September 2021

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Ahangari N, Munoz DG, Coulombe J, Gray DA, Engle EC, Cheng L, Woulfe J. Nuclear IMPDH Filaments in Human Gliomas. J Neuropathol Exp Neurol 2021;Abstract
The analysis of nuclear morphology plays an important role in glioma diagnosis and grading. We previously described intranuclear rods (rods) labeled with the SDL.3D10 monoclonal antibody against class III beta-tubulin (TUBB3) in human ependymomas. In a cohort of adult diffuse gliomas, we identified nuclear rods in 71.1% of IDH mutant lower-grade gliomas and 13.7% of IDH wild-type glioblastomas (GBMs). The presence of nuclear rods was associated with significantly longer postoperative survival in younger (≤65) GBM patients. Consistent with this, nuclear rods were mutually exclusive with Ki67 staining and their prevalence in cell nuclei inversely correlated with the Ki67 proliferation index. In addition, rod-containing nuclei showed a relative depletion of lamin B1, suggesting a possible association with senescence. To gain insight into their functional significance, we addressed their antigenic properties. Using a TUBB3-null mouse model, we demonstrate that the SDL.3D10 antibody does not bind TUBB3 in rods but recognizes an unknown antigen. In the present study, we show that rods show immunoreactivity for the nucleotide synthesizing enzymes inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthetase. By analogy with the IMPDH filaments that have been described previously, we postulate that rods regulate the activity of nucleotide-synthesizing enzymes in the nucleus by sequestration, with important implications for glioma behavior.
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Böhm M, Müller M, Paul J, Hemkeppler E, Kohnen T. Intraoperative OCT versus Scheimpflug and Swept-Source OCT measurements for anterior eye parameters. J Cataract Refract Surg 2021;Abstract
PURPOSE: To compare agreement of anterior segment parameter measurements using an intraoperative optical coherence tomography (iOCT) of a femtosecond laser (LenSx) during interface docking to the eye to preoperative Scheimpflug-tomography (Pentacam AXL) and swept-source optical coherence tomography (IOL Master 700). SETTING: Department of Ophthalmology, Goethe University, Frankfurt, Germany. DESIGN: Retrospective study. METHODS: Ninty-five eyes of 66 patients who had planned OCT-guided femtosecond laser-assisted lens surgery were included. Anterior segment measurements were performed in mydriasis prior to surgery using Scheimpflug-tomography and swept-source optical coherence tomography. After surgery iOCT images were analysed using a modification of the FIJI image processing program. Outcome measures included external anterior chamber depth (ACD), central corneal thickness (CCT) and central lens thickness (LT). RESULTS: The ACD measured with the iOCT was -0.011±0.126mm smaller (p=0.389) than with theswept-source OCT and -0.059±0.185mm than with the Scheimpflug-tomography (p=0.003). The swept-source OCT measures a -0.047±0.146mm smaller ACD than the Scheimpflug-tomography (p=0.002). The measurements of CCT using the iOCT and the Scheimpflug-tomography (-0.705±20.837μm, p=0.742) and the LT measurements of swept-source OCT and iOCT (-0.050±0.089mm, p<0.001) show no clinically relevant difference. Just the ACD between the iOCT and the Scheimpflug-tomography shows a clinically relevant difference. CONCLUSION: The comparison of the anterior segment parameters of intraoperative optical coherence tomography with swept-source optical coherence tomography showed no clinically relevant differences regarding the ACD and the lens thickness. However, Scheimpflug-tomography versus intraoperative optical coherence tomography measures a small clinically relevant difference for ACD.
