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Biomedical subjects

K M Waddell

Publications and source records attributed to K M Waddell.

8 recordsLinked to original sources
PubMed1998

Childhood blindness and low vision in Uganda.

PURPOSE: To examine the causes and outcome of subnormal vision starting in childhood in Uganda, to aid in planning for its avoidance and for rehabilitation. METHODS: All those seen having subnormal vision with onset from birth to 15 years (total 1135) (schools 1983-97; community 1988-97) were included in the study. Clinical examination was performed and a World Health Organisation (WHO) form completed, with analysis by its computer program. Main outcome measures were visual acuity, signs of eye pathology, outcome of treatment and refraction and low vision assessment. RESULTS: By WHO category 14.8% had visual impairment, 6.5% severe visual impairment, 63.2% were blind and 15.2% were too young to test. The acuities and causes were similar in school and community groups, excepting cortical visual impairment and multiple impairment, which are much commoner in the community. Cataract was the largest cause of visual impairment (30.7%) and surgical outcome was unsatisfactory. Visual loss following corneal ulceration was the second commonest cause of subnormal vision (22.0%). CONCLUSIONS: Cataract and corneal damage cause half of all subnormal vision, which is avoidable for both. Cataract surgery needs to be upgraded. To prevent corneal visual loss, primary health care should continue to be expanded, especially measles immunisation and nutrition care; rubella immunisation should be added. Special education needs to be greatly expanded. Public perceptions need changing if results are to be improved and help offered to more than the present minority.

Adolescent↗
PubMed1997

The 22nd Kellersberger Memorial Lecture, 1997. Preventing loss of sight from leprosy.

Multidrug treatment of leprosy is being dramatically successful in sterilising the infection. However complications are still occurring, spoiling the result in some patients by residual damage, including to the eye. Prevention of this damage is imperative. It is stressed that eye complications will only lead to loss of sight if they are neglected. The lesions caused by leprosy in the eye are briefly described. The dangerous lesions are lagophthalmos causing corneal exposure, and iritis causing pupil block glaucoma. Frequency of the lesions were very common in the past, but seem to be becoming much less so, though good epidemiological studies are sparse. Cataract, mostly not caused by leprosy, is the commonest cause of loss of vision. Prediction of complications would facilitate prompt treatment, but despite some clues, prediction is at present inadequate and all cases must be watched. The management of complications is discussed: studies of the indications and outcome of surgery for lagophthalmos, and of intraocular lens implantation for cataract are priorities. If knowledge is to be put into practice to prevent blindness, training of front line staff and organisation of the service is central. Experience of these practical aspects in Uganda in recent years is described.

Africa↗
PubMed1996

Carcinoma of the conjunctiva and HIV infection in Uganda and Malawi.

AIM: To investigate the association of human immunodeficiency virus (HIV) infection and carcinoma of the conjunctiva in Africa, and the role of human papilloma virus type 16 (HPV-16). METHODS: Patients in Uganda and Malawi presenting to eye clinics with lesions suspicious of carcinoma were studied. Pathological confirmation of eye lesions was sought. HIV testing of patients who were biopsied and, in Uganda, of matched case control subjects was carried out as was testing of a sample of fixed biopsies for HPV-16 by polymerase chain reaction (PCR). The HIV-1 serology, histopathology of conjunctival biopsies (conjunctival intraepithelial neoplasia (CIN), invasive carcinoma, other lesions), and prevalence of HPV-16 infection were determined. RESULTS: Of Ugandan patients, 27/38 (71%) with carcinoma (27 invasive carcinoma, 11, CIN) were HIV positive compared with 12/76 (16%) of controls (odds ratio 13, 95% confidence interval 5-38). The calculated population aetiological fraction of carcinoma associated with HIV was 66%. Of 32 Malawian patients (20 invasive carcinoma, 12 CIN), 25/29 tested (86%) were HIV positive. HPV-16 infection was found in 7/20 (35%) of carcinoma samples, 0/9 pingueculae, and 2/6 conjunctivitis samples. CONCLUSIONS: HIV infection is strongly associated with an apparent increase in the incidence of conjunctival carcinoma in Africa. While ultraviolet light is probably the prime risk factor and HPV-16 is implicated in a proportion of cases, the interactions of ultraviolet light, HIV, HPVs, and other factors are unclear in the pathogenesis of carcinoma. The disease represents another model of multifactorial epithelial carcinogenesis.

AIDS-Related Opportunistic Infections↗
PubMed1995

Is leprosy blindness avoidable? The effect of disease type, duration, and treatment on eye damage from leprosy in Uganda.

AIMS: The study was designed to measure the prevalence, range, and severity of eye involvement in leprosy patients; to relate this to disease type, duration, and treatment to identify risk factors; and to provide practical guidelines for programme managers and field staff on the prevention of blindness. METHODS: The visual outcome was assessed in a population based sample of patients in Kasese District, Uganda followed for up to two decades, and related to disease features and treatment. A total of 678 patients responded to an invitation out of 2715 registered since 1973. RESULTS: Low vision was present in 4.4% of people and blindness in 1.3%, with 1.5% and 0.6% respectively being due to leprosy. Some 12.4% of patients had iritis, of whom 33% had visual loss in one or both eyes, 3.7% of patients had lagophthalmos, and 11.7% had lens opacity. For multi-bacillary (PB) cases, the adjusted odds ratios were: for iritis 4.6 (95% CI 2.6-8.2), for lagophthalmos 1.4 (0.6-3.2), and for lens opacity 1.7 (1.0-3.0). Potentially sight threatening (PST) lesions were present in 16.8% of patients (95% CI 14.0-19.6). CONCLUSION: Levels of eye involvement in this study are low compared with many surveys. Visual loss is uncommon and is more often caused by other diseases; in the present era of multidrug therapy (MDT) it is very unlikely to be caused by leprosy. It is more common with advancing age. PST lesions, especially iritis, may occur in both PB and MB cases, even if the diagnosis of leprosy is made early and MDT started immediately; they may occur also after completion of MDT. But eye complications need not proceed to loss of sight if treated promptly, and blindness can be avoided. Training of front line staff is therefore crucial.

Adolescent↗
PubMed1972

Diphtheria-tetanus-pertussis immunization by intradermal jet injection.

An intradermal jet injector was used to administer combined diphtheria, tetanus, and pertussis (D.T.P.) vaccines to infants aged 2 to 12 months. A second dose was given one month after the first and a third six months after the second. Each dose was considerably smaller than the standard intramuscular dose. Blood samples taken one month after the third dose showed a satisfactory diphtheria and tetanus antitoxin response in all but a few cases. The antibody response to the pertussis component was not examined. Reactions were insignificant. Intradermal jet injection is proposed as a cheap, extremely rapid, and effective technique for D.T.P. immunization, especially suitable for use in remote areas where trained staff and facilities are few and many children require immunization.

Antibody Formation↗