PubMed Health⌕ Search

Biomedical subjects

R Wormald

Publications and source records attributed to R Wormald.

At least 37 records · Page 2Linked to original sources
PubMed1997

Retinal vascular network architecture in low-birth-weight men.

BACKGROUND: Low birth weight is associated with hypertension and increased cardiovascular mortality, but the mechanism of this association is not known. Hypertension is accompanied by abnormalities of the microvasculature including rarefaction. OBJECTIVE: To test the hypothesis that low birth weight is associated with an alteration in microvascular architecture. DESIGN: A stratified random sample of 100 men aged 64-74 years was selected from a cohort of men whose birth weights were known. They were of relatively high or low birth weight ('high' > or = 3700 g, 'low' < or = 3200 g) and high or low systolic blood pressure (high > or = 160 mmHg, low < or = 140 mmHg). METHODS: Retinal arteriolar geometry was defined in terms of arteriolar bifurcation angles and junction exponents (a measure of the relative diameters of parent and daughter vessels), measured from photographic diapositives using operator-directed image analysis. RESULTS: Members of low-birth-weight groups had significantly narrower bifurcation angles than did members of high-birth-weight groups (74 +/- 1 degree versus 78 +/- 1 degree, P= 0.017 by analysis of variance). There was no significant difference between angles in members of groups with high and low blood pressures. Neither birth weight nor blood pressure grouping affected junction exponents. CONCLUSIONS: Narrower bifurcation angles are associated with increased circulatory energy costs and may be related to a lower than normal microvascular density. Our finding of differences in retinal microvascular architecture might reflect a persistent alteration in vascular architecture as a result of an impairment of foetal development and could provide a mechanistic link between low birth weight and subsequently increased cardiovascular risk.

Aged↗
PubMed1996

Is the incidence of registrable age-related macular degeneration increasing?

AIMS/BACKGROUND: Age-related macular degeneration (ARMD) is a growing public health problem in Britain; currently its aetiology is unclear. The aim of this study was to test the hypothesis that the age specific incidence of blinding ARMD has increased in Britain in the past 50 years, using data on cause of visual loss in people registered as blind, published every 10 years since 1950. METHODS: Data were abstracted from published sources for the years 1950, 1960, 1970, and 1980. Data for the standard year, 1990, were provided in a database from the Office of Population Censuses and Surveys. The numbers of new registrations attributed to ARMD per head of population were compared with registrations for cataract, glaucoma, and optic atrophy. Indirect standardisation was used to control for changes in the age structure of the population over time. RESULTS: After controlling for changes in the age structure of the population, registration rates for all causes, cataract, glaucoma, and optic atrophy have decreased while registrations attributed to ARMD have increased in the order of 30-40%. CONCLUSIONS: These findings are compatible with the hypothesis that the incidence of ARMD is increasing in Britain. It is difficult to exclude potential sources of bias in these data, however, particularly with respect to classification and coding of cause; more reliable population based data on ARMD in Britain are needed.

Blindness↗
PubMed1995

Who should see eye casualties?: a comparison of eye care in an accident and emergency department with a dedicated eye casualty.

Emergency care for eye complaints is provided both by accident and emergency (A&E) departments as well as by dedicated eye casualty departments. This study examines the role of each type of department and the quality of eye care provided. Significant differences were found between the accident and emergency department and the eye casualty department in the history, examination and management of eye patients. Most notably, there were significant differences in the quality of the assessment in the two institutions. Overall 19% (19/100) of A&E records had an inadequate history, compared with 2% (1/50) for eye casualty records. Fifty-nine per cent (59/100) of A&E records contained a significant examination omission, compared with only 8% (4/50) of eye casualty records. Most of the omissions related to a failure to perform an adequate, yet simple, ocular examination including failure to record visual acuity. In 44% (44-100) of A&E cases visual acuity was not recorded or recorded incorrectly. In comparison acuity omissions in eye casualty were present in only 4% (2/50) of cases.

Adult↗
PubMed1995

Hypertensive retinopathy in Afro-Caribbeans and Europeans. Prevalence and risk factor relationships.

