Showing papers in "Ophthalmic Epidemiology in 2002"

The Roche European American Cataract Trial (REACT): A randomized clinical trial to investigate the efficacy of an oral antioxidant micronutrient mixture to slow progression of age-related cataract

Abstract: context Funding surgery worldwide for age-related cataract (ARC), a leading cause of blindness, is a huge economic burden. Non-surgical means of slowing ARC progression could benefit patients and reduce this burden. objective To determine if a mixture of oral antioxidant micronutrients [mg/day] (s-carotene [18], vitamin C [750], and vitamin E [600]) would modify progression of ARC. design REACT was a multi-centered, prospective, double-masked, randomized, placebo-controlled, 3-year trial. setting Consecutive adult American and English outpatients with early ARC were recruited. patients Four-hundred-and-forty-five patients were eligible; 297 were randomized; 231 (78%) were followed for two years; 158 (53%) were followed for three years; 36 (12%) were followed for four years. Twelve patients died during the trial (9 on vitamins; 3 on placebo (p = 0.07)). There were no serious safety issues. intervention After a three-month placebo run-in, patients were randomized by clinical center to the vitamin or placebo...

A simplified cataract grading system.

Abstract: A simplified method for grading the presence and severity of different cataract types is needed for field use in assessment of the magnitude of the cataract problem. A cataract grading system was developed by a panel of experts with the objective of making available a simple system for use with a slit lamp to allow for the reliable grading of the most common forms of cataract by relatively inexperienced observers. Three levels, reflecting progressive severity, for grading of nuclear, cortical and posterior subcapsular (PSC) cataract were included in the classification; three standard photos were used for grading nuclear cataract. Field evaluation from four different sites indicated very good to fair interobserver agreement with the use of this system following minimal training of residents in ophthalmology at each site. Further testing of this system is warranted. The WHO simplified cataract grading system should allow for the obtaining of comparable data across countries based on field assessment of the most common forms of cataract.

Causes of uveitis at The Eye Center in Saudi Arabia: a retrospective review.

Abstract: aims and background The main objective of this study was to determine the causes of uveitis at a referral center in Riyadh, Saudi Arabia. methods We carried out a retrospective review of clinical records of 200 uveitis cases referred to The Eye Center, a referral center in Riyadh, Saudi Arabia. There were 120 (60%) males and 80 (40%) females with an age range of 7 to 91 years and a mean age of 35 (SD ± 17). Patients had complete ophthalmic and medical examinations. Laboratory studies were requested whenever indicated. Patients were followed up for a minimum of 12 months. results In the period 1995–2000, we encountered 200 cases of uveitis among a total of 20,191 consecutive new cases, yielding a prevalence of 1%. Acute anterior uveitis of undetermined origin was found in 58 (29%) of 200 patients. There were 13 (6.5%) cases of Behcet's disease, 7 (3.5%) of Fuchs' heterochromic iridocyclitis, 6 (3%) of sarcoidosis, and 5 (2.5%) patients had Vogt-Koyanagi-Harada syndrome (VKH). Among the infectious causes, h...

Metastatic orbital tumors in Japan: a review of the literature

Abstract: A review of reports on metastatic orbital tumors published from 1903 to 1998 in Japan revealed 128 patients, 74 males, 52 females and 2 whose sex was not recorded. The average age was 44.8 years, but varied depending on the primary tumor. Since 1980, metastatic orbital tumors have increased in Japan, especially those from the lung, liver and adrenal gland, while metastasis from the stomach has decreased slightly. Metastasis from the breast is still common. Most metastatic orbital tumors were from the lung, followed, in order, by breast, liver, adrenal gland and stomach. Males had four times as many metastatic orbital tumors from lung cancer than did females; only females had metastases from breast cancer; almost 90% of metastases from hepatoma were in males; metastasis from renal carcinoma was 2-3 times more common in males than in females. Metastasis from the liver and stomach is seen more frequently in Japan than in the United States and Europe. Ocular signs due to orbital metastases from hepatoma, neuroblastoma and gastric cancer were apt to appear earlier than the signs of the primary lesion. Metastases to the orbit were frequently bilateral in patients with neuroblastoma and malignant lymphoma. Specific ocular signs such as ecchymosis and conjunctival hemorrhages were seen in orbital metastasis from neuroblastoma and seminoma, while ocular pain was characteristic of malignant lymphoma. Orbital metastasis was very rare in patients with carcinoma of the uterus, ovaries, bladder, pancreas, colon or rectum in both Japan, the United States and Europe.

The prevalence of Behçet’s disease above the age of 10 years The results of a pilot study conducted at the Park Primary Health Care Center in Ankara, Turkey

Abstract: PURPOSE The aim of this study was to determine the prevalence of Behcet’s disease above the age of 10 years by means of a population-based study. METHODS The epidemiological investigation (cross-sectional study) was made between May 1997 and May 1998 at the Park Primary Health Care Center, which is one of the education and research divisions of the Department of Public Health, Faculty of Medicine, Ankara University. The research aimed to cover all 17,256 (49.2% male, 50.8% female) inhabitants over 10 years of age living in this area. The screening team first surveyed and selected patients with recurrent aphthous stomatitis. These patients were further examined, free of charge, in the Preventive Ophthalmology Unit of the Public Health Center, at Ibni Sina Hospital’s Behcet Center or in other clinics if necessary. In this study the International Study Group For Behcet’s disease Criteria were used. RESULTS As the final result of the screening, 11 female and 5 male patients with Behcet’s disease were found (f...

The Sivaganga eye survey: I. Blindness and cataract surgery.

Abstract: PURPOSE To assess the prevalence of visual acuity impairment, blindness, and cataract surgery among older adults in rural southern India. METHODS Random selection of village- and urban-based clusters was used to identify a cross-sectional sample of persons 50 years of age or older from the Sivaganga district of Tamil Nadu. Subjects in 25 selected clusters were enumerated through a door-to-door survey and invited to examination sites for measurement of uncorrected, presenting, and best-corrected visual acuity and ocular examination in 1999. The principal cause was identified for eyes with presenting visual acuity worse than 6/18. Quality assurance monitoring of visual acuity measurements took place in five of the study clusters. RESULTS A total of 5081 persons in 3517 households were enumerated, and 4642 (91.4%) were examined. Thirty-six percent presented with visual acuity worse than 6/18 in the better eye. The prevalence of blindness, based on visual acuity worse than 6/60 in both eyes, was 6.0% (95% con...

Does clinical diagnosis indicate ocular chlamydial infection in areas with a low prevalence of trachoma

Abstract: The WHO has initiated a global program to eliminate trachoma. This program includes mass antibiotic administrations to reduce the prevalence of Chlamydia trachomatis, the causative agent in trachoma. DNA amplification tests are the most sensitive methods to diagnose C. trachomatis infection, but are expensive and not typically performed in trachoma-endemic areas. Trachoma programs use clinical examination to determine which communities and which individuals within communities would benefit from antibiotic treatment, so understanding the relationship between clinical activity and chlamydial infection is important. In this study, we determine what percent of individuals with clinically active trachoma are infected with chlamydia in low prevalence communities of China and Nepal (with 30% clinical activity in children). In the low prevalence areas, only 8% clinically active cases had evidence of chl...

Digital photographic screening for diabetic retinopathy in the James Bay Cree.

Abstract: This study evaluates a single, 45-degree fundus image from a non-mydriatic camera for the triage of subjects at risk for diabetic retinopathy. A complete retinal assessment by a retina specialist was the main comparator for the camera. Inter-observer agreements were calculated for the reading of digital images with different grades of retinopathy. Two hundred eyes of 100 consecutive subjects were evaluated as part of the James Bay diabetic retinopathy screening project; 62% of subjects had no retinopathy, 12% had microaneurysms only, 24% had non-proliferative retinopathy, 5% had clinically significant macular edema (CSME), and 2% had proliferative disease (PDR). The Kappa statistic for two independent observers was 0.85 (p < 0.001) for the identification of retinopathy from the digital images. The sensitivity of the digital camera for the evaluation of any retinopathy was 84.4%, for CSME and/or PDR it was over 90%. The use of a single digital retinal image for the evaluation of diabetic retinopathy was...

The Sivaganga eye survey: II. Outcomes of cataract surgery.

