Indiana University-Purdue University Indianapolis (IUPUI) / In glaucoma, the connection between the eye and the brain is severed leading to the degeneration of retinal ganglion cells (RGCs) and eventual blindness. A need exists to better understand the maturation of human RGCs as well as their degeneration, with the goal of developing new therapeutics diseases like glaucoma. Human pluripotent stem cells (hPSCs) provide an advantageous model for the study of RGC development and disease as they can be differentiated into RGCs in large, reproducible quantities. Efforts of the current studies initially focused on the development and maturation of RGCs from hPSCs. RGCs derived from hPSCs were a diverse population of cells and matured in a temporal fashion, yielding morphological and functional characteristics similar to their in vivo counterpart. CRISPR/Cas9 gene editing was then utilized to insert the OPTN(E50K) glaucomatous mutation into hPSCs to model RGC degeneration. RGCs harboring this mutation exhibited numerous degenerative phenotypes including neurite retraction an autophagy dysfunction. Within the retina, many cell types contribute to the health and maturation of RGCs including astrocytes. As such, a co-culture system of hPSC-derived RGCs and astrocytes was developed to better understand the interaction between these two cell types. When grown in co-culture with astrocytes, hPSC-derived RGCs demonstrated significantly enhanced and accelerated morphological and functional maturation, indicating an important relationship between these cells in a healthy state. Astrocytes have also been shown to encompass neurodegenerative phenotypes in other diseases of the CNS, with these deficits profoundly effecting the health of surrounding neurons. hPSC-derived astrocytes grown from OPTN(E50K)-hPSCs demonstrated cell autonomous deficits and exhibited significant effects on the degeneration of RGCs. Taken together, results of this study demonstrated the utilization of hPSCs to model RGC maturation and degeneration in glaucoma. More so, these results are one of the first to characterize astrocyte deficits caused by the OPTN(E50K) mutation and could provide a new therapeutic target for pharmacological screenings and cell replacement therapies to reverse blindness in optic neuropathies.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18499号 / 医博第3919号 / 新制||医||1005(附属図書館) / 31385 / 京都大学大学院医学研究科医学専攻 / (主査)教授 伊藤 壽一, 教授 河野 憲二, 教授 富樫 かおり / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19608号 / 医博第4115号 / 新制||医||1015(附属図書館) / 32644 / 京都大学大学院医学研究科医学専攻 / (主査)教授 大森 孝一, 教授 鈴木 茂彦, 教授 影山 龍一郎 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

yes / Purpose: To evaluate the structure–function relationship between disc margin–based rim area (DM-RA) obtained with confocal scanning laser tomography (CSLT), Bruch's membrane opening–based horizontal rim width (BMO-HRW), minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer thickness (RNFLT) obtained with spectral-domain optical coherence tomography (SD-OCT), and visual field sensitivity. Methods: We examined 151 glaucoma patients with CSLT, SD-OCT, and standard automated perimetry on the same day. Optic nerve head (ONH) and RNFL with SD-OCT were acquired relative to a fixed coordinate system (acquired image frame [AIF]) and to the eye-specific fovea-BMO center (FoBMO) axis. Visual field locations were mapped to ONH and RNFL sectors with fixed Garway-Heath (VFGH) and patient-specific (VFPS) maps customized for various biometric parameters. Results: Globally and sectorally, the structure–function relationships between DM-RA and VFGH, BMO-HRWAIF and VFGH, and BMO-HRWFoBMO and VFPS were equally weak. The R2 for the relationship between DM-RA and VFGH ranged from 0.1% (inferonasal) to 11% (superotemporal) whereas that between BMO-HRWAIF and VFGH ranged from 0.1% (nasal) to 10% (superotemporal). Relatively stronger global and sectoral structure–function relationships with BMO-MRWAIF and with BMO-MRWFoBMO were obtained. The R2 between BMO-MRWAIF and VFGH ranged from 5% (nasal) to 30% (superotemporal), whereas that between BMO-MRWFoBMO and VFPS ranged from 5% (nasal) to 25% (inferotemporal). The structure–function relationship with RNFLT was not significantly different from that with BMO-MRW, regardless of image acquisition method. Conclusions: The structure–function relationship was enhanced with BMO-MRW compared with the other neuroretinal rim measurements, due mainly to its geometrically accurate properties.

