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1.  Prevalence of Cataract in an Older Population in India 
Ophthalmology  2011;118(2-19):272-278.e2.
Purpose
To describe the prevalence of cataract in older people in 2 areas of north and south India.
Design
Population-based, cross-sectional study.
Participants
Randomly sampled villages were enumerated to identify people aged ≥60 years. Of 7518 enumerated people, 78% participated in a hospital-based ophthalmic examination.
Methods
The examination included visual acuity measurement, dilatation, and anterior and posterior segment examination. Digital images of the lens were taken and graded by type and severity of opacity using the Lens Opacity Classification System III (LOCS III).
Main Outcome Measures
Age- and gender-standardized prevalence of cataract and 95% confidence intervals (CIs). We defined type of cataract based on the LOCS III grade in the worse eye of: ≥4 for nuclear cataract, ≥3 for cortical cataract, and ≥2 for posterior subcapsular cataract (PSC). Any unoperated cataract was based on these criteria or ungradable dense opacities. Any cataract was defined as any unoperated or operated cataract.
Results
The prevalence of unoperated cataract in people aged ≥60 was 58% in north India (95% CI, 56–60) and 53% (95% CI, 51–55) in south India (P = 0.01). Nuclear cataract was the most common type: 48% (95% CI, 46–50) in north India and 38% (95% CI, 37–40) in south India (P<0.0001); corresponding figures for PSC were 21% (95% CI, 20–23) and 17% (95% CI, 16–19; P = 0.003), respectively, and for cortical cataract 7.6% (95% CI, 7–9) and 10.2% (95% CI, 9–11; P<0.004). Bilateral aphakia/pseudophakia was slightly higher in the south (15.5%) than in the north (13.2%; P<0.03). The prevalence of any cataracts was similar in north (73.8%) and south India (71.8%). The prevalence of unoperated cataract increased with age and was higher in women than men (odds ratio [OR], 1.8). Aphakia/pseudophakia was also more common in women, either unilateral (OR, 1.2; P<0.02) or bilateral (OR, 1.3; P<0.002).
Conclusions
We found high rates of unoperated cataract in older people in north and south India. Posterior subcapsular cataract was more common than in western studies. Women had higher rates of cataract, which was not explained by differential access to surgery.
Financial Disclosure(s)
The authors have no proprietary or commercial interest in any of the materials discussed in this article.
doi:10.1016/j.ophtha.2010.05.020
PMCID: PMC3146699  PMID: 20801514
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.
doi:10.1136/bjo.2003.038380
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.
Objective
To examine the association between vitamin C and cataract in the Indian setting.
Design
Population-based cross-sectional analytic study.
Participants
A total of 5638 people aged ≥60 years.
Methods
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.
Results
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.
Conclusions
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.
doi:10.1016/j.ophtha.2011.03.016
PMCID: PMC3185206  PMID: 21705085
4.  Topical Ocular Hypotensive Medication and Lens Opacification: Evidence from the Ocular Hypertension Treatment Study (OHTS) 
American journal of ophthalmology  2006;142(5):800-810.
Purpose
To determine whether topical ocular hypotensive medication is associated with refractive changes, visual symptoms, decreased visual function, or increased lens opacification.
Design
Multicenter clinical trial
Methods
We compared the medication and observation groups of OHTS during 6.3 years of follow-up with regard to the rate of cataract and combined cataract/filtering surgery, and change from baseline in visual function, refraction and visual symptoms. A one-time assessment of lens opacification was done using the Lens Opacities Classification System III (LOCS III) grading system.
Results
An increased rate of cataract extraction and cataract/filtering surgery was found in the medication group (7.6%) compared to the observation group (5.6%) (HR 1.56; 95% CI 1.05–2.29). The medication and observation groups did not differ with regard to changes from baseline to June 2002 in Humphrey visual field mean deviation, Humphrey visual field foveal sensitivity, Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity, refraction and visual symptoms. For the medication and observation groups, LOCS III readings were similar for nuclear color, nuclear opalescence and cortical opacification. There was a borderline higher mean grade for posterior subcapsular opacity in the medication group (0.43 ± 0.6 SD) compared to the observation group (0.36 ± 0.6 SD) (p=0.07).