Boland MV, Corcoran KJ, Lee AY. Changes in Performance of Glaucoma Surgeries 1994 through 2017 Based on Claims and Payment Data for United States Medicare Beneficiaries. Ophthalmol Glaucoma 2021;4(5):463-471.Abstract
PURPOSE: To evaluate trends in glaucoma procedures in the United States Medicare population and to evaluate which physicians are performing newer procedures. DESIGN: Analysis of publicly available claims and payment data. PARTICIPANTS: Surgeons and beneficiaries enrolled in United States Medicare between 1994 and 2017. METHODS: Data regarding payments to physicians by the Centers for Medicare and Medicaid Services (CMS) were downloaded for the years 2012 through 2017. Data regarding claims to CMS by physicians were requested and processed between 1994 and 2017. Procedure counts from both data sets then were normalized for changes in the Medicare population, with 1995 as the baseline. The normalized volumes of procedures over time were visualized, as were geographic distributions of surgeons and their volume of procedures. MAIN OUTCOME MEASURES: Trends in procedure counts over time, geographic distribution of surgeons, and their volume of procedures. RESULTS: The number of trabeculectomies continues to decline and now is similar to the number of tubes. Use of the relatively new trabecular bypass shunts has increased rapidly. Surgeons performing these procedures are less likely to be performing traditional glaucoma surgeries as well. The number of laser-based cyclodestruction procedures increased after introduction of the endoscopic technique and again with the introduction of so-called micropulse procedures. The procedure counts obtained with physician payment data consistently are lower than those from claims data given the limitations of the payment data. CONCLUSIONS: Glaucoma practice patterns change each time a new device or procedure is introduced. Collectively, the use of new microinvasive glaucoma surgery procedures has increased rapidly such that they now account for a significant majority of glaucoma surgeries. Given the almost complete lack of comparative data to inform surgeon choices regarding these procedures, it will be important that randomized studies are carried out to fill this gap.
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Chandramouli SA, Glaser TS, Umunakwe O, Gupta D, Margeta MA, Challa P, Kuo AN, Freedman SF. Glaucoma Drainage Devices Calculator App: A Modern Clinical Decision Tool. Ophthalmol Glaucoma 2021;4(5):550-551.
Cui Y, Zhu Y, Lu ES, Le R, Laíns I, Katz R, Wang JC, Garg I, Lu Y, Zeng R, Eliott D, Vavvas DG, Husain D, Miller JW, Kim LA, Wu DM, Miller JB. Widefield Swept-Source OCT Angiography Metrics Associated with the Development of Diabetic Vitreous Hemorrhage: A Prospective Study. Ophthalmology 2021;128(9):1312-1324.Abstract
PURPOSE: To investigate the association among widefield swept-source (SS) OCT angiography (OCTA) metrics and systemic parameters and vitreous hemorrhage (VH) occurrence in eyes with proliferative diabetic retinopathy (PDR). DESIGN: Prospective, observational study. PARTICIPANTS: Fifty-five eyes from 45 adults with PDR, with no history of VH, followed up for at least 3 months. METHODS: All patients underwent widefield SS OCTA (Montage 15 × 15 mm and high-definition (HD)-51 line scan) imaging. Images were evaluated independently by 2 graders for quantitative and qualitative widefield SS OCTA metrics defined a priori. Systemic and ocular parameters and widefield SS OCTA metrics were screened using least absolute shrinkage and selection operator and logistic or Cox regression for variable selection. Firth's bias-reduced logistic regression models (outcome, occurrence of VH) and Cox regression models (outcome, time to occurrence of VH) were used to identify parameters associated with VH occurrence. MAIN OUTCOME MEASURES: Occurrence of VH. RESULTS: Over a median follow-up of 363 days (range, 28-710 days), 13 of 55 PDR eyes (24%) demonstrated VH during the follow-up period. Presence of extensive neovascularizations (odds ratio, 8.05; 95% confidence interval [CI], 1.43-58.56; P = 0.02), defined as neovascularizations with total area of more than 4 disc diameters, and forward neovascularizations (odds ratio, 5.42; 95% CI, 1.26-35.16; P = 0.02) that traversed the posterior hyaloid face into the vitreous were associated with the occurrence of VH. The presence of flat neovascularizations (odds ratio, 0.25; 95% CI, 0.04-1.01; P = 0.05) confined to the posterior hyaloid face was associated with a lower risk of VH with borderline significance. Similarly, presence of extensive neovascularizations (hazard ratio, 18.24; 95% CI, 3.51-119.47; P < 0.001) and forward neovascularizations (hazard ratio, 9.60; 95% CI, 2.07-68.08; P = 0.002) was associated significantly with time to development of VH. CONCLUSIONS: Widefield SS OCTA is useful for evaluating neovascularizations and their relationship with the vitreous. The presence of forward and extensive neovascularizations was associated with the occurrence of VH in patients with PDR. Larger samples and longer follow-up are needed to verify the risk factors and imaging biomarkers for diabetic VH.
