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Charles N J McGhee

Publications and source records attributed to Charles N J McGhee.

At least 19 recordsLinked to original sources
PubMed2006

Ophthalmology and vision science research. Part 4: avoiding rejection--structuring a research paper from introduction to references.

As part of an ongoing series, this fourth article is the second of 2 related articles that deal with the basics of producing a high-quality manuscript. Although ophthalmology and vision science are the principal focus of this series, the general concepts essential to producing a quality manuscript are applicable to diverse fields of research. This article provides guidelines on how to present research findings in a structured form using the Introduction, Methods, Results, and Discussion (IMRaD) style. The components to be included, and equally important excluded, from each section are elucidated in detail. Commonly omitted or inaccurately or incompletely presented components of the manuscript, such as statistical analysis and references, are highlighted. The necessity to carefully refine manuscripts before submission is discussed. This article concludes by illustrating methods of appropriately dealing with referees' comments and resubmitting manuscripts. Although researchers may have to deal with rejection as part of the process, we hope that this series provides an easy-to-follow structure to maximize manuscript quality and improve the prospect of scientific publication.

Biomedical Research↗
PubMed2006

Clinicopathological features of severe corneal blood staining associated with proliferative diabetic retinopathy.

A 54-year-old man with a history of severe proliferative diabetic retinopathy in both eyes and profound visual impairment presented with severe corneal blood staining in the left eye secondary to a "spontaneous" total hyphaema and raised intraocular pressure in an eye with iris neovascularization. Despite anterior chamber washout, the cornea remained virtually opaque and thickened. The subject subsequently underwent pars plana vitrectomy with endolaser using a temporary keratoprosthesis, insertion of a Morcher iris-surround intraocular lens and penetrating keratoplasty. Histopathology of the excised corneal button revealed fine eosinophilic granules composed of aggregations of haemoglobin and its breakdown products dispersed throughout the stroma, with occasional foci of weakly positive Perl staining for intracellular haemosiderin. Fluorescence confocal microscopy revealed a marked increase in fluorescence throughout the corneal stroma and the basal epithelial layer. This case highlights the microstructural features and aspects of the surgical management of severe corneal blood staining.

Blood↗
PubMed2006

Mapping the corneal sub-basal nerve plexus in keratoconus by in vivo laser scanning confocal microscopy.

PURPOSE: To produce a two-dimensional reconstruction map of the living corneal sub-basal nerve plexus in keratoconus with in vivo confocal microscopy. METHODS: Four eyes of four subjects with keratoconus were examined by slit lamp biomicroscopy, Orbscan II slit-scanning elevation topography (Bausch & Lomb Surgical, Rochester, NY), and laser scanning in vivo confocal microscopy with the Heidelberg Retina Tomograph II, Rostock Corneal Module (Heidelberg Engineering, Heidelberg, Germany). Subjects were asked to fixate on targets arranged in a grid to enable in vivo confocal microscopy of the cornea in a wide range of positions. RESULTS: A mean of 402 +/- 57 images were obtained for each cornea, to create confluent montages. The mean dimensions of the corneal areas mapped were 6.60 +/- 0.70 mm horizontally and 5.91 +/- 0.72 mm vertically. All corneas exhibited abnormal sub-basal nerve architecture compared with patterns previously observed in normal corneas. At the apex of the cone, a tortuous network of nerve fiber bundles was noted, many of which formed closed loops. At the topographic base of the cone, nerve fiber bundles appeared to follow the contour of the base, with many of the bundles running concentrically in this region. Central sub-basal nerve density was significantly lower in keratoconus corneas (10,478 +/- 2,188 microm/mm2) compared with normal corneas (21,668 +/- 1,411 microm/mm2; Mann-Whitney; P < 0.01). CONCLUSIONS: This is the first study to elucidate the overall distribution of sub-basal nerves in the living central to midperipheral human cornea in keratoconus, using laser scanning in vivo confocal microscopy.

Adult↗
PubMed2006

Laser scanning in vivo confocal microscopy of the normal human corneoscleral limbus.

