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Biomedical subjects

A D Negrel

Publications and source records attributed to A D Negrel.

At least 19 recordsLinked to original sources
PubMed2003

[Trachoma in Senegal: results of a national survey].

A national survey was conducted to determine the prevalence of trachoma in Senegal between February and July 2000. The methodology consisted of a cross-sectional survey based on random sampling with two levels of stratification in five areas or area groups. A total of 12,328 children under 10 years of age and 8753 women over the age of 14 years were examined from 150 clusters (30 clusters per stratum). Excluding the Dakar stratum, the estimated prevalence of active trachoma (TF/TI) and severe trachoma (TI) in children under 10 years of age was 10.8% (IC 95%: 9.2-11.4) and 1.2% (IC 95%: 0.5-2.3) respectively. The corresponding prevalence for the areas around Dakar were 3.3% et 0.3%. Prevalence rates were highest between the ages of 2 and 3 years (17.4%). However these rates concealed major differences between strata since prevalence ranged from 3.3% in Dakar to 14.2% in Thiès-Diourbel. Excluding Dakar, the estimated prevalence of entropion/trichiasis and corneal opacity among women over the age of 14 years was 2.6% (IC 95%: 1.9-3.4) and 1.4% (IC 95%: 0.9-1.8). The prevalence of trichiasis was over 1% in every area except Tambacouna and reached 4% in Thiès-Diourbel. Trichiasis was observed in 17.1% of women over the age of 70. Based on extrapolation of these data to the whole country, it can be deduced that 272,020 children have active trachoma requiring medical treatment and that 115,000 persons over 14 years of age present trichiasis requiring surgical treatment.

Adolescent↗
PubMed2002

The prevalence and causes of blindness in the Sultanate of Oman: the Oman Eye Study (OES).

AIMS: To estimate the magnitude and the causes of blindness through a community based nationwide survey in Oman. This was conducted in 1996-7. METHODS: A stratified cluster random sampling procedure was used to select 12 400 people. The WHO/PBD standardised survey methodology was used, with suitable adaptation. The major causes of blindness were identified among those found blind. RESULTS: A total of 11 417 people were examined (response rate 91.8%) The prevalence of blindness in the Omani population was estimated to be 1.1% (95% CI 0.9 to 1.3), blindness being defined according to the WHO Tenth Revision of the International Classification of Diseases. Prevalence of blindness was clearly related to increasing age, with estimates of 0.08% for the 0-14 age group, 0.1% for the 15-39 age group, 2.3% for the 40-59 age group, and 16.8% for the group aged 60 +. There was a statistically significant difference between the prevalence in females (1.4%) and males (0.8%). The northern and central regions had a higher prevalence of blindness (1.3% to 3%). The major causes of blindness were unoperated cataract (30.5%), trachomatous corneal opacities (23.7%), and glaucoma (11.5%) CONCLUSIONS: Despite an active eye healthcare programme, blindness due to cataract and trachoma remains a public health problem of great concern in several regions of the sultanate. These results highlight the need, when planning effective intervention strategies, to target the eye healthcare programme to the ageing population, with special emphasis on women.

Adolescent↗
PubMed2000

Refractive Error Study in Children: results from Mechi Zone, Nepal.

PURPOSE: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and anterior segment, media, and fundus examinations were done from May 1998 through July 1998. Independent replicate examinations for quality assurance monitoring took place in all children with reduced vision and in a sample of those with normal vision in seven villages. RESULTS: A total of 5,526 children from 3,724 households were enumerated, and 5,067 children (91.7%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes in 19%, with unexplained causes in the remaining 16%. Myopia -0.5 diopter or less in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children. Hyperopia risk was associated with female gender and myopia risk with older age. CONCLUSIONS: The prevalence of reduced vision is very low in school-age children in Nepal, most of it because of correctable refractive error. Further studies are needed to determine whether the prevalence of myopia will be higher for more recent birth cohorts.

Adolescent↗
PubMed2000

Refractive Error Study in Children: sampling and measurement methods for a multi-country survey.

PURPOSE: The Refractive Error Study in Children was designed to assess the prevalence of refractive error and vision impairment in children of different ethnic origins and cultural settings. METHODS: Population-based cross-sectional samples of children 5 to 15 years of age were obtained through cluster sampling. Presenting, uncorrected, and best-corrected visual acuity, along with refractive error under cycloplegia, were the main outcome measures. Amblyopia and other causes of uncorrectable vision impairment were determined. RESULTS: Study design and sample size calculations, survey enumeration and ophthalmic examination methods, quality assurance monitoring, and da ta analyses and statistical methods are described. CONCLUSIONS: The study design, sample size, and measurement methods ensure that the prevalence of age-specific and sex-specific refractive error can be estimated with reasonable accuracy in the target populations. With commonality of methods, a comparison of findings between studies in different ethnic origins and cultural settings is possible.

