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D C Minassian

Publications and source records attributed to D C Minassian.

At least 37 records · Page 2Linked to original sources
PubMed1996

Epidemiology and implications of ocular trauma admitted to hospital in Scotland.

OBJECTIVES: To describe the current epidemiology of serious ocular trauma which necessitates admission to hospital so that health and safety strategies for the prevention of ocular injuries and their role within the national health strategy, The Health of the Nation, can be better informed. DESIGN: A prospective observational study of all patients with ocular trauma admitted to hospital under the care of a consultant ophthalmologist between 1 November 1991 and 31 October 1992. SETTING: All ophthalmic department in Scotland. SUBJECTS: All patients with ocular trauma admitted to hospital in Scotland. The population of Scotland represented the population at risk of injury. MEASURES AND MAIN RESULTS: Measures included the type and cause of injury, the place where it occurred, and awareness of risk and safety. All ophthalmic departments in Scotland participated and 428 admissions were reported. The home was the most common place for a serious injury to occur (30.2%), followed by the workplace (19.6%) and a sports or leisure facility (15.8%). The home was the single most frequent place of injury for the 0-15 year and 65 year and over age groups. Tools or machinery, either at home (13.9%) or at work (10.3%), were collectively (24.2%) the most frequent cause of injury, followed by assault (21.8%) and sports-related activities (12.5%). The most frequent type of injury was a blunt injury (54.4%). Six per cent (n = 25) of all injuries were bilateral. Only 13.2% of patients were aware of any risk of injury, with 5.6% aware of any risk at home. When applicable, protective eye wear was only available to 48.6% of patients and only 19.4% of these used it. CONCLUSION: Serious ocular trauma frequently occurs at home and the young and the elderly are particularly at risk. This represents a significant change in the epidemiology of serious ocular trauma and has important implications for prevention. Health and safety strategies specifically aimed at preventing eye injury should now include the home as a high risk environment in addition to the work-place and sports/leisure facilities. The target groups for accident prevention in The Health of the Nation strategy include those at risk of serious ocular trauma with potentially sight threatening sequelae. Those involved in implementing the national accident prevention strategy should be aware of this, for in this process it is possible that some serious eye injuries may also be prevented.

Accidents, Home↗
PubMed1996

Blindness and low vision in southeast Turkey.

In preparation for the planning of a regional prevention of blindness programme, a population-based survey of blindness and eye disease was conducted in two provinces (Diyarbakir and Mardin) of southeast Turkey. A stratified cluster random sampling procedure was used to select 8,571 persons. The main objectives of the survey were to assess the population need for basic ophthalmic services, both in rural and in rapidly growing urban communities, and to secure baseline data for subsequent evaluation of the programme. The prevalence of visual impairment (best binocular vision poorer than 6/ 18) was estimated at 1.9% with 95% confidence limits of 1.6% and 2.1%, amounting to 29,400 +/- 4500 visually imparied persons in the regional population of 1.6 million. The prevalence of blindness (best vision poorer than 3/60) was 0.4%, and an estimated 1.5% had low vision (best vision poorer than 6/18, but not blind). Compared to the blindness prevalence of 0.2% in the European Economic Community (EEC), the age-standardised prevalence of blindness in southeast Turkey was 8 times as high. The main causes of blindness in the sample were cataract (50%), corneal opacity (15%), glaucoma (12%), phthisis (6%) and optic atrophy (6%). Cataract and refractive errors were responsible for 52% and 26% of the low vision, respectively. Acute inflammatory trachoma was prevalent in a number of rural and urban communities, affecting an estimated 25,900 people in the region. The need for basic ophthalmic services was estimated for the two provinces. Some 26,600 were in need of cataract surgery, 4,400 needed eyelid surgery for trachoma-induced entropion, and 28,600 required spectacles to improve their visual acuity to 6/18 or better. More than half of the current burden of severe visual loss in the two provinces of southeast Turkey is potentially remediable through the provision of cataract surgery and of spectacles to correct aphakia. The survey findings suggest that as the age structure of the regional population approaches that of the EEC through the "ageing trend', a four-fold increase in the burden of blindness might be expected, unless improvements are made in curative and preventive ophthalmic services in parallel with the general development that improves survival.

Adolescent↗
PubMed1995

Risk factors for acanthamoeba keratitis in contact lens users: a case-control study.

