Biomedical subjects

Peter Aspinall

Publications and source records attributed to Peter Aspinall.

6 recordsLinked to original sources

PubMed2006

The eye at altitude.

High altitude retinopathy (HAR) was first described in 1969 as engorgement of retinal veins with occasional papilloedema and vitreous hemorrhage. Since then various studies have attempted to define the incidence, etiology and significance of this phenomenon, usually with small numbers of subjects. Recently studies on relatively large groups of subjects in Nepal, Bolivia and Tibet have confirmed that the retinal vasculature becomes engorged and tortuous in all lowlanders ascending above 2500m. Sometimes this leads to hemorrhages, cotton wool spots and papilloedema, which is the pathological state better known as high altitude retinopathy. These studies have also shown a significant change in both corneal thickness and intraocular pressure at altitude. The retinal blood vessels are the only directly observable vascular system in the human body and also supply some of the most oxygen-demanding tissue, the photoreceptors of the retina. New techniques are being applied in both hypobaric chamber and field expeditions to observe changes in retinal function during conditions of hypobaric hypoxia. This work allows better advice to be given to lowlanders traveling to altitude either if they have pre-existing ocular conditions or if they suffer from visual problems whilst at altitude. This especially applies to the effect of altitude on refractive eye surgery and results of recent studies will be discussed so that physicians can advise their patients using the latest evidence. Retinal hypoxia at sea level accounts for the developed world's largest cause of blindness, diabetic retinopathy. The investigation of retinal response to hypobaric hypoxia in healthy subjects may open new avenues for treatment of this debilitating disease.

Adolescent↗

PubMed2005

Language matters: the vocabulary of racism in health care.

Race equality as a matter of governance has gained momentum in most Western countries and is reflected in race/ethnicity data collection in administrative systems and the attention accorded to terminology by census agencies. However, the vocabulary of health care--both in its literature and the language of officialdom--has proved resistant to the use of this lexicon of acceptable terms, as exemplified by the portrayal of peoples as 'Oriental' and 'Negro'. What makes such language racist is the historical legacy it carries--that is, its symbolic importance. Survey evidence shows that the majority of those so described find the terms offensive. Countries have dealt with these linguistic issues in a variety of ways, including the use of the legislature and action by library associations and professional bodies in the USA. In Britain it has fallen upon the judiciary and universities to prohibit such terms. Given the momentum currently being achieved by public authorities in their response to race equality legislation, it is now time for health care to purge its language of these epithets.

Delivery of Health Care↗

PubMed2003

Posterior capsule morphology determinants of visual function.

BACKGROUND: This study explores the relative influence of fibrosis and pearl-type posterior capsule opacification (PCO) on visual function. It also examines the relevance of analyzing different central areas of posterior capsule on visual function. METHODS: Thirty-eight eyes of 33 patients had their vision tested and posterior capsules photographed digitally. Each patient then underwent Nd:YAG laser capsulotomy. Patients returned 1 week later for repeat vision tests and photography. Analyses of areas of pearls and fibrosis were performed using the EPCO software system. The difference in these values before and after Nd:YAG laser capsulotomy was compared to change in vision for each patient. The effect of analyzing the central 1.5-, 2.5- and 3.5-mm zones was studied. RESULTS: Stepwise multiple linear regression analysis shows that improvements in distance and near acuity are most strongly related to the central 1.5-2.5 mm of fibrosis and the central 3.5 mm of pearls. Improvements in contrast sensitivity are most strongly related to the central 1.5 mm of both fibrosis and pearls. CONCLUSION: In the assessment of PCO, the location and morphology of opacification correlate with visual function. Central fibrosis and paraxial pearls are important determinants of visual dysfunction.

Aged↗

PubMed2003

Quality of life in glaucoma and its relationship with visual function.

