Ian P. Howard and Brian J. Rogers
- Published in print:
- 2008
- Published Online:
- May 2009
- ISBN:
- 9780195367607
- eISBN:
- 9780199867264
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195367607.003.0018
- Subject:
- Psychology, Cognitive Neuroscience, Cognitive Psychology
The spatial separation of the eyes causes a difference in the images in the two eyes formed by a solid object. These differences, or binocular disparities, form the basis for stereoscopic vision. ...
More
The spatial separation of the eyes causes a difference in the images in the two eyes formed by a solid object. These differences, or binocular disparities, form the basis for stereoscopic vision. This chapter discusses the extent to which each of these differences is used as a basis for stereopsis. Topics covered include feature tokens for stereopsis, monocular occlusion, occlusion as a depth token, stereopsis from illusions, chromostereopsis, and irradiation stereopsis.Less
The spatial separation of the eyes causes a difference in the images in the two eyes formed by a solid object. These differences, or binocular disparities, form the basis for stereoscopic vision. This chapter discusses the extent to which each of these differences is used as a basis for stereopsis. Topics covered include feature tokens for stereopsis, monocular occlusion, occlusion as a depth token, stereopsis from illusions, chromostereopsis, and irradiation stereopsis.
Andrew M. Wallace
- Published in print:
- 2005
- Published Online:
- January 2012
- ISBN:
- 9780197262962
- eISBN:
- 9780191734533
- Item type:
- chapter
- Publisher:
- British Academy
- DOI:
- 10.5871/bacad/9780197262962.003.0010
- Subject:
- Archaeology, Archaeological Methodology and Techniques
This chapter discusses the strengths and weaknesses of techniques of 3D laser imaging based on time of flight and triangulation. Laser scanning by triangulation is a fully developed technology. ...
More
This chapter discusses the strengths and weaknesses of techniques of 3D laser imaging based on time of flight and triangulation. Laser scanning by triangulation is a fully developed technology. Through this method, it is now possible to create faithful 3D datasets from a reasonable range of surface materials. However, laser scanning has some certain drawbacks, restricting their universal applicability. For surfaces with concavities or with intricate details, occlusion may occur due to the necessary separation of the viewpoint between the viewing camera and the laser projector. In addition, the data may be corrupted by false and poor returns caused by variable material reflectance. In the time of flight system, the distance is measured by measuring the time for a focused laser beam to impact on and return from the surface of interest. In this method, the distance is computed and a 3D image can be created if the laser beam is scanned across the target. Although, the time of flight method is a more attractive alternative as it eliminates occlusion, it has disadvantages as well. The time resolution necessary to measure the range to sub-millimetre accuracy is difficult to achieve and the measured time is also affected by the magnitude of the returned signal. In addition to reviewing the pros and cons of this current technology, the chapter also discusses the development of a new approach to time-of-flight laser imaging based on time-correlated single photon counting. This new method has various advantages compared to the old methods. It has the ability to make 3D measurements on distance, poorly reflecting or transparent surfaces.Less
This chapter discusses the strengths and weaknesses of techniques of 3D laser imaging based on time of flight and triangulation. Laser scanning by triangulation is a fully developed technology. Through this method, it is now possible to create faithful 3D datasets from a reasonable range of surface materials. However, laser scanning has some certain drawbacks, restricting their universal applicability. For surfaces with concavities or with intricate details, occlusion may occur due to the necessary separation of the viewpoint between the viewing camera and the laser projector. In addition, the data may be corrupted by false and poor returns caused by variable material reflectance. In the time of flight system, the distance is measured by measuring the time for a focused laser beam to impact on and return from the surface of interest. In this method, the distance is computed and a 3D image can be created if the laser beam is scanned across the target. Although, the time of flight method is a more attractive alternative as it eliminates occlusion, it has disadvantages as well. The time resolution necessary to measure the range to sub-millimetre accuracy is difficult to achieve and the measured time is also affected by the magnitude of the returned signal. In addition to reviewing the pros and cons of this current technology, the chapter also discusses the development of a new approach to time-of-flight laser imaging based on time-correlated single photon counting. This new method has various advantages compared to the old methods. It has the ability to make 3D measurements on distance, poorly reflecting or transparent surfaces.
Ian P. Howard and Brian J. Rogers
- Published in print:
- 1996
- Published Online:
- January 2008
- ISBN:
- 9780195084764
- eISBN:
- 9780199871049
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195084764.003.0012
- Subject:
- Psychology, Cognitive Psychology
This chapter begins with a discussion of stereopsis and absolute disparity, simultaneous depth contrast, and successive depth contrast. It then covers stereoscopic interpolation, stereo and figural ...
More
This chapter begins with a discussion of stereopsis and absolute disparity, simultaneous depth contrast, and successive depth contrast. It then covers stereoscopic interpolation, stereo and figural organization, monocular occlusion, and depth-specific visual processes.Less
This chapter begins with a discussion of stereopsis and absolute disparity, simultaneous depth contrast, and successive depth contrast. It then covers stereoscopic interpolation, stereo and figural organization, monocular occlusion, and depth-specific visual processes.