PURPOSE: To elucidate the structure of the human corneoscleral limbus by in vivo laser scanning confocal microscopy and to correlate limbal epithelial dimensions and density with the central epithelium and in relation to age. METHODS: Fifty adult subjects were recruited into one of two age groups: younger (age<45 years) and older (age>or=45 years). Fifty left eyes of these 50 healthy subjects were examined by laser scanning in vivo confocal microscopy, to assess the basal epithelium of the central cornea and inferior limbus. Mean epithelial cell diameter, area, and density were calculated for the central basal epithelium, limbus-corneal basal epithelium, and limbus-palisade epithelium. RESULTS: Data were analyzed in relation to the two age groups, group A, 30+/-6 years (n=25; mean+/-SD), and group B, 60+/-11 years (n=25; P<0.01). Mean epithelial density in the limbus-cornea and limbus-palisade regions decreased significantly with age: limbus-cornea group A=7253+/-1077 cells/mm2 group B=6614+/-987 cells/mm2, P=0.03; limbus palisade group A=5409+/-799 cells/mm2, group B=5055+/-722 cells/mm2, P=0.03). Central corneal epithelial density did not change with age: group A=6162+/-503 cells/mm2, group B=6362+/-614 cells/mm2, P=0.08. Mean epithelial density was greatest at the limbus-cornea (7010+/-1081 cells/mm2) and lowest at the limbus-palisades (5289+/-847 cells/mm2). The mean width of palisade ridges was 25.0+/-6.3 microm. CONCLUSIONS: This is the first study to image clearly the living human corneal limbus by laser scanning in vivo confocal microscopy and to demonstrate quantitative changes in the basal epithelium with age.

Adult↗
PubMed2005

Clinical and microstructural analysis of patients with hyper-reflective corneal endothelial nuclei imaged by in vivo confocal microscopy.

The purpose of this study was to determine the significance of hyper-reflective corneal endothelial nuclei imaged by in vivo confocal microscopy. A retrospective analysis was performed using a database of 505 patients that had undergone in vivo confocal microscopy of the cornea. All subjects with hyper-reflective endothelial nuclei were identified and these images were analysed to determine corneal endothelial cell density and morphology. The clinical notes of these patients were reviewed and corresponding data regarding corneal thickness was obtained from a related database of Orbscan II pachymetry. Hyper-reflective endothelial nuclei were identified in 41 eyes of 39 (7.7%) patients. Diagnoses included previous cataract surgery or penetrating keratoplasty, posterior polymorphous dystrophy, Fuchs' endothelial dystrophy and irido-corneal endothelial syndrome. No patients with clinically normal corneas exhibited bright endothelial nuclei. The mean endothelial cell density in this group was 1325+/-872 cells mm(-2) and endothelial density was below age-adjusted normal values in 69.2% of patients. Both cellular polymegathism (coefficient of variation of cell area 33.9+/-7.4%) and cellular pleomorphism were noted (51.8+/-9.0% hexagonal cells). The mean central corneal thickness was 582+/-52 microm. There was no significant difference in endothelial density and morphology compared to cases that had low endothelial density but did not exhibit bright nuclei. In conclusion, this study is the first to investigate the significance of bright endothelial nuclei detected by in vivo confocal microscopy. The strong association with corneal disease states suggests that the most likely explanation for this appearance is the alteration in cellular/nuclear morphology, composition or function.

Cataract Extraction↗
PubMed2005

In vivo confocal microstructural analysis of corneal endothelial changes in a patient on long-term chlorpromazine therapy.

BACKGROUND: Deposits in the cornea and lens are a known complication of long-term chlorpromazine therapy. METHOD: A 59-year-old woman had previously taken chlorpromazine for 20 years with doses up to 1,200 mg/day, with a mean dose of 400 mg/day. She presented with gradual onset of blurred vision in her left eye. Slit-lamp biomicroscopy revealed multiple fine creamy-white deposits on her corneal endothelium and anterior crystalline lens capsule bilaterally. RESULTS: In vivo confocal microscopy of the cornea identified irregular hyper-reflective deposits on the posterior surface of the endothelium. The deposits varied from 1 microm to 70 microm in diameter and had well-defined edges. Endothelial morphology was otherwise normal bilaterally. CONCLUSIONS: This is the first report of in vivo confocal imaging of deposits resulting from long-term chlorpromazine use. Microstructural analysis of the corneal endothelium reveals that there were no abnormalities in cellular morphology resulting from these deposits.

Chlorpromazine↗
PubMed2005

Orbscan computerized topography: attributes, applications, and limitations.