PURPOSE: The aims of this study were (a) to explore patients self-reported visual disability resulting from glaucoma by means of a questionnaire developed for this purpose; (b) identify activities strongly associated with a measure of visual field loss, (c) to quantify different psychophysical aspects of visual function; (d) to assess the relationship between objective measures of visual function and patients' perception of their vision-related quality of life. PATIENTS AND METHODS: Three groups of glaucoma patients (n = 47) with mild (n = 18), moderate (n = 19), and severe visual field loss (n = 10) and a group of normal controls (n = 19) underwent a comprehensive clinical examination, completed a questionnaire and, on a separate visit, performed a number of psychophysical tests of visual function. MAIN OUTCOME MEASURES: Questionnaire responses (vision-related quality of life, general health and psychosocial variables), visual acuity, visual fields, Esterman binocular disability scores, contrast sensitivity, critical flicker frequency, color vision, dark adaptation, glare disability (brightness acuity), and stereoacuity scores were measured. RESULTS: Fifteen of the 50 questions were noted to have a strong significant relationship with a measure of visual field loss and were included in a new questionnaire scale, the Glaucoma Quality of Life - 15 (GQL-15). The scale validity showed a significant correlation with perimetric mean deviation (MD) values (r = -0.6; P < 0.0001), the reliability of the scale was high (Cronbach alpha = 0.95), and test-retest reliability of the questionnaire was strong (r = 0.87). An overall statistically significant decrease in performance-related quality of life was noted between normal subjects and all groups of glaucoma patients. A significant relationship was found between the scale questionnaire summary performance measure and a number of psychophysical tests: Pelli-Robson contrast sensitivity (r = -0.45, P < 0.001), glare disability (r = -0.41, P < 0.001), Esterman binocular visual field test (r = -0.39, P < 0.001), dark adaptation (r = 0.34, P = 0.007), and stereopsis (r = 0.26, P = 0.04). CONCLUSION: Perceived visual disability relating to certain tasks (particularly involving dark adaptation and disability glare, activities demanding functional peripheral vision such us tripping over and bumping into objects and outdoor mobility tasks) was significantly associated with the severity of binocular visual field loss. As a result, a new glaucoma-specific questionnaire scale with good performance characteristics is presented in this study. The difficulties encountered by patients in everyday life (as measured with the questionnaire) were also mirrored in their performance on a number of psychophysical tests, especially contrast sensitivity, glare disability, Esterman binocular visual field test, and dark adaptation.

Aged↗

PubMed2002

Sensitivity and specificity of frequency-doubling technology, tendency-oriented perimetry, and Humphrey Swedish interactive threshold algorithm-fast perimetry in a glaucoma practice.

PURPOSE: To evaluate the sensitivity and specificity of the screening mode of the Humphrey-Welch Allyn frequency-doubling technology (FDT), Octopus tendency-oriented perimetry (TOP), and the Humphrey Swedish Interactive Threshold Algorithm (SITA)-fast (HSF) in patients with glaucoma. DESIGN: A comparative consecutive case series. METHODS: This was a prospective study which took place in the glaucoma unit of an academic department of ophthalmology. One eye of 70 consecutive glaucoma patients and 28 age-matched normal subjects was studied. Eyes were examined with the program C-20 of FDT, G1-TOP, and 24-2 HSF in one visit and in random order. The gold standard for glaucoma was presence of a typical glaucomatous optic disk appearance on stereoscopic examination, which was judged by a glaucoma expert. The sensitivity and specificity, positive and negative predictive value, and receiver operating characteristic (ROC) curves of two algorithms for the FDT screening test, two algorithms for TOP, and three algorithms for HSF, as defined before the start of this study, were evaluated. The time required for each test was also analyzed. RESULTS: Values for area under the ROC curve ranged from 82.5%-93.9%. The largest area (93.9%) under the ROC curve was obtained with the FDT criteria, defining abnormality as presence of at least one abnormal location. Mean test time was 1.08 +/- 0.28 minutes, 2.31 +/- 0.28 minutes, and 4.14 +/- 0.57 minutes for the FDT, TOP, and HSF, respectively. The difference in testing time was statistically significant (P <.0001). CONCLUSIONS: The C-20 FDT, G1-TOP, and 24-2 HSF appear to be useful tools to diagnose glaucoma. The test C-20 FDT and G1-TOP take approximately 1/4 and 1/2 of the time taken by 24 to 2 HSF.

Aged↗

PubMedDate not supplied

Positive results.

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Data Collection↗