Download or read book Ocular Rigidity Biomechanics and Hydrodynamics of the Eye written by Ioannis Pallikaris and published by Springer Nature. This book was released on 2021-05-26 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the concept of ocular rigidity, the biomechanical properties and hydrodynamics of the human eye. The basics of anatomy and physiology are explored and the relevant data for the clinician are emphasized throughout the book. The engineering aspects as well as the clinical interpretation are presented to provide context. Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye summarises recent evidence on ocular rigidity, but also provides a complete presentation of the data so far. The authors have recently worked on ocular rigidity corneal and globe biomechanics and hydrodynamics and the new, up-to-date data on the subject are highlighted in each chapter. The aim is to provide the framework or the understanding of these parameters and to determine their relevance in health and disease. This book will be an essential read for all practicing ophthalmologists looking to gain a more in-depth understanding of this interesting area of research particularly in refractive surgery and glaucoma.

Download or read book Biomechanics of the Eye in Health and Disease written by Hans Vellara and published by . This book was released on 2018 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Purpose The structural properties of the cornea are essential to its function as a resilient, transparent, refractive surface of the eye. It exhibits classic viscoelastic biomechanical properties such as elasticity, creep, stress relaxation, and hysteresis. The advent of in vivo ocular biomechanical assessment using the CorVis ST has attracted significant interest as it enables a new investigative approach to ocular examinations, enabling quantitative structural analysis to be performed in vivo, under more physiological conditions than previously possible. This thesis is focused on the biomechanical properties of the eye in health and disease. Methods Study Participants were assessed with various examination techniques with respect to their ocular status. This includes but was not limited to: slit-lamp biomicroscopy, corneal topography, and the CorVis ST. Results An in vivo collateral globe displacement occurs when a short-acting air-pulse is applied onto the cornea. The separated corneal and orbital components of this overall displacement were isolated through external analysis of the CorVis ST. Isolation and removal of the orbital component should be employed when analysing deformation characteristics in diseases that only affect the cornea. The subsequent studies examined the usage of these separated components with various keratoplasty techniques, keratoconus, corneal collagen cross-linking, glaucoma, thyroid eye disease, and corneal dystrophies. Conclusions In vivo biomechanical assessments provided a link between early in vitro laboratory experiments and clinical practice. It provides a potentially useful adjunct to the standard clinical examination.

Download or read book Biomechanics of the Eye written by Cynthia J. Roberts and published by Kugler Publications. This book was released on 2018-04-20 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering all major components of the ocular system, this state-of-the-art text is essential for vision scientists, biomedical engineers, and advanced clinicians with an interest in the role of mechanics in ocular function, disease, therapeutics, and surgery. With every chapter, leading experts strengthen the arguments that biomechanics is an indispensable and rapidly evolving tool for understanding and managing ocular disease.

Download or read book Ocular Biomechanics in Health and Pathophysiology written by Matthew A. Reilly and published by Frontiers Media SA. This book was released on 2024-06-13 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomechanical mechanisms may contribute to a large number of visual processes and pathologies, including glaucoma, keratoconus, refractive surgery, accommodation, presbyopia, myopia, hyperopia, trauma, retinal detachment, ocular development, vitreous substitution, cataract surgery, corneal transplant, and many others. Departures from homeostatic loading may drive a large number of these processes in ways we are only beginning to recognize. This Research Topic will explore how ocular biomechanics contribute to both the homeostasis and pathophysiology of the eye and visual system. It is generally unknown whether changes in load drive changes in biomechanical properties or vice versa. Clarifying driving forces for disease and elucidating the pathophysiologic response will ultimately enable the development of targeted treatments for many ocular and visual diseases for which biomechanics plays a role.

