scholarly journals Functional intrinsic optical signal imaging for objective optoretinography of human photoreceptors

2020 ◽  
pp. 153537022097889
Author(s):  
Taeyoon Son ◽  
Tae-Hoon Kim ◽  
Guangying Ma ◽  
Hoonsup Kim ◽  
Xincheng Yao
Keyword(s):  
Optical Coherence Tomography ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Disease Diagnosis ◽  
Optical Signal ◽  
Pupillary Response ◽  
Intrinsic Optical Signal ◽  
Treatment Assessment ◽  
Retinal Photoreceptors

Functional mapping of photoreceptor physiology is important for better disease diagnosis and treatment assessment. Fast intrinsic optical signal (IOS), which arises before light-evoked pupillary response, promises a unique biomarker of photoreceptor physiology for objective optoretinography with high resolution. This study is to test the feasibility of non-mydriatic IOS mapping of retinal photoreceptors in awake human. Depth-resolved optical coherence tomography verified outer segment (OS) as the anatomic origin of fast photoreceptor-IOS. Dynamic IOS changes are primarily confined at OS boundaries connected with inner segment and retinal pigment epithelium, supporting transient OS shrinkage due to phototransduction process as the mechanism of the fast photoreceptor-IOS response.

scholarly journals Interpretation of anatomic correlates of outer retinal bands in optical coherence tomography

2021 ◽  
pp. 153537022110226
Author(s):  
Xincheng Yao ◽  
Taeyoon Son ◽  
Tae-Hoon Kim ◽  
David Le
Keyword(s):  
Optical Coherence Tomography ◽  
Adaptive Optics ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Disease Diagnosis ◽  
Eye Disease ◽  
Optical Coherence ◽  
Outer Retina ◽  
The Third

By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and treatment evaluation. A better understanding of the hyper- and hypo-reflective bands in retinal OCT is essential for accurate interpretation of clinical outcomes. In this article, we summarize the interpretations of clinical OCT and adaptive optics (AO) OCT (AO-OCT) of the outer retina in the human eye, and briefly review OCT investigation of the outer retina in animal models. Quantitative analysis of outer retinal OCT bands is compared to established parameters of retinal histology. The literature review and comparative analysis support that both inner/outer segment (IS/OS) junction and IS ellipsoid zone nonexclusively contribute to the second band; and OS, OS tips, and retinal pigment epithelium apical processes contribute to the third band in conventional OCT. In contrast, AO-OCT might predominantly detect the IS/OS junction and OS tip signals at the second and third bands due to its improved sectioning capability and possible AO effect on the sensitivities for recording ballistic and diffusive photons from different regions of the outer retina.

Changes of outer retinal thickness with increasing age in normal eyes

2020 ◽  
Vol 1 (2) ◽  
pp. 108-112
Author(s):  
Zi-Jing Li ◽  
◽  
Jian-Hui Xiao ◽  
Peng Zeng ◽  
Xiang Gao ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Outer Segment ◽  
Retinal Thickness ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Layer ◽  
External Limiting Membrane ◽  
The Cost ◽  
The Relationship ◽  
Sd Oct

AIM: To comprehensively investigate the relationship between outer retinal layer thickness and age in normal eyes. METHODS: One hundred normal eyes of 100 subjects who underwent spectral-domain optical coherence tomography (SD-OCT) were included in this retrospective study. The distances between the external limiting membrane (ELM) line and the photoreceptor inner segment/outer segment (IS/OS) line (ELM-IS/OS), the IS/OS line and the cone outer segment tips (COST) line (IS/OS-COST), the COST line and the retinal pigment epithelium (RPE) complex (COST-RPE) and the full retinal thickness (RT) were measured at the fovea and on four quarters. The relationship between thickness and age or sex was then analysed. CONCLUSION: In normal eyes, the RT thickness on the nasal quarter and the ELM-IS/OS thickness were significantly and negatively correlated with age. The IS/OS-COST and COST-RPE thicknesses were not significantly correlated with age or sex.

The photoreceptor cytoskeleton visualized

1992 ◽  
Vol 50 (1) ◽  
pp. 480-481
Author(s):  
Beth Burnside
Keyword(s):  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Polarization ◽  
Synaptic Proteins ◽  
Cell Functions ◽  
Vertebrate Photoreceptor ◽  
Numerous Cell ◽  
Turn Over

The vertebrate photoreceptor provides a drammatic example of cell polarization. Specialized to carry out phototransduction at its distal end and to synapse with retinal interneurons at its proximal end, this long slender cell has a uniquely polarized morphology which is reflected in a similarly polarized cytoskeleton. Membranes bearing photopigment are localized in the outer segment, a modified sensory cilium. Sodium pumps which maintain the dark current critical to photosensory transduction are anchored along the inner segment plasma membrane between the outer segment and the nucleus.Proximal to the nucleus is a slender axon terminating in specialized invaginating synapses with other neurons of the retina. Though photoreceptor diameter is only 3-8u, its length from the tip of the outer segment to the synapse may be as great as 200μ. This peculiar linear cell morphology poses special logistical problems and has evoked interesting solutions for numerous cell functions. For example, the outer segment membranes turn over by means of a unique mechanism in which new disks are continuously added at the proximal base of the outer segment, while effete disks are discarded at the tip and phagocytosed by the retinal pigment epithelium. Outer segment proteins are synthesized in the Golgi near the nucleus and must be transported north through the inner segment to their sites of assembly into the outer segment, while synaptic proteins must be transported south through the axon to the synapse.The role of the cytoskeleton in photoreceptor motile processes is being intensely investigated in several laboratories.

scholarly journals Monitoring New Long-Lasting Intravitreal Formulation for Glaucoma with Vitreous Images Using Optical Coherence Tomography