Conclusion
We noted an increased rate of cataract extraction and cataract/filtering surgery in the medication group as well as a borderline higher grade of posterior subcapsular opacification in the medication group on LOCS III readings. We found no evidence for a general effect of topical ocular hypotensive medication on lens opacification or visual function.
doi:10.1016/j.ajo.2006.06.052
PMCID: PMC1976472  PMID: 17056362
5.  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
6.  Association of EPHA2 polymorphisms and age-related cortical cataract in a Han Chinese population 
Molecular Vision  2011;17:1553-1558.
Purpose
The gene for Eph-receptor tyrosinekinase-type A2 (EPHA2) has been shown to be involved in the pathogenesis of age-related cataract (ARC). The aim of this study was to examine whether EPHA2 polymorphisms were associated with the susceptibility to age-related cortical cataract in a Han Chinese population.
Methods
Five single-nucleotide polymorphisms (SNPs)—rs3768293, rs3754334, rs7548209, rs707455, and rs477558—in the EPHA2 gene were genotyped in 422 Han Chinese patients with age-related cortical cataract and 317 age-, sex-, and ethnically matched healthy controls using a PCR restriction fragment length polymorphism (PCR-RFLP) assay. Data were analyzed by χ2 analysis.
Results
The results showed that the five analyzed polymorphisms in EPHA2 were in Hardy–Weinberg equilibrium both in the patients and in the controls. The frequency of the rs477558 AA genotype was significantly increased in ARC patients compared with controls (χ2=8.649, pc=0.045, odds ratio [OR] 1.555, 95% CI 1.158 to 2.089). The frequency of the rs477558 AG genotype was significantly decreased in ARC patients compared with controls (χ2=9.281, pc=0.030, OR 0.626, 95% CI 0.463 to 0.847). Significantly higher frequencies of the GG genotype and the G allele of rs7548209 were observed in ARC patients compared with controls (χ2=10.430, pc=0.015, OR 1.660, 95% CI 1.219 to 2.261 and χ2=8.537, pc=0.015, OR 1.486, 95% CI 1.138 to 1.940, respectively). On the other hand, significantly decreased frequencies of the rs7548209 CG genotype and the C allele were observed in ARC patients compared with controls (χ2=9.999, pc=0.030, OR 0.603, 95% CI 0.440 to 0.826 and χ2=8.537, pc=0.015, OR 0.673, 95% CI 0.515 to 0.879, respectively). There was no difference in the frequencies of the genotype and allele of the rs3768293, rs3754334, and rs707455 SNPs between the patients with ARC and the controls.
Conclusions
Our study suggests that both SNP rs477558 and SNP rs7548209 of EPHA2 are associated with age-related cortical cataract in a Han Chinese population.
PMCID: PMC3115745  PMID: 21686326
7.  Grading nuclear cataract: reproducibility and validity of a new method 
The British Journal of Ophthalmology  1999;83(10):1159-1163.
AIMS—To assess the reproducibility and validity of a new instrument for grading nuclear cataract—the laser slit lamp, by comparison with an established method of lens grading—the Lens Opacities Classification System III (LOCS III).
METHODS—62 volunteers (113 eyes) were examined on two occasions. At each visit, a video image of the anterior segment was captured with the laser slit lamp and stored digitally. A measure of lens opacity for each laser slit lamp image was calculated using image analysis software. Each lens was also photographed on both visits for LOCS III grading of nuclear colour and nuclear opalescence.
RESULTS—There was a linear increasing relation between the laser slit lamp measure of nuclear lens opacity and the LOCS III nuclear opalescence scores. The overall reproducibility of the laser slit lamp measurement was comparable with LOCS III (intraclass correlation coefficient of 95% (95% CI 92.9-96.5) for the laser slit lamp method; 97% (95% CI 95.6-97.9) for the LOCS III method). However, among healthy subjects, the reproducibility was lower (intraclass correlation for the laser slit lamp of 38.6% (95% CI 12.9-59.2) and 76.1% (95% CI 62.3-85.4) for LOCS III.
