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 685 records · Page 38Linked to original sources
PubMed1993

Colour vision in retinitis pigmentosa. Influence of cystoid macular edema.

In retinitis pigmentosa patients the effect of cystoid macular edema on colour vision was studied. The occurrence of cystoid macular edema decreases with increasing colour vision defect. The mutual proportion of the main types of colour vision defects remains stable until visual acuity has dropped to 0.5; at lower VA levels the number of red-green defects increases. Neither the finding of a blue-yellow colour vision defect in FM100 Hue testing nor the appearance of anomaloscopic pseudoprotanomaly is influenced by cystoid macular edema. The authors conclude that cystoid macular edema in retinitis pigmentosa patients mainly affects visual acuity and not colour vision. They also noted a familial occurrence of cystoid macular edema.

Color Perception↗
PubMed2006

Visual-vestibular interaction during goal directed locomotion: effects of aging and blurring vision.

Normal vision overrides perturbed vestibular information for the optimization of performance during goal directed locomotion, suggesting down-regulation of vestibular gain. However, it is not known if the responses to vestibular perturbation are accentuated when vision is impaired. Furthermore, both visual and vestibular systems deteriorate with age. It is not clear, however, how age-related decline in these sensory systems influences visual-vestibular interaction. Therefore, the dual purpose of the present study was to investigate the effects of aging and blurring vision, that simulated the consequences of cataracts, on visual-vestibular interaction. Young and healthy elderly walked to a target located straight ahead with either normal or blurring vision. On randomly selected trials vestibular system perturbation was achieved by applying transmastoidal galvanic vestibular stimulation (GVS). Two different galvanic stimulation intensities were used to provide insight into scaling effect of vestibular perturbation on locomotor performance and how age and vision influences this scaling effect. Maximum path deviation, frontal trunk tilt and postural coordination in the mediolateral direction were evaluated. The magnitude of the path deviation and the trunk tilt response were scaled to the magnitude of the vestibular perturbation in older adults independent of the visual condition. Older participants demonstrated increased coupling of the head and trunk segments irrespective of visual and vestibular perturbations. The results suggest that when visual information was available, the vestibular input reweighting was less effective in older individuals, as shown by the scaled responses to the GVS intensities and the inability to converge efficiently towards the target.

Acoustic Stimulation↗
PubMed1985

Color vision deficiencies in two cases of digoxin toxicity.

Color vision deficiencies are a common sign of digoxin intoxication and color vision testing can be used to diagnose digoxin toxicity. We tested two patients, a 79-year-old man and a 61-year-old man, with digoxin toxicity by means of the Farnsworth-Munsell 100-hue test, AOH-R-R plates, and Ishihara plates. Initial testing disclosed both red-green and blue-yellow color vision deficiencies. These improved when digoxin levels diminished. The deficiencies were superimposed on preexisting acquired and congenital deficits. As serum digoxin levels decreased, the color vision deficiencies lessened on all three tests. The Farnsworth-Munsell 100-hue test gave the best quantifiable measure of color vision deficiencies, but proved difficult to use for routine bedside testing.

Aged↗
PubMed1992

Noise and the absolute thresholds of cone and rod vision.

Literature data on light detection by cone and rod vision at absolute threshold are analysed in order (1) to decide whether the threshold performance of dark-adapted cone vision can, like that of rod vision, be consistently explained as limited by noise from a "dark light"; (2) to obtain comparable estimates of the dark noise and dark light of (foveal) cones and (peripheral) rods. The dark noise was estimated by a maximum-likelihood procedure from frequency-of-seeing data and compared with the dark light derived from increment-threshold functions. In both cone and rod vision, the estimated dark noise coincides with Poisson fluctuations of the estimated dark light if 17% (best estimate) of lambda max-quanta incident at the cornea produce excitations. At that fraction of quanta exciting, dark lights are equivalent to 112 isomerisations per sec in each foveal cone and 0.011 isomerisations per sec in each rod. It is concluded that (1) the threshold performance of dark-adapted cone as well as rod vision can be consistently described as noise-limited, but not by postulating a multi-quantum coincidence requirement for single receptors; (2) the underlying intrinsic activity in both the cone and the rod system is light-like as regards correspondence between noise effect and background adaptation effect. One possibility is that this activity is largely composed of events identical to the single-photon response, originating in the visual pigment, in cones as well as in rods.

Dark Adaptation↗
PubMed1994

The molecular genetics and evolution of primate colour vision.

Until recently, the genetic basis of colour vision could only be inferred from measuring the colour vision of family groups. However, in the past few years the sites of the genes for visual pigments have been located and sequenced. The genes that specify the opsins for the rod and short-wavelength cone pigments are located on the third and seventh chromosomes, respectively. In Old World primates the genes for the middle- and long-wavelength pigments are located on the q arm of the X chromosome in a head-to-tail array. The close sequence similarity of the two genes on the X chromosome leads to a high frequency of unequal inter- and intragenic recombination leading to gene deletion or the creation of hybrid genes. In New World primates there is only a single locus on the X chromosome for a middle- to long-wavelength cone pigment. However, three alleles can occur at this locus and each codes for a slightly different cone pigment. As a result there are three types of male dichromat and three types of female dichromat and trichromat in each species. Colour vision in New World primates might be an intermediate stage between the uniform dichromacy of non-primate mammals and the uniform trichromacy of Old World primates. Alternatively, colour vision in New World primates might be an adaptation to allow a wide variety of colour-vision types within a single family group.

Alleles↗
PubMedDate not supplied

Colour vision loss among disabled workers with neuropsychological impairment.

Test performance on a neurobehavioural battery was examined with respect to acquired colour vision loss among patients with a history of neurotoxin exposure. The study group included 14 men and 7 women with clinically diagnosed neuropsychological impairment (mean age: 41.3 +/- 8.1 years; mean educational level: 13.4 +/- 1.4 years). Verbal and visual ability, memory and psychomotor function were assessed with the California Neuropsychological Screening Battery. Colour vision was assessed with the Lanthony D-15 desaturated colour arrangement panel. Acquired dyschromatopsia was present in 17 patients (80.9%), 11 of whom manifested patterns of Type II colour vision loss. Simple regression analysis of neuropsychological test performance with respect to colour vision loss, using age-adjusted Z-scores, revealed significant relationships (p less than or equal to 0.05) solely for tests which rely heavily on the visual system. Significant differences in visual task test scores were also observed with the type of dyschromatopsia (Kruskal-Wallis, p less than or equal to 0.05). These findings suggest that poor performance on visual tasks and colour vision loss may both result from damage to neuro-ophthalmic pathways or that loss of integrity of the peripheral visual pathways may affect visual task performance. The authors propose that visual testing should be incorporated into neurobehavioural test batteries.

Adult↗
PubMed2004

The determinants of participation in activities of daily living in people with impaired vision.

PURPOSE: To investigate the determinants of participation in daily activities in people with impaired vision using the Impact of Vision Impairment (IVI) instrument. DESIGN: Cross-sectional study. METHODS: We recruited 319 participants with no vision rehabilitation history, distance visual acuity (VA) <6/12 (better eye), the ability to converse in English, and 18 years or older. Participants completed the 32-item IVI questionnaire and provided demographic, personal, cultural, and environmental details on vision-related functioning. Visual acuity data were either abstracted from the participants' files or assessed by qualified personnel. Participants also completed the SF-12 to evaluate physical (PCS-12) and mental health (MCS-12). RESULTS: The areas of greatest restriction of participation were associated with reading, outdoor mobility, participation in leisure activities, and shopping. In stepwise linear regression presenting VA, the PCS-12 and MCS-12 explained the variance in leisure and work (60 participants or 19%), consumer and social interaction (92 participants or 30%), household and personal care (76 participants or 24%), mobility (92 participants or 30%), emotional reaction to visual loss and (106 participants or 33%), and total IVI score (114 participants or 36%). Having age-related macular degeneration contributed marginally to the IVI domains and total score (P <.05-.01), except for the emotional domain. Belonging to a social group explained 3% and 2% of the variance in the consumer and social interaction and emotional domains, respectively (P <.05). CONCLUSIONS: Distance VA and physical and mental health explained more than a third of the variance of the total score, suggesting that an intervention aimed at improving quality of life may include strategies to improve not only vision-related rehabilitation but also mental and physical health.

Activities of Daily Living↗
PubMed2006

Improving residual vision by attentional cueing in patients with brain lesions.

Visual attention is crucial for almost all processes of visual perception, particularly when perception is difficult. We were interested in the effects of cueing spatial attention in patients with cerebral lesions who face difficulties in visual perception in areas of residual vision at the border of visual field defects. In 23 patients with visual field loss due to post-geniculate brain lesions, stimulus detection performance and reaction times were mapped with high-resolution computer-based perimetry. A cueing procedure using Gestalt completion to attract attention to areas of residual vision was implemented in this test and performance compared in attended and unattended conditions. Stimulus detection and reaction times in areas of residual vision improved significantly under attended conditions. The extent of this effect depended on the size of areas of residual vision within the cued field. Unexpectedly, facilitation was also observed, though to a lesser extent, in invalid cueing conditions, suggesting an unspecific increase of alertness in unattended areas. Our findings show that top-down influences are relevant for visual field testing. Visuo-spatial attention may change patterns of neural activation and induce short-term plasticity not only in the intact visual system but also in the presence of visual field loss after brain lesions. Attentional cueing induces a co-activation of the lesioned visual system and (intact) attentional networks in the brain inducing immediate facilitation of visual perception. This effect may be relevant for designing new strategies to permanently improve vision during neuropsychological rehabilitation.

Adult↗
PubMed2005

Changes to the subscales of two vision-related quality of life questionnaires are proposed.

BACKGROUND AND OBJECTIVE: Psychometrically sound questionnaires for the assessment of vision-related quality of life (QOL) are scarce. Therefore, the objective was to further validate two vision-related QOL questionnaires in a Dutch population of visually impaired elderly. METHODS: A total of 329 visually impaired older persons referred to low vision services completed the low vision QOL (LVQOL) and Vision-Related Quality of Life Core Measure (VCM1) questionnaires at baseline, after 1-4 weeks (retest), and after 5 months. Confirmatory factor analyses were performed on baseline data. The smallest detectable change (SDC) was assessed, based on the standard error of measurement (SEM). Change scores between the baseline and 5 months follow-up data were related to a general transition question to assess the minimal important change (MIC). Furthermore, the MIC was related to the SDC, to examine whether the MICs were detectable beyond measurement error. RESULTS: The original factor structures could not be confirmed. After omitting items and remodeling, adequate fits were obtained. SDCs comprised at least one quarter of the scale for all scales and subscales on the individual level and exceeded the MICs on every occasion. CONCLUSION: We propose MICs of 5-10 points for the scales and subscales of the LVQOL and VCM1. The questionnaires are not useful in the follow-up of individual patients.

Aged↗
PubMed2004

Functional vision with cataracts of different morphologies: comparative study.

PURPOSE: To evaluate the influence of cataract morphology on the functional vision of patients with age-related cataract and normal macular function and compare subjectively perceived functional impairments to distance visual acuity, reading acuity, and maximum reading speed between cataract types. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: Seventy-five patients awaiting first-eye cataract surgery were asked to characterize their visual difficulties in everyday life using a German version of the VF-14 questionnaire. Cataracts were categorized and graded using the Lens Opacities Classification System III. Monocular and binocular visual acuity and reading performance were determined in randomized order. RESULTS: There were significant differences in functional vision between nuclear cataracts and posterior subcapsular cataracts (PSC); the VF-14 score and the self-reported visual satisfaction were significantly lower in PSC patients (P<.05). Posterior subcapsular cataracts significantly increased self-reported impairment in distance and near vision, although the visual acuity was comparable to that in the other groups (P =.9). Significant differences in functional vision were also seen between PSC and nuclear-cortical cataracts (P<.05). No significant differences in functional vision were found between nuclear cataracts and nuclear-cortical cataracts (P>.05). CONCLUSIONS: The VF-14 questionnaire reliably evaluated functional differences caused by different cataract morphologies; these differences were underestimated when only visual acuity was measured. Patients with PSC had increased functional impairment, indicating that cataract surgical intervention is indicated at an earlier stage in these patients. The significant differences between the morphological types of cataract should be taken into consideration when the benefit of cataract surgery is to be measured on the basis of functional improvement.

Activities of Daily Living↗
PubMed2006

Associations between platelet monoamine oxidase-B activity and acquired colour vision loss in a fish-eating population.

Platelet monoamine oxidase-B (MAO-B) has been considered a surrogate biochemical marker of neurotoxicity, as it may reflect changes in the monoaminergic system in the brain. Colour vision discrimination, in part a dopamine dependent process, has been used to identify early neurological effects of some environmental and industrial neurotoxicants. The objective of this cross-sectional study was to explore the relationship between platelet MAO-B activity and acquired colour discrimination capacity in fish-consumers from the St. Lawrence River region of Canada. Assessment of acquired dyschromatopsia was determined using the Lanthony D-15 desaturated panel test. Participants classified with dyschromatopsia (n=81) had significantly lower MAO-B activity when compared to those with normal colour vision (n=32) (26.5+/-9.6 versus 31.0+/-9.9 nmol/min/20 microg, P=0.030)). Similarly, Bowman's Colour Confusion Index (CCI) was inversely correlated with MAO-B activity when the vision test was performed with the worst eye only (r=-0.245, P=0.009), the best eye only (r=-0.188, P=0.048) and with both eyes together (r=-0.309, P=0.001). Associations remained significant after adjustment for age and gender when both eyes (P=0.003) and the worst eye (P=0.045) were tested. Adjustment for heavy smoking weakened the association between MAO-B and CCI in the worst eye (P=0.140), but did not alter this association for both eyes (P=0.006). Adjustment for blood-mercury concentrations did not change the association. This study suggests a relationship between reduced MAO-B activity and acquired colour vision loss and both are associated with tobacco smoking. Therefore, results show that platelet MAO-B may be used as a surrogate biochemical marker of acquired colour vision loss.