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Yes / Combining information from optical coherence tomography (OCT) imaging and visual field testing is useful in the clinical assessment and monitoring of patients with glaucoma. Measurements of retinal nerve fibre layer thickness or neuroretinal rim width taken around the optic nerve head may be related to the visual field using a structure–function map. In this review, the structure–function mapping methods in clinical use are discussed. Typical clinical maps provide a population average, ‘one size fits all’ representation, but in recent years methods for customising structure–function maps to individual eyes have been developed and these are reviewed here. In the macula, visual field stimuli stimulate photoreceptors for which associated retinal ganglion cells are peripherally displaced. Recently developed methods that relate OCT measurements to visual field test locations in the macula are therefore also reviewed. The use of structure–function maps to relate OCT measurements to localised visual field sensitivity in new applications is also explored. These new applications include the selection of visual field test locations and stimulus intensities based on OCT data, and the formal post‐test combination of results across modalities. Such applications promise to exploit the structure–function relationship in glaucoma to improve disease diagnosis and monitoring of progression. Limitations in the validation and use of current structure–function mapping techniques are discussed. / >Heidelberg Engineering >Australian Research Council. Grant Number: LP130100055 >College of Optometrists. Grant Number: College of Optometrists Research Fellowship

Yes / The purpose of this study was to isolate and quantify the effects of observer response criterion on perimetric sensitivity, response variability, and maximum response probability. Twelve people with glaucoma were tested at three locations in the visual field (age = 47-77 years, mean deviation = -0.61 to -14.54 dB, test location Humphrey field analyzer [HFA] sensitivities = 1 to 30 dB). Frequency of seeing (FoS) curves were measured using a method of constant stimuli with two response paradigms: a "yes-no" paradigm similar to static automated perimetry and a criterion-free two interval forced choice (2IFC) paradigm. Comparison measures of sensitivity, maximum response probability, and response variability were derived from the fitted FoS curves. Sensitivity differences between the tasks varied widely (range = -11.3 dB to 21.6 dB) and did not correlate with visual field sensitivity nor whether the visual field location was in an area of steep sensitivity gradient within the visual field. Due to the wide variation in differences between the methods, there was no significant difference in mean sensitivity between the 2IFC task relative to the yes-no task, but a trend for higher sensitivity (mean = 1.9 dB, SD = 6.0 dB, P = 0.11). Response variability and maximum response probability did not differ between the tasks (P > 0.99 and 0.95, respectively). Perimetric sensitivity estimates are demonstrably altered by observer response criterion but the effect varies widely and unpredictably, even within a single test. Response bias should be considered a factor in perimetric test variability and when comparing sensitivities to nonperimetric data. The effect of response criterion on perimetric response variability varies widely and unpredictably, even within a single test. / Supported by ARC LP130100055; ARC LP150100815 (AT and AMM), College of Optometrists Research Fellowship (JD).

Yes / Measuring the spatial extent of defects may be advantageous in advanced glaucoma where conventional perimetric sensitivity measurements are unreliable. We test whether suprathreshold tests on a higher density grid can more efficiently map advanced visual field loss. Data from 97 patients with mean deviation / Supported by a College of Optometrists Research Fellowship (to JD).

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This study investigated the morphologic differences of the giant vacuoles (GVs) in the inner wall endothelium of Schlemm’s canal (SC) in human eyes perfused at either 30 mmHg or 7 mmHg (physiologic pressure in enucleated eyes) using serial block-face scanning electron microscopy (SBF-SEM) paired with three-dimensional reconstruction software. Two normal human eyes were perfused at 30 mmHg with fluorescent tracers to mark regions of active and inactive flow, followed by perfusion-fixation. Tissue wedges (n = 6) of trabecular meshwork including SC from high-, low-, and non-flow areas of each eye (determined by tracer distribution) were dissected and processed for SBF-SEM. Four types of GVs were identified: Type I GVs which lack both a basal opening and an Ipore; Type II GVs which have a basal opening but lack an I-pore; Type III GVs which have an I-pore but lack a basal opening; and Type IV GVs which possess both a basal opening and an I-pore. Types and spans of GVs were collected from the SBF-SEM images, and volumes of GVs from a random subset were measured using 3D reconstruction. Results were compared with findings from an earlier study conducted with two eyes perfused at 7 mmHg and prepared in the same manner (Soares, 2022). In total, 19,047 SBF-SEM images were analyzed between 7 mmHg (n = 9586) and 30 mmHg (n = 9461) using Reconstruct. Statistical analysis comparing data between the two pressures was performed using R. There were more GVs found at 30 mmHg (n = 1541) when compared with 7 mmHg (n = 1312), and there were more Type IV GVs at 30 mmHg when compared with 7 mmHg. Type IV GVs occurred most frequently in high-flow areas at both pressures. GVs with I-pores were greater in size (both span and volume) than GVs without I-pores in all flow areas at both pressures. Type IV GVs were larger than Type II GVs which were larger than Type I GVs at both pressures. The span of GVs without I-pores was significantly greater at 7 mmHg. However, there was no significant difference between the volumes of GVs with or without I-pores between the two pressures. The result that GVs with I-pores were larger in size than GVs without I-pores at all conditions appears to support the theory that GV size is an important contributing factor to I-pore formation. The differences in span but not volume of GVs without I-pores between two pressures suggest that GVs at high pressure may be more convex in shape and may protrude further into SC, a situation which could contribute to thinning of the cellular membrane of GVs. Finally, the result that more Type IV GVs were found in high-flow areas at both pressures implies that the changing percentage of Type IV GVs likely plays a role in regulating segmental flow. / 2025-02-26T00:00:00Z