Abstract: PURPOSE To assess the clinical outcomes of cataract surgery in rural southern India. METHODS Cluster sampling was used in randomly selecting a crosssectional sample of persons 50 years of age or older for visual acuity measurement, refraction, and ocular examination in 1999. Subjects were queried as to the date and place of surgery for each cataract-operated eye. Surgical complications were noted and the principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18. RESULTS Within the cataract-operated sample of 682 persons, 13.8% had presenting visual acuity worse than 6/60 in both eyes, 25.2% better than or equal to 6/18 in both eyes, and 37.8% were bilaterally operated on. For aphakic eyes, 50.5% presented with visual acuity better than or equal to 6/18; 82.6% with best-correction. For pseudophakic eyes, the corresponding percentages were 78.0% and 94.5%. Over one-third of all eyes were pseudophakic, and nearly threefourths had been operated on in non-governmen...

Prevalence of diabetic retinopathy and eye care in a rural area of Spain.

Abstract: objective To study the prevalence of diabetic retinopathy (DR) in a sample of 3544 patients living in a rural area of the province of Valladolid, Spain; as well as to estimate the current eye care to the diabetic population. methods Participants received a comprehensive ocular examination in their local area where they resided and a grading of DR was made using standard protocols. Physicians then provided us with the systemic and demographic data. results The population studied included 175 younger-onset and 3344 older-onset patients, all of whom were under physicians' care, distributed in an 18-county-area far from the urban center. Mean duration of the disease was 7.89 ± 7.7 years (range 0 to 59 years). 73% of participants had not received ophthalmologic care the preceding year and 63.6% had not received a dilated eye examination either. The prevalence of DR was 20.9%; macular edema was found in 5.7% of the patients. Differences in participation were found among counties and these also correlated with d...

Bias in self-reported family history and relationship to glaucoma: The Blue Mountains Eye Study

Abstract: PURPOSE To examine bias in the relationship between self-reported family history of glaucoma and its relationship to the prevalence of glaucoma and ocular hypertension. METHODS In a cross-sectional population-based study of 3654 Australians aged 49–97, participants were asked whether any first-degree relatives had been diagnosed with glaucoma. Open-angle glaucoma was diagnosed from matching optic disc and typical visual field changes, after gonioscopy. Ocular hypertension (OH) was diagnosed from elevated intraocular pressure (IOP) in subjects without glaucoma. RESULTS Glaucoma was present in 3.0% and ocular hypertension in 5.2% of subjects. A parent or sibling was reported to have glaucoma by 8.6%,including 10.5% of women and 5.9% of men. A positive family history was reported more frequently in parents (6.4%) than siblings (2.6%). Glaucoma was reported more frequently to affect mothers (5.0%) and sisters (1.6%) than fathers (1.5%) and brothers (1.2%). A first-degree family history was given by 15.7% of s...

Prevalence and causes of severe visual impairment and blindness in children in Mongolia.

Abstract: BACKGROUND: Reliable epidemiological data on the prevalence and causes of visual loss in children are difficult to obtain, but are essential for planning. No such data are available from Mongolia. AIM: To determine the prevalence and causes of severe visual impairment and blindness (SVI/BL) in children from a defined area of Mongolia, using several methods of identification. METHODS: Children with presenting visual acuities of <6/60 in the better eye who lived in 10 of the 18 provinces (Aimaks) were identified 1) by family doctors 2) in the school for the blind 3) by visiting eye departments in the capital. All eligible children were examined (or data extracted from hospital records) and the cause of visual loss determined using the WHO classification system. RESULTS: Sixty-four children with SVI/BL before refraction were identified who lived in the 10 study Aimaks. They were recruited by family doctors (52); by home visits (3); from hospital records (4); or from the school for the blind (5). The prevalence of SVI/BL before refraction was 0.19/1,000 children (95% CI 0.16-0.22), decreasing to 0.16/1,000 after refraction (95% CI 0.13-0.19) but there was considerable variation from Aimak to Aimak. The major causes of SVI/BL were lesions of the lens (34%), central nervous system disorders (19%), lesions of the whole globe (e.g. microphthalmos) (14%), and retinal conditions (12.5%). Hereditary factors were responsible for 27% of causes, and 17% of children were blind following acquired conditions of childhood. The underlying cause could not be determined in 48%. The causes of SVI/BL was analysed in a further 16 children who lived outside the study Aimaks to compare the causes in children in special education with those not in schooling, and by age. CONCLUSION: The prevalence estimate obtained was lower than anticipated, and possible reasons are discussed. The pattern of causes of SVI/BL is similar to that in children in schools for the blind in China, but is very different from other Asian countries. Meningococcal meningitis was the most common preventable cause of SVI/BL, and immunisation is being considered. Other preventable causes were rare, and the majority of children needing surgical intervention had already been identified and referred for treatment. The control of blindness in children could possibly be improved by better management of conditions requiring surgery, and by the provision of low vision devices.

Risk factors for diabetic retinopathy in the Cree of James Bay.

Abstract: background The purpose of this project was to evaluate risk factors for diabetic retinopathy in the Cree population of James Bay, Ontario. methods A retrospective cohort design was employed. The cohort was made up of all known individuals who had previously been diagnosed with diabetes in the communities of Moose Factory and Moosonee, Ontario. Hypertension, body-mass index, serum lipid levels, renal function status, and hemoglobin A1C were the main exposures of interest. Values for these variables were determined from a retrospective chart review and were sought for each individual for a five-year interval beginning one year following the diagnosis of diabetes. Relative risks for the association of these variables with diabetic retinopathy were determined through both univariate and multivariate Poisson regression. The main outcome of interest in this study was the presence or absence of any diabetic retinopathy in either eye, as determined by a retinal specialist. results Significant univariate risks for...

The National Blindness and Low Vision Prevalence Survey of Bangladesh: research design, eye examination methodology and results of the pilot study.

Abstract: PURPOSE To describe the research design and eye examination protocol of The National Blindness and Low Vision Prevalence Survey of Bangladesh and to present the main results of the rural pilot study. METHODS A thorough description of the sampling strategy, eye examination protocol and operational definitions are presented. Multi-stage stratified (rural/urban) cluster random sampling, with probability proportional-to-size procedures, will be used for selection of a cross-sectional, nationally representative sample (12,900 subjects) of the population aged > or = l30 years. Each subject will be tested for visual acuity, auto-refracted and undergo optic disc examination. Those with <6/12 visual acuity in either eye will be re-tested with their refractive correction, dilated and examined for anterior and posterior segment disease. A preliminary, separate rural pilot survey sample was conducted according to the eye examination procedures, with results reported herein. RESULTS Two-hundred-and-four (73.1%) of 279 eligible subjects were examined for the rural pilot. Forty-eight persons had presenting visual acuity worse than 6/12 in either eye. The presenting visual acuity of the better eye was used to group the subjects into the following WHO categories (brackets enclose the number of subjects after refractive correction): Blind: 4 [4]; Visually impaired: 29 [14]; Sighted: 171 [186], of whom 3 [3] were unilaterally blind. Cataract was the main cause of visual acuity of less than 6/12, followed by refractive error, and age-related macular degeneration. CONCLUSIONS The pilot survey demonstrated that the proposed examination process for the main survey was both feasible and appropriate for the purposes of this study. Particular strengths of the pilot and subsequent main survey include the use of logMAR visual acuity testing and auto-refraction of all subjects. The pilot study reveals the burden of cataract and refractive error, which are two of the five diseases specifically targeted by the WHO global blindness initiative 'Vision 2020'.

Trachoma and ethnic diversity in the Upper Rio Negro Basin of Amazonas State, Brazil.

Abstract: A trachoma survey was carried out among three culturally different populations of the Upper Rio Negro Basin in the Brazilian rain forest of Amazonas State. The results indicate that trachoma is prevalent in the region, reaching hyperendemic levels (between 50.9% and 56.4%) in all communities studied. However, the severity of the disease appears to be related to the ethnic origin of the tribes, following the rank of social and cultural values that regulate the complex interactions between the Indian groups of the region.

Comparison of Goldmann applanation tonometry with the Tonopen for measuring intraocular pressure in a population-based glaucoma survey in rural West Bengal.

