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W A Van Heuven

Publications and source records attributed to W A Van Heuven.

9 recordsLinked to original sources
PubMed1993

Is there an ethnic difference in the effect of risk factors for diabetic retinopathy?

Mexican Americans have an increased prevalence and incidence of non-insulin-dependent diabetes mellitus (NIDDM). In addition, Mexican American diabetic subjects have an increased prevalence of retinopathy relative to Caucasian diabetic subjects. In Mexican American diabetic subjects, established risk factors may have a stronger effect on diabetic retinopathy, compared to Caucasian diabetic subjects. In this report, we compare the effect of established risk factors (age at examination, gender, age at diagnosis of diabetes, duration of diabetes, glycemia, type of therapy, systolic and diastolic blood pressure, and hypertension prevalence) between Caucasian diabetic subjects (n = 478), a low-risk population for NIDDM (Wisconsin Epidemiologic Study of Diabetic Retinopathy), and Mexican American diabetic subjects (n = 231), a high-risk population for NIDDM (San Antonio Heart Study). Retinopathy was classified into two categories (any or none) as assessed by seven standard stereoscopic retinal photographs read at the University of Wisconsin Reading Center. Mexican American diabetic subjects in Texas had an increased prevalence of any retinopathy (odds ratio = 1.71, 95% confidence interval: 1.25, 2.34), compared to Caucasian diabetic subjects in Wisconsin. Longer duration of diabetes, more severe glycemia, earlier age at diagnosis, and insulin therapy were associated with diabetic retinopathy in both Mexican Americans and Caucasians. Socioeconomic status was not associated with prevalence of retinopathy. Moreover, the effect of risk factors for retinopathy was similar in both ethnic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Screening for diabetic retinopathy. The wide-angle retinal camera.

OBJECTIVE: To define the test characteristics of four methods of screening for diabetic retinopathy. RESEARCH DESIGN AND METHODS: Four screening methods (an exam by an ophthalmologist through dilated pupils using direct and indirect ophthalmoscopy, an exam by a physician's assistant through dilated pupils using direct ophthalmoscopy, a single 45 degrees retinal photograph without pharmacological dilation, and a set of three dilated 45 degrees retinal photographs) were compared with a reference standard of stereoscopic 30 degrees retinal photographs of seven standard fields read by a central reading center. Sensitivity, specificity, and positive and negative likelihood ratios were calculated after dichotomizing the retinopathy levels into none and mild nonproliferative versus moderate to severe nonproliferative and proliferative. Two sites were used. All patients with diabetes in a VA hospital outpatient clinic between June 1988 and May 1989 were asked to participate. Patients with diabetes identified from a laboratory list of elevated serum glucose values were recruited from a DOD medical center. RESULTS: The subjects (352) had complete exams excluding the exam by the physician's assistant that was added later. The sensitivities, specificities, and positive and negative likelihood ratios are as follows: ophthalmologist 0.33, 0.99, 72, 0.67; photographs without pharmacological dilation 0.61, 0.85, 4.1, 0.46; dilated photographs 0.81, 0.97, 24, 0.19; and physician's assistant 0.14, 0.99, 12, 0.87. CONCLUSIONS: Fundus photographs taken by the 45 degrees camera through pharmacologically dilated pupils and read by trained readers perform as well as ophthalmologists for detecting diabetic retinopathy. Physician extenders can effectively perform the photography with minimal training but would require more training to perform adequate eye exams. In this older population, many patients did not obtain adequate nonpharmacological dilation for use of the 45 degrees camera.

Diabetic Retinopathy↗
PubMed1989

Effects of socioeconomic status on hyperglycemia and retinopathy levels in Mexican Americans with NIDDM.

Mexican Americans have a threefold greater prevalence of non-insulin-dependent diabetes mellitus (NIDDM) than non-Hispanic Whites. Moreover, Mexican-American diabetic people have more severe hyperglycemia and diabetic retinopathy than non-Hispanic White diabetic people. Mexican Americans are predominantly of low socioeconomic status (SES), and low-SES Mexican Americans have a higher prevalence of NIDDM than higher-SES Mexican Americans. Therefore, we hypothesized that among diabetic people, low SES would be associated with more severe hyperglycemia and retinopathy. Three hundred forty-three Mexican Americans and 79 non-Hispanic Whites with NIDDM were identified from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Hyperglycemia was assessed as the sum of the fasting, 1-h, and 2-h plasma glucose concentrations during a standard oral glucose tolerance test. Retinopathy was assessed by 7 standard stereoretinal photographs. SES was assessed with three indicators: Duncan's socioeconomic index, education, and income. Contrary to expectations, low SES was not associated with greater levels of hyperglycemia or grades of retinopathy.

Blood Glucose↗
PubMed1985

Rod-cone interactions in the ERG of a patient with Bardet-Biedl syndrome.

During routine ERG testing of a patient with Bardet-Biedl syndrome, we encountered an ERG anomaly not previously reported. A white flash which produced a response during light adaptation would produce no ERG when the retina was dark-adapted. Possible explanations for this phenomenon are discussed.

Adult↗
PubMed1976

Vitreous membranes. A light and electron microscopical study.

Patients with pigmented vitreous membranes were subjected to partial vitrectomy, and the membranes were studied by light and electron microscopy. Two yellow ochre membranes from eyes removed at autopsy were also examined. The membranes were composed of degenerating red cells and a delicate matrix of collagen. Phagocytic cells of uncertain origin and migrating retinal pigment epithelial cells were present in some of the membranes. Vascular channels were observed in only two cases, in which the membranes had clinical features different from those in the remaining cases. The development of new techniques of vitrectomy and the relatively normal clinical appearance of the posterior pole of the retina in these cases both suggest the potential clinical value of vitreous membrane excision. Additional histopathologic studies of vitrectomy specimens will enhance our understanding of the indications for this procedure.

Adult↗