Contrast sensitivity important tool for industrial vision screening.
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
PURPOSE: The purpose of this study was to determine the testability of the "Co or Vision Testing Made Easy" color vision test, marketed as a screening test for young children, in a population of individuals with mental retardation. The test uses simple geometric figures that are easily identified. Previously, the test has demonstrated validity as a measure of color deficiency. METHODS: The test was presented to Special Olympic athletes, who are individuals with mental retardation or significant developmental delay, at four sites: the 1997 World Winter Games in Toronto, Canada; the Texas Summer Games in Houston, Texas; the Massachusetts Summer Games in Boston, Massachusetts; and Regional European Swim Competition in Seville, Spain. The criteria for passing was 8 correct responses on the first trial or 9 of 9 on the second attempt. RESULTS: Testability in Toronto, Canada; Houston, Texas; and Seville, Spain was high--95.5%, 98.7%, and 95.7%, respectively. Testability, however, dropped to 78.8% during the Boston, Massachusetts screening. There was no apparent difference in the testing environment that would account for the difference. The overall rate of testability was 93.2% for the 1078 athletes screened. The frequency of males identified as color deficient was similar to that expected in the general population; only two females (in Spain) failed the color vision screening. CONCLUSIONS: The "Color Vision Testing Made Easy" color vision test was successfully completed by a very high percentage of Special Olympics athletes. These results suggest that this test is useful in screening this population for color deficiencies, and that the prevalence of color vision deficiencies is approximately the same in individuals with mental retardation as in the general population.
Explore the source record for details and available documents.
The need and accuracy of a hypermetropia test, recommended as a screening test in Swedish schools, was evaluated in a series of 118 8-year-old children not wearing glasses. The distant visual acuity was determined without correction and with plus spheres of two different strengths, +1.5 D and +2.0 D respectively. When compared to the objective refraction and with an arbitrary limit of hypermetropia of +2.5 diopters, it could be shown that neither of the hypermetropia tests fulfilled the criteria of an adequate screening test. Except for two children all hypermetropics beyond +3.0 were previously known. The reading skills of the children were estimated by their teachers. No correlation was found between the degree of hypermetropia and reading difficulties. The results indicate that the hypermetropia test could be omitted from the regular vision tests of schoolchildren, at least in areas covered with an efficient pre-school vision screening.
OBJECTIVE: To determine the effectiveness of an existing screening programme based in the community for ocular and vision defects in infants considered at increased risk of such defects. DESIGN: Children with ocular or vision defect by the age of 2 were ascertained by searching records. Those from populations at high risk were matched with their results from screening tests. The characteristics of the cases among this population were compared with those of the cases in the remainder of the population. Patterns of referral and age at referral were studied in both groups. SETTING: The study was conducted within Oxfordshire Health District. SUBJECTS: 433 Children at high risk born in 1984 to mothers living in the health district at delivery and who either weighed less than 2000 g or weighed 2000 g and over and required admission to a special care nursery for longer than 24 hours. The low risk population (6254) were infants without these characteristics who were resident in the health district at the time of referral. INTERVENTIONS: Screening tests for vision or ocular defects already routinely used were applied by health visitors at 8 and 18 months to the children at high risk. MAIN OUTCOME MEASURE: Comparison of results of screening tests with vision and ocular defects detected by the age of 2. RESULTS: Screening tests in current use for vision loss and squint in this age group were insensitive and had a low positive predictive value when applied to a high risk population. Defects that were not apparent on direct inspection were unlikely to be detected by these tests. In the high risk group the relative risk of having a defect was 2.8 (95% confidence interval 1.8 to 4.5) but 85% of all cases detected by the age of 2 were in children at low risk. Referral patterns and age of referral differed in the two groups. CONCLUSIONS: Screening by health visitors of high risk populations contributes little to the detection of vision and ocular defects. This type of evaluation needs to be applied also to low risk populations, who have different referral patterns and contribute most of the cases.
Although population outcome studies support the utility of preschool screening for reducing the prevalence of amblyopia, fundamental questions remain about how best to do such screening. Infant photoscreening to detect refractive risk factors prior to onset of esotropia and amblyopia seems promising, but our current understanding of the natural history of these conditions is limited, thus limiting the prophylactic potential of early screening. Screening for strabismic, refractive and ocular disease conditions directly associated with amblyopia is more clearly proven, but the diversity of equipment, methods and subject populations studied make it difficult to draw precise summary conclusions at this point about the efficacy of photoscreening. Sensory-based testing of preschool-age children exhibits a similar combination of promise and limitations. The visual acuity tests most widely used for this purpose are prone to problems of testability and false negatives. Moreover, the utility of random-dot stereograms has been confused by misapplication, and new small-target binocularity tests, while attractive, are as yet inadequately field-proven. The evaluation standard for any screening modality is treatment outcome. However, variables in amblyopia classification and quantitative definition differences, timing of presentation, nonequivalent treatment comparisons, and compliance variability have been uncontrolled in virtually all extant studies of amblyopia treatment outcome, making it difficult or impossible to evaluate either the relative efficacy of different treatment regimens for amblyopia or the effects of age on treatment outcome within the preschool age range. The latter issue is a central one, since existence of such an age effect is the primary rationale for screening at younger rather than older preschool ages. The relatively low prevalence of amblyopia makes it difficult to achieve a high screening yield in terms of predictive value, but functionally increasing prevalence by selective screening of high risk populations causes further problems. Unless a "supertest" can be devised, with very high sensitivity and specificity, health policy decisions will be required to determine which of these two characteristics should be emphasized in screening programs. Performance of screening tests can be optimized, however, with adequate training, perhaps via instructional videotapes.