OBJECTIVE: To investigate reasons for an increase in cases of Acanthamoeba keratitis related to contact lenses. DESIGN: Case-control study. Cases were contact lens related acanthamoeba keratitis patients treated between 1 September 1989 and 31 August 1992. Controls were lens users without lens related disease who presented as new patients to the casualty department from 1 March 1992 to 31 August 1992. All subjects completed a questionnaire detailing lens use and hygiene practices. SETTING: Eye hospital. SUBJECTS: 35 cases with acanthamoeba keratitis and 378 controls. MAIN OUTCOME MEASURES: Relative risks comparing different contact lens types, socioeconomic classification, age, sex, lens use, lens wearing experience, hygiene compliance, and hygiene systems. RESULTS: The crude relative risk for developing acanthamoeba keratitis with the use of daily wear disposable lenses was 49.45 (95% confidence interval 6.53 to 2227; P < 0.001) compared with conventional soft lenses (the referent). Multivariable analysis showed that this increased risk could be largely attributed to lack of disinfection (relative risk 55.86 (10 to 302); P < 0.001) and use of chlorine based disinfection (14.63 (2.8 to 76); P = 0.001) compared with other chemical systems (the referent). None of the other outcome measures showed a significant association. CONCLUSIONS: Both failure to disinfect daily wear soft contact lenses and the use of chlorine release lens disinfection systems, which have little protective effect against the organism, are major risk factors for acanthamoeba keratitis. These risks have been particularly common in disposable lens use. Over 80% of acanthamoeba keratitis could be avoided by the use of lens disinfection systems that are effective against the organism.

Acanthamoeba Keratitis↗
PubMed1995

[Blindness in Benin].

A population-based survey of the prevalence and cause of blindness and poor vision was conducted in the Republic of Benin in 1990 using a stratified cluster random sampling procedure. The survey was designed and implemented through the collaboration of the Ministry of Health of the Republic of Benin and the Programme for the Prevention of Blindness of the World Health Organization (WHO/PBL). Survey data were analyzed at the International Centre for Eye Health, Institute of Ophthalmology, University of London, United Kingdom. In accordance with the procedures recommended by WHO/PBL, 7272 individuals were recruited and 7047 were examined. The survey achieved excellent coverage in all locations with an overall coverage of 96.9%. The prevalence of blindness (visual acuity less than 3/60 in the better eye) was 0.6% (CI95% = 0.4%-0.9%). The prevalence of poor vision (best vision less than 6/60 but not blind in the better eye) was estimated at 2.6% (CI95% = 2.1%-3.1%). The major causes of blindness were age-related cataract and glaucoma (54% and 15% respectively of blind people recruited). The major cause of poor vision were cataract, refractive errors, and macular disorders (64%, 9.6%, and 9.0% respectively of people recruited with poor vision. The survey results indicate that there is an urgent need for basic eye care services. Cataract has been designated as a priority target in the recently designed National Blindness Prevention Programme now being implemented in the Republic of Benin. With proper management of this problem, the current prevalence of blindness and poor vision could be reduced by at least 45%. At the end of this cluster study, the design effect (D = 1.56) and rate of homogeneity (ROH = 0.002) were computed for an average number of 250 people per cluster.

Adolescent↗
PubMed1994

Decreasing stromal iris pigmentation as a risk factor for age-related macular degeneration.

To evaluate iris color, change of iris color, and iris pigment epithelial defects as risk factors in age-related macular degeneration, we compared 101 patients with age-related macular changes with 102 control subjects in a case-control study. Three of 101 patients (3%) and four of 102 control subjects (4%) had epithelial iris defects. Light iris color during youth was reported by 51 of 101 patients (50.5%) and 42 of 102 control subjects (41.2%) (odds ratio, 1.46; P = .184). Of the 101 patients, 26 (25.7%) noticed their iris color to have become lighter during life compared with six of 102 control subjects (5.9%) (odds ratio, 5.5; P = .0001). At present examination, 63 of 101 patients (62.4%) had light irides compared with 43 of 102 control subjects (42.2%) (odds ratio, 2.27; P = .004). These results suggest that initial light iris color and iris pigment epithelial defects are not associated with an increased risk of age-related macular degeneration, whereas decreased stromal iris pigmentation may indicate a higher risk.