David E. Cooper
- Published in print:
- 2007
- Published Online:
- October 2011
- ISBN:
- 9780199235988
- eISBN:
- 9780191696688
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199235988.003.0013
- Subject:
- Philosophy, General, Philosophy of Religion
This chapter contemplates the question of how a doctrine of mystery can provide measure for ones' life. Firstly, it explains how the issue it addresses was reached. Secondly, it argues that one may ...
More
This chapter contemplates the question of how a doctrine of mystery can provide measure for ones' life. Firstly, it explains how the issue it addresses was reached. Secondly, it argues that one may discern how various conceptions, beliefs, and comportments are consonant to the experience of mystery. Thirdly, it discusses in detail the disconsonant concepts based on confrontation, degradation, and occlusion. The chapter concludes by discussing the finer aspects of humility.Less
This chapter contemplates the question of how a doctrine of mystery can provide measure for ones' life. Firstly, it explains how the issue it addresses was reached. Secondly, it argues that one may discern how various conceptions, beliefs, and comportments are consonant to the experience of mystery. Thirdly, it discusses in detail the disconsonant concepts based on confrontation, degradation, and occlusion. The chapter concludes by discussing the finer aspects of humility.
Noel Polk
- Published in print:
- 2008
- Published Online:
- March 2014
- ISBN:
- 9781934110843
- eISBN:
- 9781604733235
- Item type:
- book
- Publisher:
- University Press of Mississippi
- DOI:
- 10.14325/mississippi/9781934110843.001.0001
- Subject:
- Literature, 20th-century Literature and Modernism
As one of the preeminent scholars of southern literature, Noel Polk has delivered lectures, written journal articles and essays, and discussed the rich legacy of the South’s literary heritage around ...
More
As one of the preeminent scholars of southern literature, Noel Polk has delivered lectures, written journal articles and essays, and discussed the rich legacy of the South’s literary heritage around the world for over three decades. His work on William Faulkner, Eudora Welty, Walker Percy, and other writers is incisive and groundbreaking. Polk’s essays in this book maintain an abiding interest in his major area of literary study: the relationship between the smaller units of construction in a literary work and the work’s larger themes. The analysis of this interplay between commas and dashes, curious occlusions, passages, and characters who have often gone unnoticed in the critical discourse—the bricks and mortar, as it were—and a work’s grand design is a crucial aspect of Polk’s scholarship. The book is a collection of his essays from the late 1970s to 2005. Featuring an introduction that places Faulkner and Welty at the center of the South’s literary heritage, it asks useful, probing questions about southern literature and provides insightful analysis.Less
As one of the preeminent scholars of southern literature, Noel Polk has delivered lectures, written journal articles and essays, and discussed the rich legacy of the South’s literary heritage around the world for over three decades. His work on William Faulkner, Eudora Welty, Walker Percy, and other writers is incisive and groundbreaking. Polk’s essays in this book maintain an abiding interest in his major area of literary study: the relationship between the smaller units of construction in a literary work and the work’s larger themes. The analysis of this interplay between commas and dashes, curious occlusions, passages, and characters who have often gone unnoticed in the critical discourse—the bricks and mortar, as it were—and a work’s grand design is a crucial aspect of Polk’s scholarship. The book is a collection of his essays from the late 1970s to 2005. Featuring an introduction that places Faulkner and Welty at the center of the South’s literary heritage, it asks useful, probing questions about southern literature and provides insightful analysis.
Claire Nightingale and Jonathan Sandy
- Published in print:
- 2014
- Published Online:
- November 2020
- ISBN:
- 9780198714828
- eISBN:
- 9780191916793
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198714828.003.0007
- Subject:
- Clinical Medicine and Allied Health, Dentistry
Question 1.1
How would you classify this incisor relationship?
What are the other occlusal features you can see?
What are Andrew’s six keys to normal static occlusion?
What is the ...
More
Question 1.1
How would you classify this incisor relationship?
What are the other occlusal features you can see?
What are Andrew’s six keys to normal static occlusion?
What is the difference between an Angle’s and an Andrew’s class I molar relationship?...Less
Question 1.1
How would you classify this incisor relationship?
What are the other occlusal features you can see?
What are Andrew’s six keys to normal static occlusion?
What is the difference between an Angle’s and an Andrew’s class I molar relationship?...
James C. Thompson
- Published in print:
- 2012
- Published Online:
- January 2013
- ISBN:
- 9780195393705
- eISBN:
- 9780199979271
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195393705.003.0018
- Subject:
- Psychology, Cognitive Psychology
While several different neural processes contribute to the perception of biological motion, the responsiveness of a key area, the human superior temporal sulcus (STS), to biological motion appears to ...