Download or read book Corneal Biomechanics written by C.J. Roberts and published by Kugler Publications. This book was released on 2017-05-15 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: While lecturing in recent months at a number of prominent institutions, I asked some of the residents and fellows whether and how they might benefit from a book on corneal biomechanics. The typical response was the look of a deer caught in the headlights as they tried to intuit the “appropriate” answer, but had little understanding or insight as to why this would be an important and useful knowledge base for them now, or in the future. I then posed the question differently. “Would a book that explained corneal biomechanical principles and testing devices and their application in detecting eyes at risk for developing keratoconus and post-LASIK ectasia, understanding the biomechanical impact of specific types of keratorefractive surgery and riboflavin UV-A corneal collagen cross-linking, and the impact of corneal biomechanics on the fidelity of intraocular pressure measurement and risk for glaucoma progression be of interest?” Framed in this context, the answer I got was a resounding, “Yes!” Therein lies a fundamental disconnect that highlights both the opportunity and need to educate all ophthalmologists about this nascent field. This comprehensive book is strengthened by the breadth of contributions from leading experts around the world and provides an important resource for ophthalmologists at all levels of training and experience. It gives a panoramic snapshot of our understanding of corneal biomechanics today, bridging the gap between theoretical principles, testing devices that are commercially available and in development as well as current and potential future clinical applications. While there has been a long-held appreciation that all types of keratorefractive surgery have an impact and interdependence on corneal biomechanics and wound healing, the initial finite element analyses that were applied to understand radial keratotomy were limited by incorrect assumptions that the cornea was a linear, elastic, homogenous, isotropic material.1 With the advent of excimer laser vision correction, critical observations indicated that Munnerlyn’s theoretic ablation profiles did not account for either lower or higher order (e.g. spherical aberration) refractive outcomes,2 suggesting that there were important components missing from the equation—e.g., corneal biomechanics and wound healing. In a seminal editorial, Roberts3 pointed out that the cornea is not a piece of plastic, but rather a material with viscoelastic qualities. Since that time, much has been learned about spatial and depth- related patterns of collagen orientation and interweaving, as well as the biomechanical response to different keratorefractive surgeries that sever tension-bearing lamellae, as the cornea responds to and redistributes stress induced by IOP, hydration, eye rubbing, blinking and extraocular muscle forces.3-6 The first reports of post-LASIK ectasia7 highlighted the need to identify a biomechanical signature of early keratoconus as well as corneas at high risk of developing ectasia irrespective of their current topography or tomography. The introduction of two instruments into clinical use—the Ocular Response Analyzer (ORA) and the Corneal Visualization Scheimpflug Technology (Corvis ST)—that allow measurement of various biomechanical metrics further catapulted the field. The availability of these instruments in routine clinical settings allowed the systematic study of the effect of age, collagen disorders, collagen cross-linking, corneal rings, flaps of various depths, contour, sidecut angulation, pockets, and flockets, just to name of few. Future application of biomechanics to the sclera may improve our understanding of the development and prevention of myopia, as well as scleral surgeries and treatments under development for presbyopia. It was appreciated by Goldmann and Schmidt that corneal thickness and curvature would influence the measurement of applanation tonometry. The recent ability to measure some corneal biomechanical metrics have led to IOP measurement that may be more immune both to their influence and the impact of central corneal thickness (CCT). Certain chapters in this book explain how a thin cornea could be stiffer than a thick one and that stiffness is also impacted by IOP, thereby precluding simplistic attempts to adjust IOP measurements using nomograms based upon CCT alone. Also highlighted is how corneal hysteresis, the ability of the cornea to absorb and dissipate energy during the bidirectional applanation response to a linear Gaussian air puff, appears to be an independent risk factor for glaucoma progression and rate of progression.9,10 This comprehensive book starts out with a section devoted to outlining basic biomechanical principles and theories, teaching us the language of what Dupps11 has referred to as “mechanospeak”, thus providing a context and common vocabulary to better comprehend the following chapters. By first defining basic concepts such as stress-strain relationships and creep, this theoretical basis is later applied to explain the pathogenesis of corneal diseases, e.g., explaining how a focal abnormality in corneal biomechanical properties precipitates a cycle of decompensation and localized thinning and steepening, clinically expressed as ectasia progression. These early chapters further detail biomechanical differences between in-vivo and ex-vivo testing, between human and animal corneas and sclera, and between methods of testing. The second section provides a thorough description of two FDA-approved devices to measure corneal biomechanics in the clinic (i.e., the ORA and the Corvis ST), as well as an overview of potential future technologies, including OCT with air puff stimulus, ocular pulse elastography, and Brilloiun microscopy. The third and final section of the book is a thorough treatise on how to interpret the metrics derived from the waveform provided by available clinical devices; their adjunct use in ectasia risk screening; the comparative biomechanical impact of various keratorefractive surgeries and corneal procedures such as PRK, LASIK, SMILE, and corneal collagen cross-linking; the impact of corneal biomechanics on IOP measurement; and potential biomechanical markers of enhanced susceptibility to glaucoma progression. This compendium of our current knowledge of corneal biomechanics, its measurement and application, provides a strong foundation to more fully understand advances in keratorefractive and corneal surgery, diseases, and treatments, all of which are interdependent on and influence inherent corneal biomechanical properties and behavior. Both the robust aspects and limitations of our current understanding are presented, including the challenge of creating accurate and predictive finite element models that incorporate the impact of IOP, corneal thickness, geometry, and scleral properties on corneal biomechanics. This book provides a key allowing clinical ophthalmologists and researchers to grasp the basics and nuances of this exciting field and to shape it as it evolves in the future.

