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PubMed1988

Screening of vision in school: could we do better by doing less?

Assessment of vision in schoolchildren is routinely performed, but the effectiveness of the screening programmes has not been reviewed. A survey of health district screening programmes for vision in schools was performed at the end of 1984. The response rate from districts in England and Wales was 81%. All 165 of the districts that responded screened for loss of distant visual acuity; 96% screened for loss of colour vision, 73% for squint, and 67% for loss of near visual acuity. The frequency with which districts screened varied considerably. Some districts screened yearly, and various different types of tests were used. In many districts children were screened in unsuitable places, such as corridors, assembly halls, and toilets. Criteria for referral varied from one district to another, and few districts collected data appropriate for monitoring their screening programmes. Many districts screened more intensively than could be justified on the basis of the conditions tested for and the likely benefit of remedial treatment.

Child↗

PubMed1979

Subtle disturbances of vision after optic neuritis elicited by studying contrast sensitivity.

Eight patients with a subjective disorder of vision yet normal Snellen acuities after optic neuritis were shown to have an abnormal contrast sensitivity function in their affected eye. It appears that certain disorders of vision are associated with an abnormality of the contrast sensitivity function in spite of near normal visual acuity. Such an abnormality may affect pattern recognition without having an influence on Snellen acuity because of the high contrast of the latter and its predominant association with the higher spatial frequencies. Contrast sensitivity function is thus the only tool available to study those aspects of vision which have remained impervious to other subjective tests of visual function.

Adult↗

PubMed2002

Relation between colour vision loss and occupational styrene exposure level.

AIMS: To investigate the relation between colour vision loss and the exposure level of styrene. Exposure level included the current exposure concentration, past cumulative exposure, and the maximum exposure level in the past. METHODS: Colour vision was examined by the Lanthony desaturated panel D-15 test for 76 subjects exposed to styrene in a fibreglass reinforced plastics boat plant (as an exposed group) and 102 non-exposed subjects (as a control group). The current exposure level was expressed by the concentration of atmospheric styrene and end shift urinary mandelic acid (MA) and phenylglyoxylic acid (PGA) levels. The individual cumulative exposure index (CEI) was calculated, based on the exposure frequency and urinary MA concentrations measured for the past eight years. RESULTS: The Colour Confusion Index (CCI) of the exposed group showed a significant difference from the age matched controls. However, only a slight significant relation was found between CCI and the concentration of urinary MA plus PGA. In this study, the exposed group was further divided into two subgroups (as sub-MA+PGA groups) by the median of urinary MA plus PGA of each subject. The dividing line between the subgroups was 0.24 g/g creatinine, which was equivalent to an atmospheric concentration of styrene of about 10 ppm. The CCI values of both the sub-MA+PGA groups were significantly higher than that of the control group. The relation between CCI value and the maximum exposure concentration in the past eight years was examined. It was found that the CCI values of the group with the maximum exposure concentration of styrene over 50 ppm were significantly higher than that of the other groups. CONCLUSIONS: Exposure to styrene would impair colour vision even if the exposure concentration was lower than 10 ppm. Furthermore, if the maximum concentration of styrene exposure transiently exceeded 50 ppm in the past, the styrene related damage might remain. Thus, the safe limit of exposure to styrene and the relation between exposure to styrene and the degree of damage to ocular structure, retina, optic nerve, and brain need to be re-examined.

Adult↗

PubMed2007

Children unable to perform screening tests in vision in preschoolers study: proportion with ocular conditions and impact on measures of test accuracy.

PURPOSE: To examine the relative prevalence of ocular conditions among children who are unable to perform preschool vision screening tests and the impact on measures of screening test performance. METHODS: Trained nurse and lay screeners each administered a Lea Symbols visual acuity (VA) test (Good-Lite, Inc., Steamwood, IL), Stereo Smile II test (Stereo Optical, Inc., Chicago, IL), and Retinomax Autorefractor (Right Manufacturing, Virginia Beach, VA), and SureSight Vision Screener (Welch Allyn, Inc., Skaneateles Falls, NY) examinations to 1475 children who later received a comprehensive eye examination to identify amblyopia, strabismus, significant refractive error, and unexplained reduced VA. The outcomes of the examination for children for whom screeners were unable to obtain results (Unables) were compared to the outcomes of children who passed and children who failed each screening test. When estimating sensitivity, specificity, and positive and negative predictive values (PPV and NPV), Unables were classified as either screening failures or screening passers. RESULTS: Less than 2% of children were classified as Unables for each test. The percentage with an ocular condition was at least two times higher for Unables than for screening passers for six of the eight modes of screening (P < 0.05). Considering Unables as screening failures, rather than screening passers, increased the estimate of sensitivity by 1% to 3% (depending on test) and decreased the estimate of specificity by 0% to 2%; PPV decreased by 0% to 4% for most tests, whereas NPV increased by <1%. CONCLUSIONS: Preschool children who are unable to perform VIP screening tests are more likely to have vision disorders than are children who pass the tests. Because < or =2% of children were unable to do each test, referring these children for an eye examination had little impact on the PPV and NPV of the tests, as administered in VIP.

