True color scanning laser ophthalmoscopy and optical coherence tomography handheld probe

Abstract

Scanning laser ophthalmoscopes (SLOs) are able to achieve superior contrast and axial sectioning capability compared to fundus photography. However, SLOs typically use monochromatic illumination and are thus unable to extract color information of the retina. Previous color SLO imaging techniques utilized multiple lasers or narrow band sources for illumination, which allowed for multiple color but not "true color" imaging as done in fundus photography. We describe the first "true color" SLO, handheld color SLO, and combined color SLO integrated with a spectral domain optical coherence tomography (OCT) system. To achieve accurate color imaging, the SLO was calibrated with a color test target and utilized an achromatizing lens when imaging the retina to correct for the eye's longitudinal chromatic aberration. Color SLO and OCT images from volunteers were then acquired simultaneously with a combined power under the ANSI limit. Images from this system were then compared with those from commercially available SLOs featuring multiple narrow-band color imaging.

Handheld optical coherence tomography angiography

“…For handheld OCT systems, manually focusing tuning mechanisms have been demonstrated [13][14][15][16][17][18]. The manual focusing procedure is slow, and usually, the results are not ideal because the operator has to, subjectively, decide if the image is in focus or not.…”

“…Wide-field en face images (10 × 10 mm 2 ) of the human retina were retrieved from the handheld OCT instrument [15]. Besides, a series of research works on the development of handheld scanning laser ophthalmoscopy (SLO) and OCT probe have demonstrated by researchers at Duke University [16,17]. Most recently, they observed the retinal photoreceptor cells of young children based on their welldeveloped handheld probe and SLO imaging technique [18].…”

Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

“…The optics were optimized in optical design software, Zemax (Radiant ZEMAX LLC, Redmond, WA), using an eye model with a gradient index lens [13]. The eye model was modified as described in [8] with glass types adjusted to match human ocular dispersion [14]. A gimbal-less two-axis scanning MEMS micromirror (13Z1.1, Mirrorcle Technologies Inc., Richmond, CA) was used to control beam position on the subject eye.…”

“…To mitigate some of these constraints, researchers have developed handheld OCT instruments [1][2][3][4][5][6][7][8]. A few of these instruments are capable of imaging both the anterior and posterior segment [2][3][4]7], but switching between modes requires the operator to remove and/or add an additional lens or lens system.…”

A comparative study of noise in supercontinuum light sources for ultra-high resolution optical coherence tomography

“…Supercontinuum (SC) light is a well-established technology, which finds applications in several domains ranging from chemistry to material science and imaging systems [1][2]. More specifically, its ultra-wide optical bandwidth and high average power make it an ideal tool for Optical Coherence Tomography (OCT).…”