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Biomedical subjects

R P Wormald

Publications and source records attributed to R P Wormald.

At least 19 recordsLinked to original sources
PubMed2000

Randomized controlled trial of anterior-chamber intraocular lenses in Nepal: long-term follow-up.

Most of the estimated 20 million people who are blind with cataracts live in rural areas of developing countries, where expert surgical resources are scarce. We have studied the use of multiflex open-loop anterior-chamber intraocular lenses (ACIOL) in high-volume low-cost surgery. Between 1992 and 1995, a total of 2000 people attending Lahan Eye Hospital, Nepal, with bilateral cataracts reducing vision to < or = 6/36 were randomly allocated to receive intracapsular extraction (ICCE) with aphakic spectacles, or ICCE with an ACIOL. We re-examined the cohort (1305/2000, 65%) between November 1996 and April 1997 and report the findings in this article. There were 13 new cases of poor visual outcome (best corrected vision < 6/60) arising after one year: 9 in the ACIOL group and 4 in the control group; odds ratio 2.1 (95% confidence interval, 0.59-9.55). The causes of poor outcome were as follows: ACIOL group--retinal detachment (4 cases), cystoid macular oedema (2), epiretinal membrane (1), age-related macular degeneration (1), and late endophthalmitis (1); control group--retinal detachment (2 cases), late endophthalmitis (1), and primary open-angle glaucoma with age-related macular degeneration (1). In rural areas of developing countries, well-manufactured multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction.

Adult↗
PubMed1999

The National Survey of Trabeculectomy. I. Sample and methods.

PURPOSE: The National Survey of Trabeculectomy was designed to evaluate current practices of glaucoma surgery in the United Kingdom and to determine the success and complication rates of trabeculectomy on a national basis. This paper reports the survey methods, levels of consultant activity, waiting times, indications for surgery and the demographic and clinical characteristics of the patient sample. METHODS: Consultant ophthalmologists performing trabeculectomy in the United Kingdom were studied. Four consecutive patients undergoing trabeculectomy under each consultant prior to 18 June 1996 were retrospectively sampled. Patients were followed prospectively and evaluated 6 and 12 months after surgery. Data were collected by self-administered postal questionnaires. To determine the effects of selection and reporting bias a validation study of 14 randomly selected units was also conducted. RESULTS: Three hundred and eighty-two consultants recruited 1454 eligible patients for analysis. The mean age of patients was 69.2 years (standard deviation 10.9) and 51.7% were male. The underlying diagnosis was primary open angle glaucoma in 89.2%, pseudoexfoliation glaucoma in 5.4%, normal tension glaucoma in 3.8% and pigmentary glaucoma in 1.6%. There was advanced visual field damage in 50.5% of the cohort by the time of listing. The main indications for surgery were failure of medication to control intraocular pressure in 57.1%, progressive visual field loss in 26.5% and progressive optic disc damage in 4.8%. Primary surgery was undertaken in 4.8% of patients. In 80% trabeculectomy was performed within 3 months of listing. However, almost a third of consultants considered individual patient's waiting time too long. Validation studies confirmed that systematic bias did not operate in the selection of patients for the survey or in the reporting of outcomes. CONCLUSION: The findings of this survey are representative of current practices of trabeculectomy by consultants throughout the United Kingdom and show considerable variation in practice. Failure to control intraocular pressure with topical medications was the main indication for surgery. Advanced glaucomatous visual field damage was present at the time of surgery in half the sample. Though most patients were operated on within 3 months of listing, almost a third of consultants considered the wait unacceptably long.

Age Factors↗
PubMed1998

Systemic risk factors for idiopathic macular holes: a case-control study.