Aging↗
PubMed2006

Noncompliance with vision care guidelines in Latinos with type 2 diabetes mellitus: the Los Angeles Latino Eye Study.

OBJECTIVE: To determine the prevalence of and personal factors associated with noncompliance with American Diabetes Association (ADA) guidelines for vision care in a population-based sample of adult Latinos with type 2 diabetes mellitus (T2DM). DESIGN: Population-based cross-sectional study. PARTICIPANTS: Eight hundred twenty-one Los Angeles Latino Eye Study (LALES) participants with a history of T2DM and a history of treatment for T2DM. METHODS: Detailed interviews, physical examinations, and dilated eye examinations were performed on all participants. Interviews assessed sociodemographic factors, history of diabetes and eye disease, and utilization of health and eye care services. All participants with a self-reported history and treatment of diabetes were asked about health and vision care utilization and diabetes self-care. MAIN OUTCOME MEASURE: Compliance with ADA guidelines for vision care. Noncompliance was defined as having had no dilated eye examination in the previous 12 months. Logistic regression analyses were used to identify personal factors associated with noncompliance. RESULTS: Of 821 individuals who self-reported having T2DM and being on treatment for T2DM, 535 (65%) had not complied with ADA vision guidelines for persons with T2DM. When compared with those with T2DM who complied with ADA guidelines, noncompliers were more likely to be less educated (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1-2.2), to lack health insurance (OR, 2.5; 95% CI, 1.7-3.7), to have had no routine physical examination in the 12 months before the LALES examination (OR, 1.8; 95% CI, 1.3-2.5), and to have a glycosylated hemoglobin level > or = 9.0% (OR, 1.7; 95% CI, 1.1-2.6). CONCLUSIONS: Because timely and appropriate vision care can delay the onset of ocular morbidity, visual impairment, and blindness associated with diabetic retinopathy, our data suggest the need to evaluate intervention programs aimed at a targeted group of Latinos with T2DM--those who have less than a high school education, lack health insurance, have had no routine physical examination in the previous year, and have poorly controlled T2DM.

Aged↗
PubMed1976

The effects of vision on the general locomotor behaviour of the goldfish, Carassius auratus.

Comparison of the locomotor behaviour of normal, unilaterally and bilaterally blinded goldfish (Carassius auratus) demonstrated the roles of perspective vision (depth perception), which requires binocular vision, and of vision provided by only one eye, in the control of locomotion. Because normal and bilaterally blinded fish exhibited similar size and direction of angles of turn, a similar number of consecutive turns in the same direction and the same turning frequency, normal, binocular vision plays no role in the control of turning behaviour. Unilaterally blinded fish exhibited a strong bias in turning behaviour which resulted in their displaying circus movements toward the blinded side, a direction opposite to that reported by others for both invertebrates and vertebrates with unilateral sensory elimination. The mean step length was significantly increased by both uni-and bilateral blinding, and its temporal relationship with turning frequency and distance swum was also changed. Perspective vision (binocular) therefore controls these parameters. The significantly lower velocity of bilaterally blinded fish and the similarity between the other two test groups, indicated that sight by one eye only was sufficient to mediate velocity control.

Animals↗
PubMed2004

Macular perimetry in low vision.

