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Biomedical subjects

Ronald Klein

Publications and source records attributed to Ronald Klein.

At least 55 records · Page 3Linked to original sources
PubMed2006

Comparability of cup and disk diameters measured from nonstereoscopic digital and stereoscopic film images.

PURPOSE: To compare gradings of optic disk and cup diameters from stereoscopic film and nonstereoscopic digital images. DESIGN: Comparison of techniques. METHODS: setting: CLINIC-BASED. PATIENT POPULATION: Right eyes of 62 adults. observation procedures: Images of the disk were taken through pharmacologically dilated pupils with a 45-degree digital camera (6.3 megapixels) and with a stereoscopic 30-degree film camera. Measurements were taken for vertical diameters of optic disks and cups. MAIN OUTCOME MEASURES: Agreement of disk and cup measurements and cup to disk ratios. RESULTS: Optic disks and cups were slightly smaller when graded from the stereoscopic film images. Cup-to-disk ratios were similar. Correlations between film and digital images measurements were high. CONCLUSIONS: Measurements taken from nonstereoscopic digital images through a dilated pupil were similar to those taken from stereoscopic film images. Lack of stereoscopic effect may lead to small differences in measuring the optic disk and cup diameters. Nonstereoscopic digital imaging may be useful in epidemiologic studies when measures of optic cups and disks are needed.

Humans↗
PubMed2006

Apolipoprotein E gene polymorphisms are not associated with diabetic retinopathy: the atherosclerosis risk in communities study.

PURPOSE: Polymorphism of the apolipoprotein E (APOE) gene has been associated with dyslipidemia and cardiovascular disease. This study examines the association of APOE polymorphisms and diabetic retinopathy. DESIGN: Population-based cross-sectional study. METHODS: We studied 1,398 people aged 49 to 73 years with diabetes selected from four United States communities. We performed retinal photography on one randomly selected eye and graded for the presence and severity of diabetic retinopathy using a modification of the Early Treatment Diabetic Retinopathy Study scale. We performed genotyping of common polymorphic APOE alleles using polymerase chain reaction on genomic DNA from venous blood leukocytes. RESULTS: The prevalence of diabetic retinopathy and hard exudates was 15.0% and 5.3% in Caucasians (n = 935), and 24.6% and 9.7% in African-Americans (n = 463), with type 2 diabetes. APOE gene polymorphisms were not associated with diabetic retinopathy in either Caucasians or African-Americans. In African-Americans, the 2/4 genotype (n = 6) was associated with increased prevalence of hard exudates (odds ratio [OR] 4.10, 95% confidence interval [CI] 1.30 to 12.90), as was the 2/3 genotype (n = 9, OR 2.64, 95% CI 1.01 to 6.95). No association between APOE genotypes and hard exudates was found in Caucasians. CONCLUSIONS: These data suggest that APOE gene polymorphisms are not associated with diabetic retinopathy in either Caucasians or African-Americans with type 2 diabetes.

Aged↗
PubMed2006

Comparison of retinal vessel measurements in digital vs film images.

PURPOSE: To compare central retinal artery equivalents (CRAE) and central retinal vein equivalents (CRVE) from vessels measured from images captured with a digital camera and digitized images taken with a film camera. DESIGN: Comparison of techniques. METHODS SETTING: Clinic. PATIENTS: A total of 75 eyes of 48 adults. OBSERVATION PROCEDURES: Gradings of retinal vessel diameters from images produced by using two photographic techniques: directly from a 45 degrees digital camera and digitized by scanning from a 30 degrees film-based camera. MAIN OUTCOME MEASURE: Differences in CRAE and CRVE from two types of images. RESULTS: CRAE and CRVE were highly comparable between the two techniques with correlation coefficients of 0.88 and 0.87, respectively. CONCLUSION: Estimates of CRAE and CRVE from measurements taken from digitally captured and digitized film-based images were highly comparable. It is likely that inferences about factors associated with retinal vessel diameters will be unbiased by the method of imaging.

Adult↗
PubMed2006

Changes in visual acuity in a population over a 15-year period: the Beaver Dam Eye Study.