PURPOSE/BACKGROUND: The idiopathic full-thickness macular hole (IFTMH) is an important cause of poor vision in the elderly affecting predominantly women over the age of 60 years. While it is accepted that vitreoretinal traction is an important local factor in the development of IFTMH, the underlying cause is not known. The aim of this study was to identify possible systemic risk factors for the development of IFTMH. METHODS: Two hundred and thirty-seven patients with IFTMH (cases) attending the Macular Hole Clinic at Moorfields Eye Hospital were identified. These were compared with 172 patients without macular holes (controls) attending other clinics in the same hospital. Cases and controls were frequency-matched by sex. The prevalence of the following factors in both groups was ascertained by interview: ethnic origin, place of birth, housing tenure, any systemic diseases, current and lifetime consumption of medication, severe dehydrational episodes, menstrual and obstetric history, onset and severity of menopause and use of exogenous oestrogens (in women only), osteoporosis, vegetarianism, use of vitamin supplementation, and smoking and alcohol consumption. Height and weight were measured for all participants. RESULTS: Cases of IFTMH macular holes were predominantly women (67%) and aged 65 years and older (74%). We found very few systemic risk factors that were significantly associated with IFTMH. There was a higher prevalence of diabetes in controls (12% vs 5%). There was no association between the majority of indicators of oestrogen exposure in women and macular holes, but cases had a more difficult menopause as judged by the severity of hot flushes at menopause: odds ratio 2.6 (1.4-4.6). CONCLUSIONS: In common with other studies, we found only a few systemic factors associated with IFTMH. The study did confirm, however, that IFTMH is a strongly gender-related disease. There is some evidence for the role of sudden changes in hormonal balance, as seen by the increased reporting of severity of symptoms around the menopause along with (statistically non-significant) increased risks associated with hysterectomy and oophorectomy. The particular aetiological factor which puts women at increased risk of macular holes requires further studies.

Age Factors↗
PubMed1998

Does raised intraocular pressure begin in utero?

AIM: To determine whether fetal and infant growth, as assessed by weight at birth and weight at 1 year, are related to intraocular pressure. METHODS: 717 men and women born in Hertfordshire between 1920 and 1930, for whom records of birth weight and weight at 1 year were available, were examined. Visual fields were assessed using the Takagi central 25 degrees 75 point static threshold screening program. Tonometry was performed using the Perkin's tonometer. The disc was assessed by direct ophthalmoscopy through dilated pupils. RESULTS: A significant inverse relation was found between systolic blood pressure and birth weight. However, no association was found between birth weight or weight at 1 year and intraocular pressure, cup/disc ratio, or visual field defects. CONCLUSIONS: There was no evidence to support fetal or infant growth as being important factors for the subsequent development of raised intraocular pressure.

Aged↗
PubMed1998

Age-related nuclear lens opacities are associated with reduced growth before 1 year of age.

PURPOSE: The aim of this study was to assess the relationship between fetal and infant growth, as measured by birthweight and weight at 1 year and the development of age-related lens opacities. METHODS: A total of 1428 men and women who were born in Hertfordshire, United Kingdom, between 1920 and 1930, and for whom records of birthweight and weight at 1 year were available, were traced and invited for examination. Of these, 717 (50%) attended for ophthalmic examination. After dilation with tropicamide 1%, lens opacities were graded using the Lens Opacities Classification System (LOCS) III. RESULTS: In this population of English men and women aged 64 to 74 years, most opacities were of the nuclear type. There was no association between birthweight and nuclear lens opacities. Weight at 1 year was negatively correlated with nuclear opacity score in adult life (P=0.001). Subjects in the highest tertile for weight at 1 year (>23 pounds) had an odds ratio of 0.35 (95% confidence interval, 0.17 to 0.74) for having a significant nuclear lens opacity (LOCS score of > or = 3) compared with people in the lowest tertile for weight at 1 year (<21 pounds). This association remained after controlling for age, sex, smoking, social class, adult height, and diabetes. CONCLUSIONS: To our knowledge, this is the first time that such an association has been reported; it needs to be replicated in other populations. It could provide part of the explanation for the observed excess risk of cataract in developing countries.

Aged↗
PubMed1997

Randomised controlled trial of anterior-chamber intraocular lenses.