CONCLUSION—The laser slit lamp appears to give a valid measurement of nuclear cataract. The reproducibility of the instrument was high and similar to that of LOCS III. Modifications to the design would have to be made to improve its reproducibility among healthy subjects. It is simpler than other objective instruments, and could be useful in large scale studies of cataract.


PMCID: PMC1722807  PMID: 10502578
8.  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.
Purpose
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).
Design
Population-based, cross-sectional study.
Participants
6142 Latinos 40 years and older from 6 census tracts in Los Angeles County, California.
Methods
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.
Results
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).
Conclusions
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.
doi:10.1016/j.ophtha.2009.05.040
PMCID: PMC2787839  PMID: 19815276
9.  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
10.  Epigenetic Regulation of αA-crystallin in High Myopia-Induced Dark Nuclear Cataract 
PLoS ONE  2013;8(12):e81900.
Purpose
To assess the etiology of early-onset dark nucleus in high-myopic patients and its relationship with the epigenetic regulation of αA-crystallin (CRYAA).
Methods
We reviewed clinical data from patients who underwent cataract surgery at our center in 2012. Lens epithelial samples were collected during capsulorhexis, whereas young lens epithelium was donated. Cataract type and severity were graded according to the Lens Opacity Classification System III (LOCS III). DNA methylation was analyzed by pyrosequencing the CpG islands of the CRYAA promoter in the following groups: Age-Related Cataract (ARC) Nuclear Color (NC) 2–3; High-Myopic Cataract (HMC) NC2–3; ARC NC5–6; HMC NC5–6; and in young lenses graded NC1. We analyzed CRYAA expression by real-time polymerase chain reaction (PCR), reverse transcription PCR, and immunohistochemistry.
Results
The odds ratio of dark nucleus in high-myopic patients was 5.16 (95% confidence interval: 3.98–6.69; p<0.001). CpG islands in lens epithelial CRYAA promoter in the HMC NC5–6 Group exhibited the highest methylation of all the groups, but no statistically significant differences were evident between the HMC NC2–3 and ARC NC2–3 Groups. Likewise, CRYAA mRNA and protein levels in the HMC NC5–6 Group were significantly lower than the ARC NC5–6 Group and high-myopic controls.
Conclusions
High myopia is a risk factor for dark nucleus. Downregulation of CRYAA via the hypermethylation of CpG islands in its promoter could underlie the earlier onset of dark nucleus in high-myopic patients.
doi:10.1371/journal.pone.0081900
PMCID: PMC3849391  PMID: 24312600
11.  The Effect of Trabeculectomy on Cataract Formation or Progression 
Purpose
To determine the effect of trabeculectomy on cataract formation or progression in patients with chronic glaucoma.
Methods
This controlled clinical trial was performed on patients over 50 years of age with glaucoma who were referred to Imam Hossein Hospital, Tehran, Iran, from 2006 to 2007. Trabeculectomy was indicated only in one eye while the fellow eye had wellcontrolled intraocular pressure with medication(s). The fellow eyes served as controls. Lens opacity was evaluated using three criteria: visual acuity (VA), and Lens Opacification Classification System III (LOCS III) photographs and scores.
Results
Overall 82 eyes of 41 patients including 53.7% male and 46.3% female subjects with mean age of 62.5±9.3 (range 50–75) years were evaluated. Cataract progression in operated eyes was statistically significant according to VA (P=0.02), LOCS III photographs (P=0.05) and LOCS III scores (P=0.01). However, compared to fellow control eyes, cataract progression was significant according to VA (P=0.023) and LOCS III scores (P=0.057) but not based on LOCS III photographs. Mean VA reduction was 2 Snellen lines in operated eyes; there were 3 cases of cataract formation or progression without reduced VA.
Conclusion
Cataracts seem to progress following trabeculectomy; therefore it might be advisable to perform a combined procedure in older patients with moderate lens opacities.
