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.

SourceResearch connectionFrom yearThrough year

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

At least 487 records · Page 27Linked to original sources

PubMed2004

Effects of Vision herbicide on mortality, avoidance response, and growth of amphibian larvae in two forest wetlands.

The effects of Vision (glyphosate, 356 mg acid equivalents (a.e.)/L) on mortality, avoidance response, and growth of larval amphibians (Rana clamitans and Rana pipiens) were investigated using in situ enclosures deployed in two forest wetlands of northern Ontario, Canada. In addition to untreated controls, Vision was applied to yield initial concentrations ranging from 0.29 to 14.3 mg a.e./L (0.94-46.1 mg/L of Vision). Resultant 96-h median lethal concentration (LC50) values ranged from 2.70 to 11.5 mg a.e./L (8.71-37.1 mg/L of Vision) depending on the species or site involved. Substantial mortality and incidences of abnormal avoidance response occurred only at concentrations exceeding the expected environmental concentrations (EEC) (1.43 mg a.e./L, or 4.61 mg/L of Vision) as calculated by Canadian regulatory authorities. The concentration dependence of larval growth rate and maximum size varied depending on site and species. Mean growth rates and maximum sizes exposed to 1.43 mg a.e./L (EEC) treatments were the same or greater than controls. Experimental site and biotic/abiotic factors therein, such as pH and suspended sediments, substantially affected the expression of Vision herbicide toxicity in the amphibian larvae tested. Overall, results suggest that the silvicultural use of Vision herbicide in accordance with the product label and standard Canadian environmental regulations should have negligible adverse effects on sensitive larval life stages of native amphibians.

Animals↗

PubMed1995

Intermittent vision and discrete manual aiming.

This study was designed to assess how the precision requirements of discrete aiming movements affect the utility of brief visual samples provided during execution of movement. Subjects pointed with a hand-held stylus to targets with indices of difficulty of 3, 4, 5, and 6 bits with full vision, no vision, and in conditions in which 20-msec. visual samples were provided every 80, 140, or 200 msec. While intermittent vision required slightly longer movement times for targets with a high index of difficulty, subjects' accuracy was similar to the full-vision situation. Moreover, with intermittent vision, the movement trajectories resembled the full-vision and not the no-vision situation. It would appear that brief visual samples of the movement environment are sufficient for reasonably precise closed-loop control.

Adult↗

PubMed1991

Correlation between psychic and somatic symptoms and vision in aged patients before and after a cataract operation.

The connection between psychic and somatic symptoms with vision was investigated by studying 100 cataract operation patients, aged 71 to 76 years, 25 of them being men and 75 women. The investigations were conducted one day before the operation and three months afterwards. The cataract operation restored sufficient acuity of vision for reading (minimum E-test value 0.40) to 79% of the old people. Psychic symptoms were tested with the Brief Psychiatric Rating Scale, Mini-Mult MMPI, and direct questions. Somatic symptoms were studied through questionnaires. Psychic symptoms showed a statistically significant correlation with vision before the cataract operation but not afterwards. Psychic symptoms increased with deterioration of the acuity of vision and diminished when the acuity of vision improved. Somatic symptoms did not show similar association with vision but the symptoms were significantly alleviated after the cataract operation. Restoration of vision through the cataract operation normalized the old people's psychic condition and reduced their somatic symptoms to correspond with their prior chronic diseases.

Adaptation, Psychological↗

PubMedDate not supplied

Creating a vision for the twenty-first century healthcare organization.

Management approaches used by healthcare organizations have often lagged behind other businesses in more competitive industries. Companies operating in such dynamic environments have found that to cope with the rapid pace of change they must have an articulated understanding of their organization's capabilities and consensus on where the organization is headed based on predictions about the future operating environment. This statement of identity and strategic direction takes the form of a vision statement that serves as the compass for the organization's decisions for a five- to ten-year period. This article discusses the importance of vision statements in tomorrow's healthcare organizations, presents an overview of future scenarios that may provide context for organizational visions, and suggests a process for developing a vision statement. A case study is presented to illustrate how a vision statement is created. Following the guidelines presented in this article and reviewing the case study should assist healthcare executives and their boards in crafting better visions of their organizations' futures, developing more effective strategies to realize these visions, and adapting to more frequent and more significant change.