More
While several different neural processes contribute to the perception of biological motion, the responsiveness of a key area, the human superior temporal sulcus (STS), to biological motion appears to be driven largely by the need to integrate motion information with configural body form information. This need reflects the fact that the human body produces complex patterns of articulated motions at multiple spatial locations that are linked by the underlying human form. Such a global integration of motion and form information would provide several advantages to observers of human movement across a variety of otherwise challenging conditions including brief durations, occlusion, and observer movement.Less
While several different neural processes contribute to the perception of biological motion, the responsiveness of a key area, the human superior temporal sulcus (STS), to biological motion appears to be driven largely by the need to integrate motion information with configural body form information. This need reflects the fact that the human body produces complex patterns of articulated motions at multiple spatial locations that are linked by the underlying human form. Such a global integration of motion and form information would provide several advantages to observers of human movement across a variety of otherwise challenging conditions including brief durations, occlusion, and observer movement.
Emmanuel Falque
- Published in print:
- 2018
- Published Online:
- May 2019
- ISBN:
- 9780823281961
- eISBN:
- 9780823284917
- Item type:
- chapter
- Publisher:
- Fordham University Press
- DOI:
- 10.5422/fordham/9780823281961.003.0010
- Subject:
- Philosophy, Philosophy of Religion
One of the primary features of Christianity is that it accommodates the whole of the suffering of humankind, a suffering that is both moral and physical. Nonetheless the burden of suffering and ...
More
One of the primary features of Christianity is that it accommodates the whole of the suffering of humankind, a suffering that is both moral and physical. Nonetheless the burden of suffering and salvation through suffering have often been confused together. Christ does not tell us either what or why he suffers. But he guides us in how he suffers. Closed in on oneself or open to the other: These are the two ways of living suffering, by which suffering becomes a manner of living rather just a condemnation of life.Less
One of the primary features of Christianity is that it accommodates the whole of the suffering of humankind, a suffering that is both moral and physical. Nonetheless the burden of suffering and salvation through suffering have often been confused together. Christ does not tell us either what or why he suffers. But he guides us in how he suffers. Closed in on oneself or open to the other: These are the two ways of living suffering, by which suffering becomes a manner of living rather just a condemnation of life.
Doreen Oneschuk
- Published in print:
- 2004
- Published Online:
- November 2011
- ISBN:
- 9780198528067
- eISBN:
- 9780191730351
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528067.003.0007
- Subject:
- Palliative Care, Patient Care and End-of-Life Decision Making
This chapter focuses on malignant bowel obstruction (MBO), a common complication in women diagnosed with ovarian cancer, colorectal cancer, and other gynaecological malignancies. MBO generally ...
More
This chapter focuses on malignant bowel obstruction (MBO), a common complication in women diagnosed with ovarian cancer, colorectal cancer, and other gynaecological malignancies. MBO generally afflicts 25–42 per cent of patients with advanced ovarian cancer, but rarely occurs in patients with endometrial cancer. MBO develops by the existence of mechanical obstruction from an extrinsic occlusion of the bowel lumen, intraluminal occlusion of the lumen, luminal obstruction due to tumour growth in the bowel wall, and adynamic ileus. Bowel obstruction can also be caused by other non-malignant factors such as adhesion, post-irridation bowel damage, hernias, and inflammatory bowel disease. Management of MBO includes pain management, pharmacological management, and non-pharmacological management. In patients with MBO, pharmacological treatment is generally successful. Only patients who are strictly considered as appropriate candidates for surgery and parenteral nutrition are given such treatments.Less
This chapter focuses on malignant bowel obstruction (MBO), a common complication in women diagnosed with ovarian cancer, colorectal cancer, and other gynaecological malignancies. MBO generally afflicts 25–42 per cent of patients with advanced ovarian cancer, but rarely occurs in patients with endometrial cancer. MBO develops by the existence of mechanical obstruction from an extrinsic occlusion of the bowel lumen, intraluminal occlusion of the lumen, luminal obstruction due to tumour growth in the bowel wall, and adynamic ileus. Bowel obstruction can also be caused by other non-malignant factors such as adhesion, post-irridation bowel damage, hernias, and inflammatory bowel disease. Management of MBO includes pain management, pharmacological management, and non-pharmacological management. In patients with MBO, pharmacological treatment is generally successful. Only patients who are strictly considered as appropriate candidates for surgery and parenteral nutrition are given such treatments.
Norman K. Hollenberg
- Published in print:
- 1996
- Published Online:
- March 2012
- ISBN:
- 9780192623874
- eISBN:
- 9780191724671
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780192623874.003.0015
- Subject:
- Neuroscience, Sensory and Motor Systems
Arteries relax in response to some vasodilators only if the endothelium is present. The obligatory role for vasodilatation of a diffusible factor from endothelium termed ‘EDRF’ for ...