An extensive electronic search was undertaken in January 2004 to identify all relevant peer-reviewed publications on Orbscan slit-scanning/Placido computerized topography. Ninety-one publications were identified. These address elevation topography and best-fit sphere, accuracy and repeatability of anterior and posterior corneal elevation and keratometric maps, comparison of Orbscan-acquired data and Placido-based computerized videokeratography instruments, pachymetry measurement and correlation with ultrasound, screening eye-bank corneas, detection of keratoconus, identifying corneal ectasia after refractive surgery, and miscellaneous applications. Studies were analyzed and critically compared in relation to attributes, applications, and limitations of Orbscan corneal topography. The review highlights advantages of this technique in assessing the cornea in health and disease and after surgery and identifies specific aspects that require further investigation and clarification.

Cornea↗
PubMed2005

Ophthalmology and vision science research: part 2: How to commence research--Eureka or that's a little unusual?

Understanding the key elements that increase the likelihood of project success is fundamental for those embarking on research. The first article in this series placed scientific journals in perspective in relation to Journal Impact Factors and citation indices. This second article in a series primarily aimed at those commencing research, particularly in the area of ophthalmology and vision science, delineates the interrelated components that are required to complete a research project. Successful research projects seldom emerge from serendipitous observation, and most evolve through a combination of inspiration, careful planning, and a great deal of industry. Beginning researchers must first be clear about their reason(s) for pursuing research and should identify potential mentors and collaborators at the outset. This article discusses methods of identifying suitable projects and mentors. Ten component areas necessary to complete a research project are addressed, with reference to relevant published literature, under the following topic areas: mentors and collaborators; finding a research topic; confirming suitability of the topic; defining the research question; developing the hypothesis; key considerations in study design; threats to study validity; study sample size; benefits and limitations of clinical science; completing to publication. This guide is intended to be applicable to all embarking on research, but particularly to those with an interest in the visual system. The final 3 articles in this series will deal with writing a research paper to publication standard, working successfully with the journal review process, and refining electronic literature searches.

Biomedical Research↗
PubMed2005

Ophthalmology and vision science research: Part 3: avoiding writer's block--understanding the ABCs of a good research paper.

Completion of a scientific manuscript for submission to a peer-reviewed journal is a daunting task for clinicians and scientists early in their careers. In an ongoing series, this third article is the first of 2 related articles that deal with the basics of producing a high-quality research manuscript. Although ophthalmology and vision science are the principal focus of this series, the general concepts essential to producing a quality manuscript are applicable to diverse fields of research. This article highlights the exponential growth in the scientific literature over the past 40 years, considers why it is important to publish completed research, and discusses the necessity of identifying the key messages of the research, and their context, in relation to the published literature. The ethics of publishing biomedical research and scientific misconduct, such as duplicate publication or plagiarism, are outlined. To avoid later conflict, there is a critical need for coworkers to carefully address authorship order and inclusion early in the manuscript process. Internationally agreed guidelines are identified to guide this process. The importance of choosing the correct journal for a specific article and the nature of basic citation indices are discussed. The article concludes by elaborating and contrasting different scientific writing styles and emphasizing the considerable importance of developing a representative title and applying clarity and appropriate structure to the abstract.

Authorship↗
PubMed2005

Ophthalmology and vision science research. Part 1: Understanding and using journal impact factors and citation indices.

In an increasingly "publish or perish" clinical and academic environment, all clinicians and clinician-scientists involved in research must have a firm understanding of the measures commonly used to assess the quality of scientific journals and, by default, those extended to grade individual articles and authors. The publication of research is a vital part of clinical and experimental research, and citation analyses of research publications have increasingly been adopted as a means of assessing the apparent quality of journals and the research published therein. In the first of a series of articles for those embarking on ophthalmic and vision science research, this paper discusses the key features of citation analysis, concentrating on the 2004 Journal Citation Report figures for the field of ophthalmology that include 42 ophthalmology, vision science, physiological optics, and optometry journals. The Institute for Scientific Information (ISI) calculates a number of parameters including citation counts, Journal Impact Factor (JIF), Immediacy Index, and cited/citing half-life. This article discusses the methods of calculation and possible uses along with current controversies and potential abuses. The JIF and its relevance, potential bias, and limitations are discussed in depth as it has become the most widely used analysis of journal quality. The possible alternatives to ISI citation analysis are presented, and we conclude that citation analysis can be considered a reasonable measure of journal research quality only if used correctly.

Bibliometrics↗
PubMed2005

In vivo confocal microscopy of posterior polymorphous dystrophy.