Forecasting↗

PubMed1999

Restoration of vision II: residual functions and training-induced visual field enlargement in brain-damaged patients.

PURPOSE: Brain damage is often accompanied by visual field defects which have been considered to be non-treatable. In recent years, however, new diagnostic methods have revealed hitherto unknown residual vision, which was found, for instance, in transition zones near the blind visual field sectors and in spared islands of vision within the blind regions ("blindsight"). Furthermore, animal studies revealed a high degree of plasticity in the visual system suggesting the possibility that recovery of vision may be induced by systematic visual training. METHODS: Here we summarize a series of studies with patients suffering from visual field defects after brain lesion using some most recently developed computer-based programs for the diagnosis and treatment of visual field defects. Specifically, high-resolution perimetry (HRP) was applied to first diagnose residual function in or near the "blind" sector of the visual field. Thereafter, visual restitution training (VRT, see Kasten et al., Nature med. 4, 1998, p. 1083) was used daily for 6 months to provide systematic stimulation of these areas of residual vision. RESULTS: In a number of studies, we have observed not only residual visual functions within or near the field defect, but we were also able to follow the course of spontaneous recovery of visual functions within weeks or months after visual system damage. Furthermore, even long after spontaneous recovery is complete, computer-based visual restitution training (VRT) in or near the areas of residual vision results in a significant enlargement of intact areas, both after optic nerve damage and postchiasmatic lesions. Using VRT, we found a border shift of about 5 degrees of visual angle which cannot be explained by eye movements or eccentric fixation. We observed a transfer of this training effects to other tasks such as form and color detection, as well as to tests of visual exploration which were not specifically trained. Moreover, 72 % of the patients reported subjective improvements of vision. Training-induced visual field enlargement persisted for at least one year, even in the absence of training beyond 6 months of treatment. CONCLUSIONS: The visual system possesses a remarkable plasticity which becomes apparent in visual field enlargement during spontaneous recovery and specific visual training. Animal studies indicate that a minimum number of residual neurons surviving the lesion, in the order of 10%, provides a sufficient substrate for recovery of vision. Though the precise mechanisms of training-induced visual field enlargement need to be further explored, VRT can be introduced for routine clinical treatment of patients with visual field defects.

Journal Article↗

PubMed2004

Professionalism: orientation exercises for incoming osteopathic medical students and developing class vision statements.

The Philadelphia College of Osteopathic Medicine has developed an exercise to introduce professional ethics and behavior at the earliest stages of medical education. During orientation, each incoming class creates a class vision statement. After small group discussions on professional ethics, honesty, and responsibilities, representatives from each group collated student input and constructed a class vision statement reflective of student consensus on these issues. Each vision statement was recited as an oath during the white coat ceremony at the conclusion of the orientation program. Despite the fact that previous vision statements were unavailable to each incoming class, there were many commonalities among the statements created. Central elements of all vision statements include commitment to altruism, compassionate treatment of patients, and honesty and integrity in all professional interactions. Humility, the capacity to recognize and accept one's limitations in knowledge and skills, was also a key element in each statement. Three of four statements specifically recognized the teamwork and mutual respect that should be engendered among all members of the health care team. Each vision statement had prominent statements regarding the learning process during osteopathic medical school and acknowledged the importance of active and lifelong learning in the students' career paths. Student evaluation of this exercise has been positive, especially the recitation of the statement during the white coat ceremony. Results suggest that the development of a class vision statement represents a powerful mechanism for addressing the importance of professional attitudes, behaviors, and ethics at the earliest stages of medical education.

Education, Medical, Undergraduate↗

PubMed1977

Visual prognosis in advanced glaucoma: a comparison of medical and surgical therapy for retention of vision in 101 eyes with advanced glaucoma.