More
Arteries relax in response to some vasodilators only if the endothelium is present. The obligatory role for vasodilatation of a diffusible factor from endothelium termed ‘EDRF’ for endothelial-dependent relaxing factor, now identified as nitric oxide or a related nitroso-thiol has been demonstrated for many agents, including acetylcholine, bradykinin, substance P, ATP, other adenine nucleotides — and especially important for this chapter — the vasodilator action of 5-HT. Other vasodilator agents, however, such as nitrates, papaverine, isoproterenol, and prostaglandins, do not require endothelium. This chapter focuses on pharmacological considerations in atherosclerosis and in the collateral arteries that grow in response to the vascular occlusion that so often occurs with atherosclerosis.Less
Arteries relax in response to some vasodilators only if the endothelium is present. The obligatory role for vasodilatation of a diffusible factor from endothelium termed ‘EDRF’ for endothelial-dependent relaxing factor, now identified as nitric oxide or a related nitroso-thiol has been demonstrated for many agents, including acetylcholine, bradykinin, substance P, ATP, other adenine nucleotides — and especially important for this chapter — the vasodilator action of 5-HT. Other vasodilator agents, however, such as nitrates, papaverine, isoproterenol, and prostaglandins, do not require endothelium. This chapter focuses on pharmacological considerations in atherosclerosis and in the collateral arteries that grow in response to the vascular occlusion that so often occurs with atherosclerosis.
Merrick J. Moseley and Alistair R. Fielder
- Published in print:
- 1996
- Published Online:
- March 2012
- ISBN:
- 9780198523161
- eISBN:
- 9780191724558
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198523161.003.0024
- Subject:
- Neuroscience, Sensory and Motor Systems
This chapter, as its title suggests, is concerned primarily with practical issues surrounding amblyopia therapy. Imprecise or inappropriate measurement techniques have limited understandings of ...
More
This chapter, as its title suggests, is concerned primarily with practical issues surrounding amblyopia therapy. Imprecise or inappropriate measurement techniques have limited understandings of occlusion therapy. To examine these issues the chapter draws upon observations made in the literature and on some techniques recently developed in the laboratory. Finally, experimental data that indicate how proposals work in practice are presented. The discussions are necessarily restricted in scope and do not address the many neuroscientific contributions that have increased the understandings of this curious condition. Throughout this chapter the attention is focused on the amblyopic child as opposed to the infant and the chapter defines the former as being of an age at which a visual task involving ‘linear’ optotypes can be performed, either by the elicitation of a verbal response or by the child indicating the target seen at distance on a hand-held key card. Also, it makes no specific reference to the taxonomy of amblyopia although it acknowledge this to be an obvious factor likely to influence treatment outcome. At the beginning of this chapter, attention is drawn to the lack of empirical (as opposed to clinical, anecdotal) support for the use of occlusion therapy. It is suggested that this arose because of inadequate or inappropriate measurement of compliance and visual outcome.Less
This chapter, as its title suggests, is concerned primarily with practical issues surrounding amblyopia therapy. Imprecise or inappropriate measurement techniques have limited understandings of occlusion therapy. To examine these issues the chapter draws upon observations made in the literature and on some techniques recently developed in the laboratory. Finally, experimental data that indicate how proposals work in practice are presented. The discussions are necessarily restricted in scope and do not address the many neuroscientific contributions that have increased the understandings of this curious condition. Throughout this chapter the attention is focused on the amblyopic child as opposed to the infant and the chapter defines the former as being of an age at which a visual task involving ‘linear’ optotypes can be performed, either by the elicitation of a verbal response or by the child indicating the target seen at distance on a hand-held key card. Also, it makes no specific reference to the taxonomy of amblyopia although it acknowledge this to be an obvious factor likely to influence treatment outcome. At the beginning of this chapter, attention is drawn to the lack of empirical (as opposed to clinical, anecdotal) support for the use of occlusion therapy. It is suggested that this arose because of inadequate or inappropriate measurement of compliance and visual outcome.
Marian L. Chen and Alan M. Leslie
- Published in print:
- 2009
- Published Online:
- March 2012
- ISBN:
- 9780199216895
- eISBN:
- 9780191696039
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199216895.003.0004
- Subject:
- Psychology, Developmental Psychology
It has been reported that infants represent the continued existence of an object through occlusion and they can track even multiple objects. Many studies have found that infants track the discrete ...
More
It has been reported that infants represent the continued existence of an object through occlusion and they can track even multiple objects. Many studies have found that infants track the discrete numerosity of small sets of objects in multiple modalities, but the interpretation of these findings remains controversial. In this chapter, the authors evaluate the available evidence for four theories that have been proposed to explain how infants track discrete quantity namely: object indexing, sets, mental magnitudes/accumulator, and integers. Of the four theories, only the accumulator and the generative integer views posit an irreducibly numerical basis to infants' number representations. The object indexing and set accounts provide a mechanism by which infants might be able to track small numbers of discrete objects and compare them on the basis of their numerical identity without actually being able to count.Less
It has been reported that infants represent the continued existence of an object through occlusion and they can track even multiple objects. Many studies have found that infants track the discrete numerosity of small sets of objects in multiple modalities, but the interpretation of these findings remains controversial. In this chapter, the authors evaluate the available evidence for four theories that have been proposed to explain how infants track discrete quantity namely: object indexing, sets, mental magnitudes/accumulator, and integers. Of the four theories, only the accumulator and the generative integer views posit an irreducibly numerical basis to infants' number representations. The object indexing and set accounts provide a mechanism by which infants might be able to track small numbers of discrete objects and compare them on the basis of their numerical identity without actually being able to count.
