SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Investigative ophthalmology & visual science

134

To assess the connection among arterioles, venules, and capillaries in three retinal capillary plexuses using optical coherence tomography angiography (OCTA).

112

Human pluripotent stem cell (hPSC)-derived retinal organoids are a platform for investigating retinal development, pathophysiology, and cellular therapies. In contrast to histologic analysis in which multiple specimens fixed at different times are used to reconstruct developmental processes, repeated analysis of the same living organoids provides a more direct means to characterize changes. New live imaging modalities can provide insights into retinal organoid structure and metabolic function during in vitro growth. This study employed live tissue imaging to characterize retinal organoid development, including metabolic changes accompanying photoreceptor differentiation.

Concepts: Developmental biology, Stem cell, Cell biology, Cellular differentiation, Tissue, Induced pluripotent stem cell, Pluripotency, Musical form

32

To characterize the ocular surface microbiome of healthy volunteers using a combination of microbial culture and high-throughput DNA sequencing techniques.

Concepts: Molecular biology, Biotechnology, DNA sequencing, Sequencing

29

To evaluate the efficacy of anti-VEGF agents for treating choroidal neovascularization (CNV) when delivered topically using novel cell-penetrating peptides (CPPs) compared with delivery by intravitreal (ivit) injection.

Concepts: Topical, Route of administration, Routes of administration

28

PURPOSE: To explore the diagnostic performance of threshold visual field tests using subsets of the Swedish Interactive Threshold Algorithm (SITA) standard 24-2 test pattern in detecting early/moderate glaucomatous field loss. METHODS: Normal (Brusini stage 0, n=2344) and defective eyes (Brusini stage 2-3, n=2222) from a database of visual field tests (6696 eyes/3586 patients, SITA standard 24-2 algorithm) were selected and re-sampled using a bootstrap method. The positive predictive values (PPV) of each test location were calculated for the re-sampled datasets with a fail criteria of a single missed stimulus at a pattern deviation probability level of <0.01. Optimized test patterns started with the most frequent location of the maximum PPV in datasets. Eyes missing the location were removed and the PPV values of residual sample recalculated. The process was repeated until all defective eyes were detected. Receiver operating characteristic (ROC) curves were established for the PPV-optimized and five randomized patterns. Characteristics of visual field defects detected with subsets of optimized test pattern were established. RESULTS: With the PPV-optimized pattern, 95% of the field defects were detected with 30 locations and all with 43 locations. Areas under the ROC curve were greatest for the optimized pattern. With each increment in the number of test locations, the Mean Deviation of additionally detected eyes became more positive while Pattern Standard Deviation became less positive (p<0.001). CONCLUSIONS: Good diagnostic performance can be obtained with optimized subsets of the current 24-2 stimulus pattern that can provide substantial savings in test times.

Concepts: Statistics, Median, Mean, Standard deviation, Receiver operating characteristic, Deviation, Visual field, Visual field test

28

Purpose. A large body of research has linked macular lutein and zeaxanthin to reduced risk of degenerative eye disease. The earliest published hypothesis for the role of the pigments was not based on chronic protection but immediate function. Recent data on macular pigment (MP) have shown that screening the foveal cones from short-wave light does, in fact, result in improvements in photostress recovery (PR), glare disability (GD) and chromatic contrast (CC). This study examined those relations on a larger sample. Methods. 150 young healthy subjects were assessed. Plasma samples were obtained from 100 subjects for HPLC quantification of serum xanthophylls. MP density was measured using customized heterochromatic flicker photometery. GD, PR and CC were measured in Maxwellian view using a broadband xenon light source. GD was measured by increasing the intensity of an annulus until it veiled a central target. PR was measured as the time necessary to regain sight of a central target after a 5 second exposure to an intense bleaching light. CC was measured as the amount of light necessary in a 460 nm background to lose sight of a central target. Results. MP density was significantly related to serum lutein and zeaxanthin combined (r = 0.31, p = 0.002), GD (r = 0.24, p = 0.0015), PR (r = -0.18, p = 0.01), and CC (r = 0.46, p = 0.00005). Conclusions. These results confirm earlier reports of a significant relation between variation in macular pigment optical density and immediate effects on visual function. As with many species, intra-ocular yellow filters in humans appear to improve many aspects of the visual stimulus.

Concepts: Optics, Eye, Photoreceptor cell, Carotenoid, Zeaxanthin, Macular degeneration, Lutein, Xanthophyll

28

CD40-CD40 ligand (CD40L) interactions appear to play pathogenic roles in autoimmune disease. Here we quantify CD40 expression on fibrocytes, circulating, and bone marrow-derived progenitor cells. The functional consequences of CD40 ligation are determined since these may promote tissue remodeling linked with thyroid-associated ophthalmopathy (TAO).

Concepts: Bacteria, Progenitor cell, Autoimmune disease, Graves' disease, Autoimmune diseases, Clusters of differentiation

28

To study the choroidal thickness in eyes with inferior posterior staphyloma (IPS) and to elucidate its role in the development of macular complications.

Concepts: Optics, Medical imaging, Eye, Ophthalmology, Tomography, Staphyloma

28

Although cortical visual impairment (CVI) is the leading cause of bilateral vision impairment in children in Western countries, little is known about the effects of CVI on visual function. The aim of this study was to compare visual evoked potential measures of contrast sensitivity and grating acuity in children with CVI with those of age-matched typically developing controls.

Concepts: Evoked potential, Ophthalmology, Visual impairment, Vision loss, Cortical visual impairment

28

PURPOSE: Muller glia respond to retinal injury by a reactive gliosis but only rarely do mammalian glial cells re-enter the cell cycle and generate new neurons. In the non-mammalian retina, however, Muller glia act as stem/progenitor cells. Here, we test the function of Wnt signaling in the post-injury retina, focusing on its ability to influence mammalian Muller cell de-differentiation, proliferation and neurogenesis. METHODS: A Nd:YAG laser was used to create light burns on the retina of Axin2(LacZ/+) Wnt reporter mice. At various timepoints after injury, retinas were analyzed for evidence of Wnt signaling as well as glial cell response, proliferation, and apoptosis. Laser injuries were also created in Axin2(LacZ/LacZ) mice, and the effect of potentiated Wnt signaling on retinal repair was assessed. RESULTS: A subpopulation of mammalian Muller cells are Wnt responsive and when Wnt signaling is increased these cells showed enchanced proliferation in response to injury. In an environment of heightened Wnt signaling, caused by the loss of Wnt negative regulator Axin2, Muller cells proliferate after injury and adopted the expression patterns of retinal progenitor cells (RPCs). The Wnt-responsive Muller cells also exhibited long-term survival and in some cases, expressed the rod photoreceptor marker, Rhodopsin. CONCLUSIONS: The Wnt pathway is activated by retinal injury, and prolonging the endogenous Wnt signal causes a subset of Muller cells to proliferate and de-differentiate into RPCs. These data raise the possibility that transient amplification of Wnt signaling after retinal damage may unlock the latent regenerative capacity long speculated to reside in mammalian neural tissues.

Concepts: Neuron, Retina, Myelin, Glial cell, Glial cells, Radial glia, Gliosis, Muller glia