Retinal fixation point location in the foveal avascular zone

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 which the center of the FAZ locates the retinal point of fixation becomes an important therapeutic issue. Using an optimized technique for visualizing the retinal vasculature entoptically, the authors determined the location of the retinal point of fixation with respect to the foveal area vasculature in 26 eyes of 14 healthy subjects. In 23 eyes (12 subjects), a traditional FAZ was observed, the other three eyes (two subjects) had capillaries near or crossing the center of fixation. Of the 23 eyes with a traditional FAZ, 20 had centers of fixation located eccentric to the center but in the FAZ, (average deviation from the center of the FAZ, 66.5 +/- 49.5 microns) with the direction of deviation from the FAZ center appearing random. Consequently, when following protocols that advocate photocoagulation treatment with spot centers closer to the FAZ center than 300 microns, the center of the FAZ is a poor locator of a subject's retinal point of fixation. When using the FAZ as a reference, the resulting uncertainty in the location of the subject's retinal point of fixation increases the probability of significant damage to the actual point of fixation by up to 20%.     

Comparison of the use of reserpine versus alpha-methyldopa for second step treatment of hypertension in the elderly

A retrospective chart analysis was conducted on all new elderly hypertensive patients referred to a community hypertension clinic who were being treated with either reserpine or alpha-methyldopa plus a diuretic. There were no significant differences between the two groups on entry in age, gender, co-morbid diagnoses, or systolic or diastolic blood pressure. There were no significant differences between the two groups in terms of side effects over three years, but the proportion of persons having compliance problems was significantly lower in the reserpine group. Mean diastolic pressures were significantly lower after one, two, and three years, and systolic pressures were lower after one and two years in the reserpine group. Reserpine is at least as effective as alpha-methyldopa in treating hypertension in the elderly and is associated with fewer problems in compliance.     

Mortality in a public and a private hospital compared: the severity of antecedent disorders in Medicare patients.

OBJECTIVES. The objectives of this study were to determine (1) if there were significant differences between patients who died at a public hospital and those who died at a university hospital that functions as a private, community hospital, and (2) if those differences were associated with an increased risk of death. METHODS. Chart review collected variables used by the Health Care Financing Administration in mortality analyses to examine how severity of illness data contribute to accurate predictions of death in a public hospital compared with a university hospital. RESULTS. Compared with patients who died at the university hospital, public hospital patients who died had more comorbid disease, were more severely ill, more likely to be emergently admitted, and more likely to be admitted from an extended-care facility. Inclusion of severity of illness with variables previously used to predict mortality significantly improved the accuracy of mortality prediction models for the public hospital but not for the university hospital. CONCLUSIONS. The results suggest that urban public hospitals provide care to more severely ill patients. Administrative data sets may not be adequate to identify these differences between patient populations.     

Lymphocyte β2-Receptor Activity,Metoprolol Kinetics,and Response to Metoprolol in Hypertensive Black Men

Study Objectives . To evaluate whether variability in S-metoprolol kinetics and lymphocyte β₂-receptor-mediated cyclic adenosine monophosphate (cAMP) accumulation is related to the variability in antihypertensive response to metoprolol of black men. Design . Prospective, unblinded study. Setting . University-based preventive medicine clinic. Patients . Twelve hypertensive black men. Measurements and Main Results . Ambulatory blood pressure was measured over 24 hours before and after metoprolol administration. Ex vivo responsiveness of lymphocyte β₂-receptors to isoproterenol was established for each subject before initiating metoprolol therapy. Plasma samples were collected over 12 hours at the conclusion of the study, from which metoprolol enantiomer concentrations were determined by chiral high-performance liquid chromatography, and kinetic values were calculated. The 24-hour ambulatory blood pressure responses to metoprolol were highly variable, with systolic blood pressure responses ranging from −13 to +33 mm Hg and diastolic blood pressure responses ranging from −15 to +15 mm Hg. There was a significant relationship between the metoprolol-induced change in systolic blood pressure and the maximum lymphocyte β₂-receptor cAMP production (y = 0.47x −7.79; r² = 0.49, p<0.05) such that those with the highest maximum cAMP production had the greatest blood pressure increases during metoprolol therapy. There was no relationship between S-metoprolol concentration and blood pressure response. Mean oral clearance values for S- and R-metoprolol were 1320 and 2346 ml/minute, respectively. Conclusions . Lymphocyte β₂-receptor data suggest that individuals most responsive to β-receptor stimulation may be at greatest risk of blood pressure elevation during β₂-receptor blockade. The metoprolol enantiomer kinetic data are markedly different from previously published data and may represent racial differences in pharmacokinetics.     

Set shot shooting performance and visual acuity in basketball.

Common sense suggests that decreasing visual acuity will have a negative effect on basketball shooting performance. To test the hypothesis that basketball shooting performance monotonically decreases with decreasing acuity, 19 subjects attempted 25 set shots from a fixed location at each of 5 different acuity levels: 6/6 or better and vision blurred (by optical defocus) to visual acuities of 6/12, 6/24, 6/48, and 6/75. Our results revealed a small but statistically nonsignificant decrease in shooting performance between the 6/6+ and 6/12 conditions. For visual acuities between 6/12 and 6/75, the number of baskets made remained constant. We conclude that decreases in visual acuity over the range of 6/6+ to 6/75 resulting from defocus do not significantly reduce set shot shooting performance.     

Persistant corpus luteum cyst of pregnancy: sonographic evaluation of cause of third trimester bleeding.

Corpus luteum cysts are frequently observed in pregnant patients evaluated with diagnostic ultrasound. They are usually regarded as incidental findings because of their limited size and usual pattern of regression by ten weeks. The presence and persistence of larger corpus luteum cysts or other extrauterine masses may complicate pregnancy. A case of a large persistent corpus luteum cyst associated with third trimester bleeding is presented.     

Issues in quantifying atrophic macular disease using retinal autofluorescence

PURPOSE: To demonstrate the potential and limits of autofluorescence imaging in identifying and delineating areas of atrophy. METHODS: Fundus photographs and infrared scanning laser ophthalmoscope (SLO) imaging, SLO macular perimetry, and SLO autofluorescence imaging results were compared for two patients with geographic atrophy (GA) from age-related macular degeneration, one patient with pigmentary alteration of the retina, and two patients with Stargardt disease. The main outcome measure in this case series was the presence of reduced autofluorescence. RESULTS: Drusen may become undetectable during autofluorescence imaging for some patients, allowing simple identification of areas of GA with areas of reduced autofluorescence. In other patients, drusen themselves have decreased autofluorescence, despite having intact retinal function in the retina overlying them. Some patients may have areas of reduced autofluorescence that persist for many years, without evidence of the development of atrophy. In Stargardt disease, decreased autofluorescence can easily detect and delineate areas of scotoma. Areas with mottled autofluorescence may have overlying function, but the function may not be adequate to support a fixation locus in that area. CONCLUSIONS: Using decreased autofluorescence to delineate areas of atrophy may be helpful in atrophic macular disorders. For GA, correlation with fundus photographs or macular perimetry findings may be necessary to differentiate between drusen and atrophy. For Stargardt disease, the nature of areas of decreased autofluorescence may help explain visual function of those areas.