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Biomedical subjects

A Foster

Publications and source records attributed to A Foster.

At least 127 records · Page 7Linked to original sources
PubMed1995

Childhood blindness due to vitamin A deficiency in India: regional variations.

OBJECTIVES: To investigate the importance of vitamin A deficiency as a cause of childhood blindness and severe visual impairment (SVI) in India. DESIGN AND SETTING: Cross sectional survey of children with visual acuity less than 6/60 in the better eye (SVI/blindness), attending 22 schools for the blind in nine states of India. MAIN OUTCOME MEASURE: Proportion of children with blindness or SVI from corneal scarring attributable to vitamin A deficiency. RESULTS: 245 of 1318 (18.6%) of children had SVI/blindness attributable to vitamin A deficiency. The proportion of SVI/blindness due to vitamin A deficiency ranged from 7.5% (7/93) in Kerala to 26.7% (27/101) in Madhya Pradesh. In Tamil Nadu, 7.5% (9/120) of children in the capital city blind school had SVI/blindness due to vitamin A deficiency, compared with 30.4% (51/168) in a blind school in a rural area of the same state. CONCLUSION: Overall, vitamin A deficiency is the single most important cause of childhood blindness and SVI in India. There are marked variations by state and also between urban and rural locations.

Adolescent↗
PubMed1995

Causes of childhood blindness in Sri Lanka: results from children attending six schools for the blind.

AIM: The survey aimed to identify the major treatable or preventable causes of visual loss in children attending blind schools in Sri Lanka so that appropriate control measures can be implemented. METHOD: A total of 226 children with blindness (BL) or severe visual impairment (SVI) attending six schools for the blind were examined and details recorded using the WHO standard reporting form. RESULTS: Cataract was responsible for 17% of BL/SVI and was the commonest 'avoidable' cause of childhood blindness. Bilateral microphthalmos accounted for one quarter of BL/SVI. Vitamin A deficiency was not a significant cause of visual morbidity. CONCLUSION: The pattern of childhood blindness seen in this study is typical of a growing number of south east Asian countries which are developing rapidly. Childhood cataract is a major avoidable cause that can benefit from future intervention strategies.

Adolescent↗
PubMed1995

Low vision in east African blind school students: need for optical low vision services.

AIMS: There is increasing awareness of the needs of children with low vision, particularly in developing countries where programmes of integrated education are being developed. However, appropriate low vision services are usually not available or affordable. The aims of this study were, firstly, to assess the need for spectacles and optical low vision devices in students with low vision in schools for the blind in Kenya and Uganda; secondly, to evaluate inexpensive locally produced low vision devices; and, finally, to evaluate simple methods of identifying those low vision students who could read N5 to N8 print after low vision assessment. METHODS: A total of 230 students were examined (51 school and 16 university students in Uganda and 163 students in Kenya, aged 5-22 years), 147 of whom had a visual acuity of less than 6/18 to perception of light in the better eye at presentation. After refraction seven of the 147 achieved 6/18 or better. Eighty two (58.6%) of the 140 students with low vision (corrected visual acuity in the better eye of less than 6/18 to light perception) had refractive errors of more than 2 dioptres in the better eye, and 38 (27.1%) had more than 2 dioptres of astigmatism. RESULTS: Forty six per cent of students with low vision (n = 64) could read N5-N8 print unaided or with spectacles, as could a further 33% (n = 46) with low vision devices. Low vision devices were indicated in a total of 50 students (35.7%). The locally manufactured devices could meet two thirds of the need. CONCLUSION: A corrected distance acuity of 1/60 or better had a sensitivity of 99.1% and a specificity of 56.7% in predicting the ability to discern N8 print or better. The ability to perform at least two of the three simple tests of functional vision had a sensitivity of 95.5% and a specificity of 63.3% in identifying the students able to discern N8 or better.

Adolescent↗
PubMed1995

Causes of childhood blindness in east Africa: results in 491 pupils attending 17 schools for the blind in Malawi, Kenya and Uganda.

Pupils attending 12 schools for the blind in Malawi, 3 schools in Kenya and 2 schools in Uganda were examined to determine the causes of severe visual impairment or blindness (visual acuity in the better eye of less than 6/60). A total of 491 pupils aged 3-22 years was examined. Visual acuity was measured in each eye using a Snellen E chart. The anatomical site of abnormality and underlying cause of visual loss were determined by clinical examination for each eye, and for the child. Information was recorded on a standard reporting form (the WHO/PBL Eye Examination Record for Children with Blindness and Low Vision). Data were analysed for those aged less than 16 years using a database which accompanies the form. Preventable and treatable causes were identified. 260 pupils aged 5-20 years were examined in Malawi, 163 pupils aged 3-19 years were examined in Kenya and 68 pupils aged 6-22 years were examined in Uganda. Of the 491 students included in the study 309 (62.9%) were blind (BL) and 69 (14.1%) were severely visually impaired (SVI). 244 were aged less than 16 years and had SVI/BL. In these 244 children 35.2% of visual loss was due to corneal pathology, 13.5% was due to cataract and 14.8% to diseases of the retina. Corneal pathology, attributed to vitamin A deficiency and measles infection in the majority, was responsible for proportionally more SVI/BL in students in Malawi than in Uganda or Kenya.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Hereditary disease as a cause of childhood blindness: regional variation. Results of blind school studies undertaken in countries of Latin America, Asia and Africa.

