IndraLab
Statements
sparser
"Various methods have been developed for observing the retinal nerve fiber layer (RNFL) and nerve fiber layer defects (NFLDs): regular fundus photography, red-free fundus photography [ xref ], scanning laser ophthalmoscopy (SLO) [ xref ], adaptive optics SLO (AO-SLO) [ xref ], scanning laser polarimetry (GDx) [ xref ], Heidelberg Retinal Tomography (HRT) [ xref ], and optical coherence tomography (OCT)."
sparser
"Here, an imaging platform combining multimodal AO-scanning light ophthalmoscopy (AO-SLO) with AO-optical coherence tomography (AO-OCT) is developed to make a side-by-side comparison of the same RPE cells imaged across four modalities: AO-darkfield, AO-enhanced indocyanine green (AO-ICG), AO-infrared autofluorescence (AO-IRAF), and AO-OCT."
sparser
"All previously published reports have used 2D evaluation of laminar pore area with AO-SLO, [ xref ] auto-segmentation of the laminar pores with SS-OCT [ xref , xref ], or have used new types of OCT. [ xref ] However, when the disc angle is tilted, accurate evaluation of pore structure in 2D is very difficult."
sparser
"In this Letter, we use the Pittsburgh multi-offset AO-SLO [ xref ], which contains an off-axis detector that can be precisely positioned perpendicularly to the optic axis in eight different positions [ xref ], to demonstrate that while one axis will indeed present an asymmetric light distribution generating high cellular contrast, the perpendicular axis has a symmetric light distribution strongly diminishing cellular contrast for this given direction."
sparser
"Spatially and temporally co-registered AO-SLO imaging confirmed that the dark cones surrounded by reflective rods (e.g., blue arrows in xref ) seen in confocal reflectance did indeed contain intact inner segments, with a small population of cones that remained normally reflective."
sparser
"Using different AO-SLO systems, Song et al. reported mean densities between 18.500 to 24.200/mm 2 at ecc 0.9 mm [ xref ], Zhang et al. showed approximately 20 to 25.000 cones/mm 2 at ecc 1mm [ xref ], and Park et al. found densities between 18.600 and 20.200/mm 2 at ecc 1mm [ xref ]."
sparser
"It is possible to compensate for these aberrations by using imaging systems that incorporate adaptive optics (AO), consisting of a wavefront sensor that measures aberrations in ocular optics and a deformable mirror or spatial light modulator to compensate for aberrations in living eyes. xref We previously demonstrated that AO-SLO captures images of individual retinal nerve fiber bundles in normal eyes and eyes of patients with glaucoma xref , xref and showed that nerve fiber bundle width changed in proportion to NFL thickness in eyes of patients with glaucoma compared to control eyes. xref Yet, it remains unclear whether AO-SLO is useful for detecting microstructural changes in retinal nerve fibers over time."
sparser
"AO-SLO has been used in a large number of studies xref , xref – xref , xref – xref covering fundamental cell morphology and cell populations, clinical studies of retinal disease, vision restoration, therapeutics, phototoxicity, visual function of cell types, developmental processes, and neurovascular coupling and microvascular perfusion."
sparser
"Figure xref (A-J) shows the angiography of retina and choroid through green fluorescing fluorescein and micellar nanoparticle tagged with red fluorescing rhodamine-X. Comprehensively, a combined OCT/SLO system comprises AO-SLO for imaging physiological events of retinal components such as blood flow, microglia cells, capillaries, GFP expression of cone photoreceptor cells and its three-dimensional localization by combining with the widefield OCT/pv-OCT and SLO records."
sparser
"Using the results from the fine-tuning (Layer 5) method, they calculated four different cone mosaic parameters that were similar to the results found in AO-SLO images, showing the utility of their method. xref Christopher et al . demonstrated that deep learning methodologies have high diagnostic accuracy for identifying fundus photographs with glaucomatous damage to the optic nerve head in a racially and ethnically diverse population."