PURPOSE: To describe the change in visual acuity in a 15-year period. DESIGN: Population-based study. METHODS: setting: Beaver Dam, Wisconsin. participants: 4068 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, and with follow-up examinations every five years thereafter. observation procedures: Best-corrected visual acuity after refraction, assessed by a modification of the ETDRS protocol. main outcome measure: Doubling of the visual angle; incidence of visual impairment. RESULTS: Eight percent of the population developed impaired vision (20/40 or worse), 0.8% developed severe visual impairment (20/200 or worse), 7% had doubling of the visual angle, and 2% had improved vision. People 75 years of age or older at baseline were more likely to develop impaired vision (odds ratio [OR] 12.8, 95% confidence interval [CI] 9.6 to 17.1, P < .001), doubling of the visual angle (OR 7.8, 95% CI 5.6 to 10.7, P < .001), and severe visual impairment (OR 20.6, 95% CI 9.5 to 44.8, P<0.001) compared with people younger than 75 years of age. CONCLUSIONS: These data provide population-based estimates of the cumulative 15-year incidence of loss of vision over a wide spectrum of ages. In people 75 years of age or older the cumulative incidence of visual impairment accounting for the competing risk of death is 25%, of which 4% is severe, indicating a public health problem of considerable proportions as the US population in this age is expected to increase by 55% from 18 million in the year 2005 to 28 million by the year 2025.

Adult↗
PubMed2006

Prevalence of age-related macular degeneration in 4 racial/ethnic groups in the multi-ethnic study of atherosclerosis.

OBJECTIVE: To describe the prevalence of age-related macular degeneration (AMD) in 4 racial/ethnic groups (white, black, Hispanic, and Chinese) that participated in the second examination of the Multi-ethnic Study of Atherosclerosis (MESA). DESIGN: Prospective cohort study. PARTICIPANTS: Six thousand one hundred seventy-six 45- to 85-year-old subjects selected from 6 United States communities. METHODS: Fundus images were taken using a 45 degrees digital camera through dark-adapted pupils and were graded for drusen size, type, area, increased retinal pigment, retinal pigment epithelial depigmentation, neovascular lesions, and geographic atrophy using the modified Wisconsin Age-Related Maculopathy Grading System. MAIN OUTCOME MEASURE: Age-related macular degeneration. RESULTS: Prevalences of AMD were 2.4% (black), 4.2% (Hispanic), 4.6% (Chinese), to 5.4% (white) (P<0.001 for any differences among groups). The highest prevalence of any AMD occurred in those 75 to 84 years old, varying from 7.4% in blacks to 15.8% in whites and Chinese (P = 0.03). Estimated prevalences of late AMD were 0.3% (black), 0.2% (Hispanic), 0.6% (white), and 1.0% (Chinese). These differences were marginally significant (age and gender adjusted, P = 0.08). The frequency of exudative AMD was highest in Chinese (age- and gender-adjusted odds ratio, 4.30; 95% confidence interval, 1.30-14.27) compared with whites. Differences in age, gender, pupil size, body mass index, smoking, alcohol drinking history, diabetes, and hypertension status did not explain the variability among the 4 racial/ethnic groups. CONCLUSIONS: Low prevalences of AMD were found in the MESA cohort in all groups. A lower prevalence of AMD was found in blacks compared with whites. The higher prevalence of exudative AMD in Chinese needs further study.

Age Distribution↗
PubMed2006

Lens opacities associated with performance-based and self-assessed visual functions.

OBJECTIVE: To investigate the relationship of lens opacities to performance-based and self-assessed visual function in persons free of other ocular comorbidities. DESIGN: Cross-sectional cohort study. PARTICIPANTS: Beaver Dam Eye Study participants. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.

Aged↗
PubMed2006

Causes of low vision and blindness in adult Latinos: the Los Angeles Latino Eye Study.

