Two-Photon Scanning Laser Ophthalmoscope

Kamali, Tschackad; Farrell, Spencer; Baldridge, William H.; Fischer, Jörg; Chauhan, Balwantray C.

doi:10.1007/978-3-030-16638-0_9

Cited by 3 publications

(2 citation statements)

References 52 publications

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“…full-field), direction and orientation selectivity, and temporal/contrast/chromatic discrimination are missing and which would allow more specific and accurate analysis of RGC functional type; and 3) the lack of additional fluorescence channels, which would allow use of molecular markers, and of multisensor simultaneous detection. Future incorporation of a 2P excitation laser into cSLO ( 75 – 77 ) will allow invisible infrared light to be used for GECI excitation and minimize activation of photoreceptors by excitation light. This improvement will make it possible to use visible light with static and moving spot or bars to specifically stimulate rods, cones, or both and to acquire fully the spectrum of RGC activities, especially those of direction-selective RGCs that we currently cannot appreciate.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Xue

Fang

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Retinal ganglion cells (RGCs) are heterogeneous projection neurons that convey distinct visual features from the retina to brain. Here, we present a high-throughput in vivo RGC activity assay in response to light stimulation using noninvasive Ca 2+ imaging of thousands of RGCs simultaneously in living mice. Population and single-cell analyses of longitudinal RGC Ca 2+ imaging reveal distinct functional responses of RGCs and unprecedented individual RGC activity conversions during traumatic and glaucomatous degeneration. This study establishes a foundation for future in vivo RGC function classifications and longitudinal activity evaluations using more advanced imaging techniques and visual stimuli under normal, disease, and neural repair conditions. These analyses can be performed at both the population and single-cell levels using temporal and spatial information, which will be invaluable for understanding RGC pathophysiology and identifying functional biomarkers for diverse optic neuropathies.

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Section: Discussionmentioning

confidence: 99%

Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Xue

Fang

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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“…The innovative experiments by the Hunter [ 26 ] and Palczewski groups [ 27 ] demonstrate the feasibility and safety of two-photon excitation of fluorescence in the living retinas of animal models and, more recently, in living humans. One manufacturer has shown the adaptation of a short-pulse laser to a commercial scanning laser ophthalmoscope [ 28 ] for multiphoton excitation; the principal change required (in addition to the laser and filters) was the insertion of optics to correct for the effects of wavelength dispersion on the pulse duration.…”

Section: Discussionmentioning

confidence: 99%

Two-Photon Excited Fluorescence Lifetime Imaging of Tetracycline-Labeled Retinal Calcification

Hegde,

Ray,

Szmacinski

et al. 2023

Sensors

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Deposition of calcium-containing minerals such as hydroxyapatite and whitlockite in the subretinal pigment epithelial (sub-RPE) space of the retina is linked to the development of and progression to the end-stage of age-related macular degeneration (AMD). AMD is the most common eye disease causing blindness amongst the elderly in developed countries; early diagnosis is desirable, particularly to begin treatment where available. Calcification in the sub-RPE space is also directly linked to other diseases such as Pseudoxanthoma elasticum (PXE). We found that these mineral deposits could be imaged by fluorescence using tetracycline antibiotics as specific stains. Binding of tetracyclines to the minerals was accompanied by increases in fluorescence intensity and fluorescence lifetime. The lifetimes for tetracyclines differed substantially from the known background lifetime of the existing natural retinal fluorophores, suggesting that calcification could be visualized by lifetime imaging. However, the excitation wavelengths used to excite these lifetime changes were generally shorter than those approved for retinal imaging. Here, we show that tetracycline-stained drusen in post mortem human retinas may be imaged by fluorescence lifetime contrast using multiphoton (infrared) excitation. For this pilot study, ten eyes from six anonymous deceased donors (3 female, 3 male, mean age 83.7 years, range 79–97 years) were obtained with informed consent from the Maryland State Anatomy Board with ethical oversight and approval by the Institutional Review Board.

