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Biomedical subjects

B Thylefors

Publications and source records attributed to B Thylefors.

66 records · Page 4Linked to original sources
PubMed1978

Aspects of corneal changes in onchocerciasis.

The distribution of living and dead microfilariae in 160 cases of ocular onchocerciasis has been studied. A model for coding the densities in 9 different areas of the cornea has been used. The average numbers of microfilariae and onchocercal punctate opacities per square millimetre were assessed. The highest densities were found in the superficial one-third of the corneal stroma at the periphery of the nasal and temporal parts of the cornea. Sclerosing keratitis was also recorded, and the average age of the patients in this group was significantly higher than in the group with non-sclerosing onchocercal involvement. Corneal thickness measurement showed that the presence of microfilariae or onchocercal punctate opacities or a faint uveitis did not influence the values. In sclerosed areas the corneal thickness varied greatly and was dependent on the degree of the vascularisation. The routes of entry of microfilariae into the eye are discussed on the basis of the distribution patterns of microfilariae and onchocercal opacities.

Cornea↗
PubMed1978

Visual field defects in onchocerciasis.

Lesions in the posterior segment of the eye in onchocerciasis may give visual field defects, but so far no detailed investigation has been done to determine the functional visual loss. Examination of the visual fields in 18 selected cases of onchocerciasis by means of a tangent screen test revealed important visual field defects associated with lesions in the posterior segment of the eye. Involvement of the optic nerve seemed to be important, giving rise to severely constricted visual fields. Cases of postneuritic optic atrophy showed a very uniform pattern of almost completely constricted visual fields, with only 5 to 10 degree central rest spared. Papillitis gave a similar severe constriction of the visual fields. The pattern of visual fields associated with optic neuropathy in onchocerciasis indicates that a progressive lesion of the optic nerve from the periphery may be responsible for the loss of vision. The visual field defects in onchocerciasis constitute a serious handicap, which must be taken into consideration when estimating the socioeconomic importance of the disease.

Adolescent↗
PubMed1978

Ocular onchocerciasis.

Well over 20 million people in the world are infected with Onchocerca volvulus and it is probable that 200 000-500 000 people are blind as a result of this infection, which is the most important cause of blindness in certain areas of Africa and Latin America.Treatment of the disease is difficult and often produces serious adverse reactions in the patient. Combined use of diethylcarbamazine citrate and suramin is still the most suitable form of treatment. Screening for the early detection of cases at high risk of ocular manifestations must be organized, and their treatment undertaken, if blindness is to be avoided.Prevention of ocular onchocerciasis is feasible, using vector control methods to reduce transmission, but the procedures are costly and may have to be maintained for many years.Research is needed to improve treatment and to find a chemoprophylactic agent or a preventive vaccine.

Diethylcarbamazine↗
PubMed1977

Vision screening of illiterate populations.

To assess the amount of reduced vision in a population is an important public health matter, especially in areas where blinding diseases are endemic. Testing visual acuity is, however, a complex problem when a major part of the population is illiterate. The best-known test of vision is the E-test, but this produces the problem of untestability in illiterate populations.The introduction of the Sjögren hand-test as an alternative to the E-test for vision screening of unselected illiterate populations in West Africa resulted in a highly significant reduction of untestability. For certain vision levels it is possible to correlate the results of the hand-test directly with those of the E-test. The hand-test is less well defined than the E-test, but has important advantages for the purpose of vision screening of illiterate populations.

Adolescent↗
PubMed1977

The microfilarial load in the anterior segment of the eye. A parameter of intensity of onchocerciasis.

The presence of microfilariae of Onchocerca volvulus in the eye is associated with an increased risk of deterioration of existing eye lesions. An opthalmological and parasitological examination of 630 persons was carried out in a hyperendemic focus of onchocerciasis in northern Togo. The prevalence of microfilariae increased in the cornea as well as the anterior chamber up to the age of 40-50 years, then decreased. The prevalence of onchocercal punctate keratitis, on the other hand, showed a peak for the age group 10-20 years. In two-thirds of the cases microfilariae were present in the anterior chamber as well as in the cornea. The relative distribution of microfilariae between the anterior chamber and the cornea did not change with the development of severe anterior lesions but in cases with severe posterior lesions relatively more microfilariae were found in the anterior chamber than in the cornea. In all cases of severe ocular lesions the numbers of microfilariae both in the anterior chamber and in the cornea were increased. The average number of microfilariae in the eye can be used as a parameter to enumerate the severity of ocular onchocerciasis.

Adolescent↗
PubMedDate not supplied

Development of trachoma control programs and the involvement of national resources.

Trachoma, one of the commonest eye diseases in developing countries, is associated with adverse living conditions and low socioeconomic status. The control of trachoma as a blinding disease has been the target of many national campaigns. The strategy of such campaigns has usually been based on intermittent topical treatment on a mass or selective basis, together with services for trichiasis surgery and health education. National campaigns against trachoma have often been successful on a short-term basis but have not always achieved their long-term goals. Sustained efforts are needed to maintain trachoma control, an area of endeavor that lends itself well to integration with general health services, particularly on a primary health care basis. In addition to logistic aspects, treatment compliance and behavioral patterns related to living conditions must be considered in the design of trachoma control programs.

Blindness↗
PubMedDate not supplied

[Progress in the control of world blindness and future perspectives].

Worldwide, there are approximately 180 million severely visually impaired people, of whom some 45 million are blind. Cataract remains the major cause of blindness, especially in the less developed countries. Substantial improvements have been achieved in the control of blinding diseases, mainly in respect of onchocerciasis and xerophthalmia. More recently, a WHO alliance for the eradicating of trachoma by the year 2020 has been set up. In Africa, the situation remains critical in spite of significant improvements in the training of eye care personnel and the implementation of new eye care facilities. If no additional action is taken, the number of blind from cataract will steadily increase, mainly because of population growth and aging. Substantial further efforts should be made to make appropriate eye care accessible and affordable to all those in need.

Africa↗