OBJECTIVE: To describe the causes of low vision and blindness in a population-based sample of adult Latinos. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Six thousand three hundred fifty-seven Latinos 40 years and older from 6 census tracts in Los Angeles, California. METHODS: Participants underwent a detailed ophthalmologic examination including measurement of best-corrected distance visual acuity using a standard Early Treatment for Diabetic Retinopathy Study protocol, a complete anterior and posterior segment evaluation by an ophthalmologist, Humphrey Visual field testing, and optic disc and fundus photography. Consensus diagnosis of independent investigators reviewing all patient data was used to determine the major causes of low vision and blindness in adult Latinos. MAIN OUTCOME MEASURES: Primary causes of vision loss in persons with low vision and blindness. RESULTS: The leading causes of low vision were cataract, diabetic retinopathy, and age-related macular degeneration, together accounting for approximately 82% of all persons with low vision. The primary causes of blindness were age-related macular degeneration, diabetic retinopathy, and myopic degeneration, accounting for 63% of the cases of blindness. CONCLUSIONS: Many of the leading causes of low vision and blindness in adult Latinos are potentially preventable and treatable diseases. Given the projected aging and growth in the Latino population, consideration needs to be given to the development of targeted early detection and treatment programs.

Adult↗
PubMed2006

Retinal vessel diameters and obesity: a population-based study in older persons.

OBJECTIVE: Obesity is linked with large vessel atherosclerosis and diabetes. Its association with microvascular changes is less clear. We investigated the associations among retinal vessel diameters, vessel wall signs, and BMI in an older population. RESEARCH METHODS AND PROCEDURES: Retinal photographs were taken on 3654 persons aged 49+ years at baseline of the Blue Mountains Eye Study in Australia. Arteriolar and venular diameters were measured from digitized retinal photographs of the right eyes. BMI was calculated as weight (kilograms)/height (meters2). Incident obesity was defined in persons with BMI < or = 30 at baseline but > 30 after 5 years. A significant weight gain was defined as an increase in BMI of 2+ SDs (4 or more units) over the 5-year period. RESULTS: At baseline, mean BMI was 26.1 (+/-4.6) in this population. At 5-year examinations, 177 (10.0% of 1773 at risk) developed incident obesity, and 136 (6.4% of 2143 at risk) had significant weight gain. After adjusting for age, sex, smoking, triglyceride levels, and mean arterial blood pressure, persons with wider retinal venular diameters had a higher risk of incident obesity (odds ratio, 1.8; 95% confidence interval, 1.0 to 3.1, comparing the highest with lowest venular diameter quintiles) and significant weight gain (odds ratio, 1.7; 95% confidence interval, 0.9 to 3.2). These associations were attenuated with further adjustment for baseline BMI. Arteriolar diameter was unrelated with baseline or change in BMI. DISCUSSION: Wider retinal venular diameter is associated with risk of obesity, independent of hypertension, diabetes, lipids, and cigarette smoking. These data may support a role for impaired microvascular function in the course of weight gain.

Aged↗
PubMed2006

Effect of short-term, high-dose retinol on dark adaptation in aging and early age-related maculopathy.

PURPOSE: To examine the effect of a short course of high-dose retinol (preformed vitamin A) on dark adaptation in older adults with normal retinal health or early age-related maculopathy (ARM). METHODS: The study design was a randomized, double-masked, placebo-controlled experiment. Adults > or = 50 years of age whose fundus photographs for the eye to be tested psychophysically fell within steps 1 to 9 of the Age-Related Eye Disease Study (AREDS) Grading System were randomly assigned to a 30-day course of 50,000 IU oral retinol or a placebo. At baseline and 30-day follow-up, dark adaptation was tested and the Low Luminance Questionnaire (LLQ), an instrument for assessing difficulty with vision in reduced lighting, was administered. Primary outcomes of interest were rod- and cone-mediated parameters of dark adaptation, with scores on the LLQ's six subscales as secondary outcomes. RESULTS: The sample consisted of 104 participants with 52 each in the intervention and placebo groups. There were no group differences in baseline variables. At 30-days, the dark-adaptation parameters of cone time-constant, cone threshold, rod-cone break, and rod threshold did not differ. The retinol intervention group had significantly larger (i.e., steeper) rod slopes, indicating faster sensitivity recovery, than did the placebo group (P = 0.0419). There were no group differences in scores on the LLQ subscales driving, extreme lighting, emotional distress, general lighting, or peripheral vision. The retinol group had a higher score by five points on the mobility subscale compared with the placebo group (P = 0.0141). Those who had the most self-reported change on the mobility subscale at day 30 were more likely to have greater change in the speed of dark adaptation, as indicated by the rod slope parameter (r = 0.24, P = 0.0141). CONCLUSIONS: A short-term, high-dose course of retinol increased the rate of rod-mediated dark adaptation in older adults who were in the early phases of ARM or were exhibiting normal retinal aging. These results are consistent with the hypothesis that depositions and other structural changes in the retinal pigment epithelium and Bruch's membrane in aging and early ARM cause a localized retinoid deficiency.

