Purpose:
Several diseases are associated with microvasculature changes, e.g. density, vessel size, and etc. Detecting abnormalities and alterations of microvasculature will provides insightful information to investigate diseases. This paper demonstrates high-sensitive Doppler optical coherence angiography in order to non-invasively visualize microvasculature of in vivo human eye.
Methods:
Four eyes of 4 subjects without marked abnormalities were examined by high-sensitive Doppler optical coherence angiography (HS-DOCA). The distribution of microvessel blood flow was detected by high-speed spectral-domain Doppler OCT with double probing beams. The minimum detectable axial blood flow velocity is 5.44 µm/s at a signal-to-noise ratio of 15 dB. Three-dimensional blood flow distribution with this high flow sensitivity was detected. This system is operated at 27,000 axial scans per second. An imaging area of 2 × 2 mm was scanned by 512 × 256 axial scans within 5 seconds. The macula, optic nerve head (ONH), superior and inferior regions to the macula and ONH of each eye were scanned.
Results:
In 3 of 4 eyes, retinal capillary network at the macula were clearly observed. The foveal avascular zone can be shown. Complex vasculatures at the ONH were visualized in all 4 eyes. Three-dimensional distribution of branches of the retinal artery and vein and fine vessels inside the disc were shown. At the superior and inferior to the ONH, radial peripapillary capillaries were detected. The Figure shows vascular structure at (a) the fovea, (b) ONH, and (c) retina of peripapillary area in the right eye of one subject.
Conclusions:
HS-DOCA can visualize three-dimensional vasculature of retinal microvessels non-invasively. Comprehensive non-invasive ophthalmic angiography will enable frequent monitoring of the ocular vasculature and/or screening of vascular-related diseases.
Keywords: blood supply • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina