Download or read book The Structural and Functional Effects of Corneal Collagen Cross linking on Human Corneal Tissue written by Ithar Beshtawi and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Collagen written by Peter Fratzl and published by Springer Science & Business Media. This book was released on 2008-05-10 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Not only does this book provide a comprehensive review of current research advances in collagen structure and mechanics, it also explores this biological macromolecule’s many applications in biomaterials and tissue engineering. Readers gain an understanding of the structure and mechanical behavior of type I collagen and collagen-based tissues in vertebrates across all length scales, from the molecular (nano) to the organ (macro) level.
Download or read book Albert and Jakobiec s Principles and Practice of Ophthalmology written by Daniel M. Albert and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keeping up to date with advances in comprehensive ophthalmology and in the ophthalmic sub-specialties is extremely difficult because of the accelerating rapidity with which new information and technology become available and the diminishing time and opportunity for practitioners and trainees to read and learn. The first edition of Albert and Jakobiec's Principles and Practice (1994) was conceived with the idea of utilizing an electronic, updated version in which the chapters were revised by the chapter authors on an annual or semi-annual basis, but the technology was not sufficiently advanced to achieve this goal. Subsequent editions (2000 and 2008) were organized by Saunders and the last published by Elsevier (of which Springer has obtained the complete rights to move forward with the 4th edition). For nearly three decades, this text has provided its readers with authoritative and comprehensive coverage of clinical ophthalmology, written and edited by a group of authors who represented a "Who's Who" in ophthalmology. By using Springer's Meteor platform, with its ability to allow authors and editors access to updating their chapters online annually/semi-annually, and with the recruitment of select chapter authors, this work's usefulness as the standard text in ophthalmology will be maintained and expanded upon by Springer. The 4th edition of this comprehensive and authoritative text is written by hundreds of the most distinguished authorities from around the world and edited by four leaders in the field, providing today's best answers to every question that arises in ophthalmology practice. Richly illustrated with thousands of high quality, full color, clinically-relevant images, Albert and Jakobiec's Principles and Practice of Ophthalmology, 4th Edition covers every scientific and clinical principle in ophthalmology, ensuring that the reader will always be able to find the guidance needed to diagnose and manage patients' ocular problems and meet today's standards of care. Written for practicing ophthalmologists and trainees, this book delivers in-depth guidance on new diagnostic approaches, operative techniques, and treatment options, as well as coherent explanations of new scientific concept and its clinical importance. The 4th edition will prove to be the source every practicing clinician needs to efficiently and confidently overcome any clinical challenge they may face. Updates include new chapters on anterior and posterior segment diseases, as well as chapters more focused on treatment, plus thousands of new, high-quality, color images and illustrations, updated references, and information on the most cutting-edge technology used by clinicians in their practices today. Additionally, readers will enjoy the same, user-friendly, full-color design they remember from the previous edition, complete with many at-a-glance summary tables, algorithms, boxes, and diagrams that allow the reader to locate the assistance needed more rapidly than ever. .
Download or read book Corneal Regeneration written by Jorge L. Alió and published by Springer. This book was released on 2019-02-20 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides expert instruction on the varying surgical techniques currently employed for the regeneration of the ocular surface. Corneal Regeneration: Therapy and Surgery begins with a thorough discussion of current research based on data obtained in clinical human studies, and discusses the potential clinical implications for this promising new stage of eye surgery. Sections devoted to the stem cell, regenerative surgery and therapy of the ocular surface epithelium, corneal stroma, and corneal endothelium follow, each section comprehensively covering applied anatomy, current therapy and regenerative techniques, with a look to future directions of the field including eventual cell therapy. Corneal Regeneration: Therapy and Surgery is the first book of its kind, systematically covering the developments the medical community has achieved in corneal regeneration from all angles. Written and edited by leading experts in the field, researchers and ophthalmologists alike will find this to be a unique source of information on corneal regeneration, as well as a thoughtful reflection on potential applications of regenerative surgery in ophthalmology as a whole.
Download or read book Ocular Imaging written by George Asimellis and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transmission of the Ocular Media written by Edward A. Boettner and published by . This book was released on 1962 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spectral transmittance of ultraviolet, visible, and near infrared light through the ocular media of humans has been measured. Using freshly enucleated eyes, the transmittances of each component part (cornea, aqueous humor, lens, vitreous humor) were determined for the wavelength range from 0.22 to 2.8 microns. To date 9 eyes have been measured, ranging in age from 4 weeks to 75 years. Two types of measurements were made: the first to measure the total light transmitted (direct and scattered) at each wavelength and the second to measure the percent transmittance of that light passing directly through the various media without absorption or scattering. The results show that: (a) the transmission of ultraviolet radiation decreases with the age of the eye; (b) the transmission of infrared radiation appears to be independent of the age; and (c) the maximum total transmittance of the whole eye, about 81 percent, is obtained in the region from 600 to 850 millimicrons.
Download or read book Eye Pathology written by Steffen Heegaard and published by Springer. This book was released on 2014-11-10 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive, in-depth, and up-to-date resource on eye pathology that will be of great practical value for ophthalmic and general pathologists and ophthalmologists. Congenital abnormalities, inflammatory conditions, infections, injuries, degenerative diseases, and tumors are all covered with the aid of more than 700 images. In the case of tumors, the wide variety of neoplasms that occur in the eyelid, conjunctiva, retina, uveal tract, lacrimal gland and sac, orbit, and optic nerve are comprehensively reviewed, and the most recent knowledge on the relation between genetics and prognosis is presented. Entries on specific diseases are organized in a standard way, with information on etiology, epidemiology, clinical presentation, pathological characteristics, differential diagnosis, therapy, and prognosis. The authors are all recognized experts and members of the European and American ophthalmic pathology societies.
