Age-related Lens Opacities Research Articles

Glutathione and Glutaredoxin in Redox Regulation and Cell Signaling of the Lens.

The ocular lens has a very high content of the antioxidant glutathione (GSH) and the enzymes that can recycle its oxidized form, glutathione disulfide (GSSG), for further use. It can be synthesized in the lens and, in part, transported from the neighboring anterior aqueous humor and posterior vitreous body. GSH is known to protect the thiols of the structural lens crystallin proteins from oxidation by reactive oxygen species (ROS) so the lens can maintain its transparency for proper visual function. Age-related lens opacity or senile cataract is the major visual impairment in the general population, and its cause is closely associated with aging and a constant exposure to environmental oxidative stress, such as ultraviolet light and the metabolic end product, H2O2. The mechanism for senile cataractogenesis has been hypothesized as the results of oxidation-induced protein-thiol mixed disulfide formation, such as protein-S-S-glutathione and protein-S-S-cysteine mixed disulfides, which if not reduced in time, can change the protein conformation to allow cascading modifications of various kinds leading to protein–protein aggregation and insolubilization. The consequence of such changes in lens structural proteins is lens opacity. Besides GSH, the lens has several antioxidation defense enzymes that can repair oxidation damage. One of the specific redox regulating enzymes that has been recently identified is thioltransferase (glutaredoxin 1), which works in concert with GSH, to reduce the oxidative stress as well as to regulate thiol/disulfide redox balance by preventing protein-thiol mixed disulfide accumulation in the lens. This oxidation-resistant and inducible enzyme has multiple physiological functions. In addition to protecting structural proteins and metabolic enzymes, it is able to regulate the redox signaling of the cells during growth factor-stimulated cell proliferation and other cellular functions. This review article focuses on describing the redox regulating functions of GSH and the thioltransferase enzyme in the ocular lens.

Influence of lens opacities and cataract severity on quantitative fundus autofluorescence as a secondary outcome of a randomized clinical trial

The aim of this study is to investigate the impact of age-related lens opacities and advanced cataract, quantified by LOCS III grading, on quantitative autofluorescence (qAF) measurements in patients before and after cataract surgery. Images from a randomized controlled trial evaluating the impact of femtosecond-laser assisted cataract surgery (FLACS) on retinal thickness were analyzed post-hoc. One-hundred and twenty eyes from 60 consecutive patients with age-related cataract were included and assessed with qAF and optical coherence tomography (OCT) before, 1, 3 and 6 weeks after cataract surgery (randomized 1:1 to FLACS or phacoemulsification). LOCS III grading was performed before surgery. Pre- to post-surgical qAF values, as well as the impact of LOCS III gradings, surgery technique, gender, axial length and age on post-surgery qAF values was investigated using generalized linear mixed models. For this analysis, 106 eyes from 53 patients were usable. No difference in qAF was found between FLACS and phacoemulsification (p > 0.05) and results were pooled for the total cohort. Mean pre-surgical qAF was 89.45 ± 44.9 qAF units, with a significant mean increase of 178.4–191.6% after surgery (p < 0.001). No significant difference was found between the three follow-up visits after surgery (p > 0.05). Higher LOCS III cortical opacity quantifications were associated with a significantly greater increase in qAF after surgery (estimate: 98.56, p = 0.006) and nuclear opacities showed a trend toward an increased change (estimate: 48.8, p = 0.095). Considerable interactions were identified between baseline qAF and cortical opacities, nuclear opacities and posterior subcapsular opacities, as well as nuclear opacities and cortical opacities (p = 0.012, p = 0.064 and p = 0.069, respectively). Quantitative autofluorescence signals are significantly reconstituted after cataract surgery and LOCS III gradings are well associated with post-surgical qAF values. Careful consideration of age-related lens opacities is vital for the correct interpretation of qAF, especially in retinal diseases affecting the elderly.ClinicalTrials.gov Identifier: NCT03465124.

