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Biomedical subjects

L Schwab

Publications and source records attributed to L Schwab.

At least 37 records · Page 2Linked to original sources
PubMed1989

Intraocular lens implantation in developing countries: an ophthalmic surgical dilemma.

Rapid and remarkable development of intraocular lens technology during the past 10 years has made intraocular lens (IOL) implantation the standard of practice with cataract surgery in wealthy industrialized nations. However, although visual results of IOL implantation are vastly superior to aphakic spectacle correction after cataract surgery, several factors mitigate against the widespread implantation of IOLs in most developing nations: the high cost of surgical equipment, ancillary drugs, and intraocular lenses; difficulty in postoperative follow-up of cataract surgical patients; and a dearth of surgical personnel properly trained in IOL technology in developing nations. While many of these problems could be addressed through national initiatives, a major area of concern remains that of manpower, since the number of unoperated cataract patients is immense. One strategy for alternative surgical manpower development is the training of medical assistants to perform cataract surgery, as is presently being carried out in several African nations. The question arises, however, as to whether medical assistants, as opposed to ophthalmologists, are qualified to select patients and implant IOLs.

Aphakia↗
PubMed1989

Childhood blindness: dateline Africa.

Prevalence rates of childhood blindness and infant and childhood mortality in Africa are the highest in the world. Major factors contributing to these high rates are similar for both blindness and mortality: malnutrition, measles and other acute febrile infections, malnutrition with xerophthalmia, and limited or poor access to preventive and curative health services. Because of high national growth rates, stagnant economies, and the failure of national health care systems to expand with rapidly growing populations, childhood blindness in Africa likely will remain a significant international public health problem for the foreseeable future.

Adolescent↗
PubMed1988

The epidemiology of trachoma in southern Malawi.

A population-based prevalence survey of ocular disease was conducted in the Lower Shire River Valley of Malawi in 1983. A total of 5,436 children less than 6 years of age and 1,664 persons greater than or equal to 6 years were examined. The prevalence of inflammatory trachoma peaked in the 1-2-year-old age group at 48.7% and declined rapidly with age to less than 5% by age 15. The prevalence of cicatricial trachoma was low in young children and climbed gradually with age to greater than 40% among those greater than or equal to 50 years. Risk factors for inflammatory disease in young children included low socioeconomic status of the family, long walking distance to the household's primary source of water, absence of a latrine in the family compound, and presence of trachoma among siblings. Indices of crowding practices were not associated with inflammatory disease. An apparent inverse association of facewashing and inflammatory trachoma in children did not hold up when adjusted for other risk factors.

Adolescent↗
PubMed1987

Trachoma grading: observer trials conducted in southern Malawi.

A variety of grading schemes have been proposed for the clinical classification of inflammatory trachoma. During a population based study of ocular disease conducted in southern Malawi we tested a simplified version of the current WHO grading scheme. Intraobserver agreement statistics were less than satisfactory for three of four graders. Interobserver agreement when compared against either a well experienced standard ophthalmologist or a consensus grade improved over time for two of the three graders. However, initial agreement for all three graders was only fair to moderate. Previous studies of trachoma grading schemes support these unsatisfactory results. A new system of classification is needed that is both accurate and reliable in a field setting.

Adult↗
PubMed1987

Cost-effective cataract surgery in developing nations.

Today approximately twenty million people are blind (visual acuity less than 3/60 [10/200]) and tens of millions more are visually disabled (visual acuity less than 6/18 [6/60]) from cataract. Most of these people live in impoverished developing nations. The logistics of providing cataract surgical care for them are complex. Simplifying the cataract operation, employing appropriate technology, and training non-physicians in intraocular surgery is efficient cost-effective strategy in many developing African nations.

Africa↗
PubMed1987

Conjunctival melanoma in Africa.

Malignant melanoma of the eye and adnexa is rare in blacks. A highly unusual malignant melanoma of the tarsal conjunctiva in an adult Ethiopian female, believed to be the first reported in a black patient, is described. Factors that contribute to melanoma in blacks and rates of occurrence are reviewed and discussed.

Adult↗
PubMed1987

Limbal vernal keratoconjunctivitis with a hypertrophic limbal mass lesion.

A case of limbal vernal keratoconjunctivitis associated with a hypertrophic mass lesion measuring 8 X 5 X 3 mm is reported. The histopathology of this mass, which consisted of hyperplastic epithelium with eosinophilic infiltration and thickened subepithelial stroma of irregular hyperplastic collagenous connective tissue interspersed with numerous eosinophils and inflammatory cells, is presented. A large limbal-mass lesion such as this has not been previously described in association with limbal vernal keratoconjunctivitis.

Child↗
PubMed1986

Prevalence and severity of xerophthalmia in southern Malawi.

The first population-based study of xerophthalmia in Africa was conducted in the Lower Shire River Valley of Malawi in the autumn of 1983. A total of 5,436 children under six years of age were examined by three survey teams over an eight-week period. The prevalence of active xerophthalmia was 3.9%. Rates for night blindness and active corneal disease were more than five times the World Health Organization criterion for a problem of public health importance. Xerophthalmic corneal scarring occurred at a rate of 5.9/1,000, more than 10 times the World Health Organization criterion. All cases of bilateral blindness in this age group were considered to be due to vitamin A deficiency. Given recent evidence from Asia linking even subclinical vitamin A deficiency to increased risk of mortality and morbidity, this disease is not only a leading cause of blindness in this area, but may have an important impact on child survival as well.

