Showing papers by "Alfred Sommer published in 1993"

Vision change and quality of life in the elderly. Response to cataract surgery and treatment of other chronic ocular conditions.

Abstract: • Objective. —Evaluation of health care in older populations has increasingly focused on quality of life as a critical outcome of treatment. Vision is assumed to be central to functioning. Data suggest that aging, in itself, is associated with a decline in visual functioning, which, in turn, is related to a decline in physical and mental functioning. Other studies indicate that cataract surgery is followed by significant improvement in vision and visual function. Our objective was to test these assumptions. Design.—Prospective study of 1021 patients, consecutively drawn from 76 randomly selected ophthalmologists' offices in three cities. Structured interviews were completed at baseline, 2 months, and 1 year after entry. Patients. —Six hundred thirteen patients with cataracts and 408 other ophthalmic patients drawn from the same offices but treated for other chronic ocular disorders. All received refractive services as needed. Setting. —Patients from three cities (Baltimore, Md, St Louis, Mo, and San Diego, Calif) were interviewed once in their homes and twice by telephone. Interventions. —The study involved the measurement of the effects of usual treatment for cataracts and other degenerative eye diseases. Major Outcome Measures. —Visual, social, and psychological functioning. Results. —Within 1 year of treatment, change in visual function was accompanied by significant changes, in the same direction, in quality of life functions: nighttime driving, daytime driving, community activities, home activities, mental health, and life satisfaction. In addition, the patients with cataracts showed significantly greater improvement in measures of vision than did the noncataract group. Conclusions. —Regardless of treatment, improvement across quality of life functions occurred when visual function improved. Thus, many types of functional degeneration observed in older populations, attributed to a decline in vision, can be slowed, or evenreversed, when visual function is improved. Cataract surgery was effective in improving vision and quality of life functions.

Estimation of design effects and diarrhea clustering within households and villages

Abstract: The degree to which diarrheal disease clustered within households and within villages among preschool age children was examined using data from 4 population-based prevalence surveys undertaken in Malawi Zambia Indonesia and Nepal over the past decade. The design effect for each cluster survey was calculated using the diarrhea prevalence the cluster sizes and the magnitude of diarrhea clustering within the sampling unit (villages). A recently developed statistical method alternating logistic regression was used to estimate disease associations within households of up to 9 preschool age children residing within villages of up to 589 such children. Pairwise odds ratios estimating diarrhea clustering within villages ranged from 1.03 (95% confidence interval [CI] 1.01-1.07) in Zambia to 2.19 (95% CI 1.73-2.78) in Indonesia. Design effects were strongly dependent on cluster size. The design effects for clusters of size 50 would have ranged from 1.38 to 4.73. Pairwise odds ratios for diarrhea clustering within households ranged from 1.88 (95% CI 1.61-2.19) in Nepal to 10.05 (95% CI 8.46-11.94) in Indonesia. Household odds ratios were always larger than village odds ratios. The village and household pairwise odds ratio adjusted for age the type of latrine used by the household and presence of a market in the village were slightly higher than the unadjusted odds ratios. Alternating logistic regression provided useful estimates of disease clustering within villages and household while allowing for covariate adjustment. (authors)

Vitamin A, infectious disease, and childhood mortality : a 2⊄ solution ?

Abstract: Vitamin A was first discovered in 1913. Its deficiency was soon associated in animal models and case reports with stunting, infection, and ocular changes (xerophthalmia) resulting in blindness. The ocular consequences dominated clinical interest through the early 1980s. A longitudinal prospective study of risk factors contributing to vitamin A deficiency and xerophthalmia revealed a close, dose-response relationship between the severity of mild preexisting vitamin A deficiency and the subsequent incidence of respiratory and diarrheal infection (relative risk [RR], 2.0-3.0) and, most dramatically, death (RR, 3.0-10.0). Subsequent community-based prophylaxis trials of varying design confirmed that vitamin A supplementation of deficient populations could reduce childhood (1-5 years old) mortality by an average of 35%. Concurrent hospital-based treatment trials with vitamin A in children with measles revealed a consistent reduction in measles-associated mortality in Africa of at least 50%. It is now estimated that improving the vitamin A status of all deficient children worldwide would prevent 1-3 million childhood deaths annually.

Automated suprathreshold screening for glaucoma: the Baltimore Eye Survey.