Allied Health Personnel↗

PubMed2006

Lack of follow-up exams after failed school vision screenings: an investigation of contributing factors.

Programs to facilitate professional eye exams after failed school vision screenings often are based on the assumption that funding and access to services are major obstacles to care. Despite such programs, many children do not receive professional exams. The purpose of this study was to identify additional barriers to follow-up eye care. School nurses in an urban, midwestern public school district identified elementary school students who had not received follow-up eye exams after failed school vision screenings. Parents of these students were interviewed during the summer to determine financial, logistical, social/family, and perceptual barriers to care. Family issues, parental perceptions of vision problems, and difficulty planning ahead were found to be significant factors. Strategies to increase follow-up compliance and recommendations for overcoming barriers to care were also identified.

Attitude to Health↗

PubMed2000

The effectiveness of preschool vision screening by health visitors.

The aim of this study was to determine the effectiveness of preschool vision surveillance by health visitors in Warrington, a district with a secondary community orthoptic service. Of the 2041 children screened by health visitors at 3-3 1/2 years 12% were referred to the orthoptist for further assessment. Sixty-three per cent of these required more than one examination by the orthoptist and 28% were subsequently referred to an ophthalmologist for further assessment. Amblyopia was detected in 11 children, 5 had squints without amblyopia, and in addition 25 children had significant refractive errors. A retrospective review of the records of children identified with amblyopia following a school entry medical at 5 years was undertaken to detect possible failure of the earlier health visitor examination (i.e. false negatives at age 3-3 1/2 years). Possible failure of early screening was found in only two children, one of whom had a minor defect only (6/9). Vision screening for children aged 3-3 1/2 years by health visitors is an effective alternative to primary screening by orthoptists. However, the use of health visitors in this role is contrary to current national guidelines. The findings suggest that using health visitors to screen vision in preschool children makes efficient use of existing routine checks and may be the best use of orthoptic time.

Child, Preschool↗

PubMed1986

Psychophysics of reading. IV. Wavelength effects in normal and low vision.

Does the color of text influence its legibility? There are reasons why it may do so for specific groups of low-vision observers. We used psychophysical methods to measure the effects of wavelength on the reading performance of four normal observers, two dichromats, and twenty-five low-vision observers. Reading rates were measured for text scanned across the face of a television (TV) monitor. We compared performance under four luminance-matched conditions in which sets of neutral-density and Wratten color filters were placed in front of the TV screen--blue (lambda max = 430 nm), green (lambda max = 550 nm), red (lambda max = 650 nm), and gray. Under photopic conditions, the reading rates of normal subjects were independent of wavelength, with the exception of characters near the acuity limit. At lower luminances, wavelength effects could be explained by the shift from photopic to scotopic vision. It was hypothesized that light scatter or absorption in eyes with cloudy ocular media would result in depressed performance in the blue. Only one of seven subjects demonstrated this effect, which we traced to wavelength-specific absorption. Observers with advanced photoreceptor disorders tended to read blue text faster than red text. This could not be explained on the basis of photopic spectral sensitivities alone. Finally, the presence of central or peripheral field loss was not predictive of wavelength-specific effects in reading. On the whole, wavelength only occasionally plays a significant role in reading. When it does, performance tends to be depressed either in the red or the blue and to be nearly optimal for green or gray.

Adult↗

PubMed1995

Relative effects of age and compromised vision on driving performance.

The aim of this study was to determine the relative effects of age and compromised vision on driving-related skills and on-road accidents. A total of 107 subjects were tested. They represented four groups that varied in age and visual status, as follows: (1) a younger, normally sighted group; (2) an older, normally sighted group; (3) a younger, visually compromised group; and (4) an older, visually compromised group. Driving performance was assessed by self-reported and state-recorded accident frequency and by an evaluation of performance on an interactive driving simulator. The older groups had poorer driving-related skills, as measured with our interactive driving simulator, than had the younger groups, but they did not have significantly higher on-road accident rates than the younger groups. The older subjects and those with compromised vision had reduced risk-taking scores, as measured with a self-report questionnaire. In addition, all older drivers had increased eye movements and had slower simulator driving speeds, which suggests that behavioral compensation is made for visuocognitive/motor deficits. Regression analyses showed that compromised vision and visual field loss predicted real-world accidents in our study population.

