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Biomedical subjects

R Wormald

Publications and source records attributed to R Wormald.

At least 37 records · Page 2Linked to original sources
PubMed2000

Risk factors for development of post-trabeculectomy endophthalmitis.

BACKGROUND/AIMS: Although adjunctive use of antiproliferative agents improves the success rate of glaucoma filtration surgery it profoundly alters the morphology of the filtering bleb. In view of these structural changes, which have been suggested to predispose to bleb infection, the relative importance of potential risk factors in the development of post-trabeculectomy endophthalmitis was investigated. METHODS: A case-control study was performed on patients with post-trabeculectomy endophthalmitis presenting to a single academic centre over a 6 1/2 year period. Cases were diagnosed by the combination of vitreous and aqueous inflammation occurring 4 or more weeks postoperatively with control patients chosen by selecting the three patients undergoing trabeculectomy immediately following each index case. RESULTS: Analysis of these data, derived from 23 cases and 69 controls, demonstrated that an episode of blebitis and the presence of diabetes mellitus were statistically significantly associated with subsequent endophthalmitis (odds ratios (OR) 11.8, 95% CI: 2.21-88.31, p = 0.003 and OR 4.51, 95 % CI 1.02-20.29, p = 0.04 respectively). The data also suggest an association exists between antiproliferative use and endophthalmitis (OR 3.3, 95% CI 0.95-15.19, p = 0.07) as the time interval between filtration surgery and development of endophthalmitis was significantly shorter in patients treated with antiproliferative agents (p = 0.001). CONCLUSIONS: These results provide strong evidence of an increased risk of late endophthalmitis in patients who have diabetes mellitus or have had an episode of blebitis and suggest antiproliferative agents may also have an important role.

Aged↗
PubMed1999

Retrospective analysis of risk factors for late presentation of chronic glaucoma.

BACKGROUND: Why some individuals present to the ophthalmologist in the early stages of chronic glaucoma but others present with very advanced visual field loss is a question which has received little attention. This study is an attempt to identify some basic characteristics of people who present with late glaucoma. METHODS: A retrospective case-control study by medical record review was employed. 100 cases and 100 controls were identified from the notes of patients presenting to Moorfields Eye Hospital glaucoma service between July 1993 and July 1995. Cases were defined as new patients presenting with absolute field loss within five degrees of fixation and a cup to disc ratio of greater than 0.8 in one or both eyes. Controls were new patients with no absolute field loss within 20 degrees in either eye, but otherwise typical glaucomatous field loss and a cup to disc ratio of greater than 0.5 or a difference of 0.2 or more between the discs. RESULTS: The ethnic origin, sex, referral source, presenting IOP, and age of the subjects studied were independently associated with late presentation. An African Caribbean patient is estimated to be four and a half times more likely to attend with advanced field loss than a white patient of similar age, sex, IOP, and referral source (adj OR: 4.55, 95% CI [1.57, 13.18]). A female patient is estimated to be one third (0.34, [0.15, 0.74]) as likely to attend late than a male patient of the similar age, IOP, ethnic origin, and referral source. A patient referred via any source other than an optometrist with the correct diagnosis is estimated to be greater than four times (4.32 [1.89, 9.88]) more likely to be a late attender than a patient of the same sex, ethnicity, and similar age but referred with a diagnosis of glaucoma. There was a trend of increasing odds of late presentation with increasing age (adj OR per 10 years, baseline 40-49 years 1.68 [1.22, 2.20]). A patient whose presenting IOP is 21-25 mm Hg is estimated to be a quarter (0.24, [0.09, 0.64]) as likely to attend with advanced field loss than a patient of the same ethnic origin, sex, age, referral source, but with presenting IOP of greater than 31 mm Hg. CONCLUSIONS: These data strongly suggest that certain subgroups of patients with glaucoma are likely to be at greater risk of presenting with advanced and irremediable field loss.

Adult↗
PubMed1999

Risk factors for late presentation in chronic glaucoma.

PURPOSE: To identify the risk factors for having advanced glaucomatous visual field loss on the first visit at three hospital eye services. METHODS: This was a hospital-based, case-control study involving patients newly diagnosed with glaucoma at first visit to one of three ophthalmic departments in the United Kingdom. Patients with a previous history of ocular hypertension or any documented suspicion of glaucoma (within the hospital eye service) were excluded. RESULTS: Occupational group, initial intraocular pressure (IOP), family history of glaucoma, method of referral to hospital, and the number of years since the last visit to an optometrist were found to be independently associated with late presentation. A linear trend of increasing odds of late attendance was associated with increasing Standard Occupational Classification. Those in managerial (category II) and skilled (category III) groups estimated (95% confidence intervals) to be, respectively. 0.2 (0.00, 0.16) and 0.27 (0.1, 0.8) as likely to attend with advanced glaucomatous field loss as unskilled (category V) people with similar initial IOP, family history, referral route, and time since last optometrist visit. The data strongly suggest an association between IOP and advanced field loss at initial hospital examination. There was a 1.2 (1.12, 1.28) increase in the OR of late presentation per unit increase in millimeters of mercury after adjustment for the other mentioned factors. People with a family history of glaucoma were estimated to be almost one third (adjusted OR, 0.29 [0.12, 0.74]) as likely to have advanced field loss as those with no family history. People referred by any source other than an optometrist who has made the correct diagnosis of glaucoma were 4.5 times (adjusted OR, 4.53 [1.52, 13.48]) more likely to be late attenders than patients so referred but similar in other mentioned factors. These data also provide strong evidence that the more years since the last visit to an optometrist, the greater the likelihood of having advanced glaucomatous visual field loss on the first visit to the eye service (adjusted OR per year, 1.25 [1.10, 1.42]). CONCLUSIONS: These data strongly suggest that certain subgroups of people with glaucoma were at greater risk of having advanced and irremediable field loss on first visiting the eye services studied.

