Vision and Refraction Eugene M. Helveston MD (2010) by Orbit International PDF

 

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  • Published: 2010
  • Number of pages: 55
  • Format: PDF
  • File Size: 3,32 MB
  • Authors: Orbit International

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The World Health Organization estimates that 333 million people are blind or visually impaired. Nearly half of these, 154 million are suffering from uncorrected refractive error, with more than 13 million of them children. Individuals so affected are handicapped in a variety of ways from being deprived of educational opportunities to being limited in the workplace and even being burdens to their families. The economic impact both personally and in terms of society at large is huge. In contrast to how “blindness” is usually defined, the vision reduction from uncorrected refractive errors must be considered in a different light. It differs from other physical inborn or acquired blinding conditions for two important reasons: 1) in instances of vision loss from uncorrected refractive error, vision can in most cases be corrected to normal with proper optical correction provided with glasses or contact lenses, and 2) eyes are normal except for the improper focus. The most commonly affected person, the myope or nearsighted individual, can usually see well even without correction if objects are held closer to the eye at what is called the far point. Vision reduction from uncorrected hyperopia (especially if it is high) and astigmatism can cause reduction in vision at all distances and in certain circumstances can lead to permanent vision loss from amblyopia. In rare cases, prolonged uncorrected high hyperopia (farsightedness) early in life can cause permanent reduction in vision from bilateral amblyopia. More commonly, unequal refractive errors, if uncorrected, can cause permanent loss of vision in one eye, anisometropic amblyopia, affecting the eye with the higher refractive error. Acquired refractive errors occur with aging as an involutional change called presbyopia. This affects another 150 million people. Presbyopia causes individuals in the mid to late fifth decade to experience difficulty seeing at near because of decreased focusing power of the eye. This can be remedied by use of reading glasses. Some people with a low to moderate degree of farsightedness (hyperopia) are able to see clearly in younger years because they can accommodate, but have difficulty seeing at both distance and near at age 40 and beyond because of the loss of accommodation occurring with presbyopia. Another important cause for acquired loss of vision from uncorrected refractive error has been failure to provide adequate optical correction after surgical removal of a senile cataract, or by loss of glasses something which has been said to occur in nearly 75% of cases in the first year after cataract surgery. However with the advent of properly selected intraocular lenses placed at the time of cataract surgery, this type of vision loss is occurring less often. The reduction in quality of life caused by uncorrected refractive error cannot be calculated with accuracy, but it is significant and deserves attention to the following details that will be discussed in the pages that follow. v Understanding how we see and how uncorrected refractive error affects vision v Identifying those at risk for vision reduction from uncorrected refractive error v The technique and methods for measuring refractive error (refraction) v The importance of prescribing and dispensing suitable glasses, and following up for the individual’s ongoing needs

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Ophthalmology MRCP I Passmedicine 2019 Q bank (2019) by PDF

 

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  • Published: 2019
  • Number of pages: 121
  • Format: PDF
  • File Size: 4,28 MB
  • Authors:

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Strabismus Review Notes 1st Ed Updated () by Dr. Ehab Mostafa PDF

 

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  • Published:
  • Number of pages: 79
  • Format: PDF
  • File Size: 27,07 MB
  • Authors: Dr. Ehab Mostafa

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Self-assessment in Optic and Refraction 1st Edition (2007) by Professor CHUA Chung Nen PDF

 

Ebook Info

  • Published: 2007
  • Number of pages: 107
  • Format: PDF
  • File Size: 0,56 MB
  • Authors: Professor CHUA Chung Nen

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Optic and refraction play an important part in the education of ophalmologists. With the advances achieved in cataract surgery and refractive surgery, an understanding of optic and refraction is more important than ever in the understanding of visual rehabilitation in patients. This book contains multiple choice questions and short answer questions in testing the knowledge of the trainee ophthalmologists. It is recommended the book is used in conjunction with a textbook of optic and refraction such as Clinical Optics by A. R. Elkington, Helena J. Frank, Michael J. Greaney by Blackwell publishing. The last section of the book contains essential steps in clinical refraction for ametropia. The book is useful for ophthalmologists in-training in Malaysia as well as those who are taking the ophthalmology qualifying examination such as FRCOphth (Fellowship of the Royal College of Ophthalmologists) and FRCS (Fellowship of the Royal College of Surgeons).

