Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VISION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed1996

Vision in albinism.

PURPOSE: The purpose of this investigation was to study vision in albinism from 3 perspectives: first, to determine the characteristics of grating acuity development in children with albinism; second, to study the effect of illumination on grating acuity; and third, to define the effect of melanin pigment in the macula on visual acuity. METHODS: I. Binocular and monocular grating acuity was measured with the acuity card procedure in 40 children with albinism during the first 3 years of life. Recognition acuity was eventually measured in 27 of these patients. Ocular pigment was documented by a previously established method of grading iris transillumination and macular transparency. II. Grating acuity under standard and increased illumination levels was measured in 20 adults with albinism (group I) compared with that in 20 adults with nystagmus due to conditions other than albinism (group II) and 20 adults without ocular abnormalities (group III). Recognition acuity measured with the ETDRS charts was also recorded for each group. III. Best-corrected binocular acuity was measured in 29 patients with albinism who were identified with melanin pigment in their maculas by direct ophthalmoscopy. RESULTS: I. Both binocular and monocular grating acuity was reduced 2 to 3 octaves below the norm for ages 6 months to 3 years. Limited data available in the first 6 months of life did not show failure of vision to develop. Grating acuity measurements overestimated eventual recognition acuity. Mean recognition acuity was 20/111. A relationship between grating acuity development and presence or absence of ocular pigment was not found. II. Grating acuity was significantly better for groups I and II under the condition of increased illumination (P < .03). For patients with albinism, grating acuity under standard illumination was significantly better than recognition acuity (P < .001). For all groups, grating acuity under increased illumination was significantly better than recognition acuity (P < .01). III. Mean recognition acuity in patients with albinism and melanin pigment in their maculas (20/47) was significantly better than measured recognition acuity in Project I (P < .001). All had foveal hypoplasia, but 8 patients had an incompletely developed annular reflex in the macula, 6 patients showed stereoacuity, and 3 patients had no nystagmus. CONCLUSIONS: I. Grating acuity development in albinism seems to progress along a curve that is asymptotic to visual development in a normal population. II. Increasing illumination does not reduce grating acuity in patients with albinism. Grating acuity overestimates recognition acuity in these patients. III. Ophthalmoscopic detection of melanin pigment in the macula in patients with albinism is associated with better vision.

Adolescent↗
PubMed1997

Vision screening, eye examination and risk assessment of display screen users in a large regional teaching hospital.

In January 1993 the Royal Group of Hospitals Trust, which employs approximately 5000 staff, implemented the Health and Safety (Display Screen Equipment) Northern Ireland Regulations (1992). During 1994 all regular display screen equipment users were offered a vision screening test. In total 571 employees were screened using computerized vision screening software (City Visual Systems Ltd). Risk assessments were completed for 293 display screen work-stations. One hundred and twelve full eye examinations, carried out by optometrists, were performed on those who failed vision screening and on those who specifically requested an optometric assessment. Results indicate that whereas the proportion of users experiencing visual and general symptoms differed markedly from department to department (28-82%), the median number of individuals failing the screening test was 25% (range 9-40%). Those involved in uninterrupted display screen equipment work for prolonged periods reported visual and general work-related symptoms twice as frequently as those who spent less time working with DSE. The outcome of full eye examinations confirmed that less than 5% of display screen users required spectacles solely for display screen use. Work-station analysis indicated that ergonomic problems were common. The authors conclude that the successful management of health risks from display screen equipment requires simultaneous attention to work-place design, working patterns and eye care.

Adolescent↗
PubMed1997

[Evaluation of acquired color vision defects by means of the two equation method in primary open-angle glaucoma with normal pressure and in patients from the risk group].