Accidents, Traffic↗

PubMed2002

Vision-specific instruments for the assessment of health-related quality of life and visual functioning: a literature review.

Clinically objective measures such as visual acuity or visual field provide an assessment of a patient's visual status. However such measures may not reflect the degree of visual impairment the patient experiences in his or her daily activities. Visual impairment has been shown to have negative effects on health-related quality of life (HR-QOL) and a significant impact on daily functioning, including social activities. As such, there is a growing recognition of the importance of patient-reported outcomes of visual functioning. This review examines the development and psychometric properties of 22 vision-specific instruments assessing visual functioning and/or the impact of visual impairment on HR-QOL or daily activities. Issues relevant to assessing vision-specific subjective outcomes are reviewed, with specific application of the reviewed instruments. Three instruments, the Activities of Daily Vision Scale, National Eye Institute Visual Function Questionnaire, and Visual Function Index have been well validated and widely used, but others also show promise. To fully capture the benefits of a new ophthalmology treatment (or new treatment for eye disease) a valid and reliable visual instrument, in which the psychometric performance has been demonstrated in the particular ocular condition being treated, should be utilised.

Humans↗

PubMed1985

Vision screening and eye examination of school children.

In Kuopio, Finland, vision screening for school children is done by school nurses once every 2 years. All children who have impaired vision, suspected strabismus or heterophoria, suspected eye disease or ocular discomfort, are sent for an eye examination to the ophthalmologist at the Community Health Centre, Kuopio. In 1977 the number of children referred for eye examination was 741 and 1134 in 1984. One hundred consecutive eye examinations were analysed both in 1977 and 1984. There were more girls than boys in both materials: 63 girls and 37 boys in 1977 and 60 girls and 40 boys in 1984. This difference between girls and boys was statistically highly significant in 1977 and significant in 1984. There was no significant difference in age distribution in 1977 and 1984. The largest age group was the 13-year-olds; in 1977 there were 13 and in 1984 22 children in this age group. In 1977, impaired vision (34 children) and in 1984 check-up on glasses (56 children) were the most common reasons for examination. The most usual finding in both years was myopic refraction; 52 cases in 1977 and 58 cases in 1984. It is noteworthy that in 1977 there were 16 children with normal eye examination but in 1984 there were only 6. This difference is almost significant. The cooperation between the ophthalmologist and the school nurses may account for this change.

Adolescent↗

PubMedDate not supplied

Low vision examination in children with visual impairment.

Low vision aid evaluation should be part of the routine ophthalmic care of all children with subnormal vision. The evaluations establish the child's visual capacities and assess the possible benefits of optical or nonoptical aids to maximize visual function. The concerted efforts of parents, physicians, and teachers are necessary to minimize the child's visual impairment and to avoid subsequent disabilities. Examination technique and equipment is essentially that required for routine ophthalmic care with the addition of a few low vision aid devices. Particular emphasis should be placed on communicating with parents and others directly concerned with the child's education and development.

Aphakia↗

PubMedDate not supplied

Stereopsis testing in a preschool vision screening program.

We conducted a preschool vision screening study using stereopsis testing with the Random Dot E and Lang stereotests as a complement to visual acuity measurement. Over 6000 children were screened. Stereopsis testing at a threshold of 600 seconds of arc was cognitively easier for the children than visual acuity measurement. At this threshold there was no effect on reducing the rate of visual acuity overreferrals, but ten children with abnormal binocular vision were detected who were not referred by visual acuity criteria. Though a large number of children passed only one of the two stereotests, there was no significant difference in their degree of difficulty. Stereopsis testing with these two stereotests may be a useful adjunct to preschool vision screening programs though further studies are required.

Child, Preschool↗

PubMedDate not supplied

Subnormal binocular vision in the Williams syndrome.

PURPOSE: Patients with Williams syndrome have been found to have a high prevalence of strabismus. This may be due to a primary sensory abnormality. The purpose of this study was to determine the prevalence of subnormal binocular vision in patients with Williams syndrome. METHODS: Patients being followed in an interdisciplinary Williams syndrome clinic were prospectively evaluated to determine their binocular status. RESULTS: Eleven patients with Williams syndrome underwent an ophthalmologic evaluation. Twenty-seven percent of patients had strabismus (3/11). Eight patients demonstrated no measurable strabismus. Six of these patients were found to have monofixation syndrome. CONCLUSIONS: There is a high prevalence of subnormal binocular vision in Williams syndrome. This subnormal binocular vision may explain the high prevalence of strabismus in this syndrome.

Adolescent↗

PubMedDate not supplied

Screening the vision of school-aged children: an interdisciplinary research approach.

