Wichard A J van Heuven

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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(More)
We have examined two psychophysical procedures for assessing the size and shape of the human foveal avascular zone (FAZ). Both procedures used a Maxwellian view system with a rotating beam to create a high contrast entoptic view of the retinal vasculature. Most subjects readily report a clear avascular zone surrounding their fixation point. The size of this(More)
OBJECTIVE To report the structural and visual outcomes of eyes in which retinal detachment developed from retinopathy of prematurity (ROP) in the Early Treatment of Retinopathy of Prematurity (ETROP) Study. Method Infants in the ETROP Study with bilateral high-risk prethreshold ROP had 1 eye randomized to early treatment, with the fellow eye managed(More)
The site of normal fixation is often assumed to be centered in the foveal avascular zone (FAZ). This assumed anatomic relationship is used during photocoagulation therapy as an objective guide to avoid damaging critical retinal structures on or near fixation. With laser therapy being directed closer and closer to the center of the FAZ, the accuracy with(More)
PURPOSE To compare choroidal blood pressure versus flow relationships obtained by three different methods of changing the ocular perfusion pressure. METHODS Experiments were performed in pentobarbital-anesthetized rabbits with occluders on the aorta and inferior vena cava to control mean arterial pressure (MAP). The central ear artery was cannulated to(More)
We examined two patients with orbital schwannomas (neurilemomas). The echographic findings, including a sharply outlined capsule, a well-defined central cystic space within the tumor with very low internal reflectivity surrounded by smaller cysts with variable reflectivity, slight or no compressibility, and blood flow, should help to differentiate these(More)
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(More)
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(More)
The authors review (1) the range of techniques used to study the retinal vasculature near the fovea, (2) describe the need and rationale for noninvasive in vivo monitoring of the retinal vasculature, (3) present theoretic and practical considerations which show that entoptic visualization of the smallest capillaries near the fovea is optimized by a small(More)
BACKGROUND Hospital-nursery lighting has been suggested as a factor in causing retinopathy of prematurity. Despite ongoing debate, a causal relation has not been established. METHODS We conducted a prospective, randomized, multicenter study of the effects of light reduction on 409 premature infants with birth weights of less than 1251 g and gestational(More)