PURPOSE: To evaluate acquired color vision defects in glaucoma patients and glaucoma suspects. MATERIAL AND METHODS: 52 subjects (102 eyes) divided into four groups (with primary open angle glaucoma, normal tension glaucoma, ocular hypertension and with glaucoma-like optic disc) were examined with the IF-2 All-Color Anomaloscope. In all cases both the red-green equation of Rayleigh and the blue-green equation of Moreland were tested and three variables were determined: setting (matching) range (SR), calculated mid point (matching mid point) (CMP) and anomalous quotient (AQ) as compared to control group. RESULTS: No significant changes were found in the variables of the Rayleigh equation. However, in the blue-green equation SR was significantly enlarged in all tested groups and CMP was significantly shifted towards the short wavelength end of the match in first three groups. These results indicate a diminution of the color discriminating sensitivity in the short wavelength half of the visible spectrum and diminution of the blue cone sensitivity in glaucoma patients as well as in ocular hypertension (p < 0.001). In patients with glaucoma-like optic disc the setting range was enlarged in less degree (p < 0.01) without changes in the remaining variables (p > 0.05) what may be indicative of early stage of disease before the perimetric changes. CONCLUSION: Blue-green colour vision testing with the anomaloscope may serve as an additional test in the diagnostics of glaucoma. Glaucoma suspects with blue colour vision disturbances require the most careful investigation and if need be the recommendation of early treatment.

Adolescent↗
PubMed2001

A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.

BACKGROUND: Observational and experimental data suggest that antioxidant and/or zinc supplements may delay progression of age-related macular degeneration (AMD) and vision loss. OBJECTIVE: To evaluate the effect of high-dose vitamins C and E, beta carotene, and zinc supplements on AMD progression and visual acuity. DESIGN: The Age-Related Eye Disease Study, an 11-center double-masked clinical trial, enrolled participants in an AMD trial if they had extensive small drusen, intermediate drusen, large drusen, noncentral geographic atrophy, or pigment abnormalities in 1 or both eyes, or advanced AMD or vision loss due to AMD in 1 eye. At least 1 eye had best-corrected visual acuity of 20/32 or better. Participants were randomly assigned to receive daily oral tablets containing: (1) antioxidants (vitamin C, 500 mg; vitamin E, 400 IU; and beta carotene, 15 mg); (2) zinc, 80 mg, as zinc oxide and copper, 2 mg, as cupric oxide; (3) antioxidants plus zinc; or (4) placebo. MAIN OUTCOME MEASURES: (1) Photographic assessment of progression to or treatment for advanced AMD and (2) at least moderate visual acuity loss from baseline (> or =15 letters). Primary analyses used repeated-measures logistic regression with a significance level of.01, unadjusted for covariates. Serum level measurements, medical histories, and mortality rates were used for safety monitoring. RESULTS: Average follow-up of the 3640 enrolled study participants, aged 55-80 years, was 6.3 years, with 2.4% lost to follow-up. Comparison with placebo demonstrated a statistically significant odds reduction for the development of advanced AMD with antioxidants plus zinc (odds ratio [OR], 0.72; 99% confidence interval [CI], 0.52-0.98). The ORs for zinc alone and antioxidants alone are 0.75 (99% CI, 0.55-1.03) and 0.80 (99% CI, 0.59-1.09), respectively. Participants with extensive small drusen, nonextensive intermediate size drusen, or pigment abnormalities had only a 1.3% 5-year probability of progression to advanced AMD. Odds reduction estimates increased when these 1063 participants were excluded (antioxidants plus zinc: OR, 0.66; 99% CI, 0.47-0.91; zinc: OR, 0.71; 99% CI, 0.52-0.99; antioxidants: OR, 0.76; 99% CI, 0.55-1.05). Both zinc and antioxidants plus zinc significantly reduced the odds of developing advanced AMD in this higher-risk group. The only statistically significant reduction in rates of at least moderate visual acuity loss occurred in persons assigned to receive antioxidants plus zinc (OR, 0.73; 99% CI, 0.54-0.99). No statistically significant serious adverse effect was associated with any of the formulations. CONCLUSIONS: Persons older than 55 years should have dilated eye examinations to determine their risk of developing advanced AMD. Those with extensive intermediate size drusen, at least 1 large druse, noncentral geographic atrophy in 1 or both eyes, or advanced AMD or vision loss due to AMD in 1 eye, and without contraindications such as smoking, should consider taking a supplement of antioxidants plus zinc such as that used in this study.