Michael Schoenfeldt
- Published in print:
- 2009
- Published Online:
- March 2012
- ISBN:
- 9780748638734
- eISBN:
- 9780748651573
- Item type:
- chapter
- Publisher:
- Edinburgh University Press
- DOI:
- 10.3366/edinburgh/9780748638734.003.0010
- Subject:
- Literature, 16th-century and Renaissance Literature
This chapter identifies the occlusions that are created by current organisations of knowledge for Renaissance texts. It argues that the post-Cartesian segregation of cognition from corporeality ...
More
This chapter identifies the occlusions that are created by current organisations of knowledge for Renaissance texts. It argues that the post-Cartesian segregation of cognition from corporeality prevents one from stopping the connection between aesthetic practice and physiological concept in the Renaissance. The chapter then tries to determine whether passionate and argumentative poetic expressions provide happiness that is both intellectual and primeval.Less
This chapter identifies the occlusions that are created by current organisations of knowledge for Renaissance texts. It argues that the post-Cartesian segregation of cognition from corporeality prevents one from stopping the connection between aesthetic practice and physiological concept in the Renaissance. The chapter then tries to determine whether passionate and argumentative poetic expressions provide happiness that is both intellectual and primeval.
Joël Fagot and Isabelle Barbet
- Published in print:
- 2009
- Published Online:
- March 2012
- ISBN:
- 9780195377804
- eISBN:
- 9780199848461
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195377804.003.0002
- Subject:
- Psychology, Cognitive Psychology
This chapter discusses the results of a series of experiments aimed at investigating visual-information processing in baboons. Two lines of ...
More
This chapter discusses the results of a series of experiments aimed at investigating visual-information processing in baboons. Two lines of research on baboons are presented in this chapter. The first one explores the processes of perceptual grouping. In comparison to humans when similarly tested, baboons barely group spatially separated elements into a single percept. The second one addresses the issue of depth perception. Baboons perceive depth when presented with pictorial depth cues, but the study also highlights human–baboon differences in the processing of occlusion cues as indicators of depth. A local precedence effect was observed in baboons, in contrast to humans, who showed a global precedence effect. Experiments further revealed that local precedence in baboons is a direct consequence of their difficulty in overcoming the separation between the local elements, a necessary process for perceiving the whole. Moreover, baboons perceive the corridor illusion, suggesting that they gain depth information from the pictorial cues available in the image background.Less
This chapter discusses the results of a series of experiments aimed at investigating visual-information processing in baboons. Two lines of research on baboons are presented in this chapter. The first one explores the processes of perceptual grouping. In comparison to humans when similarly tested, baboons barely group spatially separated elements into a single percept. The second one addresses the issue of depth perception. Baboons perceive depth when presented with pictorial depth cues, but the study also highlights human–baboon differences in the processing of occlusion cues as indicators of depth. A local precedence effect was observed in baboons, in contrast to humans, who showed a global precedence effect. Experiments further revealed that local precedence in baboons is a direct consequence of their difficulty in overcoming the separation between the local elements, a necessary process for perceiving the whole. Moreover, baboons perceive the corridor illusion, suggesting that they gain depth information from the pictorial cues available in the image background.
Venki Sundaram (ed.)
- Published in print:
- 2018
- Published Online:
- November 2020
- ISBN:
- 9780198802907
- eISBN:
- 9780191917165
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198802907.003.0016
- Subject:
- Clinical Medicine and Allied Health, Professional Development in Medicine
Ophthalmology principally aims to prevent visual loss, restore visual function, and relieve ocular discomfort. The majority of the pathology can be directly visualized and thus requires proficient ...