A detailed analysis of 101 eyes of 76 patients with advanced glaucomatous visual field loss but with retention of good visual acuity is presented. Patients were followed for a minimum of 4 years with an average duration of follow-up of 7.1 years. Loss of central vision, defined by permanent reduction of visual acuity to less than or equal to 20/200, occurred with equal frequency in eyes treated medically (15.8%) or surgically (13.6%) for glaucoma. Sudden loss of central vision also occurred following cataract extraction (8.7%). No patient lost central vision suddenly following surgery when central vision was spared at the time of operation. In addition, all cases that eventually lost central vision, either medically or surgically, demonstrated field defects which split fixation prior to its loss. Loss of central vision is seen rarely when medical therapy maintains the average intraocular pressure below 18 mm Hg, but increases markedly with higher pressures, reaching approximately 30% when average intraocular pressure is above 22 mm Hg. Progression in field loss is rare after successful glaucoma surgery, although cataracts develop in about 32% of such eyes. Cataracts also develop in 21% of medically treated eyes. In addition, about 50% of unoperated eyes demonstrate further field loss even when central vision is maintained. In spite of very definite risks, serious consideration should be given to glaucoma filtering surgery when the intraocular pressure is consistently over 22 mm Hg in patients on medical therapy with advanced glaucoma.

Adolescent↗

PubMed2006

The lost direction in binocular vision: the neglected signs posted by Wells, Towne, and LeConte.

Studies of vision have informed theories first in philosophy and then in psychology. Over the centuries, an increasing number of phenomena have been enlisted to refute or reinforce particular theories. Nowhere has this been more evident than in binocular vision. How we see a single world with two eyes is one of the oldest and most consistently studied topics in vision research. It has been discussed at least since the time of Aristotle and it has been examined experimentally since the second century, when Ptolemy defined lines of visual correspondence for the two eyes. Prior to Wheatstone's invention of the stereoscope in the 1830s, binocular vision had been studied in terms of visual directions. The stereoscope established distance (or depth) as well as direction as dimensions of binocular vision. Subsequently, depth rather than direction has been the principal concern of students of vision, and texts in English devoted to analyses of direction rather than depth have been neglected. We examine the experiments on binocular visual direction conducted by Wells before Wheatstone, and by Towne and LeConte after him, and discuss the reasons for their neglect.

History, 17th Century↗

PubMed1986

Comparison of six colour vision tests for occupational screening.

Screening of red-green colour vision defects was done for 52 school children (22 boys and 30 girls) and 231 trade school students (226 boys and 5 girls) with three different kinds of pseudo-isochromatic plates: Ishihara (1983), Boström-Kugelberg (1972), and Standard Pseudoisochromatic Plates part 1 (SPP 1) 1978, and with three different kinds of vision screeners: Keystone View Model DVS 2, Bausch and Lomb Vision Tester, and Rodenstock Farbentestscheibe 3040.173. After these tests, each subject was examined with the Nagel Anomaloscope; this revealed 26 red-green defectives in the study group. Ishihara found 20/26 (76.9%), Boström-Kugelberg 24/26 (92.3%), and SPP 1 17/26 (65.4%) of the defectives. None of the normals were diagnosed as defectives with Ishihara or SPP 1. With Boström-Kugelberg four normals were diagnosed as defectives. Keystone found 24/26 (92.3%), Bausch and Lomb 26/26 (100%), and Rodenstock 25/26 (96.2%) of the defectives. But 9, 21, and 112 normals, respectively, were diagnosed as defective. In the present study, the Boström-Kugelberg and Ishihara plates as well as Keystone Vision Screener and Bausch and Lomb Vision tester came close to an effective screening test and could be recommended for screening red-green colour vision defects in occupational health care.

Adolescent↗

PubMed2004

Hearing and vision screening program for school-aged children.

BACKGROUND: Hearing and vision screening programs for school-aged children are common, yet little is known about their impact. OBJECTIVE: To evaluate Michigan's screening program, in which local health department (LHD) staff screen school-aged children using standardized protocols. METHODS: This project was completed in three phases: interviews with officials and screening technicians from ten LHDs, audit of LHD records regarding outcomes of screening during the 2000-2001 school year, and telephone interviews with randomly selected parents of children with an abnormal screen. RESULTS: Variations in LHD program implementation pertained to methods for tracking outcomes, screening of older children, parental notification of screening results, and availability of follow-up hearing clinics. According to LHD records, documentation of follow-up examination after an abnormal screen was low (hearing 27%, vision 25%). In contrast, most parents reported follow-up (74% hearing, 76% vision), and many reported that this resulted in treatment (50% hearing, 74% vision). In logistic regression modeling, the odds of follow-up after hearing or vision screening according to parents was not associated with income, health insurance status, or race/ethnicity. For hearing screening, the odds of follow-up decreased with school grade (p <0.001); however, the proportion who received treatment did not vary by grade. For vision screening, follow-up did not vary by grade, but the proportion who received treatment increased with grade (p =0.05). CONCLUSIONS: According to parent reports, most children had follow-up after an abnormal screen, and the majority of these children received treatment. Screening school-aged children for sensory impairment appears to be an important public health function.