Did poor eyesight influence Goya's late works? Medicine and art history in search for an interpretation of Goya's late paintings.

The aim of this article is to 'determine' the scope of Goya's eyesight difficulties and assess the extent to which those difficulties might explain his style of painting in the last years of his life. We analyse the correspondence and late works of the Aragonese painter Francisco de Goya y Lucientes (1746-1828), who has been admired for his use of colour, his energetic loose brushstrokes, his disregard for details and his bold compositions, as well as for his different artistic styles throughout his life. The evolution of Goya's style of painting in his later works seems to have been the consequence of an eyesight condition, probably age-related cataracts at an advanced stage. The faded dark backgrounds, which become blurred with the silhouette of the person portrayed, could indicate a certain degree of eye strain. This can be traced in all these works, but is especially evident in the unfinished portrait of Pío de Molina (1827-1828), as well as in the portraits of Mariano Goya, the artist's grandson (1827), and Jacques Galos (1826). It has been considered that the late and isolated Goya's sight problems were a belated consequence of his severe illness of 1792. Nevertheless, in our opinion, this is a simplistic explanation and, given the painter's age, it is logical to presume that their cause could be age-related lens opacities. This article argues that medicine may become a subsidiary science to art history, as it can provide empirical evidence of the way painters' illnesses may have a strong impact on their artworks.

Folic Acid, Vitamin B6, and Vitamin B12 in Combination and Age-Related Cataract in a Randomized Trial of Women

ABSTRACTPurpose: To examine the incidence of cataract and cataract extraction in a trial of folic acid and vitamins B6 and B12.Methods: In a randomized, double-masked, placebo-controlled trial, 5442 female health professionals aged 40 years or older with preexisting cardiovascular disease (CVD) or three or more CVD risk factors were randomly assigned to receive a combination of folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and vitamin B12 (1 mg/day), or placebo. A total of 3925 of these women did not have a diagnosis of cataract at baseline and were included in this analysis. The primary endpoint was age-related cataract, defined as an incident age-related lens opacity, responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report confirmed by medical record review. Extraction of incident age-related cataract was a secondary endpoint of the trial.Results: During an average of 7.3 years of treatment and follow-up, 408 cataracts and 275 cataract extractions were documented. There were 215 cataracts in the combination treatment group and 193 in the placebo group (hazard ratio, HR, 1.10, 95% confidence interval, CI, 0.90–1.33; p = 0.36). For the secondary endpoint of cataract extraction, there were 155 in the combination treatment group and 120 in the placebo group (HR 1.28, 95% CI 1.01–1.63; p = 0.04).Conclusions: In this large-scale randomized trial of women at high risk of CVD, daily supplementation with a combination of folic acid, vitamin B6, and vitamin B12 had no significant effect on cataract, but may have increased the risk of cataract extraction.

The Association of Dietary Lutein plus Zeaxanthin and B Vitamins with Cataracts in the Age-Related Eye Disease Study: AREDS Report No. 37

