Stephen H. Sinclair

Learn More
The response of the retinal circulation to an acute elevation in systemic blood pressure was studied in three healthy normotensive volunteers using the noninvasive laser Doppler velocimetry (LDV) technique combined with retinal vessel size measurements. Isometric exercise was employed to induce the acute rise in arterial pressure. There was no detectable(More)
The distributions of blood velocity and volumetric flow rate in individual vessels of the normal human retina were determined as a function of vessel diameter. The mean velocity of blood, Vmean, was calculated from the centerline velocity measured by bidirectional laser Doppler velocimetry (LDV). Volumetric flow rate was determined from Vmean and the vessel(More)
Autoregulation of the retinal circulation in response to an acute elevation of intraocular pressure was investigated in 17 subjects (23 eyes) with no ocular abnormalities, by means of the blue field entoptic phenomenon. This phenomenon allows a person to observe leukocytes flowing in his own macular capillaries. Subjects were instructed to compare the speed(More)
The effect of panretinal photocoagulation (PRP) on retinal volumetric blood flow rate and its regulatory response to hyperoxia was investigated in a main temporal vein of 15 eyes with proliferative diabetic retinopathy, using bi-directional laser Doppler velocimetry and monochromatic fundus photography. At an average of 4 +/- 2 months after the beginning of(More)
PURPOSE To characterize the neuroprotective mechanisms of erythropoietin (EPO) against the stress of glyoxal-advanced glycation end products (AGEs) in retinal neuronal cells. METHODS Rat retinal organ culture, primary retinal neuron culture, and retinal cell line (R28 cell) culture under glyoxal-AGEs insult were used as in vitro models. Exogenous EPO was(More)
Bidirectional laser Doppler velocimetry and monochromatic fundus photography were used to investigate retinal circulation in 26 normal subjects and in 51 insulin-treated diabetic patients with no retinopathy, background retinopathy (BDR), proliferative retinopathy (PDR), and patients with PDR who had been treated by panretinal photocoagulation (PDR-PRP).(More)
PURPOSE To explore and evaluate the protective effect of erythropoietin (EPO) on retinal cells of chemically induced diabetic rats after EPO was injected intravitreally at the onset of diabetes. METHODS Diabetes was induced in Sprague-Dawley rats by intraperitoneal injection of streptozotocin (STZ). At the onset of diabetes, a single intravitreal(More)
A new bidirectional laser Doppler velocimeter (LDV) is described for absolute measurement of the speed of red blood cells flowing in individual retinal vessels. The basic component of the instrument is a standard retinal camera that eliminates the need for a contact lens. The laser beam is delivered to the eye through the fundus illumination optical system(More)
The noninvasive Laser Doppler Velocimetry (LDV) technique was used in normal volunteers to determine retinal blood flow, F, during pure oxygen breathing at atmospheric pressure. Changes in blood flow were calculated based on Poiseuille relation, F = (pi D2/4) X Vmax, where Vmax is the red blood cell maximum or center-line velocity and D, the diameter of the(More)
BACKGROUND AND OBJECTIVE To evaluate the safety and efficacy of cataract extraction and lens implantation at the time of pars plana vitrectomy (PPV) for macular hole (MH) repair. MATERIALS AND METHODS A retrospective study was conducted of 21 eyes that had PPV for MH combined with cataract extraction and lens implantation. Visual acuities (VA) were(More)