Using Mirante, the cSLO-based multimodal imaging platform, in addition to the UWF fundus photo, the additional features like FFA, ICGA, FAF, and retro mode imaging for visualizing pathologies deeper than the retinal pigment epithelium (RPE), and detecting pathologic changes in the choroid, OCT, OCT-Angiography, and an anterior segment OCT with an additional adapter can be performed.Įidon (CenterVue) combines the cSLO with the conventional fundus imaging (white light emitting diode/LED) system to give true color-wide field fundus images. Heidelberg Spectralis multi-color imaging has additional features like OCT, OCT-angiography, and fundus auto-fluorescence (FAF). This imaging system has UWF fundus imaging, choroidal imaging, fundus autofluorescence (FAF), fundus fluorescein angiography (FFA), indocyanine green (ICG) angiography, and optical coherence tomography (OCT) imaging. The common cSLO-based fundus cameras include Optos, the non-contact ultra-widefield fundus camera with 200 degrees field of view. This reduces the scatter of light in the images acquired, forming a sharp, high-contrast image located within the focal plane.Ĭurrently, the imaging systems using cSLO-based fundus imaging are increasingly used. Ĭonfocal scanning laser ophthalmoscope (cSLO) based fundus cameras: The confocal scanning laser ophthalmoscope (cSLO) uses laser light instead of a flashlight to illuminate the retina. Ultra-wide-field image (UWFI) is a single captured retinal image that captures retinal images anterior to the vortex vein ampullae in all four quadrants. Recently a consensus nomenclature defined wide-field imaging (WFI) to be a single captured retinal image centered on the fovea and extending beyond the posterior pole but posterior to the vortex vein ampullae in all the four quadrants. Ultra-wide-field fundus imaging was defined by (diabetic retinopathy clinical research network) to be more than 100 degrees of field of area. Wide-field fundus imaging refers to taking retinal images of more than 50 degrees. Wide-field and ultra-widefield fundus cameras: Over time, there have been many upgrades to the traditional table-top fundus camera. Bengaluru, India), digital retinography system (dRS, CenterVue, Padova, Italy), EasyScan (iOptics, Den Haag, The Netherlands), TRCNW8Fplus (Topcon, Tokyo, Japan), Visucam (Zeiss, Oberkochen, Germany), Nonmyd7 (Kowa, Torrance, CA), and Canon CR-2 ( Canon, Tokyo, Japan). The commonly used table-top fundus cameras include iCam (Optovue Inc. The imaging rays pass through the central aperture of the mirror as mentioned above (Figure-4, round mirror-3 with a central aperture), through the astigmatic correction and diopter compensation lenses (Figure-4, diopter compensation lenses), then back to the single-lens reflex camera system (Figure-4, camera system). When both the illuminating rays through the pupillary border and the image at the center of the pupil are correctly aligned, the imaging rays exit through the center of the pupil, i.e., the central non-illuminated portion of the donut of the light (Figure-1, Figure-4, donut-shaped light through a dilated pupil) This donut-shaped light beam falls on another round mirror with a central aperture (Figure-4, round mirror-3 with a central aperture), and the reflection exits the camera system through the objective lens and enters through the cornea into the eye (Figure-4, donut-shaped light through a dilated pupil), the photo of which is to be taken. The light is reflected from the mirror (round mirror-2) to a series of lenses (Figure 4, series of lenses).ĭue to the presence of a mask in the uppermost lens (Figure 4, uppermost lens), the light is finally focused as a donut-shaped beam. Light from the viewing lamp is projected onto a round mirror (Figure-4, round mirror-1) and then through a set of filters (Figure-4, filters) onto another round mirror (Figure 4, round mirror -2). The parts of a typical fundus camera are shown in the figure (Figure-3). A fundus camera is a complex system with multiple lenses and a camera utilizing the principle of indirect ophthalmoscope (Figure-2).
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