Abstract: aim This study was undertaken to compare the measurement of intraocular pressure (IOP) in a population-based glaucoma survey by the Goldmann Applanation Tonometer (GAT) and the Tonopen with respect to IOP readings, the time required to measure IOP and subjects' preference for the two instruments. The purpose of the study was to see which of the two instruments could be more suitable in a rural survey, particularly house-to-house, in trying to find cases of advanced glaucoma. method The study was conducted on a total of 203 subjects as a part of a population-based glaucoma survey. The IOP of one randomly selected eye of each subject was measured, first with the GAT and subsequently with the Tonopen. The time taken for each procedure was noted and subjects' preference was ascertained. results The mean of the paired differences between the readings of the two instruments (Tonopen minus GAT) was 1 mm Hg with a standard deviation of 2.28. The Tonopen readings were within ±3 mm Hg of the GAT readings in 86.2% o...

Rapid assessment of trachoma in Hainan Province, China: validation of the new World Health Organization methodology.

Abstract: This study was undertaken to validate a WHO methodology for the rapid assessment of trachoma. Fourteen villages were chosen by random sampling in two counties in Hainan Province, China. For the rapid assessment, trichiasis patients were identified, 50 children ages 1-10 years were examined for active trachoma, and information was collected on community access to services and community risk factors. To validate the methodology, a prevalence survey was undertaken simultaneously in the same villages. For the prevalence survey, 2428 people from 1606 households in the 14 villages were chosen by random sampling. Very little active trachoma was found by either method, although the rates of trichiasis were more substantial. Ranking of the villages by the two methods for trichiasis was highly correlated (Spearman's correlation coefficient = 0.60, p = 0.02). For active trachoma, the Spearman's correlation coefficient for the ranking of villages by the two methods was 0.40 and not significant (p = 0.14), suggesting that a correlation this close may have been seen by chance alone. The observational data showed all the villages to be at risk of active trachoma (due to poor environmental hygiene conditions), suggesting that this aspect of the WHO methodology overestimates the risk for active trachoma. We conclude that, with the exception of the community assessment of risk, this rapid assessment methodology is a valid tool for the assessment of trichiasis and possibly of active trachoma in rural communities, although the level of active trachoma in this study was too low to effectively validate that aspect of the methodology.

Incremental cost-effectiveness of laser therapy for visual loss secondary to branch retinal vein occlusion.

Abstract: purpose To ascertain the incremental cost-effectiveness of therapeutic interventions for improving visual loss associated with branch retinal vein occlusion. methods A cost-utility analysis incorporating data from the Branch Vein Occlusion Study Group was performed using patient-based preferences obtained from time tradeoff utility analysis, decision analysis with Markov modeling, and economic modeling with future value analysis. The cost-effectiveness results are expressed in $/QALY (dollars expended per quality-adjusted life-year) gained. This unique model takes into account the visual acuity in the better seeing eye and the recurrent risk for visual loss in the contralateral eye. results Laser therapy for macular edema secondary to branch retinal vein occlusion was associated with an incremental $/QALY gained of $6118 (in year 2000 U.S. dollars). Two-way sensitivity analysis, varying the discount rate and the proportion of patients developing a vascular occlusion in the contralateral eye, revealed a ra...

Postmenopausal hormone use and lens opacities.

Abstract: purpose Women are at higher risk for age-related cataract than men, and it has been hypothesized that this difference is due in part to gender-related hormonal differences. methods We investigated the association between postmenopausal hormone use and lens opacities in a population of 480 postmenopausal women from the Nurses' Health Study for whom we had prospectively collected exposure data. Participants received standardized eye exams; the Lens Opacity Classification System III (LOCS III) was used to measure the degree of opacification. results A total of 342 women had some opacity in one or both eyes. Overall, we did not observe a significant association between current hormone use and presence of any type of opacity (compared to never users, multivariate relative risk: 0.85; 95% confidence interval (CI): 0.54–1.34). In ordinal logistic regression compared to never users, current hormone users had multivariate relative risks of cortical opacities of 0.80 (95% CI: 0.54–1.19) and for past users the relat...

Evaluation of E-optotypes as a screening test and the prevalence and causes of visual loss in a rural population in SW Uganda

Abstract: background Few population-based eye surveys have been conducted in sub-Saharan Africa, limiting the quality of epidemiological information on visual loss from Africa. In the present paper, we describe the prevalence of visual loss in rural Uganda and the screening accuracy of E-optotypes when used by non-medical staff. methods Residents of 15 neighbouring villages were screened for visual loss (<6/18 in either eye) using Snellen's E-optotypes. Individuals who failed were initially referred to an ophthalmic clinical officer (OCO), who retested visual acuity and subsequently referred to an ophthalmologist to determine the cause of visual loss. Subjects from two villages (248 individuals) who passed visual acuity screening were re-examined by the OCO to estimate the accuracy of the screening procedure. results Of the 4076 adults (aged 13 years and over, 69.3% of the censused population) who participated, 191 (4.7%) failed the vision screening criteria and 648 (15.9%) had non-vision impairing conditions. T...

