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Gangjun Liu, Jianlong Yang, Liang Liu, J. Peter Campbell, David Huang; Handheld swept source optical coherence tomography angiography. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5433.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a handheld optical coherence tomography (OCT) system suitable for OCT angiography (OCTA) in children.
The laser source is a swept laser (Axsun) with a repetition rate (A-line speed) of 100 kHz, a central wavelength of 1050 nm and a tuning range of 110 nm. A fiber coupler directs 20% of the optical power to the sample arm handheld probe. The light backscattered by the sample is mixed with the reference reflection at a 50/50 coupler, and the interference fringes are picked up by a pair of balanced detectors. The handheld probe weighs 0.4 kg and measures 20.6×12.8×4.6 cm (Fig .1). The probe is equipped with a mini iris camera for easy alignment. Real-time display of the en face OCT and cross-sectional OCT images in the system allows accurate centration on the fundus imaging target. The fast automatic focus is implemented with an electrically tunable lens. An extended imaging range of 6 mm allows easy axial alignment. A fast (1 second ) scan patterns were investigated. The split-spectrum amplitude and phase gradient angiography (SSAPGA) algorithm was used to compute flow signal.
High-resolution retina OCTA images from a healthy awake adult human was acquired in 1 second (Fig. 2) .
We developed a handheld OCT system and demonstrated acquisition of high-quality OCTA images by the handheld operation. OCTA from anesthetized newborns and small children should be feasible.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
(A) Schematic of the handheld OCTA probe. (B) Three-dimensional (3D) perspective view of the probe design. (C) Photography of the handheld OCTA probe with 3D-printed enclosure.
En face retina OCTA around the fovea (A) and the ONH (B) from a healthy eye by using the 1-second scan protocol. Image dimensions are 2.5×2.5 mm (200×200 pixels).
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