalmologic Society conducted detailed ophthalmologic examinations on these participants based on the Lens Opacity Classification System III. Risk factors for developing any type of cataract, and its subtypes (nuclear, cortical, posterior subcapsular and mixed), were identified from univariate and multivariate logistic regression analysis.
The prevalence of cataracts was 40.1% (95% CI, 37.8 − 42.3%) in participants over 40 years old. Older age, lower monthly household income, lower education, hypercholesterolemia, hypertension, and diabetes mellitus (DM) were independent risk factors for development of any cataract. Older age, lower monthly household income, lower education, hypercholesterolemia, and DM were independent risk factors for development of pure cortical cataracts. Older age, lower education, metabolic syndrome, and DM were independent risk factors for development of pure nuclear cataracts. Older age and DM were independent risk factors for development of pure posterior subcapsular cataracts. Older age, lower monthly household income, lower education, and DM were independent risk factors for development of mixed cataracts.
Although socioeconomic disparities are related to cataract development, this study identified several “modifiable” risk factors that may help to lower the incidence of cataracts and associated vision loss. Improved control of blood pressure, blood, glucose, and cholesterol may help to reduce the incidence of cataracts in the general Korean population.
PMCID: PMC3928645  PMID: 24410920
Cataract; Cataract subtype; Cataract risk factors; KNHANES
17.  Lens retrodots and vacuoles and their associations with the prevalence and incidence of age-related cataract 
Eye  2011;26(4):568-575.
To assess the prevalence of retrodots and vacuoles and their associations with the prevalence and long-term incidence of age-related cataract in an older Australian cohort.
Of 3654 baseline participants of the Blue Mountains Eye Study aged 49+ years (1992–1994), 2335 and 1952 were re-examined after 5 and 10 years, respectively. Lens photographs were graded for cataract, retrodots, and vacuoles. Eye-specific data were used to assess the associations between retrodots or vacuoles at baseline and the prevalence and 10-year incidence of nuclear, cortical, and posterior subcapsular (PSC) cataract and cataract surgery.
At baseline, retrodots were present in 142 persons (4%) and vacuoles in 1333 persons (40%). Prevalence of both lens features increased with increasing age (Pfor trend <0.0001). After adjusting for age and gender, vacuoles were associated with prevalent PSC cataract at baseline (odds ratio (OR), 1.60, 95% confidence interval (CI), 1.25–2.05). After adjusting for age, gender, smoking, hypertension, diabetes, education, and use of inhaled/oral steroids, baseline retrodots were associated with an increased incidence of cataract surgery (OR 2.90, 95% CI 1.71–4.91), while 3+ vacuoles at baseline were associated with an increased risk of PSC cataract (OR 3.56, 95% CI 2.13–5.95) and cataract surgery (OR 1.84, 95% CI 1.22–2.77).
Lens retrodots and vacuoles were found to be positively associated with 10-year incidence of cataract surgery, and vacuoles associated with PSC cataract, a finding suggestive of shared risk factors or pathogenesis between these two lens features and the development of PSC cataract.
PMCID: PMC3325569  PMID: 22193877
cataract; cataract surgery; lens opacities
18.  Prevalence of Early and Late Age-Related Macular Degeneration in India: The INDEYE Study 
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.
PMCID: PMC2868454  PMID: 19696177
19.  Relation of ocular trauma to cortical, nuclear, and posterior subcapsular cataracts: the Beaver Dam Eye Study 
Background: The consequences of minor ocular trauma in the general population are unclear. The relation of self reported ocular trauma to cortical, nuclear, and posterior subcapsular cataracts is described in a defined population.
Methods: Population based, cross sectional study involving all people aged 43 to 86 years, living in Beaver Dam, Wisconsin (n=4926). Ocular trauma was ascertained by interview and cataract was graded from lens photographs. The relation of ocular trauma to cortical, nuclear, and posterior subcapsular cataracts was examined.
Results: People with a history of ocular trauma were more likely to have cortical (odds ratio (OR): 1.5; 95% confidence interval (CI): 1.0 to 2.2) and posterior subcapsular (OR: 1.7; 95% CI: 1.0 to 3.1) cataracts, compared to people without a history of trauma. These associations were stronger for people with previous trauma caused by a blunt object (OR: 3.3; 95% CI: 1.6 to 6.9 for cortical cataract, and OR: 4.1; 95% CI: 1.5 to 10.8 for posterior subcapsular cataracts). However, in analyses comparing the frequencies of cataract between traumatised and non-traumatised eyes among people with unilateral ocular trauma, the ocular trauma association for cortical cataract was no longer present, although the association for posterior subcapsular cataract persisted (OR: 2.4; 95% CI: 0.8 to 7.8).
Conclusion: The data provide evidence of a possible association between self reported ocular trauma and posterior subcapsular cataract.