PMCID: PMC3498554  PMID: 23198053
Trabeculectomy; Cataract
12.  Primary posterior capsular opacification in Indian rural population undergoing cataract surgery for hypermature senile cataract 
Aim
To find out the incidence of primary posterior capsular opacification (PCO) in rural patients with a hypermature senile cataract undergoing cataract surgery.
Settings
Tertiary eye care center in central India.
Design
Prospective, observational, noncomparative study.
Materials and methods
Two-hundred eyes of 200 patients presenting with a hypermature cataract underwent manual small incision cataract surgery. A single surgeon performed all surgeries under peribulbar anesthesia. After cortical clean-up, the capsular bag was inflated with viscoelastic. The presence or absence of opacity on the posterior lens capsule and location was noted. Postoperative follow-up was done for visual acuity and need for neodymium-doped yttrium aluminum garnet (ND:YAG) laser capsulotomy.
Results
Primary PCO occurred in 76 eyes (incidence of 38%). It was peripheral in 58 eyes (76.3%) and central in 18 eyes (23.7%). At 6 weeks postoperatively, best corrected visual acuity for eyes with central primary PCO (n = 18) was 0.2–0.3 logMAR and 0–0.2 logMAR for eyes with peripheral primary PCO (n = 58). Best corrected visual acuity at the 6- and 12-month follow-up was 0–0.2 logMAR in both groups. Fibrotic primary PCO was seen in four patients. No predilection for the development of primary PCO to a particular quadrant of posterior capsule was observed. At 1 year postoperatively, eleven (14.5%) patients required ND:YAG laser capsulotomy, six (7.90%) of whom underwent ND:YAG laser capsulotomy at the 6-month follow-up. Seven patients with central primary PCO and four patients with peripheral primary PCO required ND:YAG laser capsulotomy.
Conclusion
A high incidence of primary PCO was noted in rural patients with a hypermature senile cataract undergoing cataract surgery. No serious intraoperative complications were noted. Visual outcome at 1-year follow-up was satisfactory. Need for early ND:YAG laser posterior capsulotomy should be explained to these patients before cataract surgery. No post ND:YAG capsulotomy complications were noted in any patient.
doi:10.2147/OPTH.S49396
PMCID: PMC3745297  PMID: 23966767
posterior capsular opacification; hypermature cataract; manual small incision cataract surgery
13.  A Comparison of the Efficacy of Cataract Surgery Using Aqualase® with Phacoemulsification Using MicroFlow® System 
Purpose
To compare the outcomes after phacoemulsification performed with the AquaLase® and phacoemulsification in MicroFlow® system, including surgically induced astigmatism (SIA), corneal endothelial cell damage and postoperative recovery of visual acuity.
Methods
The cataracts of Lens Opacities Classification System, version III (LOCS III) nuclear grade below 2 were subjected in this study. Nineteen eyes underwent cataract operation using AquaLase® (Alcon Laboratories, Fort Worth, Texas, U.S.A.). A control group (19 eyes) used the MicroFlow® system (Millenium, Stortz, U.S.A.) and was selected by matching age, sex, systemic disease, corneal astigmatism and corneal endothelial cell density. All the surgeries were performed by the same operator. SIA, corneal endothelial cell loss, visual acuity, and corneal thickness were evaluated postoperatively.
Results
SIA in the group using AquaLase® was less than that of the group using MicroFlow® system (P=0.022) at 2 months postoperatively. Evaluation of corneal endothelial cell loss, recovery of visual acuity and corneal thickness found no statistically significant differences between the two groups.
Conclusions
Cataract surgery using AquaLase® induces less surgically induced astigmatism in mild to moderate cataracts.
doi:10.3341/kjo.2007.21.3.137
PMCID: PMC2629670  PMID: 17804917
AquaLase; Corneal endothelial cell damage; Surgically induced astigmatism
14.  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
15.  Effect of Cataract Type and Severity on Visual Acuity and Contrast Sensitivity 
Purpose
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.
Methods
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).
Results
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.
Conclusion
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
16.  Years of sunlight exposure and cataract: a case-control study in a Mediterranean population 
BMC Ophthalmology  2007;7:18.