BACKGROUND: There are an estimated 16 million people blind in both eyes with cataracts. Most live in rural areas of developing countries where surgical resources are scarce. There is no consensus on the most appropriate type of intraocular lens in situations where high-volume low-cost surgery is required. This study was undertaken to evaluate the safety of multiflex open-loop anterior-chamber lenses (ACIOLs). METHODS: 2000 people attending Lahan Eye Hospital, southern Nepal, with bilateral cataracts reducing vision to 6/36 or less were randomly allocated to receive standard surgery--intracapsular extraction (ICCE) with aphakic correction--or ICCE with an ACIOL in their first operated eye. The primary outcome was a visual acuity of less than 6/60 in the operated eye at 1 year follow-up. Visual acuity was measured for 91% of the cohort at 1 year. The sample size was estimated to detect a doubling in poor visual outcome from an estimated rate of 4% in the standard surgery (control) group. FINDINGS: The median (range) time taken to do the surgery was 6.0 (3.0-17.2) min for the ACIOL group and 4.1 (2.4-10.3) min for the control group. 1 year after surgery, 5.0% of the ACIOL group and 5.4% of controls had functional vision less than 6/60 (OR 0.93 [0.60-1.43], p = 0.71). The causes of poor vision in the ACIOL and control groups were: correctable refractive error (22 and 29), uveitis/secondary glaucoma (13 and two), endophthalmitis (four and seven), pre-existing eye disease (four and five), retinal detachment (none and four), cystoid macular oedema (two and none), corneal ulcer (one and one), and corneal decompensation (none and one). INTERPRETATION: This study provides evidence that, in rural areas of developing countries, multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction. Further follow-up is planned.

Anterior Chamber↗
PubMed1997

Age-related macular disease in rural southern Italy.

OBJECTIVE: To report the prevalence of age-related maculopathy (ARM) in Salandra, a small, isolated southern Italian community, to test the hypothesis that an environmental factor, scarce in such a remote community but ubiquitous in modern industrial societies, might modify the risk of developing ARM. DESIGN: Population-based cross-sectional survey. MAIN OUTCOME MEASURES: Prevalence of advanced age-related macular degeneration (ARMD) (geographic atrophy or exudative maculopathy) and ARM (large, soft drusen or retinal pigment epithelium changes, or both) defined by fundus biomicroscopy and 30 degrees stereoscopic, macular photography. Self-sustenance was assessed by interview of participants and local shop retailers. The degree of genetic isolation was computed using a model that fits the genetic population structure with the frequency distribution of surnames in the community. RESULTS: A full ophthalmic examination was undertaken in 366 (63.5%) of 576 eligible participants, 354 (96.7%) of whom had clinical or photographic assessment for the presence of ARMD and 310 (84.6%) of whom had drusen characteristics graded on color transparencies for ARM. The overall prevalence of ARMD was 1.1%. Drusen larger than 50 microns and more numerous than 10 were found in 4.5% of subjects. Salandra was the birthplace of 87.2% of participants and for 77.3% of both parents of each subject. People in the community tended to consume homegrown products. CONCLUSION: The prevalence of ARM may be lower in this self-sustained farming community than elsewhere in the industrialized world.

Aged↗
PubMed1995

Glaucoma screening.

National screening programmes probably cannot be justified at present given difficulties with test validity, manpower, and some doubts about the natural history of the disease. The opportunity cost could be prohibitive, especially when resources are badly needed in other areas of ophthalmology, such as cataract programmes, diabetic retinopathy, and low vision services. The situation could change with an improved test with greater validity for primary screening and such tests are currently under investigation. The results of these investigations will not be available for at least three years. Screening for eye disease at the primary care level begs questions about manpower which need to be answered not just for glaucoma screening but also for detection of diabetic retinopathy and visual impairment in the elderly. A new cadre of ophthalmic paramedics as is already in wide use in some developing countries, who amalgamate the skills of optometrist, orthoptist, and eye trained nurse, is an interesting possibility. Meanwhile, much has to be done to improve current case finding with agreed standards of examination and referral criteria and special facilities available for those at increased risk.

Adult↗
PubMed1994

The African Caribbean Eye Survey: risk factors for glaucoma in a sample of African Caribbean people living in London.