BACKGROUND: In Germany the paediatricians use three different visual acuity tests (Pictures, Rodenstock-Test, H-Test). We investigated the effectiveness of these procedures. SUBJECTS: In this study 303 children were referred by paediatricians to the study group in the Cologne Augenklinik. They were fully examined by an orthoptist and an ophthalmologist (gold standard). RESULTS: From these data the sensitivity and specificity of the tests used by the paediatricians were calculated. Only the H-Test proved to be satisfactory. CONCLUSION: The actual situation of screening for amblyopia by paediatricians in children aged 3 1/2 to 4 is unsatisfactory in Germany. Paediatricians and ophthalmologists should use a similar test for visual acuity. Continuing education of medical personnel is desirable to ensure an adequate quality of screening.
Explore the source record for details and available documents.
OBJECTIVE: To review the test characteristics and the quality of evidence regarding available screening tests for the detection of amblyopia in preschool-aged children to help primary care practitioners select a screening strategy. DESIGN: Systematic review of published studies. DATA SOURCES: The MEDLINE database was searched from 1966 through January 1999 using a broad and inclusive strategy. A total of 9551 citations were identified. STUDY SELECTION: All studies that compared the results of commercially available screening tests in preschool-aged children to ophthalmologic examination. DATA EXTRACTION: The setting of the study, the age of the population, the type of screening test, criteria for a positive screen, criteria for the ophthalmologic examination, test characteristics, and measures of reliability were abstracted by 2 reviewers for each selected study. DATA SYNTHESIS: Four eligible articles were identified that studied the test characteristics of 3 screening tests. None of these studies were performed in a primary care setting. Each study used different criteria for failure of the ophthalmologic examination. None of the studies measured observer or test reliability. CONCLUSIONS: Few high-quality data exist regarding the performance of preschool vision screening. Important future work should include the development of a consensus gold standard ophthalmologic examination and evaluation of screening tests in the primary care setting.
BACKGROUND: The Neitz Test of Color Vision (Neitz) and Color Vision Testing Made Easy(trade mark) (CVTME) were compared to determine which test was more effective in evaluating patients with intellectual disability (i.e., mental retardation) and developmental delay. METHODS: Two hundred eight Special Olympics floor hockey athletes were screened in San Diego, California, and 93 athletes were screened in Long Beach, California for a total of 301 athletes. Each athlete was administered the CVTME and the Neitz tests. RESULTS: The pass rate for the CVTME was 94.6% (n = 93) at Long Beach and 96.2% (n = 208) at San Diego. Every athlete was able to complete the CVTME. The pass rate for the Neitz was 38.7% at Long Beach and 56.7% at San Diego. Additionally, 10.8% of the Long Beach athletes and 12.5% of the San Diego athletes were unable to understand the Neitz. In addition, there was a low level of agreement between the results from the 2 tests with kappa = 0.081 for the San Diego data and 0.028 for the Long Beach data. CONCLUSIONS: This study suggests that the CVTME continues to be the screening test of choice in evaluating color vision in individuals with intellectual disability. The Neitz had more failing scores on the first attempt and more total failing scores leading to over-referrals, making it an inappropriate screening test for individuals with intellectual disability and developmental delay.
The quality of screening for testing visual disorders is unsatisfactory. Diagnosis and therapy are generally too late to exploit the advantage therapy can give during the sensitive period of visual acuity. About 10% of the adult population show decreased visual acuity (below 0.8). These persons have a more or less distinct amblyopia. Commonly used visual acuity tests do not allow the crowding phenomenon to be measured, although it is an easily measurable amblyopia characteristic. The most frequently used visual acuity test by German health authorities (R 5/R 11 test with plate No. 120) shows 48% false-negative results. We introduced the H test for preschool children. For school children and adults we developed the C test. To detect amblyopia precisely we designed both tests so that the crowding phenomenon could be measured. Both tests were validated in more than 700 subjects. All persons received an extensive ophthalmological checkup, which was used as the reference for normality. The H test is based on the matching principle and works with musical feedback. The test can be used from the age of 3 years onward. Therefore, the advantage of early therapy can be fully exploited. The H test has a 3% percentage false-negative rate. The C test is based on the Landolt ring. The visual acuity charts are presented as a book (40 cm distance) for measuring near visual acuity and (5 m) for measuring distance visual acuity. The C test has less than 5% false-negative results. Both tests can help in different age groups to diagnose amblyopic cases.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: The Missouri State Highway Patrol (MSHP) required that its vision standards be updated in order to comply with the Americans with Disabilities Act (ADA). This act prohibits employers from using qualification standards to screen out people with disabilities, including vision, unless they are job-related and necessary. METHODS: Since 1992 the author and a team of optometry students have screened all MSHP applicants using the American Optometric Association (AOA)'s Vision Standards for Police Officers with the addition of grating contrast sensitivity. RESULTS: The mean age of this group was 24.8 years and most (87%) were male. Thirty percent wore spectacles, contact lenses, or had refractive modification. Ninety-seven percent of the applicants were able to pass all aspects of the enhanced vision screening. CONCLUSION: The initiation of optometric screening to ensure that all future troopers meet the recommended vision standards for police officers should ensure uniformity of these standards for the MSHP.