There is evidence from developed countries that genetic disease is the major cause of childhood blindness. Little data are available from most developing and newly industrialised countries concerning the relative importance of hereditary diseases as a cause of childhood blindness. Children in schools for the blind in 13 countries of Africa, Latin America and Asia were examined between 1990 and 1994 using a standardised method The anatomical site of abnormality and underlying aetiology were analysed for children with a corrected acuity in the better eye of less than 6/60 (severe visual impairment and blindness, svi/BL). In these countries II-39% of svi/BL was attributed to genetic disease. Genetic diseases were responsible for a higher proportion of childhood visual loss in countries with higher levels of socio-economic development. An autosomal recessive mode of inheritance was reported in 22-52% of children with genetic disease. Retinal dystrophies were the commonest form of genetic eye disease (49-80%) in all countries apart from Thailand and the Philippines where cataract was the commonest (43.9%). The role of consanguinity, and opportunities for further research are discussed.

Africa↗
PubMed1995

The influence of socio-biological factors on perinatal mortality in a rural area of Bangladesh.

"The present study considers data on all pregnancies that ended in a stillbirth or live birth in a rural area of Bangladesh during the years 1982 to 1984. It considers the relationships of both biological and socio-economic factors to perinatal mortality....[Results show a] lack of association with any measure of socio-economic status.... Our study has confirmed that survival of the perinatal period is separately related to both maternal age and primiparity. Once maternal age is taken into account, high parity shows no evidence of decreasing survival chances."

Age Factors↗
PubMed1994

Causes of blindness and severe visual impairment in children in Chile.

Three hundred and eighteen of 421 children (76 per cent) registered in Chile's 10 schools for the blind were examined. 84 per cent of these had severe visual loss (severe visual impairment or blindness), which was attributable to hereditary factors in 29.6 per cent, intra-uterine factors in 8.2 per cent, perinatal factors in 22.5 per cent and childhood factors in 11.2 per cent. The aetiology could not be determined in 28.5 per cent. Retinopathy of prematurity (ROP) accounted for 17.6 per cent of all children with severe visual loss; analysis of data by age-group suggested that ROP is becoming an increasingly important cause of blindness. It is estimated that one-half of the children with severe visual loss in Chile have avoidable causes of blindness. The findings are discussed in the light of possible control strategies.

Blindness↗
PubMed1994

With an eye to good practice: traditional healers in rural communities.

In Africa, certain traditional treatments for eye diseases can produce ocular damage and visual loss. However, many practices do not cause harm, and some may be beneficial. Traditional healers are often valuable resource persons, helping to provide an understanding of cultural beliefs and practices relating to eye disease, and delivering eye care at community level. These matters are discussed below with special reference to conditions in Zimbabwe.

Eye Diseases↗
PubMed1994

Traditional eye medicines and corneal ulceration in Tanzania.

A one-year prospective study into the aetiology of corneal ulceration in 103 patients attending Mvumi hospital, Tanzania, showed 25% (95% CL 16.5-33.5%) of ulcers to be associated with the use of traditional eye medicines (TEM) within the previous 7 days. There was no statistically significant difference between TEM users and non-users in terms of sex of the patients, season of presentation or age at presentation. Of 26 corneal ulcers in TEM users, 58% (n = 15) had no other identified cause of ulceration apart from TEM use. Of the remaining 11, eight showed the appearances of HSV keratitis, and three others had bacterial infection, two with Neisseria gonococcus. TEM use was associated with hypopyon at presentation (19.3 vs 2.6% in non-TEM users (P = 0.004)), and there was a trend to more central and dense corneal scarring in the TEM users group (42 vs 23%, P = 0.06). Secondary infection is an important cause of corneal scarring following TEM use, and all patients who have a TEM-associated corneal ulcer should have intensive antimicrobial treatment. TEM use will continue so long as primary eye care continues to be unavailable to the majority of the population of Africa.

Adolescent↗
PubMed1993

Methods for evaluation of anti-asthma drugs in the primate.

Use of the primate is gaining popularity in the definition of anti-asthma drugs. The present report describes three novel tests of (1) bronchodilatation, (2) hyperreactivity and (3) anti-inflammatory activity in the rhesus monkey. All tests are based on standard clinical techniques and the relevance and application of the tests to subsequent clinical evaluation is addressed.