Aged↗
PubMed1994

Bilateral macular drusen in age-related macular degeneration. Prognosis and risk factors.

BACKGROUND: In patients with unilateral visual loss related to age-related macular disease, the risk of visual loss in the second eye is documented as being between 7% and 10% per year. The risk is uncertain in those with good vision with each eye and bilateral macular drusen. METHODS: In a prospective study, 126 patients with bilateral drusen were reviewed annually for up to 3 years. Serial fundus photographs and fluorescein angiograms were analyzed independently by two readers in a masked fashion using a standardized grading scheme, including size, number, density, and fluorescence angiographic behavior of drusen. RESULTS: New lesions occurred in one or both eyes of 17 (13.5%) of the 126 patients. The cumulative incidence of exudative or nonexudative lesions was 8.55% at 1 year, at 2 years 16.37%, and 23.52% at 3 years for patients older than 65 years of age. Significant risk factors included the degree of confluence of drusen within 1600 microns of the center of the fovea (P = 0.023), focal hyperpigmentation (P = 0.004), slow choroidal filling (P = 0.023), and focal extrafoveal areas of atrophy of the retinal pigment epithelium (P = 0.042). CONCLUSIONS: The results give an estimate for the incidence of complicating lesions in patients with bilateral drusen and identify those features indicating higher than average risk of visual loss.

Aged↗
PubMed1994

The relationship between cataract and climatic droplet keratopathy in Mongolia.

This study evaluated the association between cataract, the commonest single blinding disorder worldwide, and climatic droplet keratopathy which was taken as an indicator of high exposure to ultraviolet sunlight. A sample of 4344 persons from rural Mongolia (1991-92) provided 8634 eyes for analysis of the relationship between cataract and climatic droplet keratopathy. Right and left eyes were combined (paired into matched sets), and analysed using a random-effects regression model. The results indicated an inverse association between cataract and climatic droplet keratopathy in person aged 55 years or older, whereby eyes with more advanced climatic droplet keratopathy had lower prevalence of cataract (age-adjusted odds ratio 0.53, p = 0.047). In the younger group of persons aged 40-54 years, the reverse was found, whereby cataract prevalence was higher in eyes that have climatic droplet keratopathy (age-adjusted odds ratio 13.19, p = 0.046). However, only a small proportion (4%) of all the cataracts occurred in this younger age stratum where the prevalence of cataract was 0.5%, compared to prevalence of 17% in eyes of persons aged 55 years or older. These findings cast further doubts upon the current thesis that lifetime exposure to high levels of ultraviolet sunlight is a major cause of cataract in developing countries.

Adult↗
PubMed1994

Prognostic factors in primary malignant melanoma of the conjunctiva: a clinicopathological study of 256 cases.

A series of 256 consecutive cases of invasive primary conjunctival malignant melanomas was examined to identify clinical and histopathological prognostic factors. The follow up period varied between 0.3 and 45.9 years (mean 9 years, median 6.3 years). The 5 year survival rate was estimated at 82.9%, the 10 year survival rate at 69.3%. Multiple regression analysis with the Cox proportional hazards model was used to assess sex, age, and a number of baseline features of conjunctival malignant melanoma as possible prognostic factors influencing melanoma related mortality. In assessing each potential prognostic factor, the effects of all other factors were taken into account in the modelling process. Tumours in unfavourable locations--that is, those involving the palpebral conjunctiva, fornices, plica, caruncle, and lid margins, were associated with 2.2 times higher mortality compared with (epi)bulbar melanomas. Patients with mixed cell type tumours had about three times higher mortality compared with those with pure spindle cell melanomas, and histological evidence of lymphatic invasion by tumour cells was also a prognostic feature, carrying a fourfold increase in the death rate. Multifocal tumours were associated with a fivefold increase in mortality among those with tumours in favourable (epi)bulbar locations, but were not prognostic in patients with melanomas in unfavourable sites. The death rate was significantly higher in those with initial tumour thickness of more than 4 mm, but only among patients with unfavourably located melanomas. Sex, age, and clinical origin of the tumour (primary acquired melanosis, pre-existing naevus, or de novo) were not useful prognostic indicators in this study.

Adult↗
PubMed1994

Orbital exenteration in 95 cases of primary conjunctival malignant melanoma.