Background
We aimed to investigate the relation between sunlight exposure and risk of cataract.
Methods
We carried out a frequency-matched case-control study of 343 cases and 334 controls attending an ophthalmology outpatient clinic at a primary health-care center in a small town near Valencia, Spain.
All cases were diagnosed as having a cataract in at least one eye based on the Lens Opacification Classification system (LOCS II). Controls had no opacities in either eye. All cases and controls were interviewed for information on outdoor exposure, "usual" diet, history of severe episodes of diarrhea illness, life-style factors and medical and socio-demographic variables. Blood antioxidant vitamin levels were also analyzed. We used logistic regression models to estimate sex and age-adjusted odds ratios (ORs) by quintiles of years of occupational outdoor exposure, adjusting for potential confounders such as smoking, alcohol consumption, serum antioxidants and education.
Results
No association was found between years of outdoor exposure and risk of cataract. However, exploratory analyses suggested a positive association between years of outdoor exposure at younger ages and risk of nuclear cataract later in life.
Conclusion
Our study does not support an association with cataract and sunlight exposure over adult life.
doi:10.1186/1471-2415-7-18
PMCID: PMC2234085  PMID: 18039367
17.  Torsional ultrasound mode versus combined torsional and conventional ultrasound mode phacoemulsification for eyes with hard cataract 
Purpose
To compare torsional versus combined torsional and conventional ultrasound modes in hard cataract surgery regarding ultrasound energy and time and effect on corneal endothelium.
Settings
Kasr El Aini hospital, Cairo University, and International Eye Hospital, Cairo, Egypt.
Methodology
Ninety-eight eyes of 63 patients were enrolled in this prospective comparative randomized masked clinical study. All eyes had nuclear cataracts of grades III and IV using the Lens Opacities Classification System III (LOCS III). Two groups were included, each having an equal number of eyes (49). The treatment for group A was combined torsional and conventional US mode phacoemulsification, and for group B torsional US mode phacoemulsification only. Pre- and post-operative assessments included best corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density (ECD) and central corneal thickness (CCT) were measured preoperatively, 1 day, 7 days, and 1 month postoperatively. All eyes were operated on using the Alcon Infiniti System (Alcon, Fort Worth, TX) with the quick chop technique. All eyes were implanted with AcrySof SA60AT (Alcon) intraocular lens (IOL). The main phaco outcome parameters included the mean ultrasound time (UST), the mean cumulative dissipated energy (CDE), and the percent of average torsional amplitude in position 3 (%TUSiP3).
Results
Improvement in BCVA was statistically significant in both groups (P < 0.001). Comparing UST and CDE for both groups revealed results favoring the pure torsional group (P = 0.002 and P < 0.001 for UST; P = 0.058 and P = 0.009 for CDE). As for %TUSiP3, readings were higher for the pure torsional group (P = 0.03 and P = 0.01). All changes of CCT, and ECD over time were found statistically significant using one-way ANOVA testing (P < 0.001).
Conclusion
Both modes are safe in hard cataract surgery, however the pure torsional mode showed less US energy used.
doi:10.2147/OPTH.S22879
PMCID: PMC3141862  PMID: 21792288
torsional; cumulative dissipated energy; cataract
18.  An Objective Scatter Index Based on Double-Pass Retinal Images of a Point Source to Classify Cataracts 
PLoS ONE  2011;6(2):e16823.
Purpose
To propose a new objective scatter index (OSI) based in the analysis of double-pass images of a point source to rank and classify cataract patients. This classification scheme is compared with a current subjective system.
Methods
We selected a population including a group of normal young eyes as control and patients diagnosed with cataract (grades NO2, NO3 and NO4) according to the Lens Opacities Classification System (LOCS III). For each eye, we recorded double-pass retinal images of a point source. In each patient, we determined an objective scatter index (OSI) as the ratio of the intensity at an eccentric location in the image and the central part. This index provides information on the relevant forward scatter affecting vision. Since the double-pass retinal images are affected by both ocular aberrations and intraocular scattering, an analysis was performed to show the ranges of contributions of aberrations to the OSI.