The prevalence of hypertension is particularly high in people of black African descent throughout the world, and the consequences of hypertension, such as hypertensive heart and renal disease and stroke, are also more common. But there is little consensus on whether hypertensive retinopathy follows a similar pattern. We determined the prevalence of hypertensive retinopathy and its relationships with resting and ambulatory blood pressure in a population study of Afro-Caribbeans and Europeans aged 40 to 64 years in London, UK. Retinal photographs of 651 participants were graded for hypertensive retinopathy. Age- and sex-standardized prevalence of retinopathy was 11% (95% confidence interval, 8% to 14%) in Europeans and 21% (95% confidence interval, 16% to 26%) in Afro-Caribbeans (P < .001), respectively. This ethnic difference in prevalence was greatest in normotensive women (8% in Europeans versus 20% in Afro-Caribbeans, P < .001). Resting systolic pressure was 8 mm Hg higher in normotensive Afro-Carribean compared with European women, but this could not fully account for the ethnic difference in the prevalence of retinopathy. Examination of the different relationships of age and resting and ambulatory blood pressures with hypertensive retinopathy showed that these relationships were strongest in European women and weakest in Afro-Caribbean women. We conclude that hypertensive retinopathy is more common in Afro-Caribbeans, particularly women, and that ethnic differences in resting blood pressure cannot fully account for this. The relatively weak relationship between resting and ambulatory blood pressures and retinopathy in Afro-Caribbeans suggests that factors other than blood pressure determine the high rates of hypertensive retinopathy in this group.

Adult↗
PubMed1994

The primary treatment trial: changes in the visual field analysis by computer-assisted perimetry.

Computer-assisted perimetry was performed 6-monthly on patients entered into the Primary Treatment Trial using the 30-2 program. Those patients with a minimum of five visual fields had pointwise linear regression analysis (Progressor) carried out. Two consecutive slopes significant at the 0.05 level were taken as evidence for change, either improvement or worsening. Forty-eight patients in the surgery group, 40 in the medical group and 20 in the laser group were suitable for analysis. A comparison of the eyes showing 'improvement' or 'worsening' in the surgery and medicine groups showed no difference between them. This lack occurred despite a significant difference in intraocular pressure between the two groups. The reasons for this lack of difference are discussed.

Diagnosis, Computer-Assisted↗
PubMed1994

Detection and prevention of treatable visual failure in general practice: room for improvement?

An ageing population, the introduction of sight test charges and a problem that has never been adequately addressed since the inception of the National Health Service presents general practitioners with the increasing burden of detecting and preventing visual failure which they feel poorly equipped to deal with. Ophthalmology in general practice is a fundamental requirement for the reduction of avoidable visual failure and this is probably especially true for elderly patients and diabetic patients. A postal survey of general practitioners in Brent and Harrow suggests that there is potential for major improvements in the delivery of eye care by general practitioners, often without much additional expenditure (the equipment is there but it is not used) and with minimal training requirements. Simple changes in already existing screening programmes could potentially have an immediate effect on the visual well-being of the community.

Aged↗
PubMed1993

Community ophthalmology pilot study.

A randomly selected sample of subjects over 75 years old or housebound in three London inner city general practices were screened for eye disease by an ophthalmologist and an ophthalmic trained nurse. All subjects were examined at specialist outreach clinics run at the surgery of their general practitioner (GP), except for the housebound who were assessed by domiciliary visit. Patients presenting to their GP with an eye problem during the study were also seen at the outreach clinic at the GP's request. Over the 3-month period of the study, 126 over-75s, 62 housebound and 35 GP referrals were seen. This pilot study found high prevalence rates of treatable eye disease in the elderly and housebound subjects and these are compared with the findings of other epidemiological surveys. The needs for health care provision to this sector of the community and the feasibility of providing it through outreach clinics are also discussed.

Aged↗
PubMed1993

Essential fatty acids, plasma cholesterol, and fat-soluble vitamins in subjects with age-related maculopathy and matched control subjects.