Child, Preschool↗
PubMed1986

Blindness and visual impairment in southern Malawi.

There is a paucity of reliable information on the prevalence and causes of blindness in sub-Saharan Africa, and this produces problems in designing and evaluating blindness prevention programmes. To address this problem and to provide baseline data for the evaluation of such programmes, the government of Malawi, in conjunction with a number of agencies, conducted a population-based prevalence survey of ocular disease in the Lower Shire River Valley in southern Malawi, an area where blindness is common. The prevalence of bilateral blindness found (1.27%) is similar to that in other developing countries and represents a significant public health problem. At least 60% of this blindness is preventable or easily reversible.

Adult↗
PubMed1985

Destructive epidemic Neisseria gonorrheae keratoconjunctivitis in African adults.

An epidemic of Neisseria gonorrheae keratoconjunctivitis in African adults occurred in Malawi in 1983. Sixteen patients, seven females and nine males, aged 18 to 60 years, were admitted to the inpatient ocular services at Queen Elizabeth Central Hospital in Blantyre from 1 February to 28 May 1983, all with severe bilateral purulent keratoconjunctivitis and concomitant venereal infection secondary to N. gonorrheae. Corneal melting, corneal perforation with iris prolapse, and endophthalmitis occurred in 10 eyes, of which five required enucleation. Thirteen additional eyes sustained severe visual loss secondary to corneal ulceration, leucomata, and healed corneal perforation. The route of transmission and factors of epidemicity are speculative. Because of worldwide epidemic venereal infection ophthalmologists and epidemiologists should be alert to probable sporadic N. gonorrheae epidemics in adults. Such outbreaks could occur elsewhere, especially in the developing world, and ocular gonococcal infection might become a significant cause of irreversible blindness.

Adolescent↗
PubMed1983

Surgical treatment of open angle glaucoma is preferable to medical management in Africa.

Primary open angle glaucoma is the third leading cause of blindness in Africa, causing roughly 16% of all blindness and thereby involving approx. 800,000 people on the continent. The overall prevalence and age-group breakdown of the disease is similar to that in industrialized countries, involving almost exclusively people over 40, and rising steadily thereafter with age. Factors such as a generally asymptomatic disease, definitely symptomatic medical treatment, the high cost of drugs and their irregular availability, difficulties in obtaining adequate long term chronic follow-up, and poor patient understanding of the disease all combine to make medical therapy of this condition unacceptable in Africa. Modern surgical techniques are safe, effective, and comparatively cost effective in the treatment of glaucoma. Early surgery is therefore recommended whenever possible.

Africa↗
PubMed1983

Visual disability and blindness secondary to refractive errors in Africa.

Optical defects of the light-focusing apparatus of the eye are called errors of refraction. They are responsible for 13% of all significant vision loss in Kenya, ranking third of all causes, after cataract and trachoma. As the overall prevalence of such visual impairment in the Country is 3.7%, roughly 0.5% of the population can be said to need spectacles to obtain normal vision. The comparable figure for secondary school children in Nigeria has been found to be 2.4%. In addition, patients require special spectacles after cataract surgery to obtain adequate vision; without such spectacles these patients are still 'blind' by World Health Organization criteria. These glasses can be obtained through mission societies and various charitable organizations for a little as $5 per pair, and can be manufactured locally with available ophthalmic manpower and technology. Alternatives to spectacles such as contact lenses, intra-ocular lenses and Kerato-refractive surgery are not suitable for use in developing Countries.

Africa↗
PubMed1983

Cataract and corneal opacity are the main causes of blindness in the Samburu tribe of Kenya.

An ocular status survey of the Samburu tribe of Kenya was carried out. There were 844 survey members in an age and sex stratified cluster sample. The prevalence of those who were found to have moderate visual loss or worse (less than 20/60 [6/18] in the better eye) was 3.8%. Those blind by USA criteria represented 1.7% of the total population. The two principal causes of blindness, cataract and corneal opacity, are both surgically amenable. A description of the Samburu people, the survey methods, and a summary of the survey findings are included.

Adolescent↗
PubMed1982

Appropriate ophthalmic surgical technology in developing nations.

Ophthalmologists working in developing nations are faced with shortages in surgical equipment and expendable supplies. Invention and improvisation can extend financial resources and reduce the unit cost per operation. Examples of appropriate ophthalmic technological invention are described and illustrated.

Developing Countries↗
PubMed1980

Chemical requirements of vasopressins for barrel rotation convulsions and reversal by oxytocin.

When vasopressin is administered into the lateral ventricles of rats it produces severe convulsive activity characterized by a rapid barrel rotation. Electrical recordings from the dorsal hippocampus indicate marked elevations in the amplitude and frequency at doses of 5 microliter of 2 x 10(-5) M vasopressin. No significant behavioral effects were noted with oxytocin, somatostatin, beta-melanophore-stimulating hormone, adrenocorticotropin, or leu-enkephalin. Pretreatment of the rats with intraventricularly administered oxytocin, beta-MSH, or systemically administered Dilantin prevented the vasopressin-induced seizures. With the use of chemical and enzymic modification procedures, the essential fragment and amino acids of vasopressin needed for the activity were determined. It was concluded that although the peptide could be acting by vasoconstricting blood arterioles and capillaries in the brain, it may also be exerting a direct excitatory action on neurons.

Animals↗