To evaluate whether dietary intake of luteiin/zeaxanthin and B vitamins is associated with cataract prevalence and incidence.Clinic-based, baseline cross-sectional and prospective cohort study designs.Three thousand one hundred fifteen patients (6129 eyes) enrolled in the Age-Related Eye Disease Study 55 to 80 years of age followed up for mean of 9.6 years.Participants completed baseline food frequency questionnaires. Baseline and annual lens photographs were graded centrally. Multivariate models controlling for previously identified risk factors for cataracts tested for the association of cataracts with reported dietary intake, using the lowest quintile as reference.Cataract surgery, cataract status (type and severity) at baseline, and development of cataracts.At baseline, increased dietary riboflavin and B12 were associated inversely with nuclear and cortical lens opacities. In comparisons of persons with and without cataract, persons with the highest riboflavin intake versus those with the lowest intake had the following associations: mild nuclear cataract: odds ratio (OR), 0.78; 95% confidence interval (CI), 0.63-0.97; moderate nuclear cataract: OR, 0.62; 95% CI, 0.43-0.90; and mild cortical cataract: OR, 0.80; 95% CI, 0.65-0.99. For B12, the results were: mild nuclear cataract: OR, 0.78; 95% CI, 0.63-0.96; moderate nuclear cataract: OR, 0.62; 95% CI, 0.43-0.88; and mild cortical cataract: OR, 0.77; 95% CI, 0.63-0.95. Highest dietary B6 intake was associated with a decreased risk of moderate nuclear lens opacity developing compared with the lowest quintile (OR, 0.67; 95% CI, 0.45-0.99). Highest dietary intake levels of niacin and B12 were associated with a decreased risk of development of mild nuclear or mild cortical cataracts in participants not taking Centrum (Pfizer, New York, NY) multivitamins. For participants taking multivitamins during the study, the highest intake of dietary folate was associated with an increased risk of mild posterior subcapsular lens opacity development. No statistically significant associations were found between lutein plus zeaxanthin intake and presence at baseline or development of nuclear or cortical lens opacity outcomes.These findings are consistent with earlier studies suggesting that dietary intake of B vitamins may affect the occurrence of age-related lens opacities. Further investigations are warranted.

Enhanced age‐related cataract in copper‐zinc superoxide dismutase null mice

As the lens is constantly exposed to light and oxygen that generate harmful reactive oxygen species, the importance of the intracellular antioxidant enzyme copper-zinc superoxide dismutase for the protection against age-related cataract development was explored. The development of lens opacities and the lens oxidative status were studied in different age groups of mice lacking copper-zinc superoxide dismutase and in wild-type mice. The lens opacities were quantified from lens photographs using digital image analysis. Thereafter, the lenses were homogenized and analysed regarding their contents of reduced glutathione and protein carbonyls suggestive of protein oxidation. The 18-week-old mice of both genotypes had clear lenses. At 1 year of age, the copper-zinc superoxide dismutase null mice had developed cortical lens opacities, whereas the wild-type mice did not show equivalent changes until 2 years of age. The lens contents of glutathione decreased only in the 2-year-old wild-type mice, whereas the carbonyls increased over time without any differences between the two genotypes. This study indicates that the lack of copper-zinc superoxide dismutase may accelerate age-related lens opacity development and that intracellular superoxide-derived oxidative stress may be damaging to the lens during ageing. Participation of the anti-oxidant enzyme copper-zinc superoxide dismutase in the protection against age-related cataract was thus suggested.

Retrodots in the Lens in the Beaver Dam Eye Study Cohort

To determine the prevalence of retrodots in the lens and the association of these lesions to age-related cataract, and to assess their association with visual impairment and contrast sensitivity. Longitudinal epidemiologic study. The Beaver Dam Eye Study cohort. Eye examinations including grading of standard photographs of the lens and measures of visual function. Statistical associations of retrodots with nuclear, cortical, and posterior subcapsular cataracts and with incident visual impairment and impairment of contrast sensitivity. The prevalence of retrodots at the baseline examination increased with age from 1.68% in those 43 to 54 years of age to 31.20% in those ≥ 75 years of age. After controlling for age, there was no significant difference in the prevalence of retrodots between men and women. The odds ratio (OR) for visual impairment associated with retrodots was 2.22 (95% confidence interval [CI], 1.80-2.75) after controlling for age-related cataracts and other associated characteristics. The association with impaired contrast sensitivity was not significant. Retrodots were not significantly associated with incidence of any type of age-related cataract. The 15-year cumulative incidence of retrodots in right eyes increased with age from 9.3% in those 43 to 54 years of age to 21.1% in those ≥ 75 years of age. In addition to age, incidence of retrodots was independently associated with smoking (OR, 1.27; 95% CI, 1.04-1.56 for ever vs never smoking). Retrodots are frequently occurring age-related lens opacities that are associated with decreased vision independent of the presence of age-related cataract. Their incidence is associated with smoking. Further research to determine the underlying process leading to retrodots is necessary before efforts to develop preventions are undertaken.