The role of orbital exenteration in the management of malignant melanoma of the conjunctiva has been underexplored. The outcome in 95 patients with this condition, who underwent exenteration as a primary treatment (n = 36) or after failure of other treatment (n = 59) for early to advanced stages of the disease, was evaluated. The majority of treated cases had multicentric melanomas sited at prognostically unfavourable locations. In the group of tumours with a maximum thickness of 1.0 mm no melanoma related mortality was noted. Melanomas thicker than 1.0 mm were associated with a mortality varying between 33% and 50%, independent of whether exenteration was performed as primary or secondary treatment. An especially poor outcome was noted for the group of caruncular melanomas despite exenteration. These findings indicate that total eradication of tumour should be performed at an early stage. For this purpose, a combination of debulking surgery and adjunctive cryotherapy or beta radiotherapy is more appropriate than orbital exenteration which causes disfigurement and blindness. Exenteration of the orbit should be reserved as a palliative procedure for advanced stages of neoplastic disease.

Adult↗
PubMed1994

Prevalence and causes of blindness and visual impairment in Mongolia: a survey of populations aged 40 years and older.

The survey was conducted in 3 out of the 18 administrative regions (aimaks); 4345 people aged > or = 40 years were examined, which represented 95.7% of the proposed sample. The prevalences of blindness and low vision in the sample were 1.5% (95% CI, 0.8-2.3%) and 8.1% (95% CI, 5.5-10.7%), respectively, from which the prevalences of blindness and low vision in the Mongolian population aged 40 years and older were estimated to be 1.4% and 7.7%, respectively. The prevalence of climatic droplet keratopathy was high (ranging from 15% to 50%) in this population, which included a large number of semi-nomadic cattle breeders, and was responsible for 7.2% of the blindness and 19.3% of the low vision. Cataract and glaucoma were the commonest blinding disorders, each accounting for around 35% of the blindness. Trauma accounts for a high proportion of those monocularly blind. Trachoma and xerophthalmia were not found.

Adult↗
PubMed1992

Risks of keratitis and patterns of use with disposable contact lenses.

Disposable soft contact lenses have been marketed as a safer alternative to conventional soft lenses. We undertook a case-control study of patients attending the casualty unit of an eye hospital to quantify the relative risk of keratitis in disposable lens wear and to establish associated patterns of use. All eligible contact lens users were identified and asked to complete a questionnaire (n=242). Keratitis, microbial or sterile, was the most common complication in disposable lens users, occurring in 16 of 41 subjects. The relative risks for all lens types were estimated by comparison with rigid lenses (the referent). Both extended- and daily-wear disposable lenses were associated with higher risks of keratitis than other lens types including conventional extended-wear lenses. Poor hygiene, disinfectant system failure, and lens type may all account for these statistically significant trends.

Acanthamoeba Keratitis↗
PubMed1992

Mortality and cataract: findings from a population-based longitudinal study.

The study was carried out in a rural population in central India. A random sample of 11 village communities provided 1020 persons aged 40-64 years, who were examined in 1982 and again reassessed in 1986. Statistical analysis, based on the Mantel-Haenszel method for stratified data, showed increased mortality in persons who had central lens opacities, compared with those who had trivial or no central lens opacities. The significant age-adjusted death ratio was just over 2 (2.2), as were the age/sex-adjusted and age/vision-adjusted estimates, which indicate doubling of mortality in the cataract cohort. Multiple regression analysis using the Cox proportional-hazards model gave very similar results. Statistical tests for homogeneity of death ratios across the various age/sex/vision strata were carried out, and the observed association between cataract and mortality was found to be consistent, both in males and in females, in the youngest and oldest age groups, and among those with adequate vision of 6/18 or better as well as among persons with serious visual impairment. There were no known diabetics in the study sample, which came from what could reasonably be regarded as a non-diabetic population.

Adult↗
PubMed1990

3.8 million blinded by cataract each year: projections from the first epidemiological study of incidence of cataract blindness in India.