Results
We used the OSI values to classify each eye according to the degree of scatter. The young normal eyes of the control group had OSI values below 1, while the OSI for subjects in LOCS grade II were around 1 to 2. The use of the objective index showed some of the weakness of subjective classification schemes. In particular, several subjects initially classified independently as grade NO2 or NO3 had similar OSI values, and in some cases even higher than subjects classified as grade NO4. A new classification scheme based in OSI is proposed.
Conclusions
We introduced an objective index based in the analysis of double-pass retinal images to classify cataract patients. The method is robust and fully based in objective measurements; i.e., not depending on subjective decisions. This procedure could be used in combination with standard current methods to improve cataract patient surgery scheduling.
doi:10.1371/journal.pone.0016823
PMCID: PMC3033912  PMID: 21326868
19.  The influence of cortical, nuclear, subcortical posterior, and mixed cataract on the results of microperimetry 
Eye  2011;25(10):1317-1321.
Purpose
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.
Methods
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.
Results
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.
Conclusion
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.
doi:10.1038/eye.2011.156
PMCID: PMC3194310  PMID: 21738231
microperimetry; retinal sensitivity; cataract; density of cataract; PCO score; best corrected visual acuity
20.  Screening and structural evaluation of deleterious Non-Synonymous SNPs of ePHA2 gene involved in susceptibility to cataract formation 
Bioinformation  2012;8(12):562-567.
Age-related cataract is clinically and genetically heterogeneous disorder affecting the ocular lens, and the leading cause of vision loss and blindness worldwide. Here we screened nonsynonymous single nucleotide polymorphisms (nsSNPs) of a novel gene, EPHA2 responsible for age related cataracts. The SNPs were retrieved from dbSNP. Using I-Mutant, protein stability change was calculated. The potentially functional nsSNPs and their effect on protein was predicted by PolyPhen and SIFT respectively. FASTSNP was used for functional analysis and estimation of risk score. The functional impact on the EPHA2 protein was evaluated by using SWISSPDB viewer and NOMAD-Ref server. Our analysis revealed 16 SNPs as nonsynonymous out of which 6 nsSNPs, namely rs11543934, rs2291806, rs1058371, rs1058370, rs79100278 and rs113882203 were found to be least stable by I-Mutant 2.0 with DDG value of > −1.0. nsSNPs, namely rs35903225, rs2291806, rs1058372, rs1058370, rs79100278 and rs113882203 showed a highly deleterious tolerance index score of 0.00 by SIFT server. Four nsSNPs namely rs11543934, rs2291806, rs1058370 and rs113882203 were found to be probably damaging with PSIC score of ≥ 2. 0 by Polyp hen server. Three nsSNPs namely, rs11543934, rs2291806 and rs1058370 were found to be highly polymorphic with a risk score of 3-4 with a possible effect of Non-conservative change and splicing regulation by FASTSNP. The total energy and RMSD value was higher for the mutant-type structure compared to the native type structure. We concluded that the nsSNP namely rs2291806 as the potential functional polymorphic that is likely to have functional impact on the EPHA2 gene.
doi:10.6026/97320630008562
PMCID: PMC3398778  PMID: 22829731
Computational analysis; single nucleotide polymorphism; EPHA2; cataract
21.  FOUR-YEAR INCIDENCE AND PROGRESSION OF LENS OPACITIES: THE LOS ANGELES LATINO EYE STUDY 
American journal of ophthalmology  2010;149(5):728-34.e1-2.
Purpose
To estimate the 4-year incidence and progression of lens opacities.
Design
Population-based longitudinal study.
Methods
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.
Results
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.
Conclusions
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.
doi:10.1016/j.ajo.2009.11.012
PMCID: PMC2867354  PMID: 20181327
22.  Polymorphisms in two DNA repair genes (XPD and XRCC1) – association with age related cataracts 
Molecular Vision  2011;17:127-133.