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Dana R, Farid M, Gupta PK, Hamrah P, Karpecki P, McCabe CM, Nijm L, Pepose JS, Pflugfelder S, Rapuano CJ, Saini A, Gibbs SN, Broder MS. Expert consensus on the identification, diagnosis, and treatment of neurotrophic keratopathy. BMC Ophthalmol 2021;21(1):327.Abstract
BACKGROUND: Neurotrophic keratopathy (NK) is a relatively uncommon, underdiagnosed degenerative corneal disease that is caused by damage to the ophthalmic branch of the trigeminal nerve by conditions such as herpes simplex or zoster keratitis, intracranial space-occupying lesions, diabetes, or neurosurgical procedures. Over time, epithelial breakdown, corneal ulceration, corneal melting (thinning), perforation, and loss of vision may occur. The best opportunity to reverse ocular surface damage is in the earliest stage of NK. However, patients typically experience few symptoms and diagnosis is often delayed. Increased awareness of the causes of NK, consensus on when and how to screen for NK, and recommendations for how to treat NK are needed. METHODS: An 11-member expert panel used a validated methodology (a RAND/UCLA modified Delphi panel) to develop consensus on when to screen for and how best to diagnose and treat NK. Clinicians reviewed literature on the diagnosis and management of NK then rated a detailed set of 735 scenarios. In 646 scenarios, panelists rated whether a test of corneal sensitivity was warranted; in 20 scenarios, they considered the adequacy of specific tests and examinations to diagnose and stage NK; and in 69 scenarios, they rated the appropriateness of treatments for NK. Panelist ratings were used to develop clinical recommendations. RESULTS: There was agreement on 94% of scenarios. Based on this consensus, we present distinct circumstances when we strongly recommend or may consider a test for corneal sensitivity. We also present recommendations on the diagnostic tests to be performed in patients in whom NK is suspected and treatment options for NK. CONCLUSIONS: These expert recommendations should be validated with clinical data. The recommendations represent the consensus of experts, are informed by published literature and experience, and may improve outcomes by helping improve diagnosis and treatment of patients with NK.
Douglas KA, Douglas VP, Gaier ED, Chwalisz BK. Ptosis as Clinical Presentation in a Patient With Emery-Dreifuss Muscular Dystrophy Type 5. J Neuroophthalmol 2021;41(3):e333-e334.
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Foulsham W, Chen XN, Vavvas DG. ALTITUDE-ASSOCIATED INTRAOCULAR PRESSURE CHANGES IN A GAS-FILLED EYE. Retin Cases Brief Rep 2021;15(5):564-567.Abstract
PURPOSE: Intraocular gases are commonly used in vitreoretinal surgery. Patients are routinely advised against air travel before the complete absorption of intraocular gas. Consequently, reports on air travel in patients with large intraocular gas bubbles are highly unusual. Here, we report the intraocular pressure changes of a patient ascending to an altitude of 2,600 feet in a helicopter with a 50% fill perfluoropropane (C3F8) gas bubble in his left eye. METHODS: Case report and literature review. RESULTS: A 61-year-old male patient underwent pars plana vitrectomy for a rhegmatogenous retinal detachment, with fluid-gas exchange using 16% C3F8. With a 50% fill bubble in the left eye, the patient took a short helicopter trip ascending to a maximum altitude of 2,600 feet. Before take-off, intraocular pressure in the operated eye was 14 mmHg. The average increase in intraocular pressure was 10.8 mmHg per 1,000 feet of ascent, with a maximum recorded intraocular pressure of 42 mmHg. The patient denied both ocular pain and loss of vision but did report changes in the appearance of the gas bubble meniscus at 2,100 feet. CONCLUSION: Short-term low-altitude air travel may be tolerated by some patients with intraocular gas in situ. Further studies are required to define the conditions by which patients with gas bubbles may fly safely.
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Laíns I, Wang JC, Cui Y, Katz R, Vingopoulos F, Staurenghi G, Vavvas DG, Miller JW, Miller JB. Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Prog Retin Eye Res 2021;84:100951.Abstract
The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.
