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PubMed1993

VISION USA--optometry's national charity program.

BACKGROUND: There are an estimated 18 million uninsured working Americans and their families who are unable to afford the cost of eye care. These individuals often fall between the cracks of government and private health care assistance. Members of the American Optometric Association have developed the VISION USA program to provide free eye care to those who might otherwise not receive it. METHODS: Nearly 8,000 doctors of optometry nationwide have volunteered to provide free eye examinations in their offices for VISION USA patients. Patients are screened for eligibility and matched to the nearest available participating doctor using a computerized ZIP code matching system. Examinations are usually provided each year during March in observance of Save Your Vision Week. RESULTS: In the first three years of the program, services have been provided to over 115,000 individuals. For over 21 percent of the patients seen, this was their first eye examination ever. More than 86 percent of the patients had one or more vision problems. More than 70 percent were given new or updated prescriptions. CONCLUSION: The VISION USA program is helping to meet a significant unmet need for eye care which exists within a segment of the American population. The program is an outstanding example of the willingness of doctors of optometry to give back to their communities, and to those in need, some of what they have gained from the practice of their profession.

Adolescent↗

PubMed1993

[A preliminary enquiry into the normal values of vision in motor vehicle drivers].

A study on distant vision, visual sense and colour vision in 2,218 motor vehicle drivers in Inner Mongolia Region was carried out and the effect of age on vision was analysed. The results showed that vision in drivers diminish with increasing age and the age threshold for visual acuity was 45 years. This paper discusses the normal values of vision in two age groups of pre-and-after the threshold age line, and these results may offer a scientific basis for drawing up occupational examination standards for drivers at their posts or under training.

Adolescent↗

PubMed1998

Methanol-induced vision loss.

BACKGROUND: Accidental or purposeful consumption of small amounts of methanol can lead to severe vision loss or death. Vision loss is rapid--usually symmetric--and most often affects the central (or centrocecal) visual field, although peripheral visual loss may occur as well. Fixed, dilated pupils and optic atrophy, with or without excavation, are the most common findings in persons with methanol-induced vision loss. CASE REPORT: A 35-year-old man was examined after consuming methanol in the form of windshield wiper fluid. Despite relatively rapid treatment for the patient's methanol poisoning and associated metabolic acidosis, permanent, severe vision loss with associated optic neuropathy developed. Because of the finding of fixed, dilated pupils on the patient's initial presentation, severe vision loss was an expected result for this patient. CONCLUSIONS: Prompt recognition and proper medical treatment are the main factors in successful management of methanol poisoning. Even if proper and timely medical response is achieved, however, the patient may still experience permanent neurologic sequelae or death. Notably, pupillary status may provide the best prognostic information for both morbidity and mortality.

Acidosis↗

PubMed1996

The etiology of vision impairment in target population.

PURPOSE: research the etiology of vision impairment in target persons over 45 years old in Doumen county, Guangdong province. METHODS: Depending on the prevalences of the blindness among the person aged over 50 years, the theoretic sample rate is 1,000/4,8733 x 100% = 2.05%. The 8 districts were divided into 3 parts according to the local economic situation and the proportion of the population in the areas. In fact, the sampling rate is 932/10055 = 88.34%. RESULTS: We found that impairment < 0.3 accounted for 10.94%. The prevalence of bilateral blindness and low vision was 1.61% and 3.22%, respectively. Both prevalences of blindness and low vision were increased with age. The leading cuase of blindness was cataract (45.2%). The second was corneal opacity (16.7%). Prevalences of the low vision and the blindness were higher in females than in males (P < 0.005). CONCLUSIONS: Curable and preventable diseases were the leading cause for the blindness (70%). Prevalences of blindness and the low vision increase with age. We will continually follow up the population over 50 years of age in Doumen county.

Age Factors↗

PubMed1998

Tunnel vision information: a paradox of ethics, economics, politics and science.

BACKGROUND: Improvement in vision with spinal manipulation was first observed in the early 1970s. Reports of the phenomenon appeared in the 1980s in the popular press and at scientific meetings, but it was not until the mid-1990s that general discussion of the potential value of this knowledge occurred. Considering the far-reaching implications of the possible ability to improve brain function by spinal manipulation, the delay in consideration and implementation of this concept is a paradox in general terms and a total mystery in the case of the chiropractic profession. OBJECTIVE: To provide explanations for the delay in scientific assessment of the discovery that vision improves, in appropriate patients, when the spine is manipulated and to discuss the implications of this finding. This discovery is now called the "tunnel vision information." DISCUSSION: A schema of pathological hierarchy is depicted in which the level of intervention of spinal manipulation outranks other forms of treatment. The significance of this precedence is portrayed. Possible reasons for the failure to address this hierarchy in light of the tunnel vision information are discussed with reference to established protocols, medical politics, the presentation of the data, the failure of scientific editorship and the illogical aspects of the illness itself. CONCLUSION: In the future, the delay from the initial observation of the tunnel vision discovery to its free discussion in scientific literature may seem incongruous, particularly if the health benefits which it augurs are realized.

Chiropractic↗

PubMed2004

Development of an instrument to assess vision-related quality of life in young children.

PURPOSE: Quality of life (QOL) instruments are increasingly utilized in ophthalmological research. Measuring vision-related QOL in young children is complicated by constantly evolving abilities related to normal growth and development. Our aim was to develop vision-related QOL instruments for children in different age ranges <==7 years, and to provide initial validation of these instruments. DESIGN: Cross-sectional study. METHODS SETTING: Multicenter. PATIENTS: 773 pediatric patients (age <==7 years) with a wide range of ophthalmological diagnoses. PROCEDURE: Questionnaire. A 61-item prototype instrument with a wide variety of items was applied to 403 consecutive patients. The usefulness of items was evaluated as a function of age in order to derive two age-group specific instruments and to find the age limit dividing the age groups. Thus, age-specific versions of a Children's Visual Function Questionnaire (CVFQ) were defined for ages <3 years and >/=3 years, and applied to a convenience sample of patients. OUTCOME: Subscale scores. Factor analysis helped identify underlying dimensions of the data, and corresponding subscales were defined. Validation was provided by examining the internal consistency reliability and by exploring the associations between scores and clinical characteristics. RESULTS: Subscales for General health, General vision, Competence, Personality, Family impact, and Treatment were defined, with internal consistency reliabilities ranging from 0.60 to 0.86. The association between subscales scores and age was weak, whereas strong correlations were found with the level of visual impairment and type of visual diagnosis. CONCLUSION: The CVFQ assesses the impact of visual impairment on children and their families, and is expected to become a useful tool for the pediatric vision research community.

Child↗

PubMed2002

Reading speed test for potential central vision measurement.

This study examines the validity and reliability of a reading speed test as a measure of potential central vision. Reading speed was calculated in words per minute (wpm) from the time taken to read 30 words of 1.20 logMAR size text. Scores were obtained from subjects with cataract (n = 48), macular disease(n = 35), peripheral vision loss(n = 14) and normal eyes (n = 10). Subjects with macular disease (27.0 +/- 13.2 wpm) read much slower than subjects with cataract (91.9 +/- 13.6 wpm). Little difference was found between subjects with cataract, peripheral vision loss (91.5 +/- 14.7 wpm)and normal eyes (103.8 +/- 15.5 wpm). Repeat testing gave values within +/- 16% of reading speed. These results suggest that a reading speed test using large text could be useful as a potential central vision test in cataract patients.

Aged↗

PubMed2006

Why Cyclops could not compete with Ulysses: monocular vision and mental images.

The present research demonstrates that the limitations of congenitally blind people in tasks requiring the processing of mental images are specifically related to the absence of binocular vision and not to the absence of vision per se. We contrasted three different groups of participants: sighted; visually impaired, with reduced binocular vision; monocular, with a normal visual acuity although in one eye only. Visually impaired participants (i.e. blurred vision) show a pattern of performance comparable to that of the sighted. In contrast, monocular participants show a similar pattern of performance to congenitally blind individuals despite being able to see perfectly well. These results shed new light on the relationship between perception and imagery and on the characteristics of sequential and simultaneous processes in the human brain.

Adult↗

PubMed1994

Vision evaluation in people with Down's syndrome.

We tested the colour vision of 72 people with Down's syndrome using the Ishihara test and an anomaloscope. We found that 13 of the subjects, 6 males and 7 females, had defective colour vision according to Pickford's classification. In monocular vision 10 eyes were protan (five simple, three extreme and two deviant), one eye was simple deuteranomalous and the remaining eyes were normal: in binocular vision four of the subjects were protan (two simple and two deviant), two subjects were deutan (one simple and one deviant) and the rest were normal. Many of our subjects had lens opacities, strabismus, nystagmus, hypermetropia, high myopia and astigmatism, confirming literature reports. The contrast sensitivity function measured with the VCTS test showed a considerable loss of low-frequency sensitivity in our subjects compared to a normal population, which was more marked in the more severely impaired subjects.

Adolescent↗

PubMed2004

School vision screening, ages 5-16 years: the evidence-base for content, provision and efficacy.