Download or read book Webvision written by Helga Kolb and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding Corneal Biomechanics Through Experimental Assessment and Numerical Simulation written by Ahmed Elsheikh and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ocular Biomechanics Group was established in 2002 with one clear target; to develop a virtual reality model of the human eye that can be used effectively and reliably to predict ocular response to surgery, injury and disease. This ambitious, and seemingly illusive, target helped plan our activities over the last 6 years and will still be focusing our efforts as we strive to create the necessary knowledge using experimental methods, build the predictive tools using programming and analysis means, and validate the findings in both the laboratory and the clinic. This book presents an overview of our biomechanical studies from laboratory material characterisation to finite element numerical simulation. The chapter describes what has been achieved and points at the remaining gaps in our knowledge. It explains that while much remains unknown in ocular behaviour, we are now in a good position to use available knowledge to progress predictive modelling and use it in actual applications such as improving the accuracy of tonometry techniques, planning of refractive surgeries and design of contact lenses. The discussion focuses on the cornea, although scleral biomechanics receive some mention. The chapter also refers to microstructural, biomechanical and topographic studies conducted by other research groups. Coverage of these studies has been necessary to provide a more complete image of current understanding of corneal biomechanics.

Download or read book Vitreous written by J. Sebag and published by Springer. This book was released on 2014-10-01 with total page 917 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vitreous body long has been the most mysterious of all ocular structures, owing perhaps to its seeming simplicity. There have been few concerted, sustained efforts to unravel the mysteries of how vitreous is composed and what role it plays in normal physiology as well as pathology. Over the years, however, many studies have produced important findings concerning vitreous biochemistry, structure, physiology, and pathobiology. Published on the 25th anniversary of Sebag's first book on Vitreous, this second installment is nearly five times longer than its predecessor, reflecting how much has been learned in the past quarter century. This well-constructed compendium not only addresses the most current scientific knowledge, but also reviews clinical perspectives in a manner that lends richness to the scope of the book. Written by 90 authors, this book has 56 chapters organized into 7 sections: Biochemistry; Anatomy, Development, and Aging; Pathology/Pathobiology; Physiology and Phamacotherapy; Posterior Vitreo-Retinal Surgery; Peripheral Vitreo-Retinal Surgery; and Pharmacologic Vitreolysis. With a foreword by Coleman & Lincoff and an introduction by Wallace Foulds, Sebag's latest tome on vitreous is destined to be the authoritative text for years to come.