Localization of low molecular weight crystallin peptides in the aging human lens using a MALDI mass spectrometry imaging approach

Low molecular weight (LMW) peptides, derived from the breakdown of the major eye lens proteins, the crystallins, accumulate in the human lens with age. These LMW peptides are associated with age-related lens opacity and cataract, with some shown to inhibit the chaperone activity of α-crystallin. However, the mechanism(s) giving rise to the production of these peptides, as well as their distribution within the lens, are not well understood. In this study, we have mapped the distribution of these crystallin-derived peptides present in human lenses of different ages using matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS). Our data showed that most of these LMW peptides emerge in the lens at early middle-age, with peptides greater than 1778 Da in mass being confined to the water insoluble fractions, and to a lesser extent the water soluble fractions of older lenses. MALDI-IMS analyses showed that four peptides, derived from αA-, αB- and γS-crystallins, were confined to the lens nuclear fibre cells upon emergence during early middle-age, but were present in both the cortex and nucleus of old lenses. In contrast, another major peptide, derived from the C-terminal breakdown of βA3-crystallin, was present in the cortical and nuclear regions of both young and old lenses. A comparison between age-matched cataractous and non-cataractous lenses showed no distinct differences in LMW peptide profiles, indicating that although cataract may be a potential consequence caused by the emergence of these peptides, it does not contribute directly to the peptide-generating process.

Distribution Pattern of Lens Opacity Among A Rural Population in South Western Nigeria

To determine prevalence of the morphological types of age-related lens opacity in Southwestern Nigeria as part of need assessment survey towards planning an eye health care service. Multistage cluster sampling was used in selecting a representative cross-sectional sample of persons 50 years of age or older among the residents of the rural wards in Akinyele Local Government Area in southwestern Nigeria. Lens opacity was graded using the World Health Organization cataract grading system. One thousand two-hundred persons were recruited for the survey and 1031 (85.9%) had grading of lens opacity. The mean age of the participants was 64.9 years and 51.1% were male. Five hundred and ninety persons had definite lens opacity (crude prevalence rate 57.2%; 95% Confidence interval [CI] 54.1-60.3) (standardized prevalence 47.0%; 95% confidence interval 46.7-47.3). The prevalence for participants aged 70 years and above (82.5%; 95% CI 78.2-86.3) was three times more than for participants aged 50-59 years (29.2%; 95% CI 24.2-34.6). Nuclear opacity was the most prevalent type of lens opacity (20.9%; 95% CI 18.4-23.5). Sixty percent of the grade 3 lens opacity was found among participants aged 70 years and above. This is the first population-based survey on prevalence of lens opacity subtype in this West Africa subregion. The prevalence of lens opacity in the rural Akinyele local government is high. Nuclear sclerosis was the most prevalent form among this rural population.

A Randomized, Double-Masked, Placebo-Controlled Clinical Trial of Multivitamin Supplementation for Age-Related Lens Opacities: Clinical Trial of Nutritional Supplements and Age-Related Cataract Report No. 3

A Randomized, Double-Masked, Placebo-Controlled Clinical Trial of Multivitamin Supplementation for Age-Related Lens Opacities: Clinical Trial of Nutritional Supplements and Age-Related Cataract Report No. 3

Distribution Pattern of Lens Opacity Among A Rural Population in South Western Nigeria