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Review of Ophthalmology Quick Text Review & MCQs 7th Ed (2019) by AK Khurana PDF

 

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  • Published: 2019
  • Number of pages: 221
  • Format: PDF
  • File Size: 62,24 MB
  • Authors: AK Khurana

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PassMedicine 2021 Ophthalmology (2021) by Dr. AboHaneen PDF

 

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  • Published: 2021
  • Number of pages: 45
  • Format: PDF
  • File Size: 0,51 MB
  • Authors: Dr. AboHaneen

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Modern Update of Ocular and Orbital Ultrasound () by Prof. Dr. med. Mario de La Torre PDF

 

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  • Published:
  • Number of pages: 184
  • Format: PDF
  • File Size: 52,71 MB
  • Authors: Prof. Dr. med. Mario de La Torre

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In producing this book the 3 authors have combined an instruction on how to perform accurate and reproducible ultrasound images together with an atlas of ultrasound scans. We have including every aspect of ultrasound imaging of the anterior and posterior segment together with orbital images. Whether your interest is angle closure glaucoma, cataract and refractive surgery, vitreo retinal disease, uveal tumours, uveitis or orbital disease there is something for everyone in this book who has an interest in imaging the eye. The authors have more than 100 years of combined International ultrasound experience. Professor de La Torre is from Peru, Dr Puech from France and Dr Good from the UK. They have travelled the world teaching and giving presentations on Ocular Ultrasound. Ocular ultrasound has a long history. In 1949 Howry and co-workers built the first medical diagnostic ultrasound machine from old American Air Force parts including the running rotating gear from a B29 gun turret! Early ultrasound systems relied on water baths to transmit the ultrasound waves and were restricted to imaging deep cavities and organs. Transducers of 10MHz did not appear until the early 1960s and Mundt and Hughes described the first application of diagnostic ultrasound of the eye in 1956 using a 4 MHz industrial flaw detection system. In 1957 Oksala and Lehtinen were the first to use A scan ultrasound to study a variety of ocular conditions producing a catalogue including retinal detachment, vitreous hemorrhages, foreign bodies and ocular tumours, and were the first to describe ultrasound as a means of measuring the length of the eye. In 1961 Yammamoto et al described an ultrasound Biometry system which used a transducer with a translucent central area to view the retina. Coleman and Carlin were the first to use focussed transducers in 1967. The early ultrasound systems required the use of an oscilloscope screen to view the images. Baum and Greenwood were the first to develop a two dimensional B-scan system in 1959 using a 15 MHz probe. In 1972 Bronson was the first to provide a hand-held B-scan system using a transducer membrane. In 1972 preface Karl Ossoinig pioneered the use of A-mode ultrasound to provide accurate diagnosis of ocular lesions using a calibrated S shaped amplifier. His Stanardized A-scan technique is used to this day and is described in detail in this book. Ossoinig was instrumental in providing the World’s first practical diagnostic ophthalmic A and B-mode ultrasound system in collaboration with an Austrian company; the Ketztechnik 7100 MA system. In the following decades ultrasound systems improved enormously particularly in probe development; led by Biovision instruments (BVI) who became Quantel Medical. Increasing probe frequency produces a linear increase in axial resolution but with a linear sacrifice in depth of focus. 50 MHz Ultrabiomicroscopic (UBM) probes to image the anterior segment were not developed until 1990 by Pavlin and Foster. In 1998 Michel Puech showed that the posterior pole can be imaged using high frequency probes up to 50 MHz, with a long focus, opening the pathway to the development of the 20 MHz probe for the posterior pole used in current practice. The phrase “standing on the shoulders of giants” was never more pertinent than in the field of ocular ultrasound. Modern ultrasound systems incorporate digital LED display screens and highly focussed probes such as the Quantel 20 5A annular probe which allows 20 MHz high resolution images of the whole globe and anterior orbit including giving an image of 5 layers of the retina and is shown in this book. The current development in ultrasound equipment has never been more exciting and it is the hope of the authors to provide an insight into the enormous range of the use of ocular ultrasound in modern ophthalmology. One of the aims of the book is to encourage the every-day use of ocular ultrasound in all ophthalmological specialities. Performing ultrasound and obtaining the kind of images seen in this book is we believe a “magical” experience and the term “you see something new every day” is certainly true in the performance of ocular ultrasound. We are very grateful for the collaboration between Laboratoires Théa and Quantel Medical in having the foresight to produce an Ophthalmic Ultrasound book available to all. We hope you enjoy reading this book as much as we have enjoyed writing it. Mario, Michel and Peter