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 217
Author(s):  
Maria Jesus Rodrigo ◽  
Amaya Pérez del Palomar ◽  
Alberto Montolío ◽  
Silvia Mendez-Martinez ◽  
Manuel Subias ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Relative Intensity ◽  
Therapeutic Option ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Aggregate Size ◽  
Daily Practice ◽  
Optical Coherence ◽  
Non Invasive ◽  
Invasive Method

Intravitreal injection is the gold standard therapeutic option for posterior segment pathologies, and long-lasting release is necessary to avoid reinjections. There is no effective intravitreal treatment for glaucoma or other optic neuropathies in daily practice, nor is there a non-invasive method to monitor drug levels in the vitreous. Here we show that a glaucoma treatment combining a hypotensive and neuroprotective intravitreal formulation (IF) of brimonidine–Laponite (BRI/LAP) can be monitored non-invasively using vitreoretinal interface imaging captured with optical coherence tomography (OCT) over 24 weeks of follow-up. Qualitative and quantitative characterisation was achieved by analysing the changes in vitreous (VIT) signal intensity, expressed as a ratio of retinal pigment epithelium (RPE) intensity. Vitreous hyperreflective aggregates mixed in the vitreous and tended to settle on the retinal surface. Relative intensity and aggregate size progressively decreased over 24 weeks in treated rat eyes as the BRI/LAP IF degraded. VIT/RPE relative intensity and total aggregate area correlated with brimonidine levels measured in the eye. The OCT-derived VIT/RPE relative intensity may be a useful and objective marker for non-invasive monitoring of BRI/LAP IF.

scholarly journals Metabolism in the Zebrafish Retina

2021 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Natalia Jaroszynska ◽  
Philippa Harding ◽  
Mariya Moosajee
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
The Body ◽  
Therapeutic Approaches ◽  
Retinal Photoreceptors ◽  
Sufficient Energy ◽  
Metabolic Products ◽  
Sight Loss ◽  
Choroidal Vasculature ◽  
The Brain

Retinal photoreceptors are amongst the most metabolically active cells in the body, consuming more glucose as a metabolic substrate than even the brain. This ensures that there is sufficient energy to establish and maintain photoreceptor functions during and after their differentiation. Such high dependence on glucose metabolism is conserved across vertebrates, including zebrafish from early larval through to adult retinal stages. As the zebrafish retina develops rapidly, reaching an adult-like structure by 72 hours post fertilisation, zebrafish larvae can be used to study metabolism not only during retinogenesis, but also in functionally mature retinae. The interplay between rod and cone photoreceptors and the neighbouring retinal pigment epithelium (RPE) cells establishes a metabolic ecosystem that provides essential control of their individual functions, overall maintaining healthy vision. The RPE facilitates efficient supply of glucose from the choroidal vasculature to the photoreceptors, which produce metabolic products that in turn fuel RPE metabolism. Many inherited retinal diseases (IRDs) result in photoreceptor degeneration, either directly arising from photoreceptor-specific mutations or secondary to RPE loss, leading to sight loss. Evidence from a number of vertebrate studies suggests that the imbalance of the metabolic ecosystem in the outer retina contributes to metabolic failure and disease pathogenesis. The use of larval zebrafish mutants with disease-specific mutations that mirror those seen in human patients allows us to uncover mechanisms of such dysregulation and disease pathology with progression from embryonic to adult stages, as well as providing a means of testing novel therapeutic approaches.

scholarly journals Directional optical coherence tomography reveals melanin concentration-dependent scattering properties of retinal pigment epithelium

2019 ◽  
Vol 24 (06) ◽  
pp. 1 ◽  
Author(s):  
Ratheesh K. Meleppat ◽  
Pengfei Zhang ◽  
Myeong Jin Ju ◽  
Suman K. Manna ◽  
Yifan Jian ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Optical Coherence

scholarly journals Optical Coherence Tomography: An Adjunctive Tool for Differentiating between Choroidal Melanoma and Metastasis

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Vicktoria Vishnevskia-Dai ◽  
Dinah Zur ◽  
Shiran Yaacobi ◽  
Iris Moroz ◽  
Hadas Newman ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Retinal Thickness ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Choroidal Melanoma ◽  
Case Series ◽  
Subretinal Fluid ◽  
Optical Coherence ◽  
Choroidal Melanomas ◽  
Anterior Choroidal

Purpose.To investigate the value of optical coherence tomography (OCT) for differentiation between choroidal melanoma and metastasis based on characteristics of the anterior choroidal surface and the chorioretinal interface.Methods.This retrospective observational case series included 29 patients with untreated choroidal melanomas and 21 patients with untreated choroidal metastases. Regularity and lobularity characteristics of the anterior choroidal surface were evaluated in a masked manner. Retinal and retinal pigment epithelium (RPE) findings were documented as well.Results.OCT demonstrated a regular and smooth anterior choroidal surface in 89.7% of the eyes with melanoma and in 47.6% of the eyes with metastasis (p=0.002; sensitivity = 89.7%; specificity = 52.4%). The anterior choroidal contour was lobulated in 81.0% of the eyes with metastasis versus 17.2% of the eyes with melanoma (p<0.001; sensitivity = 82.8%; specificity = 81.0%). RPE thickness and neuroretinal characteristics (e.g., retinal thickness, the presence of cysts, and the presence of subretinal fluid) were similar in both choroidal tumors.Conclusion. OCT may serve as a noninvasive adjunctive tool for the differential diagnosis of choroidal tumors. Choroidal melanomas usually demonstrate regular surfaces on OCT, while choroidal metastases usually have an irregular and lobulated surface.

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