Aged↗
PubMed2006

Retinal vascular caliber, cardiovascular risk factors, and inflammation: the multi-ethnic study of atherosclerosis (MESA).

PURPOSE: To describe the relationship of retinal arteriolar and venular caliber with cardiovascular risk factors, including inflammatory biomarkers, in a multiethnic population of whites, blacks, Hispanics, and Chinese. METHODS: A cross-sectional study comprising 5979 persons aged 45 to 84 years residing in six U.S. communities. Retinal vascular caliber was measured and summarized from digital retinal photographs. Standard cardiovascular risk factors, including biomarkers of inflammation (e.g., high-sensitivity C-reactive protein [hsCRP], interleukin [IL]-6, and plasma fibrinogen) and endothelial dysfunction (e.g., soluble intercellular adhesion molecule [sICAM]-1 [, plasminogen activator inhibitor [PAI]-1) were assessed. RESULTS: Mean retinal arteriolar caliber was 144.1+/-14.4 (SD) microm, and venular caliber 214.0+/-22.2 microm. In models controlling for age, gender, race-ethnicity, and center, smaller retinal arteriolar caliber was related to higher systolic and diastolic blood pressure, hypertension status, current alcohol consumption, greater body mass index, and higher levels of total homocysteine; larger retinal arteriolar caliber was related to diabetes, current cigarette smoking, and higher levels of plasma fibrinogen; and larger retinal venular caliber was related to diabetes, current cigarette smoking, greater body mass index and waist-hip ratio, higher levels of serum glucose, plasma triglyceride, plasma LDL-cholesterol, hsCRP, plasma fibrinogen, IL6, sICAM-1, and PAI-1 and lower levels of HDL-cholesterol. In multivariate analyses, blacks and Hispanics had larger retinal arteriolar and venular calibers than did whites and Chinese. CONCLUSIONS: Retinal arteriolar and venular caliber is associated with a range of cardiovascular risk factors, including hypertension, diabetes, measures of obesity, and dyslipidemia. Venular caliber is also associated with systemic inflammation.

Arterioles↗
PubMed2006

The 30-year natural history of type 1 diabetes complications: the Pittsburgh Epidemiology of Diabetes Complications Study experience.

Declining incidences in Europe of overt nephropathy, proliferative retinopathy, and mortality in type 1 diabetes have recently been reported. However, comparable data for the U.S. and trend data for neuropathy and macrovascular complications are lacking. These issues are addressed using the prospective observational Pittsburgh Epidemiology of Childhood-Onset Diabetes Complications Study. Participants were stratified into five cohorts by diagnosis year: 1950-1959, 1960-1964, 1965-1969, 1970-1974, and 1975-1980. Mortality, renal failure, and coronary artery disease (CAD) status were determined on the complete cohort (n = 906) at 20, 25, and 30 years. Overt nephropathy, proliferative retinopathy, and neuropathy were assessed at 20 and 25 years on the subset of participants with a clinical examination. There was a decreasing trend by diagnosis year for mortality, renal failure, and neuropathy across all time intervals (P < 0.05), with the 1950-1959 cohort having a fivefold higher mortality at 25 years than the 1970s' cohorts. Proliferative retinopathy and overt nephropathy showed nonsignificant declines at 20 years (P < 0.16 and P < 0.13, respectively) and no change at 25 years. CAD event rates, which were lower than the other complications, also showed no trend. Although some type 1 diabetes complications (mortality, renal failure, and neuropathy) are declining, others (CAD, overt nephropathy, and proliferative retinopathy) show less favorable changes by 30 years.

Age of Onset↗
PubMed2006

Modeling chronic glycemic exposure variables as correlates and predictors of microvascular complications of diabetes.