More
Ophthalmology principally aims to prevent visual loss, restore visual function, and relieve ocular discomfort. The majority of the pathology can be directly visualized and thus requires proficient ocular examination techniques and visual recognition skills. Another distinguishing aspect of ophthalmology is the overlap between medical and surgical conditions. Common systemic diseases such as diabetes and hypertension have ocular features, and diseases involving every organ of the body can have ocular manifestations. A thorough medical knowledge is paramount, as is the ability to collaborate with other medical teams. Intraocular surgery for conditions such as cataract is technically challenging, as ocular tissues are so delicate. It therefore requires high levels of fine hand–eye coordination. As an ophthalmologist, you will be faced both with acute eye conditions, some of which are sight-threatening and require prompt diagnosis and management, and with chronic conditions, which require monitoring and treatment for many years. You will be exposed to patients of all ages, from premature babies to the elderly, so good communication with a wide range of patient groups and their families is essential. Patients often say that what they fear most is losing their sight. Therefore, empathy and support for patients with debilitating visual impairment are imperative. The questions in this chapter will test your knowledge of acute emergency ophthalmic presentations and the understanding and interpretation of ophthalmic examination, as well as ocular conditions that have systemic associations. In addition, questions relating to ophthalmic risk factors, communication, and probity are included. Eye problems can be daunting to many medical students and doctors. Through practice in examining patients and recognizing key conditions, confidence can be gained in how best to manage these patients and, importantly, when to refer them to other specialties. Ophthalmology incorporates a unique and appealing mix of medical and surgical conditions. It is a rapidly advancing specialty with recent significant advances in diagnostic and therapeutic options. It also provides an opportunity for a good work–life balance.
Less
Ophthalmology principally aims to prevent visual loss, restore visual function, and relieve ocular discomfort. The majority of the pathology can be directly visualized and thus requires proficient ocular examination techniques and visual recognition skills. Another distinguishing aspect of ophthalmology is the overlap between medical and surgical conditions. Common systemic diseases such as diabetes and hypertension have ocular features, and diseases involving every organ of the body can have ocular manifestations. A thorough medical knowledge is paramount, as is the ability to collaborate with other medical teams. Intraocular surgery for conditions such as cataract is technically challenging, as ocular tissues are so delicate. It therefore requires high levels of fine hand–eye coordination. As an ophthalmologist, you will be faced both with acute eye conditions, some of which are sight-threatening and require prompt diagnosis and management, and with chronic conditions, which require monitoring and treatment for many years. You will be exposed to patients of all ages, from premature babies to the elderly, so good communication with a wide range of patient groups and their families is essential. Patients often say that what they fear most is losing their sight. Therefore, empathy and support for patients with debilitating visual impairment are imperative. The questions in this chapter will test your knowledge of acute emergency ophthalmic presentations and the understanding and interpretation of ophthalmic examination, as well as ocular conditions that have systemic associations. In addition, questions relating to ophthalmic risk factors, communication, and probity are included. Eye problems can be daunting to many medical students and doctors. Through practice in examining patients and recognizing key conditions, confidence can be gained in how best to manage these patients and, importantly, when to refer them to other specialties. Ophthalmology incorporates a unique and appealing mix of medical and surgical conditions. It is a rapidly advancing specialty with recent significant advances in diagnostic and therapeutic options. It also provides an opportunity for a good work–life balance.
Ron A. Adelman and Patricia Pahk
- Published in print:
- 2010
- Published Online:
- November 2020
- ISBN:
- 9780195389685
- eISBN:
- 9780197562734
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195389685.003.0012
- Subject:
- Clinical Medicine and Allied Health, Ophthalmology
Pathologic processes involving the retina or choroid can present with a wide variety of visual field defects. Usually visual field defects of retinal diseases directly correlate with the fundus ...
More
Pathologic processes involving the retina or choroid can present with a wide variety of visual field defects. Usually visual field defects of retinal diseases directly correlate with the fundus findings. Visual field changes are often the result of damage to the retina or scarring but, in conjunction with other clinical findings, they may help narrow the differential diagnosis. Most of the macular lesions result in visual field defects that do not respect the vertical or horizontal midline. Occasionally inflammatory disorders result in visual field defects that do not directly correlate with the retinal findings. For example, patients with multiple evanescent white dot syndrome (MEWDS) may have an enlarged blind spot. Macular disorders can cause central or paracentral scotomas depending on the location of the lesion. Causes of macular pathology include drusen, atrophy from dry age-related macular degeneration (AMD), retinal hemorrhage, choroidal neovascular membrane, macular edema, macular hole, macular scar, pathologic myopia, and macular dystrophies of the retina or choroid. Central serous chorioretinopathy (CSCR) can show a relative defect that is anatomically correlated with the area of subretinal or sub RPE (retinal pigment epithelium) fluid accumulation. Residual pigmentary changes in inactive CSCR can also cause a relative depression in the corresponding visual field. Pathologic myopia can present with a variety of visual field defects depending on the retinal findings, such as posterior staphyloma or choroidal neovascular membrane. AMD may show nonspecific changes in the central or paracentral visual field that correlate with the structural damage to the retina and choroid. Geographic atrophy in dry AMD can cause a dense scotoma correlated with the pattern of the atrophy. Choroidal neovascular membranes can cause a depression in the correlating visual field due to edema or hemorrhage. Disciform scars in endstage AMD can also cause a dense scotoma. Macular holes may cause a small central scotoma. Pattern dystrophies are a family of disorders with a common pathology at the level of the RPE. Butterfly dystrophy, an autosomal dominant disorder, and Sjögren reticular dystrophy, an autosomal recessive disorder, are two examples of pattern dystrophies.