Animals↗
PubMed1993

Causes of blindness in children attending four schools for the blind in Thailand and the Philippines. A comparison between urban and rural blind school populations.

Using WHO definitions of visual loss and a standardised methodology, 256 children were examined in schools for the blind in Thailand (1 school) and the Philippines (3 schools). 244 (95%) were blind (BL) or severely visually impaired (SVI). Causes of SVI and blindness were classified anatomically and aetiologically, and avoidable causes identified. Causes of visual loss in Khon Kaen, Thailand (n = 65) and Manila, Philippines, (n = 113) were similar, with conditions of the whole globe accounting for 27.7 and 27.4% of SVI/BL; retinal disease 29.2 and 23.0%; cataract 16.9 and 16.8%; corneal disease 12.3 and 13.4%; and optic nerve disease and glaucoma 6.2 and 8.8%. Perinatal factors accounted for 20.0 and 23.0% of SVI/BL; hereditary disease 13.8 and 17.7%; and 12.3 and 15.0% was due to events occurring during childhood. The underlying aetiology could not be determined in 50.8 and 41.6% of cases, respectively. In the two schools together twenty six children (15%) were blind from retinopathy of prematurity (ROP) and 16 (9%) from corneal scarring attributed to Vitamin A deficiency. 103 of 178 (58%) children had avoidable causes of visual loss. In the Filipino towns of Baguio and Davao (n = 66), the causes of visual loss were different from those in Khon Kaen and Manila, with 54.8 and 42.9% of SVI/BL being due to corneal disease, and only 3.2 and 8.5% to retinal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Causes of childhood blindness: results from west Africa, south India and Chile.

Using World Health Organization definitions of visual loss and a standardised methodology, 905 children were examined in Chile, West Africa and South India. Of these 806 (89%) suffered from blindness (BL) or severe visual impairment (SVI). Causes of SVI and BL were classified anatomically and aetiologically, and avoidable causes identified. In W. Africa (n = 284) the major anatomical cause of SVI/BL was corneal scar/phthisis bulbi (35.9%). Retinal disease accounted for 20.4%, cataract 15.5% and glaucoma 13.0%. Aetiologically 33.8% of SVI/BL was due to childhood factors and 21.1% to hereditary disease. In S. India (n = 305) the major anatomical cause of SVI/BL was corneal scar/phthisis bulbi (38.4%). Retinal disease accounted for 22.6%, cataract 7.4% and glaucoma 3%. Aetiologically 37.0% of SVI/BL was due to childhood factors and 29.8% to hereditary disease. In Chile (n = 217) the major anatomical cause of SVI/BL was retinal disease (47.0%). Cataract accounted for 9.2%, glaucoma 8.3% and 6.9% was due to corneal pathology. Aetiologically 30.4% of SVI/BL was due to hereditary factors, and 20.8% to perinatal factors of which four-fifths (16.6%) was due to retinopathy of prematurity. Avoidable conditions accounted for 70%, 47% and 54% of cases in W. Africa, S. India and Chile respectively.

Adolescent↗
PubMed1993

Visual loss in an onchocerciasis endemic community in Sierra Leone.

The visual acuities of 1625 individuals recruited to a community-based clinical trial of ivermectin in southern Sierra Leone were measured, and the prevalence of visual loss in this rural population where onchocerciasis is hyperendemic was determined. Ocular examination was performed before treatment to establish the cause of visual loss. Using WHO definitions, 1.3% were blind (less than 3/60 in both eyes), 4.3% were visually impaired (between 6/24 and 3/60 in the better eye), and a further 3.4% were uniocularly blind (less than 3/60 in one eye and better than 6/24 in the other). Cataract and onchocerciasis were the major causes of visual loss in this population. More than half of the ocular morbidity was preventable or treatable by public health measures or basic curative medicine. These findings are discussed in the light of the available health and eye care services.

Blindness↗
PubMed1993

Results of community-based eyelid surgery for trichiasis due to trachoma.

In many parts of Africa patients with upper-lid trichiasis due to trachoma have very limited access to ophthalmologists or hospital facilities. In order to reach these patients it is necessary for trained paramedical eye workers to operate on patients close to where they live. The results of trichiasis surgery performed by an ophthalmic nurse in Tanzania were evaluated. A total of 156 operations were performed on 94 patients over a 2 year period by an eye nurse in central Tanzania. One hundred and forty four eyes in 86 patients were followed for a minimum of 9 months (range 9-36; mean 25.5 months). One eye developed a wound infection and nine eyes developed minimal central notching of the upper eyelid, but without corneal exposure. Survival time analysis showed a probability of survival without recurrent trichiasis of 81% at 24 months (95% CI 74% to 88%) and 79% at 36 months (95% CI 71% to 87%). It is concluded that trichiasis surgery may be safely and effectively performed in the community by a trained ophthalmic nurse.

Blindness↗