OBJECTIVE: The degree to which chronic glycemic exposure (CGE) (fasting plasma glucose [FPG], HbA1c [A1C], duration of diabetes, age at onset of diabetes, or combinations of these) is associated with or predicts the severity of microvessel complications is unsettled. Specifically, we test whether combinations of components correlate and predict complications better than individual components. RESEARCH DESIGN AND METHODS: Correlations and predictions of CGE and complications were assessed in the Rochester Diabetic Neuropathy Study, a population-based, cross-sectional, and longitudinal epidemiologic survey of 504 patients with diabetes followed for up to 20 years. RESULTS: In multivariate analysis, A1C and duration of diabetes (and to a lesser degree age at onset of diabetes but not FPG) were the main significant CGE risk covariates for complications. A derived glycemic exposure index (GE(i)) correlated with and predicted complications better than did individual components. Composite or staged measures of polyneuropathy provided higher correlations and better predictions than did dichotomous measures of whether polyneuropathy was present or not. Generally, the mean GE(i) was significantly higher with increasing stages of severity of complications. CONCLUSIONS: A combination of A1C, duration of diabetes, and age at onset of diabetes (a mathematical index, GE(i)) correlates significantly with complications and predicts later complications better than single components of CGE. Serial measures of A1C improved the correlations and predictions. For polyneuropathy, continuous or staged measurements performed better than dichotomous judgments. Even with intensive assessment of CGE and complications over long times, only about one-third of the variability of the severity of complications is explained, emphasizing the role of other putative risk covariates.

Adolescent↗
PubMed2005

Retinal microvascular abnormalities and MRI-defined subclinical cerebral infarction: the Atherosclerosis Risk in Communities Study.

BACKGROUND AND PURPOSE: Retinal microvascular abnormalities reflect cumulative small vessel damage from elevated blood pressure and may reflect subclinical cerebral microvascular changes. We examined their associations with MRI-defined cerebral infarcts. METHODS: Population-based, cross-sectional study of 1684 persons 55 to 74 years of age without a history of clinical stroke, sampled from 2 US southeastern communities. Retinal photographs were obtained and graded for presence of retinal microvascular abnormalities, including arteriovenous nicking, focal arteriolar narrowing, retinal hemorrhages, soft exudates and microaneurysms. Photographs were also digitized, and retinal vessel diameters were measured and summarized as the arteriole-to-venule ratio (AVR). Cerebral MRI scans were graded for presence of cerebral infarct, defined as a lesion > or =3 mm diameter in a vascular distribution with typical imaging characteristics. RESULTS: There were a total of 183 MRI cerebral infarcts. After adjustment for age, gender, race, 6-year mean arterial blood pressure, diabetes, and other stroke risk factors, cerebral infarcts were associated with retinal microvascular abnormalities, with odds ratios 1.90 (95% CI, 1.25 to 2.88) for arteriovenous nicking, 1.89 (95% CI, 1.22 to 2.92) for focal arteriolar narrowing, 2.95 (95% CI, 1.30 to 6.71) for blot hemorrhages, 2.08 (95% CI, 0.69, 6.31) for soft exudates, 3.17 (95% CI, 1.05 to 9.64) for microaneurysms, and 1.74 (95% CI, 0.95 to 3.21) for smallest compared with largest AVR. In stratified analyses, these associations were only present in persons with hypertension. CONCLUSIONS: Retinal microvascular abnormalities are associated with MRI-defined subclinical cerebral infarcts independent of stroke risk factors. These data suggest that retinal photography may be useful for studying subclinical cerebrovascular disease in population-based studies.

Aged↗
PubMed2005

Impact of aging and age-related maculopathy on inactivation of the a-wave of the rod-mediated electroretinogram.

This study examined the impact of aging and age-related maculopathy (ARM) on the inactivation of phototransduction in rod photoreceptors by measuring the recovery of the a-wave using a paired flash electroretinogram technique. Measurements were made on 32 older adults in normal retinal health, 25 with early ARM, 7 with late ARM, and 20 young adults for comparison purposes. ARM presence and severity were defined by the Wisconsin Age-Related Maculopathy Grading System based on grading of fundus photographs. The inactivation of rod phototransduction exhibited an aging-related slowing. Those with early ARM did not exhibit inactivation slowing over and above what would be expected based on normal retinal aging. Persons in the late stages of ARM exhibited dramatic slowing in inactivation kinetics.

Adult↗
PubMed2005

Meta-analysis of genome scans of age-related macular degeneration.