Less
Pathologic processes involving the retina or choroid can present with a wide variety of visual field defects. Usually visual field defects of retinal diseases directly correlate with the fundus findings. Visual field changes are often the result of damage to the retina or scarring but, in conjunction with other clinical findings, they may help narrow the differential diagnosis. Most of the macular lesions result in visual field defects that do not respect the vertical or horizontal midline. Occasionally inflammatory disorders result in visual field defects that do not directly correlate with the retinal findings. For example, patients with multiple evanescent white dot syndrome (MEWDS) may have an enlarged blind spot. Macular disorders can cause central or paracentral scotomas depending on the location of the lesion. Causes of macular pathology include drusen, atrophy from dry age-related macular degeneration (AMD), retinal hemorrhage, choroidal neovascular membrane, macular edema, macular hole, macular scar, pathologic myopia, and macular dystrophies of the retina or choroid. Central serous chorioretinopathy (CSCR) can show a relative defect that is anatomically correlated with the area of subretinal or sub RPE (retinal pigment epithelium) fluid accumulation. Residual pigmentary changes in inactive CSCR can also cause a relative depression in the corresponding visual field. Pathologic myopia can present with a variety of visual field defects depending on the retinal findings, such as posterior staphyloma or choroidal neovascular membrane. AMD may show nonspecific changes in the central or paracentral visual field that correlate with the structural damage to the retina and choroid. Geographic atrophy in dry AMD can cause a dense scotoma correlated with the pattern of the atrophy. Choroidal neovascular membranes can cause a depression in the correlating visual field due to edema or hemorrhage. Disciform scars in endstage AMD can also cause a dense scotoma. Macular holes may cause a small central scotoma. Pattern dystrophies are a family of disorders with a common pathology at the level of the RPE. Butterfly dystrophy, an autosomal dominant disorder, and Sjögren reticular dystrophy, an autosomal recessive disorder, are two examples of pattern dystrophies.
Mark Textor
- Published in print:
- 2017
- Published Online:
- September 2017
- ISBN:
- 9780199685479
- eISBN:
- 9780191765636
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780199685479.003.0009
- Subject:
- Philosophy, History of Philosophy, Philosophy of Mind
Brentano never investigated whether the ‘peculiar feature’ of inner perception—that it can never become inner observation—that distinguishes our awareness of the mental from other forms of perceptual ...
More
Brentano never investigated whether the ‘peculiar feature’ of inner perception—that it can never become inner observation—that distinguishes our awareness of the mental from other forms of perceptual awareness could serve as the mark of the mental. However, his students Stumpf and Husserl developed marks of the mental that are inspired by this idea. The chapter clarifies Husserl’s Thesis that mental phenomena have no appearances, argues that it is superior to Brentano’s Thesis, and defends it against objections from Reinach and Husserl himself. Husserl himself threw out the baby with the bathwater when he later rejected Husserl’s Thesis. A precisified form of this idea can still unify our intuitions about the mental.Less
Brentano never investigated whether the ‘peculiar feature’ of inner perception—that it can never become inner observation—that distinguishes our awareness of the mental from other forms of perceptual awareness could serve as the mark of the mental. However, his students Stumpf and Husserl developed marks of the mental that are inspired by this idea. The chapter clarifies Husserl’s Thesis that mental phenomena have no appearances, argues that it is superior to Brentano’s Thesis, and defends it against objections from Reinach and Husserl himself. Husserl himself threw out the baby with the bathwater when he later rejected Husserl’s Thesis. A precisified form of this idea can still unify our intuitions about the mental.
Ronald L. Gross
- Published in print:
- 2013
- Published Online:
- November 2020
- ISBN:
- 9780195382365
- eISBN:
- 9780197562703
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195382365.003.0056
- Subject:
- Clinical Medicine and Allied Health, Ophthalmology
Intrinsic to glaucoma surgery using a tube shunt is the management of early postoperative hypotony. This consideration is unavoidable in all cases when using a tube shunt without an intrinsic valve ...
More
Intrinsic to glaucoma surgery using a tube shunt is the management of early postoperative hypotony. This consideration is unavoidable in all cases when using a tube shunt without an intrinsic valve and must still be considered in tube shunts that contain a valve, as the valve may not function as anticipated. Unfortunately, in the attempt to avoid hypotony and its associated complications, we are faced with elevated intraocular pressure (IOP) and its associated difficulties. However, the attempt to control IOP is not the only consideration when anticipating intentional tube occlusion. Additional factors such as technical complexity of the procedure, predictability of IOP in the early postoperative period, potential to reverse occlusion either partially or completely, and the impact on the long-term function of the tube shunt must be considered. The desired endpoint when occluding a tube intentionally is the complete prevention of flow to the tube shunt reservoir. The standard ways to occlude the tube are an external encircling ligature or an internal occluding suture, otherwise known as an “obturator” or a “ripcord,” or some combination thereof. With the external suture technique, prior to placing the reservoir, a 7–0 or 8–0 polyglactin 910 (Vicryl™ , Ethicon, Inc., Somerville, New Jersey) suture is tightly tied around the tube approximately 4–6 mm from the reservoir (Figure 35.1). It is anticipated that this suture will dissolve in about one month, opening the tube. However, the timing of opening may be highly variable between individuals, and that variability may be problematic. Alternatively, a 9–0 polypropylene suture can be placed around the tip of an anterior chamber tube with release performed by laser lysis. To prevent the polypropylene suture from floating freely in the anterior chamber after release, a pass should be made through the wall of the tube during placement. Alternatively, with the “ripcord” technique, the end of a 3–0 polypropylene suture without the needle is threaded into the distal opening of the tube at the reservoir for a distance of 4–6 mm.