Purpose: To determine prevalence of the morphological types of age-related lens opacity in Southwestern Nigeria as part of need assessment survey towards planning an eye health care service. Method: Multistage cluster sampling was used in selecting a representative cross—sectional sample of persons 50 years of age or older among the residents of the rural wards in Akinyele Local Government Area in southwestern Nigeria. Lens opacity was graded using the World Health Organization cataract grading system. Results: One thousand two-hundred persons were recruited for the survey and 1031 (85.9%) had grading of lens opacity. The mean age of the participants was 64.9 years and 51.1% were male. Five hundred and ninety persons had definite lens opacity (crude prevalence rate 57.2%; 95% Confidence interval [CI] 54.1–60.3) (standardized prevalence 47.0%; 95% confidence interval 46.7–47.3). The prevalence for participants aged 70 years and above (82.5%; 95% CI 78.2–86.3) was three times more than for participants aged 50–59 years (29.2%; 95% CI 24.2–34.6). Nuclear opacity was the most prevalent type of lens opacity (20.9%; 95% CI 18.4–23.5). Sixty percent of the grade 3 lens opacity was found among participants aged 70 years and above. Conclusion: This is the first population-based survey on prevalence of lens opacity subtype in this West Africa subregion. The prevalence of lens opacity in the rural Akinyele local government is high. Nuclear sclerosis was the most prevalent form among this rural population.

A Randomized, Double-Masked, Placebo-Controlled Clinical Trial of Multivitamin Supplementation for Age-Related Lens Opacities: Clinical Trial of Nutritional Supplements and Age-Related Cataract Report No. 3

To evaluate the effect of a multivitamin/mineral supplement on development or progression of age-related lens opacities. Randomized, double-masked, single center, placebo-controlled clinical trial. One thousand twenty participants, 55 to 75 years old and with early or no cataract, were randomly assigned to a daily tablet of a multivitamin/mineral formulation or a placebo. Baseline and annual lens photographs were graded for severity of lens opacities according to a modification of the Age-Related Eye Disease Study system for classifying cataracts. The primary outcome was a prespecified increase from baseline in nuclear, cortical, or posterior subcapsular cataract (PSC) opacity grades or cataract surgery. Secondary outcomes included an increase in type-specific opacity grades, cataract surgery, and visual acuity (VA) loss from baseline > or =15 letters. Participants were observed for an average of 9.0+/-2.4 years. There was a decrease in total lens events in participants assigned to the multivitamin/mineral formulation compared with those assigned to the placebo (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.68-0.98; P = 0.03). Nuclear events were significantly less common (HR, 0.66; 95% CI, 0.50-0.88; P = 0.004) and PSC events significantly more common (HR, 2.00; 95% CI, 1.35-2.98; P<0.001) in participants taking the multivitamin/mineral formulation than in those assigned to the placebo. No statistically significant treatment effects were seen for cortical opacities, moderate VA loss, or cataract surgery. Lens events were less common in participants who took the multivitamin/mineral formulation, but treatment had opposite effects on the development or progression of nuclear and PSC opacities, the 2 most visually important opacity subtypes.

Dietary Carotenoids, Vitamins C and E, and Risk of Cataract in Women

To examine in prospective data the relation between dietary intake of carotenoids and vitamins C and E and the risk of cataract in women. Dietary intake was assessed at baseline in 39,876 female health professionals by using a detailed food frequency questionnaire. A total of 35,551 women provided detailed information on antioxidant nutrient intake from food and supplements and were free of a diagnosis of cataract. The main outcome measure was cataract, defined as an incident, age-related lens opacity responsible for a reduction in best-corrected visual acuity in the worse eye to 20/30 or worse based on self-report confirmed by medical record review. A total of 2031 cases of incident cataract were confirmed during a mean of 10 years of follow-up. Comparing women in the extreme quintiles, the multivariate relative risk of cataract was 0.82 (95% confidence interval, 0.71-0.95; test for trend, P = .04) for lutein/zeaxanthin and 0.86 (95% confidence interval, 0.74-1.00; test for trend, P = .03) for vitamin E from food and supplements. In these prospective observational data from a large cohort of female health professionals, higher dietary intakes of lutein/zeaxanthin and vitamin E from food and supplements were associated with significantly decreased risks of cataract.