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Spectacle Prescription – A Practical Guide () by Dr Harbansh Lal PDF

 

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  • Published:
  • Number of pages: 52
  • Format: PDF
  • File Size: 3,35 MB
  • Authors: Dr Harbansh Lal

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Respected Seniors and Dear Friends It gives me an immense pleasure to write a foreword to Spectacle Prescription – A Practical Guide authored by Dr Harbansh Lal. This textbook will be very useful for Optometrists, postgraduate students and Ophthalmologists in general in practice. The process of clinical refraction is the most common and one of the first skill that we teach our students and it is the procedure that they are required to repeat more than any other procedure during their training. Best corrected visual acuity obtained via skilfully performed retinoscopy and subjective refraction, is the primary measure that guides much of our treatment and surgery. The practical guidelines and tricks for prescribing spectacles are taught neither frequently enough nor well enough. Most of the students are often left to learn these practical points by trial and error, with not enough time, or not enough interest, to engage senior colleagues to learn from their wisdom and experience. This textbook provides simple and elegant exposure to the practical points of refraction. It begins with basic terminology and then includes such important topics like clinical refraction, retinoscopy and spectacles prescription guidelines. The latter half of the textbook teaches subjective refraction by case examples, an entertaining method of embellishing upon, and adding to, the principles previously presented, in real world patient situation. This practical guide is a concise account, yet also comprehensive and will prove to be a valuable guide for spectacle prescription.

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Local Anaesthesia for Ophthalmic Surgery (2012) by Royal College of Anaesthetists and the Royal College of Ophthalmologists PDF

 

Ebook Info

  • Published: 2012
  • Number of pages: 38
  • Format: PDF
  • File Size: 0,50 MB
  • Authors: Royal College of Anaesthetists and the Royal College of Ophthalmologists

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There have been major advances in every aspect of the management of the ophthalmic surgical patient. These include the shift to day care, increased focus on the patient, and the involvement of the entire ophthalmic team in all components of the process. A working party of the Royal College of Anaesthetists and the Royal College of Ophthalmologists was convened to update the 2001 ‘Guidelines on Local Anaesthesia for Intraocular Surgery’. The working party agreed unanimously to change this to ‘Guidelines on Local Anaesthesia for Ophthalmic Surgery’. These guidelines will now cover the management of patients undergoing most routine ophthalmic procedures and are not limited to intraocular surgery. The purpose of these guidelines is to provide information for all members of the ophthalmic team in order to promote safe and effective local anaesthesia for ophthalmic patients. They are intended to apply to practice in the United Kingdom.

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Al-Azhar MCQ Bank of Ophthalmology (2012) by Attiat Mostafa PDF

 

Ebook Info

  • Published: 2012
  • Number of pages: 20
  • Format: PDF
  • File Size: 0,72 MB
  • Authors: Attiat Mostafa

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