Less
Intrinsic to glaucoma surgery using a tube shunt is the management of early postoperative hypotony. This consideration is unavoidable in all cases when using a tube shunt without an intrinsic valve and must still be considered in tube shunts that contain a valve, as the valve may not function as anticipated. Unfortunately, in the attempt to avoid hypotony and its associated complications, we are faced with elevated intraocular pressure (IOP) and its associated difficulties. However, the attempt to control IOP is not the only consideration when anticipating intentional tube occlusion. Additional factors such as technical complexity of the procedure, predictability of IOP in the early postoperative period, potential to reverse occlusion either partially or completely, and the impact on the long-term function of the tube shunt must be considered. The desired endpoint when occluding a tube intentionally is the complete prevention of flow to the tube shunt reservoir. The standard ways to occlude the tube are an external encircling ligature or an internal occluding suture, otherwise known as an “obturator” or a “ripcord,” or some combination thereof. With the external suture technique, prior to placing the reservoir, a 7–0 or 8–0 polyglactin 910 (Vicryl™ , Ethicon, Inc., Somerville, New Jersey) suture is tightly tied around the tube approximately 4–6 mm from the reservoir (Figure 35.1). It is anticipated that this suture will dissolve in about one month, opening the tube. However, the timing of opening may be highly variable between individuals, and that variability may be problematic. Alternatively, a 9–0 polypropylene suture can be placed around the tip of an anterior chamber tube with release performed by laser lysis. To prevent the polypropylene suture from floating freely in the anterior chamber after release, a pass should be made through the wall of the tube during placement. Alternatively, with the “ripcord” technique, the end of a 3–0 polypropylene suture without the needle is threaded into the distal opening of the tube at the reservoir for a distance of 4–6 mm.
Steven F. Perry, Markus Lambertz, and Anke Schmitz
- Published in print:
- 2019
- Published Online:
- November 2019
- ISBN:
- 9780199238460
- eISBN:
- 9780191864056
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780199238460.003.0008
- Subject:
- Biology, Animal Biology, Developmental Biology
Every animal that has a respiratory faculty has some mechanism for regulating its perfusion and ventilation. A prerequisite for such regulation is some way of sensing internal and external levels of ...
More
Every animal that has a respiratory faculty has some mechanism for regulating its perfusion and ventilation. A prerequisite for such regulation is some way of sensing internal and external levels of respiratory-relevant gases. The regulatory entities can be peripheral, central, or both. This chapter looks at the control of breathing in aquatic and terrestrial invertebrates and concludes that the main signal for aquatic species is oxygen, whereas the internal pH/PCO2 is most important for the control of air breathing, regardless of the phylogenetic group to which the animal may belong.Less
Every animal that has a respiratory faculty has some mechanism for regulating its perfusion and ventilation. A prerequisite for such regulation is some way of sensing internal and external levels of respiratory-relevant gases. The regulatory entities can be peripheral, central, or both. This chapter looks at the control of breathing in aquatic and terrestrial invertebrates and concludes that the main signal for aquatic species is oxygen, whereas the internal pH/PCO2 is most important for the control of air breathing, regardless of the phylogenetic group to which the animal may belong.
Omar Niss and Russell E. Ware
- Published in print:
- 2017
- Published Online:
- April 2017
- ISBN:
- 9780199398911
- eISBN:
- 9780199398942
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199398911.003.0034
- Subject:
- Public Health and Epidemiology, Public Health
This chapter discusses sickle cell disease and related conditions, including biochemical, pathological, and clinical abnormalities and factors to be considered in nutritional evaluation (e.g., ...
More
This chapter discusses sickle cell disease and related conditions, including biochemical, pathological, and clinical abnormalities and factors to be considered in nutritional evaluation (e.g., growth, nutritional status). Dietary management is specifically discussed, including protein and caloric needs, vitamins and minerals, and effects therapies on growth and development).Less
This chapter discusses sickle cell disease and related conditions, including biochemical, pathological, and clinical abnormalities and factors to be considered in nutritional evaluation (e.g., growth, nutritional status). Dietary management is specifically discussed, including protein and caloric needs, vitamins and minerals, and effects therapies on growth and development).