Aged↗
PubMed1996

Vision in Leber congenital amaurosis.

OBJECTIVE: To determine if vision changed with age in infants and children with Leber congenital amaurosis. PATIENTS: Grating acuity and dark-adapted visual thresholds were tested in 36 patients with Leber congenital amaurosis. Longitudinal assessments were obtained for 24 patients and analyzed for significant changes over time. Visual acuity and threshold and the courses of visual acuity and threshold were examined for significant associations with hyperopia, fundus appearance, and complicated vs uncomplicated status. RESULTS: Measurable grating acuities ranged from 0.16 to 6 cycles per degree (median, 1.27 cycles per degree or about 20/500), and dark-adapted visual thresholds were elevated 1.0 to 5.6 log units (median, 2.33 log units). Eighteen patients never had demonstrable grating acuity, and 12 had no light perception. Among those with serial tests, visual acuity improved or remained stable in 10 patients and declined in 4. Dark-adapted visual thresholds were stable in those with improving or stable visual acuities but worsened in 5 patients, including the 4 whose visual acuity worsened. No significant associations of visual acuity, dark-adapted visual threshold, the course of visual acuity, or the course of dark-adapted visual threshold with hyperopia, fundus appearance, or complicated vs uncomplicated status were found. CONCLUSIONS: Visual capabilities varied widely. Vision was stable in the majority by longitudinal measures but increased in a few and deteriorated in others. Neither ocular characteristics nor complicated vs uncomplicated status predicted visual function. Thus, if vision and its course are to be known in a patient with Leber congenital amaurosis, it must be tested.

Aging↗
PubMed2000

Acute onset of decreased vision and hearing traced to hemodialysis treatment with aged dialyzers.

CONTEXT: A recent event in which 7 patients at 1 hospital developed decreased vision and hearing, conjunctivitis, headache, and other severe neurologic symptoms 7 to 24 hours after hemodialysis drew attention to the issue of the long-term integrity of dialysis machines and materials. OBJECTIVE: To determine the cause of the adverse reactions that occurred during this event. DESIGN, PATIENTS, AND SETTING: Retrospective cohort study of all 9 patients who received hemodialysis at hospital A on September 18, 1996, the day of the outbreak. A case-patient was defined as any hospital A patient with acute onset of decreased vision and hearing and conjunctivitis after dialysis on that day. Non-case-patients were all others who underwent dialysis at hospital A on that day but did not develop adverse reactions. In an attempt to reproduce the conditions of the event, cellulose acetate dialysis membranes of various ages were retrieved from other sources and tested for physical and chemical degradation, and degradation products were identified, characterized, and injected intravenously into rabbits. MAIN OUTCOME MEASURES: Clinical signs and symptoms, time to resolution of symptoms, mortality, and dialyzer type and age, for case- vs non-case-patients. RESULTS: Seven of the 9 patients met the case definition. In addition to diminished vision and hearing, conjunctivitis, and headache, some case-patients had blood leak alarm activation (n=6), confusion/lethargy (n=5), corneal opacification (n=4), cardiac arrest (n=2), or other neurologic signs and symptoms. One case-patient died during hospitalization after the event; 5 of 7 case-patients died within 13 months. Resolution of signs and symptoms varied but persisted more than 3 years or until death in 3 of the 6 patients who survived hospitalization. All case-patients but no non-case-patients were exposed to 11.5-year-old cellulose acetate dialyzers (all of these dialyzers were discarded by the hospital before our investigation). Laboratory investigation of field-retrieved 0- to 13.6-year-old dialyzers of similar type indicated significant chemical degradation in the older membranes. In vivo injection of extracts of membrane degradation products produced iritis and hemorrhages in rabbits' eyes. CONCLUSIONS: Severe patient injury was associated with exposure to aged cellulose acetate membranes of dialyzers, allowing cellulose acetate degradation products to enter the blood. Clinicians should be aware that aged cellulose acetate membranes may cause severe adverse reactions.