The Flies and Eyes project: design and methods of a cluster-randomised intervention study to confirm the importance of flies as trachoma vectors in The Gambia and to test a sustainable method of fly control using pit latrines.

Abstract: The Flies and Eyes project is a community-based, cluster-randomised, intervention trial based in a rural area of The Gambia. It was designed to prove whether flies are mechanical vectors of trachoma; to quantify the relative importance of flies as vectors of trachoma and to test the effectiveness of insecticide spraying and the provision of latrines in trachoma control. A total of 21 clusters, each composed of 300-550 people, are to be recruited in groups of three. One cluster from each group is randomly allocated to receive insecticide spraying, one to receive pit latrines and the remaining to act as a control. The seven groups of clusters are recruited on a step-wise basis separated by two months to aid logistics and allow all seasons to be covered. Standardised, validated trachoma surveys are conducted for people of all ages and both sexes at baseline and six months post intervention. The Muscid fly population is monitored using standard traps and fly-eye contact is measured with catches of flies direct from children's faces. The Flies and Eyes project has been designed to strengthen the evidence base for the 'E' component of the SAFE strategy for trachoma control. The results will assist programme planners and country co-ordinators to make informed decisions on the environmental aspects of trachoma control.

From visual function deficiency to handicap: measuring visual handicap in Mali.

Abstract: BACKGROUND/AIMS Blindness is a major public health problem in developing countries, even though most could be prevented by relatively simple hygienic and medical interventions. Relatively few patients use the quality health care services available, despite their low cost, due to problems of access or socio-cultural barriers. This health services research project stressed the need for measurement of subjective self-perceived health. The objectives of this study were twofold: a) To translate, adapt and integrate the cultural context found in Mali and validate two instruments for measuring, respectively, perceived vision and quality of life. b) To study the relationship between these variables and visual deficiencies by gender. METHODS The perceived vision and quality of life questionnaires were based on a translation of the Aravind questionnaire, adapted to Mali. The resulting perceived vision questionnaire comprises 13 questions, grouped according to five subscales (global vision, visual perception, sensory adaptation, visual field and depth perception). Furthermore, the 13 questions on quality of life were grouped into four subscales (personal care, mobility, social life and psychological). For both questionnaires, a global score could be computed. These two questionnaires were administered to a representative sample of 203 subjects with impaired vision, aged over 40, in a rural area in Mali. RESULTS The acceptability of the questionnaires was good (1% missing data). The convergent validity was adequate for all but one subscale (psychological). The discriminate validity is acceptable for three of the six subscales where measurement can be made (visual perception, personal care, mobility). The Cronbach alpha coefficients indicate good reliability for the global scores. CONCLUSIONS Analysis of mean results confirms the validity of the International Classification of Disease (ICD) definition of blindness (seeing less than 0.05 results in a steep decrease in quality of life). Moreover, blindness affects the quality of life of women more severely than that of men; this may be related to the availability of social support.

Levels of agreement between parents' and children's reports of near work

Abstract: purpose To assess whether parents and children report the same information regarding children's near vision activities when given similar questionnaires. methods Data from questionnaires administered to 406 children and their parents were analyzed to evaluate the agreement between parent and child reports. The questionnaires were completed during the 1994 testing of the Orinda Longitudinal Study of Myopia. Each child and parent was asked to categorize how often the child reads for pleasure. In addition, each subject was asked to estimate how many hours per week were spent in each of five visual activities. The weighted kappa statistic, paired t-tests, and polytomous logistic regression were used for analyses. results A weighted kappa = 0.42 (moderate agreement) was found in the comparison of child-reported vs. parent-reported classification of reading. Agreement between parent- and child-reported number of hours spent doing homework (0.21), reading for pleasure (0.31), watching television (0.31), playing ...

Consistency of observations from echograms made centrally in the Collaborative Ocular Melanoma Study COMS Report No. 13.