Li Y, Mitchell W, Elze T, Zebardast N. Association Between Diabetes, Diabetic Retinopathy, and Glaucoma. Curr Diab Rep 2021;21(10):38.Abstract
PURPOSE OF REVIEW: The strength of the relationship between diabetes, diabetic retinopathy (DR), and glaucoma remains controversial. We review evidence supporting and refuting this association and explore mechanistic pathological and treatment relationships linking these diseases. RECENT FINDINGS: While studies have shown diabetes/DR may increase the risk for glaucoma, this remains inconsistently demonstrated. Diabetes/DR may contribute toward glaucomatous optic neuropathy indirectly (either by increasing intraocular pressure or vasculopathy) or through direct damage to the optic nerve. However, certain elements of diabetes may slow glaucoma progression, and diabetic treatment may concurrently be beneficial in glaucoma management. Diabetes plays a significant role in poor outcomes after glaucoma surgery. While the relationship between diabetes/DR and glaucoma remains controversial, multiple mechanistic links connecting pathophysiology and management of diabetes, DR, and glaucoma have been made. However, a deeper understanding of the causes of disease association is needed.
Liou V, Yoon M. Comparative Incidence of Periocular Surgical Site Infections with Increased Surgical Mask Use during the COVID-19 Pandemic. Ocul Immunol Inflamm 2021;:1-6.Abstract
PURPOSE: To evaluate the effect of surgical mask use on infection rates for office-based periocular surgeries during the pandemic. METHODS: An Institutional Review Board-approved retrospective review of medical records identified patients who had an office-based oculofacial plastic surgery procedure during the pandemic between March and December 2020. Statistical analysis was used to compare this group to patients that underwent procedures between March and December 2019, prior to the pandemic when neither surgeon nor patient wore a surgical mask. RESULTS: The study consisted of 680 patients. Thirty-one different types of procedures were encountered. The incidence of infections in 2020 compared to 2019 was not statistically significant (1.12% (n = 3) versus 1.21% (n = 5), p = 1). All patients with infections were treated with oral antibiotics and improved without long-term complications. CONCLUSIONS: Periocular surgical site infections are uncommon, and the wearing of surgical masks by patient and surgeon during our office-based oculofacial procedures did not change the incidence of SSIs.
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Maidana DE, Gonzalez-Buendia L, Miller JW, Vavvas DG. Local photoreceptor cell death differences in the murine model of retinal detachment. Sci Rep 2021;11(1):18798.Abstract
To investigate local cell death differences in the attached and detached retina at different regions in a murine experimental retinal detachment model. Subretinal injection of sodium hyaluronate was performed in eight-week-old C57BL/6J mice. Retinal regions of interest were defined in relation to their distance from the peak of the retinal detachment, as follows: (1) attached central; (2) attached paracentral; (3) detached apex; and (4) detached base. At day 0, the outer nuclear layer cell count for the attached central, attached paracentral, detached apex, and detached base was 1247.60 ± 64.62, 1157.80 ± 163.33, 1264.00 ± 150.7, and 1013.80 ± 67.16 cells, respectively. There were significant differences between the detached base vs. attached central, and between detached base vs. detached apex at day 0. The detached apex region displayed a significant and progressive cell count reduction from day 0 to 14. In contrast, the detached base region did not show progressive retinal degeneration in this model. Moreover, only the detached apex region had a significant and progressive cell death rate compared to baseline. Immediate confounding changes with dramatic differences in cell death rates are present across regions of the detached retina. We speculate that mechanical and regional differences in the bullous detached retina can modify the rate of cell death in this model.
Mukharesh L, Torun N, Bouffard MA. Perimetry Pitfalls in the Era of COVID-19. J Neuroophthalmol 2021;41(3):e283-e285.
Muralidharan S, Ichhpujani P, Bhartiya S, Singh RB. Eye-tunes: role of music in ophthalmology and vision sciences. Ther Adv Ophthalmol 2021;13:25158414211040890.Abstract
Although the healing effect of music has been recognized since time immemorial, there has been a renewed interest in its use in modern medicine. This can be attributed to the increasing focus on holistic healing and on the subjective and objective aspects of well-being. In ophthalmology, this has ranged from using music for patients undergoing diagnostic procedures and surgery, as well as for doctors and the operation theatre staff during surgical procedures. Music has proven to be a potent nonpharmacological sedative and anxiolytic, allaying both the pain and stress of surgery. This review aims to explore the available evidence about the role of music as an adjunct for diagnostic and surgical procedures in current ophthalmic practices.