Data from a population based longitudinal study of randomly selected communities in Central India have for the first time provided direct estimates of age specific incidence of blindness from cataract. Person-time denominators have been used to compute age specific incidence rates (risk) of blindness from cataract for populations aged 35 and older. These age specific incidence measures have been applied to the 'population at risk' in each 5-year age class in order to estimate the total number of new cases of cataract blindness that occur in the country each year. The findings indicate that an estimated 3.8 million persons become blind from cataract each year in India (approximate 95% confidence limits: 3 to 4.5 million). The reasons why the estimates are considered as minima, and their implications concerning future national planning of ophthalmic services, are briefly discussed.

Adult↗
PubMed1990

[Prevalence and causes of blindness in the Congo].

A population-based survey on the prevalence of blindness and eye disease has been conducted throughout the Congo. This was the first time such a survey had been carried out in a central African country with an equatorial climate. In comparison with data available from other African countries, the two rather unexpected characteristics resulting from the survey were lower blindness prevalence rates and the extremely rare cases of bilateral corneal scarring. In accordance with sampling procedures recommended by the WHO Programme for the Prevention of Blindness, 7041 people were selected and examined. The prevalence of blindness (visual acuity less than 3/60 in the better eye) was 0.3% (5700 people). The prevalence of low vision (visual acuity between 6/24 and 3/60 in the better eye) was 2.1% (40,000 people). The major causes of blindness and low vision were cataract (81% and 80%, respectively) and glaucoma (9% and 3.4%, respectively). A total of 22,000 people in the Congo require cataract surgery. Almost four-fifths of the current burden of blindness in this country is potentially curable through the provision of cataract surgery and aphakic glasses.

Aged↗
PubMed1989

'Sterile' corneal infiltrates in contact lens wearers.

Ninety four patients with 'sterile' keratitis presenting consecutively over a nine month period to the Accident and Emergency Department of Moorfields Eye Hospital were studied. This condition was found to account for 0.49% of all new casualties. A significant association was found in these patients, compared with controls, with contact lens hygiene, particularly for daily wear soft contact lenses, and contact lens case contamination by bacteria suggesting that these may be important factors in the aetiology of 'sterile' keratitis. Compared to gas permeable hard contact lenses the relative risk of developing 'sterile' keratitis in our patients was found to be 2.3 times higher with extended wear soft contact lenses, 1.56 times higher with daily wear soft contact lenses and 0.509 with polymethylmethacrylate lenses (test of trend p-value less than 0.05). The results indicate that 'sterile' corneal infiltrates are related to contact lens hygiene and in part to contact lens case contamination by bacteria and also to the type of lens worn.

Adult↗
PubMed1989

Dehydrational crises: a major risk factor in blinding cataract.

An earlier case control investigation has indicated a strong relationship between dehydrational crises and risk of presenile cataract. A second methodologically distinct case control study of risk factors in cataract has been carried out in a population very different in terms of environmental and sociocultural characteristics from the population investigated in the earlier study in Central India. The results strongly confirm the findings from the first study and indicate that an estimated 38% of blinding cataract may be attributable to repeated dehydrational crises resulting from severe life threatening diarrhoeal disease and/or heatstroke. The risk of blinding cataract was strongly related to level of exposure to dehydrational crises in a consistent and dose dependent manner, thus indicating a causal association. The findings are discussed in relation to possible sources of bias in the study, confounding in the data, and the steps that were taken to minimise their undesirable effects.

Adult↗
PubMed1988

Epidemiological methods in prevention of blindness.

A major objective of the Prevention of Blindness programme of the World Health Organisation (WHO PBL Programme) is that by the year 1989 National Prevention of Blindness Programmes should be established in 60 developing countries which have a huge excess of avoidable blindness. To date, this has been achieved in 57 developing countries. Centres in a number of academic institutions have been designated "WHO Collaborating Centres for Prevention of Blindness". These are actively supported by the WHO PBL Programme to undertake collaborative survey and research work in developing countries. A principal aim of such work is to generate epidemiologically sound information that could form the bases for rational planning, implementation and proper evaluation of programmes for prevention of blindness. This paper outlines the main epidemiological methods that have been employed recently, by a WHO collaborating centre based at the Institute of Ophthalmology in London, in population based eye surveys and in epidemiological research in a number of developing countries. The key aspects of the methodology are discussed in detail in the context of practical experience. The outcome of the studies are also mentioned briefly. The three distinct types of epidemiological studies discussed are: (1) Population-based sample surveys, (2) Longitudinal cohort (follow-up) studies and (3) Hospital-based case-control studies.

Adult↗