The optometric profession in the UK has a major role in the detection, assessment and management of ocular anomalies in children between 5 and 16 years of age. The role complements a variety of associated screening services provided across several health care sectors. The review examines the evidence-base for the content, provision and efficacy of these screening services in terms of the prevalence of anomalies such as refractive error, amblyopia, binocular vision and colour vision and considers the consequences of their curtailment. Vision screening must focus on pre-school children if the aim of the screening is to detect and treat conditions that may lead to amblyopia, whereas if the aim is to detect and correct significant refractive errors (not likely to lead to amblyopia) then it would be expedient for the optometric profession to act as the major provider of refractive (and colour vision) screening at 5-6 years of age. Myopia is the refractive error most likely to develop during primary school presenting typically between 8 and 12 years of age, thus screening at entry to secondary school is warranted. Given the inevitable restriction on resources for health care, establishing screening at 5 and 11 years of age, with exclusion of any subsequent screening, is the preferred option.

Adolescent↗

PubMed2006

Subtle binocular vision anomalies in migraine.

A literature review reveals old references to an association between migraine headache and binocular vision anomalies, but a lack of scientific evidence evaluating these claims. In a masked case control study, we investigated binocular vision using standard clinical tests in people with migraine and in controls. Some test results suggest that heterophoria and fixation disparity are more common in the migraine group. The migraine group also had slightly reduced stereopsis. We found significant correlations between some migraine variables and some binocular vision variables (e.g., duration of worst headache and impaired stereopsis) but our analyses do not suggest that a causal relationship is likely. In conclusion, people with migraine have on average a slightly higher prevalence of heterophoria and aligning prism, and reduced stereopsis compared with controls. However, the differences are subtle and our data do not support the use of binocular vision interventions prescribed solely on the basis of the presence of migraine.

Adult↗

PubMed2003

The effects of intermittent vision on prehension under binocular and monocular viewing.

The aim of the present study was to examine the effects of intermittent binocular and monocular vision on the preparation and execution of the transport and grasp phases of prehension, and hence the temporal limit of binocular and monocular integration. Participants in two groups (speed or accuracy) performed prehensile movements of two amplitudes (20 and 40 cm) to either a large or small object (6 x 6 x 2 and 6 x 4x 2 cm) under conditions of binocular and monocular viewing. The interval between visual samples was manipulated with liquid crystal goggles (continuous vision, 20on/60off, and 20on/120off ms). A kinematic analysis indicated that participants modified variables associated with the preparation and execution of prehension in the intermittent vision conditions when instructed to emphasize accuracy. Participants instructed to emphasize speed, modified variables associated with the preparation phase only. The impact of intermittent vision was similar under binocular and monocular viewing. Thus, for prehension, it appears that consecutive binocular or monocular samples need to occur less than 60 ms apart in order to be fully integrated for limb control.

Adult↗

PubMed1987

Assessment of the Catford drum in visual acuity testing and its use as a measurement of visual performance in low-vision patients.

Objective measurements of visual acuity were determined with the Catford drum in 82 eyes of patients in our Low-Vision Clinic who typically suffered from visual loss due to macular disease. The results were compared with subjective measurements of visual acuity by the Snellen chart. The findings indicated a significant overestimation of Snellen visual acuities by the Catford drum in 90.2% of eyes tested by a factor of 1.05 to 20.0, average 4.73. The correlation coefficient for the study was +0.40. This differs from the original results of Catford and Oliver in 1971. In addition, the Catford drum was used on follow-up visits in the same patients to assess 'visual performance'. The initial results showed an improvement in visual acuities when the Catford drum was used in 12 of 15 patients, while the Snellen acuities remained stable when retested after one month of basic instruction and use of standard low-vision aids. This improvement in 'Catford' acuity was by a factor of 0.3 to 10.0, average 4.08. This is thought to represent the patient's ability to learn the use of eccentric viewing or parafoveal retinal areas for vision. It confirms previous intuitive findings and helps to explain why low-vision patients seem to function at a higher level than expected from their Snellen visual acuities.

Follow-Up Studies↗

PubMedDate not supplied

Vision, visual-information processing, and academic performance among seventh-grade schoolchildren: a more significant relationship than we thought?

OBJECTIVE: To compare visual and visual-information processing skills between children with and without mild reading and academic problems and examine the incidence of visual deficits among them. METHOD: Seventy-one seventh graders classified as proficient (n = 46) and nonproficient (n = 25) readers were compared with respect to scores on an accepted vision screening, on tests of visual-perception, visual-motor integration, and academic performance. Further, academic performance and visual-information processing were compared between children who failed and passed the vision screening. RESULTS: Visual deficits were found in 68% of the participants, and among significantly more boys than girls. Nonproficient readers had significantly poorer academic performance and vision-screening scores than the proficient readers. Participants who passed the visual screening performed significantly better in visual perception than those who failed. CONCLUSION: Visual function significantly distinguishes between children with and without mild academic problems, as well as on visual-perception scores. The high occurrence of visual deficits among participants warrants consideration of vision deficits among schoolchildren with academic performance difficulties.