Musayeva A, Unkrig JC, Zhutdieva MB, Manicam C, Ruan Y, Laspas P, Chronopoulos P, Göbel ML, Pfeiffer N, Brochhausen C, Daiber A, Oelze M, Li H, Xia N, Gericke A. Betulinic Acid Protects from Ischemia-Reperfusion Injury in the Mouse Retina. Cells 2021;10(9)Abstract
Ischemia/reperfusion (I/R) events are involved in the pathophysiology of numerous ocular diseases. The purpose of this study was to test the hypothesis that betulinic acid protects from I/R injury in the mouse retina. Ocular ischemia was induced in mice by increasing intraocular pressure (IOP) to 110 mm Hg for 45 min, while the fellow eye served as a control. One group of mice received betulinic acid (50 mg/kg/day p.o. once daily) and the other group received the vehicle solution only. Eight days after the I/R event, the animals were killed and the retinal wholemounts and optic nerve cross-sections were prepared and stained with cresyl blue or toluidine blue, respectively, to count cells in the ganglion cell layer (GCL) of the retina and axons in the optic nerve. Retinal arteriole responses were measured in isolated retinas by video microscopy. The levels of reactive oxygen species (ROS) were assessed in retinal cryosections and redox gene expression was determined in isolated retinas by quantitative PCR. I/R markedly reduced cell number in the GCL and axon number in the optic nerve of the vehicle-treated mice. In contrast, only a negligible reduction in cell and axon number was observed following I/R in the betulinic acid-treated mice. Endothelial function was markedly reduced and ROS levels were increased in retinal arterioles of vehicle-exposed eyes following I/R, whereas betulinic acid partially prevented vascular endothelial dysfunction and ROS formation. Moreover, betulinic acid boosted mRNA expression for the antioxidant enzymes SOD3 and HO-1 following I/R. Our data provide evidence that betulinic acid protects from I/R injury in the mouse retina. Improvement of vascular endothelial function and the reduction in ROS levels appear to contribute to the neuroprotective effect.
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Nguyen QD, Anesi SD, Chexal S, Chu DS, Dayani PN, Leng T, Meleth AD, Sallam AA, Sheppard JD, Silverstein SM, Toyos M, Wang RC, Foster CS. Management of repository corticotropin injection therapy for non-infectious uveitis: a Delphi study. Acta Ophthalmol 2021;99(6):669-678.Abstract
PURPOSE: Diagnosis and management of non-infectious uveitis (NIU), a major cause of blindness worldwide, are challenging. Corticosteroids, the cornerstone of therapy, are not appropriate for long-term use, and while non-biologic and biologic immunomodulators may be used for some patients, data on their efficacy and safety in this population are limited. Repository corticotropin injection (RCI), believed to affect uveitis by multiple mechanisms, has received regulatory approval for treatment of ophthalmic diseases including posterior uveitis, but is not widely used or discussed in guidelines for the management of uveitis and ocular inflammatory diseases. METHODS: The index study employed a modified Delphi process with a panel of 14 US-based ophthalmologists. Consensus recommendations were developed through a series of three questionnaires. Panellists rated statements on a Likert scale from -5 (strongly disagree) to +5 (strongly agree). RESULTS: The Delphi panel provided consensus recommendations on examinations and testing needed for diagnosis, treatment goals, and the use of corticosteroids, as well as the use of non-biologic and biologic immunomodulators. The panel reached consensus that RCI may be considered for posterior and pan-uveitis, and dosing should be individualized for each patient. Dose reduction/discontinuation should be considered for excessive RCI-related toxicity, hyperglycaemia and/or diabetic complications, excessive costs, or remission ≥ 2 years. Patients should be weaned from RCI if uveitis is stable and well controlled. Adverse events during RCI therapy can be managed by appropriate interventions, with dose reduction/discontinuation considered if events are severe or recurrent. CONCLUSIONS: Expert consensus suggests RCI may be an appropriate treatment option for some patients with uveitis when other therapies are ineffective or intolerable.