Lens Opacities Associated with Performance-Based and Self-Assessed Visual Functions

To investigate the relationship of lens opacities to performance-based and self-assessed visual function in persons free of other ocular comorbidities. Cross-sectional cohort study. Beaver Dam Eye Study participants. Lens photographs were taken and graded by protocols for age-related lens opacities. During the study evaluation, best-corrected visual acuity, near vision, and contrast sensitivity (performance-based visual functions) were measured. Questions were asked about visual function in particular settings (self-assessed visual functions). After the exclusion of other ocular comorbidities, performance-based visual functions were associated significantly (P< or =0.001 for each association) with severity of lens opacities, including relatively early lens opacities. Self-assessed visual functions were associated less consistently with severity of lens opacities (P<0.02 for all). In age-stratified analyses, there were fewer significant associations of self-assessed visual functions with severity of lens opacities for persons younger than 65 years than for persons 65 or older. Lens opacities across the range of severities were associated with measurable decreases in visual functions; the associations, especially for self-assessed functions, tended to be greater at older ages. It is likely that successful measures to decrease the severity of lens opacities will have a greater impact on older persons.

Centrum Use and Progression of Age-Related Cataract in the Age-Related Eye Disease Study: A Propensity Score Approach. AREDS Report No. 21

To evaluate the effect of the multivitamin Centrum on the development and progression of age-related lens opacities. Clinic-based prospective cohort study. Four thousand five hundred ninety individuals with at least one natural lens and photographic follow-up (median, 6.3 years) were assessed for development or progression of lens opacities. Progression of "any" lens opacity or type-specific opacity was ascertained from lens photographs taken at baseline and at annual visits beginning at year 2. The Age-Related Eye Disease Study (AREDS) showed no statistically significant effect of a high-dose antioxidant formulation on progression of lens opacities. Centrum also was provided to approximately two thirds of the study participants. Because Centrum use was elective, a logistic regression model of baseline characteristics was used to generate a propensity score for Centrum use. Repeated-measures logistic regression, adjusted for propensity score and other covariates, was used to evaluate associations of Centrum use and lens opacity. Centrum use, adjusted for propensity score and other covariates, was associated with a reduction in "any" lens opacity progression (odds ratio [OR] = 0.84, 95% confidence interval [CI] = 0.72-0.98, P = 0.025). Results for individual lens opacity types suggested that Centrum use was protective for nuclear opacity events (OR = 0.75, 95% CI = 0.61-0.91, P = 0.004). Observational data from the AREDS and other studies suggest that use of a multivitamin may delay the progression of lens opacities. A National Eye Institute-sponsored clinical trial scheduled for completion in 2007 will provide additional data on Centrum use and cataract development.

Fruit and vegetable intake and the risk of cataract in women

Prospective data on cataract in relation to total fruit and vegetable intake are limited. We aimed to examine whether higher fruit and vegetable intake reduces the risk of cataract and cataract extraction in a large, prospective cohort of women. Fruit and vegetable intake was assessed at baseline in 1993 among 39 876 female health professionals with the use of a validated, semiquantitative food-frequency questionnaire. A total of 35 724 of these women were free of a diagnosis of cataract at baseline and were followed for incident cataract and cataract extraction. Cataract was defined as an incident, age-related lens opacity responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report confirmed by medical record review. Individuals, rather than eyes, were the unit of analysis. During an average of 10 y of follow-up, 2067 cataracts and 1315 cataract extractions were confirmed. Compared with women in the lowest quintile of fruit and vegetable intake, women with higher intakes had modest 10-15% reduced risks of cataract (P for trend < 0.05). For cataract extraction, no significant inverse trend was observed (P for trend = 0.12). These prospective data suggest that high intake of fruit and vegetables may have a modest protective effect on cataract.

