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Author: FangJun Bao
Publisher: Frontiers Media SA
ISBN: 2832522572
Category : Science
Languages : en
Pages : 124
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Book Description
Author: FangJun Bao
Publisher: Frontiers Media SA
ISBN: 2832522572
Category : Science
Languages : en
Pages : 124
Get Book Here
Book Description
Author: C.J. Roberts
Publisher: Kugler Publications
ISBN: 9062998763
Category : Medical
Languages : en
Pages : 328
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Book Description
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.
Author: Feng Wen
Publisher: Frontiers Media SA
ISBN: 2832501257
Category : Medical
Languages : en
Pages : 373
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Book Description
Author: Cynthia J. Roberts
Publisher: Kugler Publications
ISBN: 9062998860
Category : Medical
Languages : en
Pages : 546
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Book Description
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.
Author: Taraprasad Das
Publisher: Springer Nature
ISBN: 9819701384
Category :
Languages : en
Pages : 497
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Book Description
Author: Sujata Das
Publisher: Springer Nature
ISBN: 9811942625
Category : Medical
Languages : en
Pages : 298
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Book Description
The book covers various aspects of the management of keratoconus, which is a leading cause of visual impairment in young adults. It focuses on the epidemiology and risk factors of keratoconus with a special focus on Southeast Asia. Keratoconus affects the quality of vision, thereby affecting the quality of life. While most patients present with defective vision, many are diagnosed accidentally during screening for refractive surgery. The book covers the varied epidemiology of keratoconus across different parts of the world. It discusses many systemic and ocular diseases associated with keratoconus. The book covers the newer diagnostic techniques and various treatment procedures for keratoconus, helping in diagnosing keratoconus in the early stages and closely watching the progression. It discusses various contact lenses to improve vision quality; widely used collagen crosslinking, and its various modifications for halting the progression. It also explains the surgical approach for keratoconus, such as penetrating keratoplasty, lamellar keratoplasty and other lens-assisted procedures. The book is relevant for general ophthalmologists and cornea specialists.
Author: Mohamed H. Doweidar
Publisher: Academic Press
ISBN: 012816610X
Category : Science
Languages : en
Pages : 436
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Book Description
Advances in Biomechanics and Tissue Regeneration covers a wide range of recent development and advances in the fields of biomechanics and tissue regeneration. It includes computational simulation, soft tissues, microfluidics, the cardiovascular system, experimental methods in biomechanics, mechanobiology and tissue regeneration. The state-of-the-art, theories and application are presented, making this book ideal for anyone who is deciding which direction to take their future research in this field. In addition, it is ideal for everyone who is exploring new fields or currently working on an interdisciplinary project in tissue biomechanics. - Combines new trends in biomechanical modelling and tissue regeneration - Offers a broad scope, covering the entire field of tissue biomechanics - Contains perspectives from engineering, medicine and biology, thus giving a holistic view of the field
Author: Mazen M Sinjab
Publisher: JP Medical Ltd
ISBN: 9350909871
Category : Medical
Languages : en
Pages : 384
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Book Description
Refractive surgery is eye surgery to improve the refractive state of the eye and reduce or eliminate the need for glasses or contact lenses. The most common type of refractive surgery uses lasers to reshape the curvature of the cornea. This book is a comprehensive guide to refractive surgery. Presented in five steps, it begins with discussion on corneal imaging and its clinical application. The second step examines key refractive procedures and step three offers advice on rules and guidelines for refractive surgery. Step four is a guide to actually starting the procedure and avoidable complications. The final section describes a clinical case study. Enhanced by nearly 500 high quality images, diagrams and tables, each chapter includes key points and clinical tips to assist understanding. Key points Comprehensive guide to refractive surgery Presented in step by step format Key points and clinical tips in each chapter Includes nearly 500 images, diagrams and tables
Author: Jorge L. Alió
Publisher: Springer
ISBN: 3319438816
Category : Medical
Languages : en
Pages : 367
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Book Description
As a degenerative disorder of the eye, keratoconus can cause substantial distortion of vision, with multiple images, streaking, and sensitivity to light all reported by patients. Keratoconus: Recent Advances in Diagnosis and Treatment updates ophthalmologists about the innovations that have occurred within the last decade, discussing the diagnostic imaging techniques that have been developed for keratoconus diagnosis, understanding of how examination techniques are related to the evolution of keratoconus, and how to indicate the different therapeutic tools that have been created for keratoconus over the last several years. Additionally, fundamentals for new diagnostic elements, based on the mathematical, physical and biomechanical data are analyzed in depth for a better understanding of the essential diagnostic steps for the clinician to guide patients towards the most adequate therapeutic tool in the case. Modern keratoplasty techniques, assisted by femtosecond lasers or other devices, are also covered and these techniques, along with the emerging conservative treatments, have added to more precise control of the evolution of the disease.
Author: Pain, Pritam
Publisher: IGI Global
ISBN: 1799890805
Category : Medical
Languages : en
Pages : 306
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Book Description
With the advent of digital computers and rapidly developing computational techniques, computer simulations are widely used as predictive tools to supplement experimental techniques in engineering and technology. Computational biomechanics is a field where the movements of biological systems are assessed in the light of computer algorithms describing solid and fluid mechanical principles. This rapidly developing field must be constantly studied and updated as it continues to expand. Advances in Computational Approaches in Biomechanics examines the current trends and applications of intelligent computational techniques used to analyze a multitude of phenomena in the field of biomechanics and elaborates a series of sophisticated techniques used for computer simulation in solid mechanics, fluid mechanics, and fluid-solid interface. Covering a range of topics such as injury prevention, element analysis, and soft tissues, this publication is ideal for industry professionals, practitioners, researchers, academicians, instructors, and students.