Acute Disease↗
PubMed2000

A lantern color vision test for the rail industry.

BACKGROUND: Correct identification of wayside signal colors is critical for safe operation of railway equipment. However, evaluating color discrimination using just a screening test may not be occupationally relevant. METHODS: A lantern test (CNLAN) was designed to provide a functional assessment of color discrimination for the rail industry. It was validated against a simulated field trial. 81 individuals with normal color vision and 74 individuals with congenital red-green defects participated. Color vision was classified using the Nagel Anomaloscope. RESULTS: Using a criterion based on the worst-normal performance, 97% of the individuals with a color vision defect failed both the CNLAN and simulation trial. This value is slightly lower than the 100% who failed both the Ishihara test and simulation. However, the Ishihara test also failed 3.7% of the color-normals who passed both the simulation and lantern, whereas by definition none of the color-normals failed the lantern. CONCLUSIONS: This lantern test provides a reasonable functional assessment of one's ability to identify rail signal colors; especially when a strict failing criterion is applied to screening tests.

Accidents, Occupational↗
PubMed1976

Active power and causal flow in Aristotle's theory of vision.

Aristotle's theory of vision has been characterized as naive, incommensurate with his theory of audition, and of historical interest only. This view is based on an analysis which fails to acknowledge the role of the concepts acting upon and active power in the theory. The meaning of these terms and the role Aristotle assigned them in vision and in sensation generally is demonstrated. It is argued that with the inclusion of these concepts (1) the theory of vision is sufficiently sophisticated and modern to be more than comparable with more recent perceptual theorizing, and (2) theoverall integrity of Aristotle's sensory philosophy is preserved. It is further argued that given the cohesiveness and comprehensiveness of Aristotle's psychological works, more attention should be given them by modern psychologists.

Greece, Ancient↗
PubMed1994

Treatment of abnormal eye movements that impair vision: strategies based on current concepts of physiology and pharmacology.

Certain abnormal eye movements, especially pathological nystagmus, degrade vision and cause illusory motion of the seen environment. These symptoms are due to excessive movement of images of stationary objects on the retina. Recently, the pathophysiology underlying several types of nystagmus and saccadic oscillations was better defined by the development of animal models and by experimental pharmacological studies. Despite this, few reliable therapies are currently available for these abnormal eye movements. In clinical studies, a number of drugs reportedly helped individual patients, but few drugs have been subjected to double-blind trials. An alternative approach to pharmacological suppression of abnormal eye movements is optical stabilization of images on the retina, which is helpful in selected patients. Weakening of the extraocular muscles, using botulinum toxin or surgery, is prone to cause diplopia and may induce plastic-adaptive changes that render the effect temporary. In some patients, treatment of an underlying condition, such as the Arnold-Chiari malformation, reduces nystagmus and improves vision. There is a need for multicenter trials to evaluate systematically potential treatments of abnormal eye movements that impair vision.

Animals↗
PubMedDate not supplied

Molecular genetics of Drosophila vision.

The fruitfly, Drosophila melanogaster, is an excellent organism for dissecting the components of vision genetically. Many mutations have been generated that affect a diversity of processes important in vision. Through a combined application of molecular and genetic approaches many of the genes important in Drosophila vision are now being identified.

Animals↗
PubMed2004

Combined effect of vision and hearing impairment on depression in elderly Chinese.