Adolescent↗
PubMed1998

The Madurai Intraocular Lens Study. I: A randomized clinical trial comparing complications and vision outcomes of intracapsular cataract extraction and extracapsular cataract extraction with posterior chamber intraocular lens.

PURPOSE: The Madurai Intraocular Lens Study (MIOLS) was designed to compare safety, efficacy, and quality of life outcomes after either intracapsular cataract extraction with aphakic glasses (ICCE-AG) or extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/ PC-IOL). METHODS: The Madurai Intraocular Lens Study was a nonmasked randomized controlled clinical trial conducted at a single hospital. Thirty-four hundred patients with age-related cataracts and having a best-corrected visual acuity less than or equal to 20/120 in the better eye were randomly assigned to either of the two cataract operative procedures. The main clinical outcomes were safety (complication rates) and efficacy (best-corrected visual acuity at 1 year equal to or better than 20/40). In addition, a subset of 1,700 trial participants received questionnaires before surgery, at 6 months after surgery, and at 1 year after surgery to measure visual functioning and vision-related quality of life. RESULTS: Details of study design, study organization, clinical and quality of life outcome variables, sample size calculations, patient eligibility criteria and recruitment, randomization and masking, participant flow, adherence to follow-up, quality assurance, and statistical methods are presented. CONCLUSIONS: The Madurai Intraocular Lens Study has sufficient power to detect clinically significant differences between the treatment options. There were no statistically significant differences between the two treatment groups for any of the major study variables at baseline. A high level of quality assurance was maintained throughout the October 1993 to June 1996 study period. The results should be applicable to all settings where the requisite expertise and resources are present.

Adult↗
PubMed1998

Prevalence of blindness and cataract surgery in Nepal.

BACKGROUND: A national eye care programme was launched in Nepal in the early 1980s. The impact of this programme on blindness and cataract surgery prevalence was evaluated in two geographic zones. METHODS: People aged 45 years and older were sampled using a stratified cluster design. Within randomly selected clusters, door to door enumeration was followed by visual acuity measurement and eye examinations at conveniently located sites. The full survey was preceded by a pilot study where operational methods were refined and quality assurance measures carried out. RESULTS: Of the 5112 enumerated individuals 90% were examined. Blindness, defined as presenting visual acuity less than 6/60 in both eyes, was found in 5.3% (95% CI 3.6, 6.8) of individuals examined, with cataract being the principal cause in at least one eye in 78% of cases. Considering both cataract operated and unoperated cataract blind cases, surgical coverage was approximately 42%. CONCLUSION: The findings suggest that blindness prevalence may have decreased slightly from that estimated in a 1981 national survey, both overall and cataract related. Similarly, cataract surgical coverage may have increased somewhat. None of these changes, however, are at statistically significant levels. Accordingly, the blindness problem remains challengingly high.

Aged↗
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↗
PubMed1987

[Monobloc lamellar autokeratoplasty (MLAK) and corneal cicatrization. Apropos of a comparative trial in a control group and a group treated with a L-cystine and pyridoxine hydrochloride combination].

In pterygium cure, one piece lamellar corneo-conjunctival autokeratoplasty allows to perform a reproducible corneal injury in human clinic, and thus, to study the epithelial healing. The authors describe a comparative test on 2 groups of 18 subjects each, receiving in this blind study, either classical post-operative treatment (witness group), or in addition to this treatment: L-Cystine and Pyridoxine Chlorhydrate. Two tests are analysed: the duration of epithelial healing in one day (negative fluorescein test) and post operative "well being" (estimated on the intensity of photophobia, tears and pain). Statistical analysis (non parameter tests) display a significant difference in favor of the group treated by Cystine B 6.

Adult↗
PubMed1980

[Ocular lesions in lepromatous leprosy (author's transl)].

Ocular lesions observed in III cases of lepromatous or borderline leprosy are described. Tables are included which indicate the visual acuity, corneal sensitivity, and lesions noted in the appendages. Particular attention is paid to lesions in the pars plana, which include true posterior cyclitis having the appearance of "ants eggs" or "pearls" deposits on the retina, associated with vascular lesions and peripheral hyalitis. The absence of associated mucular edema is strongly emphasized. The etiopathogenicity of lesions of this type is probably directly related to leprous erythema nodosum. Detailed studies should be conducted on the chronological stages of these affections and their subsequent progression.

Adolescent↗
PubMedDate not supplied

Quality of life assessment in blindness prevention interventions.

This article discusses the importance of self-reported visual function and quality of life (QOL) assessment in evaluating the effectiveness of eye care and prevention of blindness interventions. Traditional clinical measurements do not provide an adequate characterization of the burden of visual disability faced by the patient in day-to-day activities. The validity, reliability and responsiveness of QOL questionnaires should be demonstrated before general use of such instruments is advocated. A visual function questionnaire currently undergoing psychometric evaluation as part of a clinical study of cataract surgery in India is presented.

Blindness↗