Download or read book Corneal Regeneration written by Mark Ahearne and published by . This book was released on 2020 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume details different laboratory techniques used to develop regenerative therapies that help treat corneal blindness. Chapters guide readers through methods and protocols on optimal cell culture conditions, gene-editing techniques, multiple types of scaffold for corneal regeneration, how to evaluate the success of these therapies, and cell and material characterization techniques. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Corneal Regeneration: Methods and Protocols aims to be useful for new and experienced laboratory researchers working on different aspects of corneal regeneration.
Download or read book Astigmatism written by Michael Goggin and published by BoD – Books on Demand. This book was released on 2012-02-29 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the development, optics and physiology of astigmatism and places this knowledge in the context of modern management of this aspect of refractive error. It is written by, and aimed at, the astigmatism practitioner to assist in understanding astigmatism and its amelioration by optical and surgical techniques. It also addresses the integration of astigmatism management into the surgical approach to cataract and corneal disease including corneal transplantation.
Download or read book Management of Complications in Refractive Surgery written by Jorge L. Alio and published by Springer. This book was released on 2018-01-02 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: This illustrated guide is written by international opinion leaders with extensive experience in the practice of refractive surgery. It is the first book devoted to refractive complications (with practical hints and case reports on outcomes) to provide ophthalmic surgeons with the most adequate solutions for the most frequent problems. All complications are described and lavishly illustrated. The book provides ophthalmic surgeons with the most adequate solutions for the most frequent problems they face in their daily practice.
Download or read book Organ Tissue Engineering written by Daniel Eberli and published by Springer. This book was released on 2021-04-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The notion of being able to engineer complete organs has inspired an entire generation of researchers. While recent years have brought significant progress in regenerative medicine and tissue engineering, the immense challenges encountered when trying to engineer an entire organ have to be acknowledged. Despite a good understanding of cell phenotypes, cellular niches and cell-to-biomaterial interactions, the formation of tissues composed of multiple cells remains highly challenging. Only a step-by-step approach will allow the future production of a living tissue construct ready for implantation and to augment organ function. In this book, expert authors present the current state of this approach. It offers a concise overview and serves as a great starting point for anyone interested in the application of tissue engineering or regenerative medicine for organ engineering. Each chapter contains a short overview including physiological and pathological changes as well as the current clinical need. The potential cell sources and suitable biomaterials for each organ type are discussed and possibilities to produce organ-like structures are illustrated. The ultimate goal is for the generated small tissues to unfold their full potential in vivo and to serve as a native tissue equivalent. By integrating and evolving, these implants will form functional tissue in-vivo. This book discusses the desired outcome by focusing on well-defined functional readouts. Each chapter addresses the status of clinical translations and closes with the discussion of current bottlenecks and an outlook for the coming years. A successful regenerative medicine approach could solve organ shortage by providing biological substitutes for clinical use - clearly, this merits a collaborative effort.
Download or read book Ocular Tissue Engineering written by Dimitrios Karamichos and published by MDPI. This book was released on 2018-10-01 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Ocular Tissue Engineering" that was published in JFB
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 Corneal Collagen Cross Linking written by Mazen M. Sinjab and published by Springer. This book was released on 2016-11-09 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides comprehensive coverage of corneal collagen cross-linking (CXL), a major management modality for keratoconus and ectatic corneal disorders. All aspects are covered, including refractive and non-refractive surgery indications, models of application, safety, efficacy, performance, outcome measures, evidence of CXL, complications, contraindications, use in children, and controversies. The discussion reflects the considerable progress that has been made in understanding of the modality since its development in the late 1990s. Detailed attention is paid to new concepts, changing surgical techniques and indications, the latest evidence-based science and research, and the future of CXL. Guidance is also provided on the use of CXL in combination with other modalities, such as LASIK, PRK, intracorneal ring implantation and others. The text is accompanied by numerous high-quality color illustrations. Corneal Collagen Cross Linking will provide the reader with a sound grasp of the technique and its use and will hopefully also serve as a stimulus to further research and advances.
Download or read book The Mechanics and Thermodynamics of Continua written by Morton E. Gurtin and published by Cambridge University Press. This book was released on 2010-04-19 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mechanics and Thermodynamics of Continua presents a unified treatment of continuum mechanics and thermodynamics that emphasises the universal status of the basic balances and the entropy imbalance. These laws are viewed as fundamental building blocks on which to frame theories of material behaviour. As a valuable reference source, this book presents a detailed and complete treatment of continuum mechanics and thermodynamics for graduates and advanced undergraduates in engineering, physics and mathematics. The chapters on plasticity discuss the standard isotropic theories and, in addition, crystal plasticity and gradient plasticity.
Download or read book Corneal Regenerative Medicine written by Bernice Wright and published by Humana Press. This book was released on 2013-05-21 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuous regeneration of the cornea is necessary to maintain this tissue in the transparent state that is essential for vision. Therapy for repair of the damaged anterior cornea is currently addressed through the transplantation of donor corneas or the delivery of limbal epithelial stem cells (LESC) to the ocular surface using amniotic membrane (AM) as a supporting scaffold. Research on the bioengineering of corneal equivalents as replacement tissue is underway to develop viable corneal prosthetics. Corneal Regenerative Medicine: Methods and Protocols provides a concise overview of essential techniques in the field of corneal regenerative medicine, highlighting novel strategies to guide the management of key therapies within this area of medicine. Divided into four convenient sections, topics include the identification, characterisation and cultivation of LESC, as well as the investigation of biopolymers used as the basis for corneal substitutes. Written in the successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and easily accessible, Corneal Regenerative Medicine: Methods and Protocols covers the fundamental techniques useful for both the laboratory and clinical settings.