Download or read book Mechanobiology in Health and Disease written by Stefaan Verbruggen and published by Academic Press. This book was released on 2018-08-09 with total page 527 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanobiology in Health and Disease brings together contributions from leading biologists, clinicians, physicists and engineers in one convenient volume, providing a unified source of information for researchers in this highly multidisciplinary area. Opening chapters provide essential background information on cell mechanotransduction and essential mechanobiology methods and techniques. Other sections focus on the study of mechanobiology in healthy systems, including bone, tendons, muscles, blood vessels, the heart and the skin, as well as mechanobiology studies of pregnancy. Final chapters address the nascent area of mechanobiology in disease, from the study of bone conditions, skin diseases and heart diseases to cancer. A discussion of future perspectives for research completes each chapter in the volume. This is a timely resource for both early-career and established researchers working on mechanobiology. Provides an essential digest of primary research from many fields and disciplines in one convenient volume Covers both experimental approaches and descriptions of mechanobiology problems from mathematical and numerical perspectives Addresses the hot topic of mechanobiology in disease, a particularly dynamic field of frontier science

Download or read book Vital Dyes in Vitreoretinal Surgery written by Carsten H. Meyer and published by Karger Medical and Scientific Publishers. This book was released on 2008 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chromovitrectomy is a novel approach to visualize the vitreous or retinal surface during vitreoretinal surgery. In recent years, the widely used indocyanine green (ICG) has made the surgical maneuver of inner limiting membrane peeling tremendously safer and efficient. Also, numerous dyes have been applied in experimental settings with promising or devastating results. This volume highlights the major clinical and experimental results of currently used novel vital dyes. The first chapters describe the transparent structure of the vitreous body and summarize historical considerations to visualize its structure by optical coherence tomography, dye injections or autologous cells during surgery and for diagnostic purposes. The following contributions describe the advantages and disadvantages of ICG during vitreoretinal surgery and experimental applications. Alternative approaches by recently approved vital dyes such as trypan blue, patent blue and brilliant blue are evaluated in the subsequent chapters. Finally the last few chapters give an outlook on novel vital dyes, which are currently under evaluation, as well as alternative enzymatic approaches to remove the vitreous from the retinal surface. Being a timely update this publication will be indispensable reading for vitreoretinal surgeons and ophthalmic researchers.

Download or read book Biomaterials and Regenerative Medicine in Ophthalmology written by Traian Chirila and published by Elsevier. This book was released on 2009-12-18 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an increasingly aged population, eye diseases are becoming more widespread. Biomaterials have contributed in recent years to numerous medical devices for the restoration of eyesight, improving many patients’ quality of life. Consequently, biomaterials and regenerative medicine are becoming increasingly important to the advances of ophthalmology and optometry. Biomaterials and regenerative medicine in ophthalmology reviews the present status and future direction of biomaterials and regenerative medicine in this important field.Part one discusses applications in the anterior segment of the eye with chapters on such topics as advances in intraocular lenses (IOLs), synthetic corneal implants, contact lenses, and tissue engineering of the lens. Part two then reviews applications in the posterior segment of the eye with such chapters on designing hydrogels as vitreous substitutes, retinal repair and regeneration and the development of tissue engineered membranes. Chapters in Part three discuss other pertinent topics such as hydrogel sealants for wound repair in ophthalmic surgery, orbital enucleation implants and polymeric materials for orbital reconstruction.With its distinguished editor and international team of contributors, Biomaterials and regenerative medicine in ophthalmology is a standard reference for scientists and clinicians, as well as all those concerned with this ophthalmology. Reviews the increasingly important role of biomaterials and regenerative medicine in the advancement of ophthalmology and optometry Provides an overview of the present status and future direction of biomaterials and regenerative medicine in this important field Discusses applications in both the anterior and prosterior segments of the eye with chapters on such topics as synthetic corneal implants and retinal repair and regeneration

