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R.A. Leitgeb, W. Drexler, L. Schmetterer, T. Bajraszewski, A.F. Fercher; HIGH SPEED, ULTRA HIGH RESOLUTION MORPHOLOGIC AND REAL TIME DOPPLER FLOW IMAGING OF THE HUMAN RETINA BY FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2201.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To demonstrate in–vivo high speed ultrahigh resolution imaging of intra retinal structures on the level of histology and to acquire in real–time Doppler flow data of retinal vessels with Fourier domain optical coherence tomography (FDOCT). Methods: A FDOCT system was interfaced to a modified commercial OCT 1 Instrument (Carl Zeiss Meditec Inc.), employing a compact Titanium:sapphire laser with 130 nm bandwidth (Femtolasers Inc.) allows for visualization of intra retinal structures with ultra high resolution and high detection speed. In contrast to time domain OCT, FDOCT does not require any depth scanning since the full depth structure is obtained synchronously. The broadband light source yields an axial resolution of ∼ 3 µm in retinal tissue. In addition extraction of the recorded signal phase allows to display color encoded flow tomograms within retinal vessels in real time. Results:We recorded retinal tomograms at different regions with detection speeds of 10000 up to 25000 A–scans/second and compared them to tomograms obtained with time domain OCT systems. The fundus camera system admitted to select specific regions that contained retinal vessels. Within those regions we recorded a series of tomograms and calculated the Doppler flow speeds. The color encoded tomograms allowed distinguishing between arteries and veins and displaying pulsative flow in real time with 4 tomograms per second. Systolic and diastolic phase of the heart cycle were easily identified and the pulsatilitywas calculated accordingly. The velocity resolution was ∼200µm/s in tissue. Conclusions: We demonstrate the capability of FDOCT to obtain in–vivo UHR OCT with tomograms that show the same resolution and signal to noise ratio but more than 20 times higher acquisition speed as compared to those obtained with standard, time domain based OCT systems. The high detection speed admits real time display of pulsating vessels and color encoded Doppler flow tomograms similar to color Doppler ultrasound but allows for micrometer axial resolution.
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