Ocular components before and after acquired, nonaccommodative esotropia.

BACKGROUND: Acquired nonaccommodative esotropia describes the sudden onset of a constant, comitant strabismus of idiopathic origin in children >6 months of age. CASE REPORT: We present a case of acquired nonaccommodative esotropia at 20 months of age in a subject participating in the Berkeley Infant Biometry Study, a longitudinal study of emmetropization and ocular component development in infants between 3 months and 3 years of age. Ocular components for this child were normal before the onset of strabismus (within 2 SD's of the mean for orthotropic study participants) for refractive error, corneal power, lens radii, lens power, and ocular axial dimensions. Refractive error postsurgically was significantly more hyperopic and crystalline lens power lower than average at +2.38 D and 37.2 D, respectively. CONCLUSIONS: The lack of abnormal ocular parameters is consistent with the idiopathic etiology of acute onset esotropia. This case suggests that ocular component values may not be useful for assessing the risk of acquired nonaccommodative esotropia.

Peripheral refraction and ocular shape in children.

PURPOSE: To evaluate the relation between ocular shape and refractive error in children. METHODS: Ocular shape was assessed by measuring relative peripheral refractive error (the difference between the spherical equivalent cycloplegic autorefraction 30 degrees in the nasal visual field and in primary gaze) for the right eye of 822 children aged 5 to 14 years participating in the Orinda Longitudinal Study of Myopia in 1995. Axial ocular dimensions were measured by A-scan ultrasonography, crystalline lens radii of curvature by videophakometry, and corneal power by videokeratography. RESULTS: Myopic children had greater relative hyperopia in the periphery (+0.80 +/- 1.29 D), indicating a prolate ocular shape (longer axial length than equatorial diameter), compared with relative peripheral myopia and an oblate shape (broader equatorial diameter than axial length) for emmetropes (-0.41 +/- 0.75 D) and hyperopes (-1.09 +/- 1.02 D). Relative peripheral hyperopia was associated with myopic ocular component characteristics: deeper anterior and vitreous chambers, flatter crystalline lenses that were smaller in volume, and steeper corneas. Lens thickness had a more complex association. Relative peripheral hyperopia was associated with thinner lenses between refractive error groups but changed in sign to become associated with thicker lenses when analyzed within each refractive error group. Receiver operator characteristics analysis of the ocular components indicated that vitreous chamber depth was the most important ocular component for characterizing the myopic eye, but that peripheral refraction made a significant independent contribution. CONCLUSIONS: The eyes of myopic children were both elongated and distorted into a prolate shape. Thinner crystalline lenses were associated with more hyperopic relative peripheral refractions across refractive error groups, but failure of the lens to thin may account for the association between thicker lenses and more hyperopic relative peripheral refractions within a given refractive group. Increased ciliary-choroidal tension is proposed as a potential cause of ocular distortion in myopic eyes.

Optical and structural development of the crystalline lens in childhood.

PURPOSE: To document the development of key optical and structural parameters of the crystalline lens throughout childhood and examine possible mechanisms by which lens power remains coordinated with the growth of the eye to maintain emmetropia. METHODS: Using cycloplegic autorefraction, video-based phakometry, and ultrasonography, the authors measured refractive error and crystalline lens parameters in 994 children in the first through eighth grades, who participated in the Orinda Longitudinal Study of Myopia, between one and five times from 1989 through 1993. Polynomial growth curves were fit to the data by maximum likelihood estimation. The average annual rates of change in each parameter from each subject's longitudinal data were also estimated. RESULTS: The lens radii of curvature flattened throughout childhood, yet decreases in lens equivalent power stopped after 10 years of age. This indicates that the refractive index of the lens increased during later childhood. Lens thinning in early childhood also ceased after 10 years of age. The spherical volume of the lens showed no appreciable net increase, but the axial length of the eye continued to grow throughout childhood. The prevalence of myopia in our data increased sharply at age 10 years, reaching 21.3% by the age of 14 years. CONCLUSIONS: Concurrent thinning and flattening of the crystalline lens imply that the lens is mechanically stretched by the equatorial growth of the eye during childhood. Changes in the patterns of lens development near the age of 10 years, concurrent with the onset of myopia, suggest that forces arise which interfere with equatorial growth. Such forces might diminish the decreases in lens power and amplify axial elongation to promote myopia.

The effect of parental history of myopia on children's eye size.

OBJECTIVE: To evaluate whether eye size and shape are different in children based on their parental history of myopia. DESIGN: A community-based cohort study of schoolchildren (aged 6 to 14 years), the Orinda (Calif) Longitudinal Study of Myopia. SETTING: Four campuses of the Orinda Union School District, a predominantly white, high socioeconomic status community. PARTICIPANTS: A cross-sectional volunteer sample of 716 children (662 non-myopic) in the first, third, and sixth grades in 1989, 1990, and 1991. All children in those grades were eligible for inclusion in the study. INTERVENTION(S): None. MAIN OUTCOME MEASURES: Refractive error (measured by autorefraction), corneal curvature (measured by photokeratoscopy), crystalline lens power (measured by video phakometry), and axial ocular dimensions (measured by ultrasonography). RESULTS: With prevalent cases of myopia excluded and grade in school and "near work" controlled for, children with two myopic parents had longer eyes and less hyperopic refractive error (analysis of covariance, P < or = .01) than children with only one myopic parent or no myopic parents. A model incorporating parental history is only improved by the addition of near work for the prediction of refractive error. CONCLUSIONS: Even before the onset of juvenile myopia, children of myopic parents have longer eyes. These results suggest that the premyopic eye in children with a family history of myopia already resembles the elongated eye present in myopia.