PMCID: PMC1770991  PMID: 11815338
20.  Risk of Cataract in Persons with Cytomegalovirus Retinitis and the Acquired Immune Deficiency Syndrome 
Ophthalmology  2012;119(11):2343-2350.
To evaluate cataract risk in eyes of patients with AIDS and cytomegalovirus (CMV) retinitis and to identify risk factors.
Prospective cohort study.
Patients with AIDS and CMV retinitis.
Patients 13 years of age and older were enrolled between 1998 and 2008. Demographic and clinical characteristics, slit-lamp biomicroscopy findings, and dilated ophthalmoscopy results were documented at quarterly visits. Cataract status was determined at the initial visit (prevalence) and at follow-up visits (incidence).
Main Outcome Measures
For cataract, a high grade of lens opacity by biomicroscopy to which best-corrected visual acuity worse than 20/40 was attributed. Eyes that had undergone cataract surgery before enrollment or between visits also were counted as having cataract.
Seven hundred twenty-nine eyes of 489 patients diagnosed with CMV retinitis were evaluated. Higher prevalence was observed for patients with bilateral versus unilateral CMV retinitis (adjusted odds ratio [aOR], 2.74; 95% confidence interval [CI], 1.76–4.26) and, among unilateral CMV retinitis cases, for eyes with retinitis versus without retinitis (15% vs. 1.4%; P<0.0001). The age-adjusted prevalence of cataract among CMV retinitis cases was higher than that in a population-based sample (P<0.0001). Cataract prevalence increased with age (aOR, 11.77; 95% CI, 2.28–60.65 for age ≥60 years vs. younger than 40 years) and longer duration of retinitis (aOR, 1.36; 95% CI, 1.20–1.54 per year). Among eyes with CMV retinitis initially free of cataract, the cataract incidence was 8.1%/eye-year (95% CI, 6.7%–10.0%). Prior retinal detachment was associated with higher cataract risk (if repaired with silicone oil: adjusted hazard ratio [aHR], 10.37; 95% CI, 6.51–16.52; otherwise: aHR, 2.90; 95% CI, 1.73–4.87). Large CMV retinitis lesions also were associated with higher risk of cataract (for involvement of 25–49% retinal area: aHR, 2.30; 95% CI, 1.51–3.50; for ≥50% involvement: aHR, 3.63; 95% CI, 2.18–6.04), each with respect to ≤24% involvement, as were anterior segment inflammation (aHR, 2.27; 95% CI, 1.59–3.25) and contralateral cataract (aHR, 2.52; 95% CI, 1.74–3.66).
Cytomegalovirus retinitis is associated with a high absolute and relative risk of cataract. Among several risk factors, large retinal lesion size and use of silicone oil in retinal detachment repair are potentially modifiable, albeit not in all cases. Cataract is likely to be an increasingly important cause of visual morbidity in this population.
PMCID: PMC3650486  PMID: 22853972
21.  Ocular Risk Factors for Age-related Macular Degeneration: The Los Angeles Latino Eye Study (LALES) 
American journal of ophthalmology  2010;149(5):735-740.
To assess the association of ocular factors and age-related macular degeneration (AMD) in Latinos.
Population-based, cross-sectional study of 6357 self-identified Latinos aged 40 years and older.
Ophthalmic examination included subjective refraction, measurement of axial length, evaluation of iris color, Lens Opacities Classification System II (LOCS II) grading of cataracts, and stereoscopic macular photographs for AMD lesions. Generalized estimating equation analysis incorporated data from both eyes to estimate odds ratios adjusted for covariates.
After controlling for confounders (age, gender and smoking), prior cataract surgery was associated with advanced AMD (OR: 2.8, 95% CI 1.0, 7.8), increased retinal pigment (OR: 1.6, 95% CI 1.0, 1.5) and retinal pigment epithelial depigmentation (OR: 2.2, 95% CI 1.1, 4.4). The presence of any lens opacity was associated with soft drusen (OR: 1.2; 95% CI 1.0, 1.5). Longer axial length (per mm) was associated with a decreased odds of soft drusen, increased retinal pigment, and geographic atrophy (GA) (ORs: 0.8 [95% CI 0.7, 0.9], 0.8 [95% CI 0.7, 0.9], 0.7 [95% CI 0.5, 0.9], respectively. Myopia was inversely associated with soft drusen (OR: 0.8; 95% CI 0.7, 1.0). Lighter colored irises were associated with GA (OR: 5.0; 95% CI 1.0, 25.3).
Cross-sectional associations of ocular factors such as cataract, cataract surgery, and refractive errors with early AMD lesions found in Latinos were consistent with those in whites. Additionally, prior cataract surgery was associated with advanced AMD.