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Pamir Z, Bauer CM, Bennett CR, Kran BS, Merabet LB. Visual perception supported by verbal mediation in an individual with cerebral visual impairment (CVI). Neuropsychologia 2021;160:107982.Abstract
Cerebral visual impairment (CVI) often presents with deficits associated with higher order visual processing. We report a case of an individual with CVI who uses a verbal mediation strategy to perceive and interact with his visual surroundings. Visual perceptual performance was assessed using a virtual reality based visual search task combined with eye tracking. Functional magnetic resonance imaging (fMRI) was employed to identify the neural correlates associated with this strategy. We found that when using verbal mediation, the individual could readily detect and track the target within the visual scene which was associated with robust activation within a network of occipito-parieto-temporal visual cortical areas. In contrast, when not using verbal mediation, the individual was completely unable to perform the task, and this was associated with dramatically reduced visual cortical activation. This unique compensatory strategy may be related to the individual's use of verbal working memory for the purposes of understanding complex visual information.
Pundlik S, Baliutaviciute V, Moharrer M, Bowers AR, Luo G. Home-Use Evaluation of a Wearable Collision Warning Device for Individuals With Severe Vision Impairments: A Randomized Clinical Trial. JAMA Ophthalmol 2021;139(9):998-1005.Abstract
Importance: There is scant rigorous evidence about the real-world mobility benefit of electronic mobility aids. Objective: To evaluate the effect of a collision warning device on the number of contacts experienced by blind and visually impaired people in their daily mobility. Design, Setting, and Participants: In this double-masked randomized clinical trial, participants used a collision warning device during their daily mobility over a period of 4 weeks. A volunteer sample of 31 independently mobile individuals with severe visual impairments, including total blindness and peripheral visual field restrictions, who used a long cane or guide dog as their habitual mobility aid completed the study. The study was conducted from January 2018 to December 2019. Interventions: The device automatically detected collision hazards using a chest-mounted video camera. It randomly switched between 2 modes: active mode (intervention condition), where it provided alerts for detected collision threats via 2 vibrotactile wristbands, and silent mode (control condition), where the device still detected collisions but did not provide any warnings to the user. Scene videos along with the collision warning information were recorded by the device. Potential collisions detected by the device were reviewed and scored, including contacts with the hazards, by 2 independent reviewers. Participants and reviewers were masked to the device operation mode. Main Outcomes and Measures: Rate of contacts per 100 hazards per hour, compared between the 2 device modes within each participant. Modified intention-to-treat analysis was used. Results: Of the 31 included participants, 18 (58%) were male, and the median (range) age was 61 (25-73) years. A total of 19 participants (61%) had a visual acuity (VA) of light perception or worse, and 28 (90%) reported a long cane as their habitual mobility aid. The median (interquartile range) number of contacts was lower in the active mode compared with silent mode (9.3 [6.6-14.9] vs 13.8 [6.9-24.3]; difference, 4.5; 95% CI, 1.5-10.7; P < .001). Controlling for demographic characteristics, presence of VA better than light perception, and fall history, the rate of contacts significantly reduced in the active mode compared with the silent mode (β = 0.63; 95% CI, 0.54-0.73; P < .001). Conclusions and Relevance: In this study involving 31 visually impaired participants, the collision warnings were associated with a reduced rate of contacts with obstacles in daily mobility, indicating the potential of the device to augment habitual mobility aids. Trial Registration: ClinicalTrials.gov Identifier: NCT03057496.
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Ruan Y, Jiang S, Musayeva A, Pfeiffer N, Gericke A. Corneal Epithelial Stem Cells-Physiology, Pathophysiology and Therapeutic Options. Cells 2021;10(9)Abstract
In the human cornea, regeneration of the epithelium is regulated by the stem cell reservoir of the limbus, which is the marginal region of the cornea representing the anatomical and functional border between the corneal and conjunctival epithelium. In support of this concept, extensive limbal damage, e.g., by chemical or thermal injury, inflammation, or surgery, may induce limbal stem cell deficiency (LSCD) leading to vascularization and opacification of the cornea and eventually vision loss. These acquired forms of limbal stem cell deficiency may occur uni- or bilaterally, which is important for the choice of treatment. Moreover, a variety of inherited diseases, such as congenital aniridia or dyskeratosis congenita, are characterized by LSCD typically occurring bilaterally. Several techniques of autologous and allogenic stem cell transplantation have been established. The limbus can be restored by transplantation of whole limbal grafts, small limbal biopsies or by ex vivo-expanded limbal cells. In this review, the physiology of the corneal epithelium, the pathophysiology of LSCD, and the therapeutic options will be presented.

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