The authors are registered nurses (RNs) and members of an Interdisciplinary Vision Screening Research Group investigating how best to screen children's vision, incorporating the assessment of binocular visual function. The aims of this pilot study were: to detect any visual skill problems of children in a Reception class (n = 28) using the Oyarzun Vision Screening Kit; to describe the behaviour of the children during the screening; to calculate the time taken to screen each child and to establish the interrater reliability (IRR) between the RNs and an optometrist. Thirteen of the children (46%) had at least one visual problem, necessitating follow-up assessment. Other results and research implications are also discussed.

Child↗

PubMed2000

[Strabismus and binocular vision disorders in premature infants with retinopathy treated with cryotherapy].

PURPOSE: To assess frequency of refraction errors, abnormal eye position and binocular vision disorders in children with retinopathy treated with cryotherapy. MATERIAL AND METHODS: Subjects of the study were 67 children, aged 2-7, treated with cryotherapy for active phase retinopathy. RESULTS: The largest group consisted of children with good visual acuity (48%). Refraction error was found in 94% of the examined eyes. Hypermetropia was more common (54%) than myopia (40%). Majority of the examined children had squint, and esotropia was much more frequent (52%). The deviation in 37% of children was over 10 degrees. In the group with birth weight under 1000 grams as well as in those with birth weight 1000-1500 grams the squint occurred in 48%, and in children weighing over 1500 grams in 4.0%. Only 54% of the studied children had normal binocular vision. CONCLUSIONS: Retinopathy of prematurity is a risk factor for development of refraction errors, strabismus and amblyopia. In infants with retinopathy of prematurity treated with cryotherapy it is necessary to have vision check-ups during their early childhood years.

Child↗

PubMed2000

Vision readiness at Seymour Johnson Air Force Base.

Ensuring that our forces are vision ready, i.e., they have the appropriate visual acuity, optical devices, and eye health to perform their mission, is essential on today's battlefield. A study was conducted at Seymour Johnson Air Force Base to determine the prevalence of vision readiness in a deploying fighter squadron. Of the 204 personnel screened, 59 wore glasses or contact lenses. Of these 59, 15 individuals (25%) were optically ready and 44 individuals (75%) were not optically ready to deploy. Optical readiness is defined as having the correct type and number of optical devices. Of the 15 individuals (25%) who were optically ready, 13 (87%) had had a professional eye examination within 12 months. Of the 44 individuals (75%) who were not optically ready, 36 (82%) had been examined within 1 year. Pearson's chi 2 test (chi 2 = 1.59, degrees of freedom = 3, significance = 0.66) indicated that there was no significant association between readiness and the date of the last examination. This study reveals that although personnel are having regular periodic professional eye examinations, optometry personnel, commanders, and deploying airmen must take a more active role in ensuring that our forces are vision ready.

Aerospace Medicine↗

PubMed2000

Test-retest reliability of the College of Optometrists in Vision Development Quality of Life Outcomes Assessment.

BACKGROUND: Medical diagnoses such as headaches, diplopia, nausea, and asthenopia are conditions that are often treated with optometric vision therapy. Improvement of such subjective conditions after a regimen of therapy is often difficult to objectively quantify. The goal of this study was to verify the test-re-test reliability of a new clinical survey instrument, the College of Optometrists in Vision Development (COVD) Quality of Life Outcomes Assessment, which allows the analysis of symptoms data. METHODS: The first-year class of optometry students at the Oklahoma College of Optometry at Northeastern State University were administered the instrument in a group setting on two different occasions, two weeks apart. Nineteen students completed both test and re-test. Statistical analysis by the Wilcoxon Signed Rank Test and paired t test were performed. RESULTS: Each subject reported some of the 30 symptoms on both test and re-test. The instrument was found to be reliable. Wilcoxon Signed Rank Analysis showed no significant differences in test-retest scores, either pooled or item-by-item. A paired t-test group and item analysis were insignificantly different between scores. Spearman's rho correlation for test-retest of each subject was 0.878. Eighty-nine percent (17 of 19) scored insignificantly different between administrations. Ninety percent of the items (27 of 30) were found to vary insignificantly between the two administrations. CONCLUSIONS: The COVD Quality of Life Outcomes Assessment is a reliable tool to measure changes in symptoms on the basis of optometric intervention--specifically, vision therapy.

Humans↗

PubMed2001

Vision care: a compensation cornerstone.

Vision care is a benefit that provides advantages for both employers and employees, and it has become an essential element of most competitive benefit packages. Well-designed vision care programs offer participants choice, options, self-help and value. An option that employers may want to consider is reduced prices on laser vision correction procedures.

Contact Lenses↗