Subject(s)
Heart-Assist Devices , Shock, Cardiogenic/surgery , Animals , Coronary Artery Bypass , Equipment Design , SheepABSTRACT
The bidirectional laser Doppler technique and monochromatic photography were used to measure the absolute blood flow rate in the major temporal retinal arteries in seven patients following unilateral scleral buckling and encircling procedures, and in two patients before and after removal of scleral buckling elements. In the seven patients who had undergone uncomplicated scleral buckling procedures the arterial flow rates were on average 50% lower (p = 0.01) in the surgically treated eyes than in the contralateral eyes. Removal of scleral buckling elements in two patients produced increases of 73% and 44% in arterial blood flow rates.
Subject(s)
Retinal Artery/physiopathology , Scleral Buckling/adverse effects , Adult , Blood Flow Velocity , Female , Humans , Intraocular Pressure , Lasers , Male , Retinal Detachment/physiopathologyABSTRACT
An electro-optical eyetracker measures eye movement to stabilize a laser beam on the fundus in one dimension. Motion is detected by laser illumination of a fundus feature. The illuminated area is imaged on an intensified linear CCD. Electronics determine the intensity centroid of this image. Centroid motion on the CCD corresponds to eye movement in one dimension. Galvanometer-controlled mirrors reposition (at a 1-kHz rate) the illuminating beam on the fundus. The same mirrors reposition the centroid at the CCD center. Additional beams are also stabilized on the fundus. For typical fixational eye movement amplitudes and frequencies the beams follow the fundus feature within +/-10 microm.
ABSTRACT
A two-dimensional confocal imaging scanner uses galvanometer-controlled mirrors which are silvered on both sides to separate illumination and collectiono pticalp aths.
ABSTRACT
Three methods of three-dimensional imaging of the vitreous and the fundus of the human eye are compared. Equations are derived for the theoretical depth resolution of stereophotogrammetry, scanning laser tomography, and scanning laser triangulation. Scanning laser triangulation provides superior depth resolution without requiring axial scanning. A description of a prototype scanning laser triangulator is given.