PURPOSE: This study was designed to delineate the morphologic features of posterior polymorphous dystrophy (PPD) using in vivo confocal microscopy. METHODS: Six patients with clinically diagnosed PPD were examined by slit-lamp biomicroscopy, Orbscan II slit-scanning elevation topography, and in vivo confocal microscopy. RESULTS: Endothelial cell densities ranged from 613 to 3,405 cells/mm and endothelial polymegathism was noted in all cases, whereas endothelial pleomorphism was not a prominent feature. Three cases exhibited bright endothelial nuclei. A variety of abnormal curvilinear and vesicular abnormalities were imaged by in vivo confocal microscopy, with lesions ranging between 6 and 159 microm in diameter. Abnormal endothelial cells were visible within some of these lesions. Six cases showed hyperreflectivity at the level of Descemet's membrane around the lesions. Deep stromal keratocytes appeared to aggregate around, or were compressed by, the endothelial lesions in one case. CONCLUSIONS: We report the largest case series of PPD imaged by in vivo confocal microscopy. The ability of in vivo confocal microscopy to assess the living cornea over time enables monitoring of disease progression and thus the potential to identify and correlate development of, or changes in, microstructural features. As more data become available, these analyses may enable the formulation of prognostic and diagnostic criteria.

Adult↗
PubMed2005

In vivo microstructural analysis of the cornea in Maroteaux-Lamy syndrome.

PURPOSE: This report describes the clinical and in vivo microstructural features of the cornea in a case of Maroteaux-Lamy syndrome. METHODS: A 17-year-old female with Maroteaux-Lamy syndrome was examined by slit-lamp biomicroscopy, Orbscan II slit-scanning elevation topography, and in vivo confocal microscopy. RESULTS: Slit-lamp biomicroscopy revealed bilateral, altered corneal transparency involving the posterior half of the stroma. Funduscopy revealed bilateral small, crowded optic discs, and radial macula retinal folds. On in vivo confocal microscopy, the middle and posterior stroma were clearly visualized and exhibited well-defined, unusually shaped keratocytes. These cells contained single or multiple hyporeflective regions with well-defined borders that ranged from 1 to 11.6 microm in diameter. These abnormal keratocytes were particularly abundant in the posterior stroma and sparse in the anterior stroma. CONCLUSIONS: This is the first case of Maroteaux-Lamy syndrome in which altered corneal transparency has been imaged by in vivo confocal microscopy and macula retinal folds have been described.

Adolescent↗
PubMed2005

Imaging the microstructural abnormalities of meesmann corneal dystrophy by in vivo confocal microscopy.

PURPOSE: To delineate the microstructural features of Meesmann corneal dystrophy using in vivo confocal microscopy. METHOD: Three subjects with clinically diagnosed Meesmann corneal dystrophy were examined by slit-lamp biomicroscopy and slit-scanning in vivo confocal microscopy. RESULTS: On slit-lamp biomicroscopy, all subjects demonstrated large bilateral multiple epithelial cystic lesions extending to the midperiphery. On in vivo confocal microscopy, these lesions appeared as hyporeflective areas in the basal epithelial layer. The majority were circular, oval or teardrop shaped and ranged between 48 mum and 145 mum in diameter. Large elongated intraepithelial clefts were also seen. Reflective spots were visible within most of the lesions and these may represent the fibrillogranular material (termed peculiar substance) and tonofilament bundles observed in electron microscopy studies. An additional finding was the fragmented appearance of the subbasal nerve plexus. CONCLUSION: We present the first case series of Meesmann corneal dystrophy imaged by in vivo confocal microscopy and describe the associated microstructural features. Delineation of these features facilitates the use of the confocal microscope to aid diagnosis and management of corneal dystrophies.

Corneal Dystrophies, Hereditary↗
PubMed2005

The New Zealand National Eye Bank study 1991-2003: a review of the source and management of corneal tissue.