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Sejtszintű képalkotás a retina in vivo vizsgálatában: jelen és jövő

Végh

Magda

Kilin

et al. 2021

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Összefoglaló. A látószerv különböző betegségei, valamint egyes szisztémás megbetegedések részben vagy kifejezetten az ideghártya károsodásával járnak. A patológia segítségével ma már tudjuk, hogy ezek a betegségek a retina mely rétegének vagy rétegeinek elváltozásait okozzák: míg az időskori maculadegeneratio a külső retinában található fotoreceptorokat érinti kifejezetten a fovea centralis területén, addig a glaucoma a belső retina ganglionsejtjeinek pusztulásával, valamint e sejtek opticusrostjainak károsodásával jár a stratum ganglionaréban és a stratum neurofibrarumban. Az emberi retina sejtjei azonban egyelőre nem maradéktalanul karakterizáltak, az egyes sejttípusok számát csak becsülni tudjuk, így nem írhatók le az egyes sejtszintű elváltozások sem kellő pontossággal. A szövettani feldolgozás és vizsgálat megfelelő részletességgel tájékoztat a diagnózisról és az elváltozás súlyosságáról, értelemszerűen azonban ez a módszer in vivo nem használható a mindennapi klinikai gyakorlatban. A sejtszintű elváltozások ismerete az egyes kórképekben felvetette és szükségessé tette olyan in vivo, a klinikumban is alkalmazható vizsgálómódszerek kifejlesztését, amelyek lehetőséget nyújtanak a retina neurális és egyéb sejtjeinek celluláris és szubcelluláris szintű vizsgálatára, ideértve a vér alakos elemeit is, amelyek egészséges vagy neovascularis eredetű erekben áramlanak. A jelenleg is használt klinikai vizsgálatok mellett ezek a képalkotó módszerek segítségül szolgálhatnak a diagnózis megerősítésében vagy elvetésében, emellett az elváltozás súlyosságának megítélésében, valamint a progresszió vagy remisszió monitorozásában. Orv Hetil. 2021; 162(22): 851–860. Summary. Diseases of the visual system as well as many systemic illnesses are usually associated with retinal damage. With the help of pathology, we can clearly identify the affected layer(s): while age-related macular degeneration mostly damages the photoreceptors in the outer retina at the central fovea, glaucoma promotes ganglion cell death in the ganglion cell layer and damages respective neural fibers. However, the diverse cell types of the human retina have not been fully characterized yet, thus in most cases our knowledge on cellular pathologies is not precise enough. While histopathological preparation and examination of the retinal tissue provide more detailed information about the diagnosis and the severity of the condition, unfortunately, it cannot be used in vivo in everyday clinical practice. Our understanding of the cellular changes in different diseases has revealed a need for new everyday clinical examination methods that can be used in vivo to asses cellular and subcellular changes in neural and other cells of the retina, such as blood cells flowing in healthy vessels or in vessels of neovascular origin. In addition to the currently used clinical examination methods, these imaging methods could help confirm or dismiss diagnoses, assess the severity of a condition, and monitor disease progression or remission. Orv Hetil. 2021; 162(22): 851–860.

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Two-Photon Scanning Laser Ophthalmoscope

Cited by 3 publications

References 52 publications

Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Two-Photon Excited Fluorescence Lifetime Imaging of Tetracycline-Labeled Retinal Calcification

Sejtszintű képalkotás a retina in vivo vizsgálatában: jelen és jövő

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Two-Photon Scanning Laser Ophthalmoscope

Cited by 3 publications

References 52 publications

Longitudinal in vivo Ca 2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Longitudinal in vivo Ca 2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Two-Photon Excited Fluorescence Lifetime Imaging of Tetracycline-Labeled Retinal Calcification

Sejtszintű képalkotás a retina in vivo vizsgálatában: jelen és jövő

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Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

Longitudinal in vivo Ca ²⁺ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level