Download or read book Selected Health Conditions and Likelihood of Improvement with Treatment written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-07-12 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Social Security Administration (SSA) administers two programs that provide disability benefits: the Social Security Disability Insurance (SSDI) program and the Supplemental Security Income (SSI) program. SSDI provides disability benefits to people (under the full retirement age) who are no longer able to work because of a disabling medical condition. SSI provides income assistance for disabled, blind, and aged people who have limited income and resources regardless of their prior participation in the labor force. Both programs share a common disability determination process administered by SSA and state agencies as well as a common definition of disability for adults: "the inability to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months." Disabled workers might receive either SSDI benefits or SSI payments, or both, depending on their recent work history and current income and assets. Disabled workers might also receive benefits from other public programs such as workers' compensation, which insures against work-related illness or injuries occurring on the job, but those other programs have their own definitions and eligibility criteria. Selected Health Conditions and Likelihood of Improvement with Treatment identifies and defines the professionally accepted, standard measurements of outcomes improvement for medical conditions. This report also identifies specific, long-lasting medical conditions for adults in the categories of mental health disorders, cancers, and musculoskeletal disorders. Specifically, these conditions are disabling for a length of time, but typically don't result in permanently disabling limitations; are responsive to treatment; and after a specific length of time of treatment, improve to the point at which the conditions are no longer disabling.

Download or read book Cell Adhesive Interactions in Ocular Health and Diseases written by Vasantha Rao and published by Frontiers Media SA. This book was released on 2022-11-25 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Practical Treatise on the Diseases of the Eye written by Mackenzie and published by . This book was released on 1840 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Introduction to Biomechanics written by Jay D. Humphrey and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed to meet the needs of undergraduate students, "Introduction to Biomechanics" takes the fresh approach of combining the viewpoints of both a well-respected teacher and a successful student. With an eye toward practicality without loss of depth of instruction, this book seeks to explain the fundamental concepts of biomechanics. With the accompanying web site providing models, sample problems, review questions and more, Introduction to Biomechanics provides students with the full range of instructional material for this complex and dynamic field.

Download or read book Clinical Ocular Prosthetics written by Keith R. Pine and published by Springer. This book was released on 2015-07-10 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first textbook to offer a comprehensive account of ocular prosthetics and the evidence used to underpin and support this field of healthcare. It does so by bringing together information from ophthalmology, prosthetic eye and contact lens literature, and from experts actively engaged in these fields. The book describes the psychological, anatomical and physiological aspects of eye loss as well as surgical procedures for removing the eye, patient evaluation, constructing prosthetic eyes (including prosthetic and surgical techniques for dealing with socket complications), the socket’s response to prosthetic eyes, prosthetic eye maintenance and the history of prosthetic eyes. Though primarily intended for prosthetists, ophthalmologists, ophthalmic nurses, optometrists and students in the fields of ocular medicine, maxillofacial medicine and anaplastology, the book also offers a useful resource for other health workers and family members who care for prosthetic eye patients, and for those patients seeking a deeper understanding of the issues affecting them than they can find elsewhere.

Download or read book Methods in Protein Biochemistry written by Harald Tschesche and published by Walter de Gruyter. This book was released on 2011-12-23 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a survey of recent developments in protein biochemistry. Top researchers in the field of protein biochemistry describe modern methods to address the challenges of protein purification by three-phase partitioning, and their folding and degradation by the functions of chaperones. The significance of peptide purity for fibril formation is addressed as well as the use of target oriented peptide arrays in palliative approaches in mucoviszidose. The design and application of protein epitope mimetics just as the structural resolving of the misfolding of various mutant proteins in serpinopathies enlarge our tools in resolving pathophysiological imbalances.