Achievement↗

PubMed1991

Binocular contrast sensitivity testing for low vision patients.

Contrast sensitivity testing is often included in primary care and low vision examinations. This test is designed to provide information regarding the quality of a patient's vision. This clinical study provides a method to assess the binocularity of a low vision patient with contrast sensitivity testing. The method allows the practitioner to determine if monocular or binocular conditions are optimal for the use of a near low-vision device.

Adult↗

PubMed1997

Vision profile of the athletes of the 1995 Special Olympics World Summer Games.

BACKGROUND: Special Olympics were organized in 1968 by Eunice Shriver as a program of physical fitness for individuals with mental handicaps. Numerous epidemiologic studies report an increase in visual problems in this population. METHODS: A comprehensive vision screening was conducted at the 1995 Special Olympic World Summer Games to identify the prevalence of visual anomalies in this select group. Testing included visual acuity, refractive error, ocular motor skills, stereopsis, color vision, contrast sensitivity, eye-hand coordination, eye-foot coordination, and an ocular health evaluation. RESULTS: Nine hundred five special athletes, ranging in age from 8 to 58 years, participated in the screening. More than 65% of the participants had not received eye care for more than 3 years. The most commonly reported symptom was difficulty in seeing. Other ocular health problems included refractive errors, poor distance monocular acuity, and strabismus. CONCLUSION: The results of the study indicate that Special Olympians have a high prevalence of vision anomalies that may go undetected. This population demonstrates a high prevalence of refractive errors, decreased visual acuity, ocular health problems, and strabismus. In addition, based on the number of individuals who have not received eye care within the last year, there is a need to increase the availability of vision care to these and other people with mental retardation.

Adolescent↗

PubMed2001

Effects of low-level occupational exposure to styrene on color vision: dose relation with a urinary metabolite.

To investigate the threshold effects of chronic low-level occupational exposure to styrene on color vision, we examined color discrimination in 105 male workers exposed to styrene (mean age 37.7 years; mean length of exposure 6.2 years; mean urinary concentration of mandelic acid 0.21 g/L) and in 117 referents (mean age 37.7 years). We also assessed the effects of styrene by examination of the nature of the relation between disorders of nervous function and age, alcohol consumption, and other variables. A standardized questionnaire was adopted to collect information about work history, occupational or nonoccupational solvent exposure, alcohol consumption, and drug use. Color vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the color confusion index (CCI). There was a dose-dependent relationship between the urinary concentration of mandelic acid and color vision loss. The CCIs of the subgroups whose urinary mandelic acid levels were 0.1-0.2 and >0.2 g/L were significantly higher than those of each referent group (P<0.05 and P<0.01, respectively), but not in the subgroup whose urinary mandelic acid level was lower than 0.1 g/L. Our study suggests that a low level of styrene, presumably 0.1-0.2 g/L, involves the risk of inducing adverse effects on color vision. After confounding factors were adjusted for, the urinary mandelic acid level had a significant positive relationship with color vision.

Adult↗

PubMedDate not supplied

Changes of color vision in ocular hypertension.

Fifty-six ocular hypertension (OHT) patients were examined for 2-3 days in the Eye Clinic of Kuopio University Hospital. No glaucomatous changes were found. Twenty-seven of them were found to have several risk factors for developing glaucoma and medication was started. Twenty-nine of the patients did not show risk factors and had no medication. Color vision was examined with the Farnsworth-Munsell 100 (FM 100) hue test and Besançon anomalometer, later Color Vision Meter 712 at the beginning of the study and 3 years later. None of the 56 patients showed any glaucomatous changes after 3 years of the study. In the treatment group, the FM 100 test showed significantly (paired t-test, p = 0.004) improved error scores after 3 years. In the non-treatment group, 19 patients did not develop risk factors; they had no significant changes in the color vision results. In 10 patients of the non-treatment group, risk factors had developed with elevated intraocular pressure and medication was started for them after 3 years. Their color vision results in the blue anomalous quotient (AQ) of the anomalometer had significantly shifted to the blue part of the equation (paired t-test, p = 0.04). The other color vision results had not changed significantly. The significantly improved FM 100 scores in the treatment group could mean, that the treatment has a beneficial effect for the OHT eyes at risk for developing glaucoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