BACKGROUND: Sensory impairment and depression are common in old age and the relation between depression and vision as well as hearing impairment have been established. However, few studies have directly compared their effects and examined the impact of dual sensory loss. The purpose of this study is to compare impacts of self-reported hearing and vision loss as well as the effect of double sensory impairment on depression. METHOD: This article analyzes cross-sectional data collected from a representative community sample of 2,003 Chinese elderly people aged 60 or above in Hong Kong. Respondents were interviewed in a face-to-face format and data including vision and hearing impairment, socio-demographic variables, health indicators, family support, and depression were obtained. RESULTS: Logistic regression analyses revealed that visual impairment was significantly related to depression even after age, gender, marital status, education, self-reported health status, the presence of 11 diseases, functional limitation and family support were controlled but hearing loss was not. Hearing impairment did not add to the likelihood of depression where visual impairment was already present. CONCLUSION: The impact of visual impairment on psychological well-being among elderly Chinese is more robust than hearing loss. Therefore, aged care service practitioners must take this risk factor into consideration in their preventive intervention and treatment for psychological well-being.

Age Distribution↗
PubMed2006

Vision and oral health needs of individuals with intellectual disability.

Over the past 20 years, there has been an increased emphasis on health promotion, including prevention activities related to vision and oral health, for the general population, but not for individuals with intellectual disability (ID). This review explores what is known about the prevalence of vision problems and oral health conditions among individuals with ID, presents a rationale for the increased prevalence of these conditions in the context of service utilization, and examines the limitations of the available research. Available data reveal a wide range of prevalence estimates for vision problems and oral health conditions, but all suggest that these conditions are more prevalent among individuals with ID compared with the general population, and disparities exist in the receipt of preventive and early treatment for these conditions for individuals with ID. Recommendations for health improvement in these areas include better health planning and monitoring through standardized population-based data collection and reporting and increased emphasis on health promotion activities and early treatment in the healthcare system.

Adolescent↗
PubMed1986

Color vision tests to identify elevated digoxin levels.

The purpose of this study was to determine the usefulness of color vision screening in identifying patients with elevated digoxin levels (greater than or equal to 2.0 ng/ml). Test-retest color vision measurements were obtained on 56 subjects with elevated digoxin levels and 93 non-digoxin subjects. Two tests, the Ishihara and Sahlgren's Saturation Test (SST), identified digoxin levels of 2.9 ng/ml or more. These tests also yielded a high percentage of improved retest scores among subjects with elevated digoxin levels (greater than or equal to 2.7 ng/ml) of more than 4-days duration and a low percentage of improved retest scores among the non-digoxin group. The Ishihara, SST, and other bedside color vision tests may prove useful in the routine monitoring of patients on digoxin therapy, especially those with a high risk for toxicity.

Adult↗
PubMed1991

Results obtained with low vision aids. A retrospective study.

In this retrospective study of 261 patients (181 female and 80 male) the results obtained in a special low vision clinic are described. The mean age of the patients was 73.5 years (range 16-95 years). Visual acuity of the best eye was less than or equal to 0.08 in 26 patients (10.0%); better than 0.08 but less than or equal to 0.25 in 130 (50%); 0.30 in 62 (23.8%) and better than 0.30 in 42 patients (16.1%). Persons with a visual acuity better than 0.30 either could not read normal print or had restricted visual fields. Main causes of visual impairment were macular degeneration (38.9%), diabetic retinopathy (16.1%), glaucoma (8.4%) and cataract (7.4%). Low vision aids could be prescribed for 208 persons (79.7%). Follow-up of an average of 12 months (range, 3-22 months) was carried out in 250 cases (96%). In this period 24 patients (9%) died. At least 161 persons (62%) used their aids regularly, i.e. 77% of the patients who were given a low vision aid.

Adolescent↗
PubMed1994

Prevalence and causes of blindness and low vision in the Casteldaccia Eye Study.

In a population-based survey performed on the middle-aged and elderly population of Casteldaccia, Sicily, we found that the prevalence of blindness was 0.47% and the prevalence of low vision 1.22%. Unilateral blindness affected 2.81% of the population and unilateral low vision 4.12%. Visual impairment was much more frequently seen in subjects aged 70 years or more than in younger persons. The main cause of visual impairment was cataract, followed by amblyopia, which was responsible for many cases of unilateral low vision.