The purpose of the study was to estimate the prevalence of and risk factors for chronic glaucoma in a sample of African Caribbean people over 35 years of age living in the London Borough of Haringey. A cross-sectional voluntary sample of persons were subjected to detailed ophthalmic assessment including automated tangent screen suprathreshold visual field testing, applanation tonometry and stereoscopic disc evaluation in 50 community-based survey clinics over an 8 month period. Cases and suspects were referred to Moorfields Eye Hospital for more detailed assessment and confirmation of the diagnosis. Of 873 eligible persons examined (out of a total of 1022), 32 definite cases of glaucoma were identified, a prevalence of 3.9%; 42% of these had been previously diagnosed. Approximately 10% of the sample required further assessment and follow-up when ocular hypertensives and glaucoma suspects were included. An age-standardised comparison with the findings of the Roscommon survey revealed a relative risk for glaucoma for Haringey blacks compared with Irish whites of 3.7. Significant risk factors for glaucoma included age, African birthplace and darker skin colour. Neither diabetes nor hypertension reached significance. Despite the lack of a population base, this study provides strong evidence that the 4 times greater risk of glaucoma estimated for American blacks compared with whites applies equally to the United Kingdom population. Community-based facilities are required to raise awareness of the risk among this ethnic minority in this country and case-finding resources should be provided to meet local needs.

Africa↗
PubMed1994

A pilot study into the prevalence of ophthalmic disease in the Indian population of Southall.

A pilot study was carried out to determine the prevalence of ophthalmic disease in the Indian community of Southall and to ascertain the best methods applicable for a larger formal study. Three sites were chosen for the study, a Sikh gurdwara, a mosque and a Hindu temple. The subjects were volunteers aged 30 years and over who had visited the appropriate place of worship at least twice in the previous month. A total of 184 subjects were examined. The prevalence of blindness was 2.7% by the World Health Organization (WHO) criteria, while 9.8% had uniocular blindness. The prevalence of glaucoma and ocular hypertension was 2.7% and 7%, respectively. Of the 184 subjects examined, 58% had cataract and 3.8% had age-related maculopathy. The prevalence of visually disabling trachomatous eye disease was 9.7%. The prevalence of diabetes mellitus was 17.9%, and that of hypertension 22.8%. This small study suggests that people with origins from the Indian subcontinent have a higher prevalence of ophthalmic disease than the Caucasian population.

Adult↗
PubMed1993

Epidemiological function of BD8 certification.

The quality of information collected during certification for blindness and partial sight was assessed using a combination of review of the literature on registration and analysis of 17,695 BD8 certificates received by the Office of Population Censuses and Surveys (OPCS) between June and November 1990. Three problems were identified which affect the epidemiological function of these data: interpretation of the definitions of blindness and partial sight has changed over time; the degree of under-certification is unknown (although it could be as high as 64% for blind and 77% for partially sighted people); and the cause of visual disability recorded by the ophthalmologist may not always be adequately transmitted into the statistical analyses. Guidelines for completion of part 5 of the BD8 form need to be developed. Strategies for improving the quality of these data are discussed.

Adolescent↗
PubMed1993

'Correctable undetected visual acuity deficit' in patients aged 65 and over attending an accident and emergency department.

The rate of occurrence of correctable undetected visual acuity deficit (CUVAD) in a population of patients aged 65 and over was investigated, using a pinhole screening method, to compare the sociodemographic and optical eye care habits of patients with or without a functionally significant CUVAD. Of 136 patients 46 (34%) were found to have a functionally significant CUVAD in one or both eyes which was not significantly associated with optician or general practitioner contact, age, sex, social class, living situation, or number of medications. Half the patients with significant CUVAD had not attended for 2 years mainly because of financial considerations. Three quarters attended of their own volition; only one in seven were prompted by opticians' postal invitations. It was concluded that a significant degree of CUVAD could be detected using a simple procedure which can be carried out by general practitioners as part of their general elderly health screen.

Aged↗
PubMed1992

Visual problems in the elderly population and implications for services.