PURPOSE: To evaluate donor demographics and source, donor tissue processing and storage, biologic contamination, and the utilization and distribution of corneal tissue procured by the New Zealand National Eye Bank. METHODS: As part of a prospective longitudinal study, the electronic records of the NZNEB for the 13-year period 1991-2003 were analyzed for each year with respect to donor demographics, donor source and cause of death, death-to-preservation interval, storage methods, endothelial assessment, biologic contamination, corneal tissue utilization, and distribution. RESULTS: During the study period, 3221 corneas were retrieved from 1628 donors (69.8% male, 30.2% female), with the mean age of donors 59.4 years (SD 18.3 years) and range 4 to 95 years. No significant correlation was identified between donor age group (using 10-year intervals) and the proportion of corneas suitable for transplantation. Donors were procured from the Coroner's service (67.6%), public hospitals, (23.5%) and multiorgan donors (7.1%). The most common causes of donor death were cardiovascular disease, trauma, and cerebrovascular disease. Average storage duration increased from 3.5 to 11.8 days when organ culture replaced hypothermic storage in 1992. Biologic contamination occurred in 5% of all donor corneas. The most common bacterial and fungal isolates were coagulase-negative staphylococci and Candida spp, respectively. A significant decrease in contamination rate over the years of the study was identified. Overall, 79.4% of corneal tissue procured was used for corneal transplantation (75.8% for penetrating keratoplasty, 2.1% for lamellar keratoplasty, and 1.5% for unspecified transplants), and 21.6% was discarded. Most common reasons for discarding tissue were biologic contamination, abnormal serology, and failed endothelial assessment. CONCLUSION: Analysis of the NZNEB database provides valuable information in relation to eye banking and corneal transplantation in New Zealand. Significant trends were identified in donor demographics, donor procurement source, improved donor tissue processing and storage, decreased biologic contamination, and increased utilization of corneal tissue.

Adolescent↗
PubMed2005

Assessing the accuracy of Orbscan II post-LASIK: apparent keratectasia is paradoxically associated with anterior chamber depth reduction in successful procedures.

PURPOSE: To establish a relationship between the forward protrusion of the cornea (keratectasia), following successful LASIK, and anterior chamber depth. METHODS: One hundred and fifteen eyes of 59 patients who had undergone Zyoptix LASIK and 39 eyes of 21 patients who had undergone PlanoScan LASIK at the Eye Institute, Centre for Refractive Surgery, Remuera, Auckland, New Zealand, were included in the study. The results of Orbscan II acquisitions, taken before and 8.3 weeks +/- 4.0 (mean +/- standard deviation) following the procedure, were analysed to determine the amount of forward protrusion of the central 2 mm diameter of the posterior surface. The apparent keratectasia was then related to the Orbscan II anterior chamber depth (ACD) measurement in a linear mixed model analysis that included 'right or left eye', 'sex', 'type of LASIK procedure', 'change in pachymetry', 'postoperative pachymetry', 'change in anterior corneal curvature', 'postoperative anterior corneal curvature', 'planned ablation depth' and 'time until follow-up' as factors and covariates. RESULTS: The mean +/- SD amount of keratectasia determined by Orbscan II was 22.8 +/- 26.8 microm for the Zyoptix group and 16.9 +/- 24.6 microm for the PlanoScan group. The reduction in depth of the anterior chamber was 14.7 +/- 79.3 microm for the Zyoptix group and 18.2 +/- 68.8 microm for the PlanoScan group. The mixed model analysis demonstrated strong relationships with postoperative pachymetry and change in anterior corneal curvature (P < 0.001 and P < 0.001, respectively). Furthermore, the statistical model showed a marked significant difference in the Orbscan II assessment of keratectasia and change in ACD (P < 0.001). CONCLUSION: Using the Orbscan II device, the forward protrusion of the posterior corneal surface appears to coincide with a paradoxical reduction in depth of the anterior chamber. Although the keratectasia found in this study is accompanied by thin postoperative corneas and larger central pachymetry change, the contradictory decrease in anterior chamber depth creates uncertainty of measurement, and of ectasia as a mechanism of regression.

Adult↗
PubMed2005

Inherited corneal disease: the evolving molecular, genetic and imaging revolution.

Advances in molecular genetics and in vivo ocular imaging modalities have enhanced our understanding of the corneal dystrophies. To date at least 11 genes have been identified, in which mutations manifest in corneal disease. In addition there are at least eight other loci identified to which corneal dystrophies have been linked. The information gained from the knowledge of gene function, aberrant protein production, or altered enzyme activity in the cornea, has resulted in greater knowledge of the pathophysiological mechanisms in these disorders. In vivo confocal microscopy has recently enabled microstructural study of dystrophic corneas throughout the disease course, rather than being limited to histopathological analysis of tissue removed at corneal transplantation. This perspective article summarizes the current knowledge, with emphasis on the genes, mutant proteins and resultant mechanisms that lead to manifestations of disease, along with characteristic findings with in vivo confocal microscopy.

Biomedical Research↗