A matched-control study of plasma retinol, alpha-tocopherol, carotenoid, and cholesterol concentrations and the polyunsaturated fatty acid content of plasma and erythrocyte phospholipids was undertaken in 65 elderly patients with age-related maculopathy and 65 control subjects matched for age and sex. Despite the high statistical power of the study and large variations between subjects in the variables under consideration, no significant differences were noted between patients and control subjects. However, several statistically significant differences were noted between male and female subjects independent of their classification with maculopathy or as controls and age: plasma cholesterol, total phospholipids, alpha-tocopherol, and beta-cryptoxanthin concentrations were higher in females than in males. The mean plasma cholesterol concentration for the upper tertile of the whole sample was 7.6 mmol/L. Plasma concentrations of total carotenoids, alpha-carotene, and beta-carotene, but not alpha-tocopherol, were significantly lower in smokers than in non-smokers. The results of this study do not provide any evidence in favor of changing the dietary intake of polyunsaturated fatty acids or fat-soluble vitamins to protect against age-related maculopathy.

Aged↗
PubMed1993

Prevalence of glaucoma in the west of Ireland.

County Roscommon in the west of Ireland is a relatively remote rural area whose population of 55,000 is served by two community medical ophthalmologists and three optometrists. Eye surgical services are not available within the county. In order to assess the needs of the community for prevention of blindness from glaucoma, a simple random sample of the population of County Roscommon was taken for a community based glaucoma survey. A total of 2186 people over the age of 50 were examined which represented a 99.5% response rate. The high response rate was achieved by the community basis of the study and vigorous follow up of non-attenders. Intraocular pressure was measured using applanation tonometry, disc evaluation by both direct ophthalmoscopy and stereoscopic biomicroscopy, and visual field analysis using the Henson CFS 2000 and experimental computer controlled video perimetry. Diagnostic criteria were consistent with the preferred practice pattern of the American Academy of Ophthalmology. A crude prevalence of approximately 2% for primary open angle and normal tension glaucoma was found. The population profile of intraocular pressure showed a pattern which decreased with increasing age unlike the Framingham and Ferndale studies but similar to Japanese data.

Age Factors↗
PubMed1993

Age-related Bruch's membrane change: a clinical study of the relative role of heredity and environment.

For many years there has been controversy concerning the role of genetic influences in the pathogenesis of age-related macular disease. It is widely believed that the lesions causing visual loss occur in response to age-related changes in Bruch's membrane which are recognised clinically as drusen. In this study the density, size, and confluence of drusen as shown on colour photographs were compared in eyes of 50 spouses and 53 sibling pairs ascertained during a prospective study of age-related macular disease. Concordance between pairs of drusen--number, size, and density-were determined by kappa statistic and chi 2 test for trend. Drusen were absent in one sibling and 26 spouses of patients. There was a trend towards concordance of drusen characteristics between siblings but not between spouses, although the difference achieved 5% significance only for the number and density of drusen in the central macula. The difference of concordance between the probands and spouses and the probands and siblings was significant for all characteristics. These findings support the belief that genetic factors influence age-related changes in Bruch's membrane. They also imply that environmental factors are less important or alternatively that the environmental variation between households included in our study was not great enough to be evident.

Aged↗
PubMed1990

Clinical and pathological features of chronic glaucoma in north-east Ghana.

Of 34 consecutive patients with chronic glaucoma seen in north-east Ghana, 22 (65%) were male and seven (21%) were aged under 40 years. Only 17% of eyes had a visual acuity better than 6/18 at presentation. Sixteen of 23 patients who underwent gonioscopy had PAS of which 13 had positive skin snips for onchocerciasis, compared with two out of seven patients with positive skin snips who had open angle glaucoma (p = 0.003). Of 22 trabecular meshworks examined by light microscopy ten (45%) showed marked melanin pigmentation which was more common in younger patients but did not correlate with onchocerciasis infection.

Adolescent↗
PubMed1990

Chronic glaucoma in northern Ghana--a retrospective study of 397 patients.

A retrospective study of 397 patients with chronic glaucoma in North-East Ghana seen in 1986/87 showed 71% of the patients to be male and 26% to be aged under 40 years. Fifty two per cent of eyes were already blind (V/A less than 3/60) at presentation. Blindness was associated with younger age at presentation, and greater distance of residence from the hospital. Only 19% of patients undergoing treatment were attending for follow-up at six months. Of those patients treated medically who returned for follow-up at six months only 17% had an intraocular pressure less than 22 mmHg. While of the patients treated surgically 84% of those seen at six months had an IOP below 22 mmHg.

Adolescent↗