Abstract: Purpose To evaluate automated suprathreshold perimetric screening for glaucoma in a population-based survey of ocular disorders in east Baltimore, Maryland. Methods A population-based sample of persons > or = 40 years of age residing in 16 clusters was selected for an ocular screening examination that included automated suprathreshold testing with the Full Field 120 program of the Humphrey Field Analyzer. Subjects who failed the test underwent manual testing to confirm the defect. Subjects were referred for definitive examination by an ophthalmologist if they had an abnormal field, visual acuity worse than 20/30, intraocular pressure > 21 mm Hg, optic disc damage, a history of glaucoma, or shallow angles. The sensitivity and specificity of the automated visual field testing for identifying glaucoma was estimated and compared with other methods to screen for glaucoma. Results Of 5,341 subjects > or = 40 years of age who underwent a screening eye examination at neighborhood centers, 4,735 (89%) completed the automated field test. The median test time was 7.25 minutes per eye. Screening test results were abnormal in one or both eyes in 1,234 (26%) of the subjects. Kinetic perimetry was performed on 95% of these subjects, and defects were confirmed for 448 (36%) of them. Hence, 9.5% of the 4,735 subjects who completed the automated test were referred for definitive examination because the defect on automated perimetry was confirmed on manual testing. For a specificity of 90%, the sensitivity of the screening visual field test to detect glaucoma was 52% for 17 or more relative or absolute defects, higher than that of intraocular pressure at 39% for a cut-off of 20.5 mm Hg, vertical cup-to-disc ratio at 45% for a cut-off of 0.53, narrowest remaining rim width at 42% for a cut-off of 0.16, and was comparable to a combination of these and other nonfield parameters. Conclusion Suprathreshold testing performed better than nonperimetry-based screening tests for glaucoma. However, a number of logistical weaknesses of this visual field screening method were identified.

Clustering of Xerophthalmia within Households and Villages

Abstract: The clustering of xerophthalmia within households and villages was estimated among preschool age children using data from studies conducted in Malawi, Zambia, Indonesia and Nepal over the past decade. Pairwise odds ratios (OR) were used to measure the magnitude of clustering. This OR measures the risk of xerophthalmia for a preschool child given that another randomly chosen preschool child from the same household (or same village but different household) had xerophthalmia, relative to the risk if that randomly chosen preschool child did not have xerophthalmia. Village pairwise OR ranged from 1.2 in Malawi to 2.2 in Nepal. Household pairwise OR ranged from 4.4 in Malawi to 9.7 in Indonesia, indicating that xerophthalmia clustering was much greater within households than villages. The magnitude of this clustering was as large, or larger than, infectious outcomes such as diarrhoea, fever and cough. Although xerophthalmia was associated with a weekly history of infectious morbidity, the clustering of diarrhoea, fever and cough explained very little of the xerophthalmia clustering observed in each of these studies, Hence, other household factors such as food availability and dietary practices should be examined for their role in the clustering of xerophthalmia within certain households.

A priming dose of oral vitamin A given to preschool children may extend protection conferred by a subsequent large dose of vitamin A

Abstract: A randomized trial tested whether a priming dose of vitamin A would extend the protection of a subsequent 60,000-micrograms retinol equivalent (RE) oral dose Seventy-five xerophthalmic and 74 age- and neighborhood-matched non-xerophthalmic preschool children were randomized to one of three oral regimens of vitamin A, receiving peanut oil only (Group A), 7500 micrograms RE (Group B) or 60,000 micrograms RE (Group C), followed in all instances by 60,000 micrograms RE 1 wk later Serum retinol was measured 2, 4, 6 and 12 mo following the second dose by technicians unaware of the children's treatment status Among xerophthalmic children, mean values differed across treatment groups at 2 mo (C > A) and tended to be different at 12 mo (C > A and B > A) Among non-xerophthalmic children mean retinol concentrations differed across treatment groups at 6 mo, but not in a consistent way (A > C > B), and at 12 mo (C > A and B > A) Xerophthalmic children reverted to biochemical deficiency faster than non-xerophthalmic children A small or large priming dose may extend the protection conferred by a 60,000-micrograms RE dose, supporting the use of repeated, spaced doses of vitamin A for treating xerophthalmia Similar retinol concentrations in Groups B and C at 12 mo suggest the 60,000-micrograms RE prophylactic dose currently recommended by the World Health Organization need not be increased