Dietary fat intake and early age-related lens opacities

Dietary fat may affect lens cell membrane composition and function, which are related to age-related cataract. The objective of the study was to examine the association between long-term dietary fat intake and the prevalence of age-related nuclear, cortical, and posterior subcapsular lens opacities. Women (n = 440) aged 53-73 y from the Boston area without previously diagnosed cancer, diabetes, or cataract were selected from the Nurses' Health Study cohort. Intakes of total fat and selected fatty acids were calculated as the average of intake data from 5 food-frequency questionnaires collected between 1980 and the study eye examination (1993-1995). Nuclear opacity was defined as grade >/=2.5, cortical opacity as grade >/=1.0, and posterior subcapsular opacity as grade >/=0.5 according to the Lens Opacities Classification System III. There were significant positive associations between linoleic and linolenic acid intakes and the prevalence of nuclear opacity. The odds ratios for nuclear opacity in women with intakes in the highest quartile and women with intakes in the lowest quartile were 2.2 (95% CI: 1.1, 4.6; P for trend = 0.02) for linoleic acid and 2.2 (95% CI: 1.1, 4.5; P for trend = 0.05) for linolenic acid. There were no significant associations between intakes of any type of fat and either cortical or posterior subscapular opacity. High intake of the 18-carbon polyunsaturated fatty acids linoleic acid and linolenic acid may increase the risk of age-related nuclear opacity. Further study is needed to clarify the relation between dietary fat and cataract risk.

Is hyperleptinemia involved in the development of age-related lens opacities?

Is hyperleptinemia involved in the development of age-related lens opacities?

Nine-year incidence of lens opacities in the Barbados Eye Studies

Objective To provide 9-year cumulative incidence of age-related lens opacities in a predominantly black population. Design Population-based cohort study, after 9 years of follow-up (n = 2793; 81% participation). Main outcome measures Nine-year cumulative incidence and progression of lens opacities, by type, based on the Lens Opacities Classification System II at the slit lamp. Results Black participants had a higher 9-year incidence of overall lens changes than white participants (age- and gender-adjusted relative risk [RR], 1.8; 95% confidence interval [CI], 1.2–2.8), as well as of cortical opacities (RR, 3.2; 95% CI, 1.7–6.2). In black participants, incidence rates of any cortical and any nuclear opacities were 33.8% and 42.0%, respectively, and higher than for any posterior subcapsular (PSC) opacities (6.3%). The incidence increased with age for all 3 types, and women had a higher risk of cortical and nuclear opacities ( P<0.05). Single cortical opacities were the most frequent type to develop by the 9-year follow-up (23.2%), followed by nuclear-only opacities (17.1%) and mixed opacities (15.3%). Progression rates of pre-existing opacities were 22.0% for cortical, 17.8% for nuclear, and 25.8% for PSC opacities. Conclusions The 9-year follow-up of this cohort indicated a high incidence and progression of cortical and nuclear opacities, highlighting the public health importance of cataract in black populations.

Polymorphism of estrogen metabolism genes and cataract

Cataract is the leading cause of visual impairment in older adults in the world. Age-related lens opacities are common and are frequent causes of loss of vision. The incidence of cataract increases significantly with increasing age in women only. The onset coincides with estrogen deficiency that occurs after menopause. Hormone replacement therapy has proven beneficial to selected postmenopausal women. Estrogen effects on biological system are modulated via the estrogen receptors (ER) and/or estrogen metabolites. Although ER have been detected in ocular tissue, whether ER polymorphism is related to cataract is not known at present. The polymorphisms of estrogen metabolizing enzymes are also related to the serum concentration and activity of estrogen. Polymorphism such as cytochrome P450c17 (A2/A2), cytochrome P450c1A (vt/vt) will result in increased formation of catechol estrogen, while people with catechol- O-methyltransferase (COMT) polymorphism COMT (L/L) will have decreased metabolism of catechol estrogen and decreased level of methoxyestradiol. COMT was also involved in tamoxifen metabolism which may further decrease the activity of COMT in breast cancer patients treated with tamoxifen. It is known that a 4–7% increase in cataract was found in tamoxifen-treated breast cancer patients than non-user. The 7.0% COMT (L/L) genotype in general population corresponded well with the 4–7% of cataract formation in tamoxifen-treated breast cancer patients. Our hypothesis is that breast cancer patients with COMT (L/L) genotype may be at increased risk of cataract formation after tamoxifen treatment.