Adolescent↗

PubMed1996

Baltimore Vision Screening Project.

PURPOSE: This study estimates the prevalence of common visual disorders (amblyopia, strabismus, refractive errors) in a group of inner-city school children. In addition, the study addresses the issue of access to care for vision-screening programs, specifically for children with recognized difficulties in obtaining routine medical care. METHODS: School children from an inner-city elementary school were enrolled into a prospective vision-screening program combining the identification arm (screening) and diagnostic/treatment arm (ophthalmic examination). The screening consisted of Snellen E optotypes presented at a 10-foot test distance. Each child failing the vision screening was examined by an ophthalmologist at the school using standard protocol. This allowed the authors to examine all children identified through the vision-screening program. RESULTS: Six-hundred eighty children were screened during the 1993 to 1994 school year. Eleven percent (76) failed the vision screening and were examined, 68 of whom failed the ophthalmic examination. The estimated prevalence of visual morbidity was as follows: amblyopia, 3.9%; strabismus, 3.1%, and refractive errors, 8.2%. CONCLUSION: Amblyopia, strasbismus, and refractive errors were found in relatively high frequencies for this population sample of inner city children. These findings underscore the necessity of comprehensive vision-screening programs that integrate follow-up care. Children with limited access to specialized eye care must be provided with a mechanism for obtaining these services.

Amblyopia↗

PubMed2002

Monocular vision leads to a dissociation between grip force and grip aperture scaling during reach-to-grasp movements.

It has been argued that visual perception and the visual control of action depend upon functionally distinct and anatomically separable brain systems. Electrophysiological evidence indicates that binocular vision may be particularly important for the visuomotor processing within the posterior parietal cortex, and neuropsychological and psychophysical studies confirm that binocular vision is crucial for the accurate planning and control of prehension movements. An unresolved issue concerns the consequences for visuomotor processing of removing binocular vision. By one account, monocular viewing leads to reliance upon pictorial visual cues to calibrate grasping and results in disruption to normal size-constancy mechanisms. This proposal is based on the finding that maximum grip apertures are reduced with monocular vision. By a second account, monocular viewing results in the loss of binocular visual cues and leads to strategic changes in visuomotor processing by way of altered safety margins. This proposal is based on the finding that maximum grip apertures are increased with monocular vision. We measured both grip aperture and grip force during prehension movements executed with binocular and monocular viewing. We demonstrate that each of the above accounts may be correct and can be observed within the same task. Specifically, we show that, while grip apertures increase with monocular vision, consistent with altered visuomotor safety margins, maximum grip force is nevertheless reduced, consistent with a misperception of object size. These results are related to differences in visual processing required for calibrating grip aperture and grip force during reaching.

Adaptation, Physiological↗

PubMed2002

Relationship between vision impairment and ability to perform activities of daily living.

PURPOSE: To determine the relationship between clinical measures of vision impairment and the ability to perform activities of daily living (ADLs). METHODS: One hundred and twenty subjects with low vision from a variety of causes participated in the study. Vision impairment was assessed under binocular conditions by measuring distance visual acuity, near word acuity, Melbourne Edge Test contrast sensitivity, Pelli-Robson Chart contrast sensitivity and visual fields. The ADL performance was assessed using the Melbourne Low Vision ADL Index (MLVAI), which is in part an observed performance assessment of instrumental ADLs and in part a self-report assessment of basic self-care ADLs. RESULTS: All vision measures had a high, statistically significant correlation with MLVAI total score. Near word acuity, had the strongest correlation (r(s) = -0.86, p < 0.001), followed by Melbourne Edge Test contrast sensitivity (r(s) = 0.80, p < 0.001). Visual field had the weakest correlation (r(s) = 0.56, p < 0.001). Together, age, near word acuity, Melbourne Edge Test contrast sensitivity and visual field accounted for 82.2% (adjusted R2, p < 0.001) of the variance in MLVAI total score. All correlations obtained were higher for the observed performance assessment of instrumental ADLs than for the self-report assessment of basic self-care ADLs. CONCLUSIONS: Clinical vision impairment measures are highly correlated with capacity to perform ADLs, as measured by the MLVAI.