Work activity and fatal heart attack studied by multiple logistic risk analysis.

A group of 3975 San Francisco longshoremen in cohorts classified annually by work activity (WA) was followed for fatal heart attack (FHA) over a 22-year period. In 57,632 person-years of follow-up, 410 men died from heart attack. A multi-factor logistic analysis was used to study work energy output adjusted for age, race, systolic blood pressure, smoking, body mass index, glucose intolerance and EKG status as predictors of FHA. After adjustment for these factors, men with a high WA of 7 kcal/min above basal metabolism at the beginning of a yearly follow-up period had a FHA rate about one-half the rate for men in the lowest WA category of 1 kcal/min above basal metabolism (p = 0.0003). In addition, the predictability of average WA during the four years preceding a yearly follow-up period was isolated to see if the lower risk associated with high WA derives from selective factors. After adjustment for factors described above and also for rate of change in WA used to represent selective factors, subjects with WA of 7 kcal/min still had about one-half the FHA rate observed for men at the lowest WA level (p = 0.0006). The findings from these and other phases of the analysis are consistent with the hypothesis that a substantial protective effect against FHA results from vigorous physical exertion.

Energy expenditure, cigarette smoking, and blood pressure level as related to death from specific diseases.

In a 22-year followup of 3686 San Francisco longshoremen, the roles of physical activity, cigarette smoking habit, and systolic blood pressure level were evaluated independently in relation to risk of death from a broad range of diseases. Smoking pattern and blood pressure status were established in 1951 and job activity was assessed annually during the followup period. Lower levels of energy expenditure predicted increased risk of fatal heart attack and perhaps of stroke. Heavy cigarette smoking predicted increased risk of death from heart attack, cancer, chronic obstructive respiratory disease, and pneumonia. Higher levels of systolic blood pressure were associated with death from all cardiovascular diseases, diabetes mellitus, and cirrhosis. Tacit to these findings: sedentary living takes its toll largely through heart disease and stroke; the toxicity of cigarette smoking is associated with a broader range of diseases, including heart attack, cancer, and respiratory disease; and higher level of blood pressure related to an even broader range of cardiovascular disease than either of the other characteristics studied.

A study of comparative blood pressure measures in predicting risk of coronary heart disease.

The Western Collaborative Group Study is a prospective study of 3,154 employed men, aged 39-59 years. Coronary heart disease (CHD) occurred in 257 subjects during 8.5 years of follow-up. The multiple logistic risk model was used to assess the comparative strength of systolic, diastolic, mean arterial and pulse pressure for the prediction of CHD in two age decades after adjustment for age, serum cholesterol, cigarette smoking, behavior pattern and weight. The risk of CHD was more strongly associated with the systolic than the diastolic pressure. The general practice of assessing the importance of blood pressure based only on the diastolic component should be reassessed.

Multivariate prediction of coronary heart disease during 8.5 year follow-up in the Western Collaborative Group Study.

The Western Collaborative Group Study is a prospective study of 3,154 employed men aged 39 to 59 years. Ischemic heart disease occurred in 257 subjects during 8.5 years of follow-up. Risk of coronary heart disease was studied with use of the multiple logistic risk model. The incidence of coronary heart disease had a highly significant association with serum cholesterol level, behavior pattern, cigarette smoking and systolic blood pressure in younger (39 to 49 years) and older (50 to 59 years) men and also with age and corneal arcus in the younger group. Type A behavior pattern was strongly related to the incidence of coronary disease in both age groups, independent of interrelations of behavior patterns with any other risk factor.

Multivariate prediction of coronary heart disease in the Western Collaborative Group Study compared to the findings of the Framingham study.

The Western Collaborative Group Study (WCGS) is a prospective epidemiological study of 3,154 initially well men, aged 39059 years at intake in 1960-61, who were employed in ten participating companies in California. Clinical coronary heart disease (CHD) occurred in 257 men during a follow-up period of eight and one-half years. Coronary heart disease risk is predicted using the additive multiple logistic model with the risk factors: age, cholesterol, systolic blood pressure, hematocrit, ECG status, smoking at intake, and relative body weight. The predicted individual CHS risk levels, using the logistic results derived from the WCGS data, are highly correlated with predicted risk levels using a Framington study (FS) equation for these same risk factors with 12-year follow-up. The observed number of CHS events in the WCGS is not significantly different from the expected number of events derived from the FS logistic equation, after correction of length of follow-up. Multiple logistic analysis of the direct association between CHD incidence and behavior pattern gives an approximate relative risk of 1.9 (P = 0.0006) and 2.1 (P = 0.0015) for Type A compared to Type B men aged 39-49 and 50-59 years, respectively. It is estimated that removal of the excess risk associated with Type A behavior would correspond to a 31% (standard error = 6.6%) reduction of coronary heart disease incidence in the Western Collaborative Group Study population.

The relationship of reported parental history to the incidence of coronary heart disease in the Western Collaborative Group Study.

The relationship of a reported parental history of coronary heart disease (CHD) to the incidence of CHD was determined in this prospective study of CHD in an intake population of 39-59-year old men. Reported parental history of CHD was found to be associated with level of schooling, the type A behavior pattern, serum cholesterol and beta/alpha lipoprotein ratio. Men with reported parental history had an increased incidence of angina pectoris in both age defined by symptomatic myocardial infarction and sudden coronary death. Adjustment then was made simultaneously for the confounding effects of the risk factors found to be associated with the prevalence of parental history of CHD. After such adjustment a reported parental history of CHD was still found to have a significant association (p = 0.01) with the combined incidence of symptomatic myocardial infarction and angina pectoris in subjects under 50 years of age.