Abstract
Abstract: :
Purpose: To determine the feasibility of performing wide–angle (200°+) fluorescein angiography using a modified Optos Panoramic200 imaging system. Methods: A standard Optos Panoramic200 ultrawide image acquisition system produces a 200° field of view via scanning lasers and the use of a novel ellipsoidal mirror, which has two focal points. The conventional unit contains red and green diode lasers and separate detectors. A blue 488 nm wavelength laser was added to excite intravenously injected sodium fluorescein into fluorescence, while the fluorescence was detected using the green channel detector. Acquisition time was 0.25 seconds for each image during the transit. In a pilot project, angiograms were obtained in human subjects, 5 normal eyes and 10 eyes with retinal vascular disease, including diabetes and venous occlusion were imaged. Results: Images of virtually the entire retinal vasculature were rendered with this unit. Capillary non–perfusion, retinal neovascularization, and venous occlusive disease were clearly seen in the entire retinal vasculature, yielding dramatic images not possible by conventional methods. The resolution of the angiograms was somewhat less than with conventional angiography, and was estimated to be on the order of 10–13 microns at the fovea. The perifoveal capillary bed could be seen in 1/3 of the eyes studied. Conclusions: Wide–angle angiography can be performed in a straightforward manner using modifications of existing non–mydriatic wide field imaging hardware. Such angiography may be invaluable in demonstrating peripheral retinal vascular disease and capillary drop–out before such alterations would be detected by conventional imaging techniques. Such early detection of peripheral lesions may be valuable prognostically as well as therapeutically in certain retina vascular or inflammatory diseases. A Phase One multi–centered trial using this device is underway.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal neovascularization • clinical (human) or epidemiologic studies: systems/equipment/techniques