Adult↗
PubMed1995

A behavioral model of excitotoxicity: retinal degeneration, loss of vision, and subsequent recovery after intraocular NMDA administration in adult rats.

To establish a new behavioral animal model of excitotoxicity, we injected adult rats intraocularly with a single dose of 2, 20, or 100 nmol of N-methyl-D-aspartate (NMDA). We quantified visual impairment by plotting the size of the visual field in which the rats successfully oriented towards a small, moving target. In comparison to the saline-injected (contralateral) control side, the side injected with 2 nmol of NMDA was not significantly impaired. When injected with higher doses, the rats were nearly blind immediately after surgery, with only about 20% (20 nmol NMDA) or 10% (100 nmol NMDA) of residual vision. Within about 3 weeks, however, visual performance returned to near-normal levels. Simultaneous intraocular administration of a non-competitive NMDA-antagonist, MK-801 (1 nmol), resulted in complete behavioral protection. NMDA administration led to a dose-dependent loss of cells within the ganglion cell layer, as assessed in whole-mounted retinae which were retrogradely labelled with horseradish peroxidase (HRP). Whereas 2 nmol of NMDA led to the loss of about 30% of retinal ganglion cells (RGCs), at higher NMDA doses only 13% of the RGCs survived. After the injection of 20 nmol of NMDA, large-diameter RGCs (> 22 microns) survived the lesion to a greater extent than small diameter cells (8-21 microns); at 100 nmol cells of all diameters were equally affected. The number of Nissl-stained cells with small diameters (< 11 microns), presumed to be displaced amacrine cells, was also affected by NMDA, although to a lesser degree. Analysis of behavioral performance (vision score) and the number of cells in the retina revealed a correlation of r = 0.76 between visual performance and the number of HRP-filled RGCs immediately after surgery. Lower correlations were found between visual performance and cells stained with Nissl of diameters smaller than 11 microns (presumed RGCs without retinofugal connections; r = 0.55 and r = 0.58, respectively). Because of the spontaneous recovery of vision, all correlations declined to values near 0 after 3 weeks. Thus, despite a dramatic loss of RGCs following NMDA administration, visual deficits recover significantly in adult rats within 2-3 weeks.

Animals↗
PubMed1986

A self-similar stack model for human and machine vision.

A new model is proposed that not only exhibits the major properties of primate spatial vision but also has a structure that can be implemented efficiently in a machine vision system. The model is based on a self-similar stack structure with a spatial resolution that varies with eccentricity. It correctly reproduces the visual cortical mapping function, yet it has the important attribute that it can produce invariant responses to local changes in the size and position of image features. By proposing a novel purpose for cortical "bar-detectors", the model can also produce invariance to more general distortions. The structure of the model allows efficient hierarchical search to be made and it naturally embraces the concept of "attention area". Exploitation of this model has already confirmed these properties and has also revealed its robust ability to control the focus and gain of machine vision systems.

Cybernetics↗
PubMed1992

Absence of blue-yellow color vision loss among workers exposed to toluene or tetrachloroethylene, mostly at levels below occupational exposure limits.

Possible color vision loss was examined with Lanthony's new color test and Ishihara's color vision test in 261 solvent workers and 120 controls (48 men and 72 women). The solvent workers were exposed to either predominantly toluene [46 ppm as geometric mean (GM); 63 men and 111 women], tetrachloroethylene alone (13 ppm; 30 men and 34 women), or a mixture (14 men and 9 women) of tetrachloroethylene (12 ppm) and trichloroethylene (7 ppm). The only instances of color vision loss that were detected in either the exposed workers or the controls were six cases of red-green loss (all in men). These six cases of red-green loss showed an unbiased distribution between the exposed workers and the nonexposed controls.

Adult↗