Abstract: purpose To describe the methods used by the Collaborative Ocular Melanoma Study (COMS) Echography Center for grading tumor echograms and to assess reliability of the grading system. methods Tumor echograms were graded at the COMS Echography Center using a specific protocol. To assess consistency, a five-percent random sample of all echographic gradings received as of June 30, 1996 was selected by the COMS Coordinating Center for re-evaluation at the COMS Echography Center. The results were compared with original data. Agreement between the two sets of gradings was evaluated by calculating overall percent agreement, and by using the kappa statistic for categorical features and intra-class correlation coefficients (ICC) for continuous measures. results Overall agreement between original gradings and regradings was high. Agreement, based on the kappa statistic, between the original grading and the regrading was classified as ‘moderate,’ ‘substantial,’ or ‘almost perfect’ for nearly every variable graded. Kap...

Use of vitamin and zinc supplements and age-related maculopathy: the Blue Mountains Eye Study.

Abstract: purpose To investigate relationships between vitamin and zinc supplement use and age-related maculopathy in a population-based sample. methods We studied 2873 (79%) of the 3654 participants aged 49– 97 years who attended the cross-sectional Blue Mountains Eye Study and completed a detailed food frequency questionnaire, including type, dose and duration of supplement use. ARM was assessed during a masked grading of macular photographs. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression. results After adjusting for multiple confounders, we found that no vitamin or zinc supplements were significantly associated with reduced prevalence of any ARM lesions in either eye. The OR for use of any vitamin supplement was 1.3 (CI 0.9–1.7, p = 0.11) for individuals with any retinal pigment changes. It was 1.1 (CI 0.8–1.5, p = 0.59) for those with any soft (large) drusen and 1.5 (CI 0.7–3.0, p = 0.31) for those with late ARM lesions. The lack of association between supplement in...

Comment on visual acuity.

Abstract: In their article, Lam et al. used the rule that ‘any two prevalences whose 95% confidence intervals did not overlap were considered significantly different at the 5% level.’ They did not specify what they would do when the confidence intervals overlap, and this is reflected in their analysis of the data. Moreover, the ‘5% level’ is not the significance level of the test combining the two confidence intervals, being merely the complement of 95%, and so is redundant in this sense. A clear example of where the confidence intervals overlapped but no conclusion was drawn occurs in Table 1 on the overall impairment within HHANES between Cuban Americans and Mexican Americans after adjusting for age and gender. Since a conclusion was drawn regarding Puerto Ricans and Cuban Americans in the HHANES Overall Age and Gender Adjusted Rates, where the 95% confidence intervals did not overlap, it seems inconsistent that none should be drawn regarding Cuban Americans and Mexican Americans within that category of rates, without justification. Elsewhere in Table 1, when the 95% confidence intervals did overlap as in the HHANES Severe Age and Gender Adjusted rates, the statement that there are ‘no significant differences in the prevalence rates of . . . severe impairment’ is disputable. The use of confidence intervals for comparing samples was considered by Tsakok. The article recommends that the null hypothesis of homogeneity (of the rates in the present case) should be rejected not only when there is no overlap between the confidence intervals, but also when there is insufficient overlap between them, under the null hypothesis. The exact significance level is derived from the confidence levels, in the frequentist sense. The Tsakok technique is implemented with the software GSP (General Statistical Package). Applying this to Table 1, it is found that there is a significant difference in the HHANES Overall Age and Gender Adjusted Rates Ophthalmic Epidemiology 0928-6586/02/US$ 16.00

Differences between screening sites in a glaucoma screening program

Abstract: objective To determine the differences in demographic variables, glaucoma risk factors, and visual acuity by type of screening site. methods We conducted glaucoma screenings throughout the city of Baltimore. A questionnaire collected information about age, race, and risk factors: having a relative with glaucoma, having diabetes, having a past eye injury or surgery, and not having an eye examination within two years. We also tested visual acuity and visual fields. We categorized screening sites into work places, senior centers, health fairs, and church groups, and created age-race groups by combining age and race categories. results This study is based on 1,366 people screened at 42 different sites. The majority of people screened were African-American (65%) and female (58%), with a mean age of 48 years. We found significant age and race differences between the screening sites. After stratifying by age-race groups, we found statistically significant associations between screening sites and not having a rec...