BACKGROUND: Detection of residual visual function is critical for vision rehabilitation. Macular perimetry may provide essential information in this regard. In the presence of reduced vision, fixation maintenance is paramount for perimetric test validation. We performed a study to determine the validity of perimetric test results in the presence of low vision, as expressed by the relation between scotoma location, acceptable fixation maintenance and visual acuity. METHODS: The study was a prospective observational case series. Macular perimetry testing was performed with the Humphrey Automated Perimeter in eyes of consecutive patients attending our low-vision clinic between July and December 1999. The main outcome measures referred to scotoma location, acceptable fixation maintenance and visual acuity. RESULTS: We tested 46 eyes of 46 patients, 24 men and 22 women aged 33 to 88 years (mean 69.0 [standard deviation 15.41] years). Of the 35 eyes with best corrected visual acuity of 20/200 or better, 18 (51.4%) had acceptable fixation maintenance (p = 0.052), and 31 (88.6%) had scotoma patterns displaced eccentrically (p < 0.001). INTERPRETATION: We conclude that in the presence of residual vision of 20/200 or better, acceptable fixation maintenance is possible, probably with a new preferred retinal locus, and, as a result, scotoma patterns are recorded eccentrically. Therefore, perimetric results in such cases should be viewed as valid, and interpretation should always account for eccentric fixation. Concomitant testing with scanning laser ophthalmoscopy or eye tracking equipment could further clarify this issue.

Adult↗
PubMed2004

Enhancing vision care integration: 1. Development of practice algorithms.

BACKGROUND: Appropriate access to the best quality of vision care is enhanced when patients receive eye care services from the right professional, at the right time, and in the right place. This paper, the first in a two-part series, describes the development of an integrated framework for vision care delivery. Specifically, two patient-centred vision care algorithms for the multidisciplinary management of diabetic retinopathy and the red eye are outlined, and the process that resulted in their development is described. METHODS: The method used relies on a description of a multidisciplinary collaboration that occurred among ophthalmologists, optometrists, general practitioners and representatives of the Nova Scotia Department of Health with the aim of developing an integrated patient-focused multidisciplinary framework for vision care delivery. RESULTS: The process of collaborative negotiation among the four groups resulted in the development of multidisciplinary algorithms for the screening of patients with diabetes mellitus and the treatment of those presenting with a red eye. INTERPRETATION: Professional scope of practice has always been a contentious issue among health care professions. However, where parties agree to work within an atmosphere of respect and to accept guidance in areas of disagreement from a third party respected by all, compromise is possible. The result was the development of two vision care algorithms and ongoing efforts on the development of other algorithms.

Algorithms↗
PubMed2000

Vision and laterality: does occlusion disclose a feedback processing advantage for the right hand system?

The main purpose of this study was to examine whether manual asymmetries could be related to the superiority of the left hemisphere/right hand system in processing visual feedback. Subjects were tested when performing single (Experiment 1) and reciprocal (Experiment 2) aiming movements under different vision conditions (full vision, 20 ms on/180 ms off, 10/90, 40/160, 20/80, 60/120, 20/40). Although in both experiments right hand advantages were found, manual asymmetries did not interact with intermittent vision conditions. Similar patterns of results were found across vision conditions for both hands. These data do not support the visual feedback processing hypothesis of manual asymmetry. Motor performance is affected to the same extent for both hand systems when vision is degraded.

Adolescent↗
PubMed2000

Influence of monocular deprivation during infancy on the later development of spatial and temporal vision.

Using the method of limits, we measured spatial and temporal vision in 15 patients, aged 4-28 years, who had been monocularly deprived of patterned visual input during infancy by a dense cataract. All patients showed losses in both spatial and temporal vision, with greater losses in spatial than in temporal vision. Losses were smaller when there had been more patching of the non-deprived eye. The results indicate that visual deprivation has smaller effects on the neural mechanisms mediating temporal vision than on those mediating spatial vision.

Adolescent↗
PubMedDate not supplied

Bilateral simultaneous optic nerve dysfunction after periorbital trauma: recovery of vision in association with with chiropractic spinal manipulation therapy.

OBJECTIVE: To discuss the recovery of optic nerve function after chiropractic spinal manipulation in a patient with loss of vision as a result of facial fracture from a fall. CLINICAL FEATURES: In a fall down a stairwell, a 53-year-old woman with migraines fractured her right zygomatic arch, which was later treated surgically. Approximately 3 weeks after the accident, vision in her contralateral eye became reduced to light perception. Electrophysiologic studies revealed that the function of both optic nerves was diminished, the right significantly more than the left. Single photon emission tomography showed pancerebral ischemic foci. INTERVENTION AND OUTCOME: Chiropractic spinal manipulation was used to aid recovery of vision to normal over a course of 20 treatment sessions. At times, significant improvement in vision occurred immediately after spinal manipulation. Progressive recovery of vision was monitored by serial visual field tests and by electrophysiologic studies. Unfortunately, the patient refused a further single photon emission tomographic study when visual recovery was complete. CONCLUSION: This case report adds to previous accounts of progressive and expeditious recovery of optic nerve function in association with spinal manipulation therapy.

Chiropractic↗