sparser
"Regarding the measurement of total cone density, current AO-FC and AO-SLO systems have two relevant benefits over AO-OCT systems: First, the images are less prone to motion artefacts due to faster en-face acquisition times; second, they often utilize image-averaging algorithms, improving the overall image quality and thus cone depiction [ xref , xref – xref ]."
sparser
"Although we recently demonstrated an improved image contrast of in-vivo human retinal ganglion cells using a multi-offset aperture AO-SLO 4(a) [ xref ] compared to the work of Rossi et al. [ xref ], there was still regions where we could not clearly identify the cells because of low contrast."
sparser
"She presented several AO-SLO studies that tracked disease progression by evaluating changes in the cone photoreceptor mosaic and noted that cone spacing and regularity have been correlated with photoreceptor function. xref The subtle, cellular-level data gathered from the addition of AO can provide critical information on changes in retinal disease, ranging from rare retinal dystrophies xref to prevalent conditions, such as age-related macular degeneration. xref Moreover, AO-SLO can be coupled with other techniques, such as microperimetry, to measure both structure and function at the cellular level. xref Austin Roorda, PhD, concluded, “The cellular-level access that we get with AO drives the paradigm shift in how we use ophthalmoscopy to study eye disease."
sparser
"This could be further substantiated with non-confocal AO-SLO imaging of the inner segment. xref Alternatively, cone loss could be causally related to dichromacy in which the dark holes are a consequence of incomplete replacement of lost cones with cones of another type during retinal development, as suggested in hypothesis 1."
sparser
"Applying the principles of spectroscopy and known absorption properties of hemoglobin, Schuman discussed using visible-light OCT to evaluate with very high resolution the oxygen saturation of the various layers of the eye attributable to the known absorption spectrum of hemoglobin. xref Used in conjunction with other technologies, such as OCTA or AO-SLO, structure and function can be evaluated simultaneously with visible-light OCT, providing powerful new insights into the pathology of eye disease. xref , xref "
sparser
"In future work, introduction of cell-type-specific fluorescent optogenetic reporters into other relevant cell types, including rods, Müller glia, and bipolar cells, will enable detection of individual cell–cell interactions in vivo with AO-SLO, while refined analysis with AO-OCT may reveal the fate of individual rods and other cells ( xref )."
sparser
"While these developments have been captured in prior reviews, they are often framed by what AO-OCT can achieve after all of its technological problems are overcome—capturing pristine 3D views of the cellular retina that are not possible using other imaging modalities such as AO-SLO and AO fundus ophthalmoscopy."
sparser
"AO-SLO revealed that nerve fiber bundles were narrowed but present in many areas in which NFL defects were observed on fundus photography and red-free SLO imaging. xref For this reason, we refer to abnormalities on AO-SLO images as “nerve fiber bundle narrowing” and those on red-free fundus photograph and red-free SLO imaging as “NFL defects.”"
sparser
"Here, we expand upon this earlier report by longitudinally characterizing persistent, widespread dark cones observed within and near the macula using multimodal AO scanning light ophthalmoscopy (AO-SLO) and AO optical coherence tomography (AO-OCT), alongside detailed analysis of retinal function in a patient with OT ( xref )."
sparser
"While a lower eccentricity-dependent decline of cone density was described for the horizontal meridians in histology and AO-SLO (referred as “cone streak”), a statistical difference was so far only reported by Park et al. who found the same effect of meridians on cone density as we did (N,T > I, S) at ecc 1.0mm, but not at other eccentricities [ xref – xref ]."
sparser
"The literature already contains an abundance of recent excellent reviews on high-resolution retinal imaging, mostly on the combination of AO and SLO (AO-SLO), including two in this journal ( xref , xref , xref , xref , xref , xref , xref , xref , xref ), and on the combination of AO and OCT (AO-OCT) ( xref , xref , xref ), the subject of this review."
sparser
"This stands in contrast to our previous AO-SLO observations of the cones at greater eccentricities, although it is in agreement with AO-OCT cone counts at the same locations. xref Also in disagreement with our more eccentric AO-SLO data, we did not find greater irregularity in cone packing, as measured by the standard deviation in the number of sides or in intercone distances."
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