PMCID: PMC2856762  PMID: 20138605
22.  A clinical study of radiation cataract formation in adult life following γ irradiation of the lens in early childhood 
AIMS—To analyse long term effects on the lens of radium irradiation during infancy.
METHODS—An infant cohort (n = 20, median age 6 months) treated for skin haemangioma with one or two radium-226 needles located at or within the orbital rim was examined 30 to 45 years after γ radiation. Detailed information about the treatment procedure was available for all cases. Subcapsular opacities were graded semiquantitatively according to a scale based on extent and density of the opacities.
RESULTS—A high prevalence of light to moderate posterior, subcapsular, and cortical cataract formation was found in the lenses on the treated side irradiated with a mean dose ranging from approximately 1 to 8 Gy. The cataract formation increased as a function of dose. The presence of subcapsular punctate opacities and vacuoles in the lenses on the untreated side receiving irradiation of an estimated dose varying around 0.1 Gy indicates a higher sensitivity than expected.
CONCLUSION—The growing lens during infancy is sensitive to radium irradiation at doses lower than those previously stated. The eye lens seems suitable for studies of effects of low dose radiation since damaged cells are retained in the lens for a lifetime.

PMCID: PMC1722161  PMID: 9215051
23.  Loss of contrast sensitivity in diabetic patients with LOCS II classified cataracts. 
Contrast sensitivity function (CSF) was assessed in a population of diabetics with moderate cataracts to determine if CSF testing provides more information about visual dysfunction than Snellen or Lotmar interferometric visual acuity. With the Lens Opacities Classification Systems Version II (LOCS II) of cataract classification it was possible to grade accurately the type and severity of cataract and nuclear brunescence. The presence of statistically significant relationships between increasing LOCS II classification (worsening cataract) and diminished function, even when the regression model was controlled for Snellen visual acuity, supports the thesis that CSF measurements do provide more information about cataract related visual loss than Snellen acuity alone. Statistically significant (p < or = 0.05) relationships existed between different morphological types of cataract, nuclear colour, and CSF at specific frequencies. The frequencies affected differed with cataract type or nuclear colour, and with distance and near CSF.
PMCID: PMC504413  PMID: 8435406
24.  The assessment of lens opacities in clinical practice: results of a national survey 
AIM—To investigate the examination of lens opacities in routine ophthalmic clinical practice.
METHOD—A questionnaire survey was mailed to 703 consultant ophthalmologists in the UK. The surgeons were asked which lens feature(s) they assessed in their clinics when deciding whether to offer cataract surgery.
RESULTS—489 replies were received. A broad range of lens opacities was assessed, with differences between surgeons for some opacities with high prevalences in the population, particularly cortical opacities. Many (74% of 467) surgeons assessed one or more lens opacities (anterior subcapsular cataract, vacuoles, water clefts, coronary flakes, focal dots, retrodots, fibre folds) which may be visually important but which have received relatively little attention by researchers.
CONCLUSIONS—Some classes of lens opacity which are traditionally measured by researchers may be ignored in clinical practice and opacities which are traditionally ignored by some researchers are regarded as clinically important by a substantial number of surgeons.

PMCID: PMC1723872  PMID: 11222338
25.  Prevalence of Cataract Type in Relation to Axial Length in Subjects with High Myopia and Emmetropia in an Indian Population 
American journal of ophthalmology  2007;145(1):176-181.
To compare the prevalence of different types and densities of age-related cataract in subjects with high myopia and emmetropia in the Indian urban clinic-based population.
Prospective observational clinic-based case-control study.
An observational case-control study of 800 healthy eyes was undertaken at Iladevi Cataract & IOL Research Center, Ahmedabad, India. Subjects with high myopia (axial length [AXL] ≥ 26.0 mm) (n = 400 eyes) and those with emmetropia (AXL 21.0–23.99 mm) were examined (n = 400 eyes). The type of cataract was categorized as: nuclear, cortical, and posterior subcapsular cataract (PSC). Nuclear density was measured based on the Emery and Little classification.
In all the age groups (40+ years old), nuclear cataract was more often encountered in subjects with high myopia (Odds ratio: 3.8, 95% CI 2.9 – 5.2, P <0.001); PSC and mixed cataracts were frequently encountered in subjects with emmetropia (P <0.001). Prevalence of nuclear cataract was higher in subjects with high myopia with increasing AXL when compared with other types of cataract (P <0.001). In all the age groups, the nuclear density was significantly higher than grade 3 in subjects with high myopia when compared to those with emmetropia (P < 0.001 in <70 years of age, P = 0.003 in >70 years of age).
Nuclear cataract was strongly associated with high axial myopia. The density of the cataract was higher in the high myopia group. No association was observed between PSC or cortical cataract and high axial myopia.
PMCID: PMC2199267  PMID: 17936714

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