A genetic contribution to the development of age-related macular degeneration (AMD) is well established. Several genome-wide linkage studies have identified a number of putative susceptibility loci for AMD but only a few of these regions have been replicated in independent studies. Here, we perform a meta-analysis of six AMD genome screens using the genome-scan meta-analysis method, which allows linkage results from several studies to be combined, providing greater power to identify regions that show only weak evidence for linkage in individual studies. Results from non-parametric analysis for a broad AMD clinical phenotype (including two studies with quantitative traits) were extracted. For each study, 120 genomic bins of approximately 30 cM were defined and ranked according to maximum evidence for linkage within each bin. Bin ranks were weighted according to study size and summed across all studies; the summed rank (SR) for each bin was assessed empirically for significance using permutation methods. A high SR indicates a region with consistent evidence for linkage across studies. The strongest evidence for an AMD susceptibility locus was found on chromosome 10q26 where genome-wide significant linkage was observed (P=0.00025). Several other regions met the empirical significance criteria for bins likely to contain linked loci including adjacent pairs of bins on chromosomes 1q, 2p, 3p and 16. Several of the regions identified here showed only weak evidence for linkage in the individual studies. These results will help prioritize regions for future positional and functional candidate gene studies in AMD.

Aging↗
PubMed2005

Retinal arteriolar narrowing, hypertension, and subsequent risk of diabetes mellitus.

BACKGROUND: Microvascular disease and hypertension have been linked with risk of diabetes mellitus. We examined the association of retinal arteriolar narrowing, a marker of chronic hypertension, with incident diabetes. METHODS: Prospective cohort study of 3251 nondiabetic persons aged 43 to 86 years living in Wisconsin. The diameters of retinal vessels were measured from baseline retinal photographs of participants. Retinal measurements were summarized as the retinal arteriole-to-venule ratio, with smaller ratios indicating narrower arteriolar diameters. Incident diabetes cases were ascertained at the 5-year and 10-year follow-up examinations. RESULTS: There were 249 incident diabetes cases. Participants with narrower retinal arteriolar diameters had a higher incidence of diabetes (cumulative incidences of 5.1%, 7.0%, 9.2%, and 11.7%, comparing decreasing quartiles of arteriole-to-venule ratio). After controlling for baseline casual blood glucose level, glycosylated hemoglobin level, body mass index, and other risk factors, retinal arteriolar narrowing was significantly associated with risk of incident diabetes (multivariable-adjusted relative risk, 1.53; 95% confidence interval, 1.03-2.27; comparing smallest to largest arteriole-to-venule ratio quartiles). Participants with both hypertension and retinal arteriolar narrowing had a 3-fold higher risk of incident diabetes (multivariable-adjusted relative risk, 3.41; 95% confidence interval, 1.66-6.98) than normotensive participants without arteriolar narrowing. CONCLUSIONS: Retinal arteriolar narrowing is related to risk of incident diabetes. These data suggest a possible link between systemic arteriolar narrowing associated with hypertension and diabetes development.

Adult↗
PubMed2005

Polygenic effects and cigarette smoking account for a portion of the familial aggregation of nuclear sclerosis.

Cataract is the most common cause of blindness worldwide. Nuclear cataract, an advanced stage of nuclear sclerosis, is the most common type of age-related cataract. The authors assessed data from 2,089 persons within 620 extended pedigrees who participated in the 1988-1990 Beaver Dam Eye Study in Wisconsin to determine whether the observed familial aggregation of nuclear sclerosis could be explained by inheritance of a major gene. Familial correlations were examined and segregation analyses were performed on nuclear sclerosis measurements adjusted for age, sex, and pack-years of cigarette smoking. There was modest correlation among close family members after adjustment for age, sex, and pack-years of cigarette smoking: 0.084 between parents and offspring, and 0.198 between sibling pairs. Although results do not support involvement of a single major locus in the etiology of nuclear sclerosis, models that allowed for familial correlation, attributable in part to polygenic effects, did provide a better fit to the observed data than models without a polygenic effect. This finding suggests that several genes of modest effect may influence development of nuclear lens opacity, possibly in conjunction with environmental factors. Cigarette smoking was an important covariate in these analyses. Overall, results highlight the complex etiology of nuclear sclerosis.

Adult↗