Purpose
Age related cataract is the leading cause of blindness in the world today. The association between DNA damage to the lens epithelium and the development of lens opacities has been reported in many studies. Polymorphisms of DNA repair enzymes may affect repair efficiency and thereby lead to the development of age related cataract.
Methods
In this study, we aimed to determine the frequency of polymorphisms in two DNA repair enzyme genes, xeroderma pigmentosum complementation group (XPD) codon 312 and X-ray complementing group1 (XRCC1) codon 399, in a sample of 208 cataract patients (69 with cortical, 69 with nuclear and 70 with posterior sub capsular) and 151 sex and age matched healthy controls. XPD genotype was determined by Amplification Refractory Mutation System (ARMS) while XRCC1 was genotyped using the PCR-RFLP method.
Results
There was a significant difference between frequencies for XPD-312 Asn/Asn genotype in cataract patients (21.6%) and healthy controls (13.2%; p=0.03, OR=1.97, 95% CI=1.06–3.63). Considering the types of cataract, XPD-312 Asn/Asn genotype was found to be significantly different in patients with cortical (29%) type in comparison to controls (13.2%; p=0.03, OR=2.39, 95% CI=1.11–5.12). No statistically significant difference was found for the genotypic and allelic distributions of the polymorphism in XRCC1. The MDR interaction analysis revealed weak synergism between the markers XPD-Asp312Asn and XRCC1-Arg399Gln contributing to cataract. It also showed that the AA genotype of XPD-Asp312Asn polymorphism when present in combination with the GA genotype of XRCC1-Arg399Gln had a fivefold and with AA had a fourfold risk for developing cataract.
Conclusions
The present study suggests that a polymorphism in XPD codon 312 may be associated with the development of maturity onset cataract. This is the first report on the association of XPD Asp312Asn polymorphism with maturity onset cataract.
PMCID: PMC3021570  PMID: 21245954
23.  Comparison of age-specific cataract prevalence in two population-based surveys 6 years apart 
BMC Ophthalmology  2006;6:17.
Background
In this study, we aimed to compare age-specific cortical, nuclear and posterior subcapsular (PSC) cataract prevalence in two surveys 6 years apart.
Methods
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.
Results
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.
Conclusion
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.
doi:10.1186/1471-2415-6-17
PMCID: PMC1524813  PMID: 16623958
24.  Study of nuclear cataract progression using the National Eye Institute Scheimpflug system. 
AIMS--A study was conducted to determine the capability of the recently developed National Eye Institute (NEI) Scheimpflug cataract imaging system in detecting changes in the nuclear region of the lens over a 1 year period. METHODS--Twenty five eyes with pure nuclear cataracts with mean nuclear densities < or = 0.30 optical density units (ODU) as well as 30 normal control eyes were each examined at baseline and 12 months later. Computerised densitometry using the NEI Scheimpflug cataract imaging system was performed. Clinical grading of the lenses was also done using the Lens Opacities Classification System II (LOCS II). For densitometry, a change of plus or minus 0.023 ODU (the 99% range) in mean density in the nuclear area was considered a progression or regression at 1 year. RESULTS--Using the Scheimpflug densitometry, 14 of the 25 cataractous eyes showed significant progression at 1 year. In the normal control group, only three of the 30 eyes showed significant progression. In contrast, using the LOCS II clinical grading, only two of the 25 cataractous eyes showed a one step increase, two of the 30 controls progressed at 1 year, and none regressed. There was no significant difference in visual acuity. CONCLUSION--This study suggests the value of the NEI Scheimpflug cataract imaging system in detecting nuclear change within 1 year. However, clinically significant changes may require longer follow up periods. These data will be useful in planning future longitudinal studies of nuclear cataracts, such as for clinical trials of anticataract drugs.
Images
PMCID: PMC505159  PMID: 7626567
25.  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.
Objective
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).
Design
Clinic-based prospective cohort study.
Participants
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.
Methods
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.
Results
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.
Conclusions
Our findings are largely consistent with the results of previous studies, providing further evidence for possible modifiable risk factors for age-related cataract.
doi:10.1016/j.ophtha.2011.03.032
PMCID: PMC3178670  PMID: 21684602

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