OBJECTIVE: To determine the prevalence of visual disability and common eye disease among elderly people in inner London. DESIGN: Cross sectional random sample survey. SETTING: Inner London health centre. SUBJECTS: Random sample of people aged 65 and over taken from practice's computerised age-sex register. MAIN OUTCOME MEASURES: Presenting binocular Snellen 6 m distance acuity and best monocular 3 m Sonksen-Silver acuity to classify prevalence of blindness by World Health Organisation criteria (less than 3/60 in better eye) and American criteria for legal blindness (better eye equal to 6/60 or less) and of low vision by WHO criteria (best acuity 6/18) and visual impairment by American criteria (less than 6/12 or 20/40 but greater than 6/60 or 20/200 in better eye). Principal cause of visual loss by diagnosis, referral indication by cause to hospital eye service, and proportion of cases known to primary care. RESULTS: 207 of 288 (72%) eligible people were examined. 17 (8%) housebound subjects were examined at home. The prevalence of blindness was 1% by WHO criteria and 3.9% by American criteria. The prevalence of low vision (WHO criteria) was 7.7%. The prevalence of visual impairment (American criteria) was 10.6%. Cataract accounted for 75% of cases of low vision. Only eight out of 16 patients with low vision were known by their general practitioner to have an eye problem. 56 subjects (27%) would probably have benefited from refraction. Comparisons with studies in the United States and Finland suggested higher rates in this sample, mainly due to the prevalence of disabling cataract. CONCLUSION: There seems to be a considerable amount of undetected ocular disease in elderly people in the community.

Aged↗
PubMed1992

Clinical risk factors for failure in glaucoma tube surgery. A comparison of three tube designs.

We studied a cohort of 165 eyes that had undergone tube implant surgery for glaucoma, with a minimum follow-up of 12 months (range, 12 to 72 months). Of the 57 cases (34.5%) in which surgery failed to control intraocular pressure (less than 22 mm Hg), 15 (26%) occurred by 3 months, 36 (63%) by 12 months, and 46 (80%) by 24 months. Cox regression modeling was used to evaluate independent risk factors in the absence of additional therapy. The use of a two-piece (anterior chamber-to-encircling band) tube system was associated with a 2.4 times higher risk of failure (P less than .001) compared with a one-piece system. Neovascular glaucoma was associated with a 2.1 times higher risk of failure (P less than .037) than other types of glaucoma. Late failure of tube implant surgery is common and there is a steady attrition rate over a 2-year follow-up period.

Adult↗
PubMed1992

Stereopsis and ageing.

This study reports the prevalence of defective stereopsis in an elderly population. Of 728 individuals over the age of 65 who attempted a Frisby stereotest, only 27% had full stereopsis and 29% had no stereopsis. In the elderly population defective stereopsis is a common finding in the absence of any other ocular morbidity. The prevalence of defective stereopsis increased with age. This finding was noted as a part of a survey of eye health of elderly people living in an inner city. The finding was not associated with any symptoms. The significance of this finding is discussed.

Aged↗
PubMed1992

Macular disease in an elderly population.

In order to obtain more accurate information concerning the prevalence of macular diseases in an elderly population, a clinical study was undertaken on a sample of 430 members of the general population over the age of 65 years in London. Degenerative age-related macular changes were clinically visible in about 25%, and 2.8% had a lesion causing loss of visual acuity due to macular disease. Age was the only risk factor identified for age-related changes. No correlation was identified with the prevalence of hypertension, smoking, or diabetes mellitus between groups. In addition, symmetry was shown in the number of drusen, as well as their size, density and fluorescence in the central and peripheral areas between the eyes of affected subjects. The prevalence data from this study represent a baseline for the interpretation of hospital-based data and for the planning of health care.

Aged↗
PubMed1991

Preschool vision screening in Cornwall: performance indicators of community orthoptists.

The performance of community orthoptists was retrospectively assessed in a primary preschool screening programme that has been established in Cornwall since 1982. The outcome of screening was compared between random samples of two birth year cohorts corresponding to the second and fourth years of existence of the screening programme (1980, n = 298 and 1982, n = 300). The mean age at screening was significantly later for the second cohort (4.3 years compared with 4.4 years) but otherwise performance indicators improved in the second cohort. Community orthoptists achieved a sensitivity of about 90% and specificity of 99% during the study. It is unlikely that the more commonly used two tier system of health visitors referring to a community orthoptist could achieve this degree of accuracy.

Child, Preschool↗