Adult↗
PubMed1998

Visual acuity and its relationship to early growth, eye disease, and aging in north Hertfordshire.

We investigated the relationship between visual acuity, early growth and eye disease in a retrospective cohort study of 700 individuals in North Hertfordshire. Records of birth weight and weight at one year were used to determine early growth. We measured visual acuity and age-related eye diseases using standard instruments in those same individuals (now aged 63 to 73). Visual acuity below the legal threshold for driving in the UK (6/11 or poorer) was present in 13% of subjects. There was no clear association between birth weight or weight at one year and visual acuity. Vision impairment was found to be associated with refractive error, cataract, age-related maculopathy, and elevated macular threshold. After controlling for the effects of eye disease, increasing age remained a significant predictor of poorer visual acuity.

Aged↗
PubMed1998

BD8 certification of visually impaired people.

BACKGROUND: There is debate as to the completeness of the blind and partial sight registers in England and Wales. The purpose of this study was to estimate the proportion of eligible visually impaired people attending the hospital eye service who have a BD8 certificate and to identify factors associated with not being certified. METHODS: Cross sectional survey of patients attending outpatients by medical record review analysed by multiple logistic regression. RESULTS: 51% (43%, 58%) of patients identified as eligible for registration did not have a BD8 certificate. The severity of visual impairment and the main diagnosis in terms of requirements for treatment, permanence of visual loss, and visual field loss were independently associated with non-certification. A partially sighted patient is estimated to be three times more likely to not have a BD8 certificate as a blind patient of similar diagnosis (adj OR: 3.4 (95% CI: 1.7, 6.8)). A patient whose impairment is due to abnormal visual fields is estimated to be greater than three times more likely to be non-certified than one with low visual acuity of similar severity and cause (adj OR: 3.6 (95% CI: 1.0, 12.7)). People whose impairment is potentially reversible are estimated to be eight times (8.3 (2.2, 31.4)) more likely not to have a certificate compared with people who had permanent non-treatable visual loss; and in those with permanent visual loss, a requirement for ongoing treatment was found to be associated with a lower odds of certification. CONCLUSIONS: These data strongly suggest that epidemiological data collected during registration are biased towards permanent, non-treatable causes of visual loss and those which affect central rather than peripheral vision. Certain subgroups of the visually impaired are likely to be at greater risk of non-certification. BD8 guidelines need to be simplified.

Aged↗
PubMed1998

Impaired motion sensitivity as a predictor of subsequent field loss in glaucoma suspects: the Roscommon Glaucoma Study.

AIM: To determine if impaired motion sensitivity is a significant predictor of subsequent field loss in glaucoma suspects. METHOD: A population based prospective study; a 5 year follow up of all glaucoma suspects who had been identified from a population based random sample survey in the west of Ireland. 78 glaucoma suspects whose visual field function was annually measured by Henson CFS 2000 and for whom data on family history of glaucoma, ocular status, and motion impairment had been recorded. Visual field loss was defined as Henson visual field survival score of 94 or less. RESULTS: 18 people developed visual field loss in at least one eye. Motion impairment at baseline was associated with a 2-18 times greater risk of development of the visual field loss (p < 0.001). This association was independent of sex, family history of glaucoma, intraocular pressure, and C/D ratio at baseline. The Cox's proportional hazards regression analysis confirmed the above results after adjustment for age and the C/D ratio. CONCLUSION: Motion impairment is an independent predictor of visual field loss in glaucoma suspects, although it is not clear how long motion impairment precedes visual field loss.

Age Factors↗
PubMed1998

Brain natriuretic peptide: identification of a second natriuretic peptide in human aqueous humour.

AIMS/BACKGROUND: To measure aqueous humour levels of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in humans. To compare peptide levels in glaucomatous and control eyes to test the hypothesis that these peptides are increased in glaucoma. BNP and ANP are cyclic endopeptides whose principal biological effects are natriuresis and vasodilatation. Experimental glaucoma in animal models results in elevated aqueous ANP. Intravenous ANP administration in both animals and humans causes lowering of intraocular pressure (IOP). There are equivocal data to support a role for ANP in IOP regulation in human eyes. There are as yet no published data on BNP in human aqueous humour. METHOD: This was a case-control study. Cases were primary open angle, pseudoexfoliation, and mixed mechanism glaucoma eyes undergoing trabeculectomy. Controls were cataract extraction eyes. There were 47 trabeculectomy eyes (44 patients) and 47 cataract extraction eyes (46 patients) matched for age, sex, race, systemic medications, and type of anaesthetic. 100-200 microliters of aqueous humour were aspirated by paracentesis as the first step in the surgical procedure. Peptide levels were later measured by radioimmunoassay. RESULTS: The presence of BNP and ANP in human aqueous humour was confirmed. BNP was present in higher concentrations than ANP. BNP levels tended to be greater in control eyes--glaucoma median 56.5 (range 0-3526.5) pg/ml versus control median 65.16 (range 0-1788) pg/ml (Wilcoxon signed rank test p = 0.78). ANP levels tended to be greater in glaucoma eyes than in controls: glaucoma median 3 (range 0-68.5) pg/ml versus control median 0 (range 0-60) pg/ml (Wilcoxon signed rank test p = 0.82). ANP and BNP were log linearly related in both groups (r glaucoma group = 0.961, r control group = 0.894). CONCLUSION: This is the first report of BNP and ANP in human aqueous humour. Peptide levels did not differ significantly between glaucoma and cataract extraction eyes. A linear relation between log BNP and ANP was found. Further studies are required to clarify the role of these peptides in aqueous humour production and IOP regulation.

Adult↗
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.

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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↗