Activities of Daily Living↗

PubMed1987

Clinical use of the Pepper Visual Skills for Reading Test in low vision rehabilitation.

The Pepper Visual Skills for Reading Test (VSRT) is an assessment instrument designed by Whittaker et al. to evaluate the reading skills of patients with macular degeneration who were able to read to their satisfaction before their vision loss. The VSRT was administered to 10 patients with macular degeneration and central scotomas from the Low Vision Optometry Program at the Hines Veterans Administration Hospital Central Blind Rehabilitation Center and the Visual Impairment Center to Optimize Remaining Sight (VICTORS) at Westside Veterans Administration Medical Center, Chicago. Reading skills were measured before and after a low vision treatment program. Results indicate that this test may be useful in designing low vision training programs, evaluating the progress of individual patients receiving low vision services, and evaluating low vision programs designed to rehabilitate those with reading difficulty.

Aged↗

PubMed1994

Interocular suppression produced by rivalry stimuli: a comparison of normal and abnormal binocular vision.

This study compares interocular suppression in subjects with early strabismus and/or anisometropia with binocular rivalry suppression in subjects with normal binocular vision. A psychophysical test-probe paradigm was used to measure the changes in luminance-increment detection thresholds associated with periods of phenomenal suppression. In subjects with normal binocular vision, rivalry suppression induced by viewing orthogonally oriented grating pairs produced a distinctive wavelength-dependent change in visual sensitivity; specifically, there was a greater reduction in sensitivity for short (e.g., 450 nm) vs. middle or long wavelength stimuli (e.g., 560 nm). In contrast, subjects with abnormal binocular vision, regardless of the type of early abnormal visual experience, showed more reduction in sensitivity for a 560-nm stimulus than for the short-wavelength, 450-nm stimulus. Moreover, the pattern of sensitivity change in subjects with abnormal binocular vision was the same for suppression induced by either rivalry stimuli or stimuli that would normally promote fusion. The results clearly indicate that interocular suppression in subjects with abnormal binocular vision is qualitatively different from normal binocular rivalry. Evidently, the processes that mediate binocular rivalry are very susceptible to environmental influences during early vision development and can be disrupted easily.

Adolescent↗

PubMed2000

Improvements in clinical and functional vision and quality of life after second eye cataract surgery.

PURPOSE: To determine whether there is a need for second eye cataract surgery or whether cataract surgery in one eye provides sufficiently adequate vision. METHODS: The vision of 43 patients was assessed using a battery of clinical vision tests, performance-based functional vision tests, and quality of life questionnaires, both before and a few months after cataract surgery. Twenty-five patients underwent second eye surgery and 18 patients underwent first-eye surgery. To determine whether cataract surgery returned vision to normal levels, a control group of 25 subjects of a similar age with normal, healthy eyes was also assessed. RESULTS: Overall, greater improvements occurred in most aspects of vision after first eye surgery than after second eye surgery. However, second eye surgery provided similar improvements in mobility orientation and self-reported night driving to those after first eye surgery, and substantially greater improvements in stereoacuity and reductions in anisometropia. CONCLUSIONS: The study provides additional evidence to support the need for second eye cataract surgery. Second eye surgery may be particularly important to improve mobility orientation and the avoidance of falls.

Aged↗

PubMed2003

Effect of firefighter masks on monocular and binocular peripheral vision.

Peripheral vision can impact essential job functions of firefighters and other workers who use Self-Contained Breathing Apparatus and other full face masks. It is important for physicians to know how these masks alter peripheral vision. Also, one must understand the effect of monocular vision on peripheral vision. Using the Goldman Perimeter Machine we measured peripheral vision in the monocular and binocular state, with and without two different types of masks. The results show that monocularity causes an average loss of 23 degrees in the nasal meridian. The use of the masks did not affect this difference. Also, the masks caused an average loss of 28 degrees of peripheral vision in the inferior meridian. How these losses affect the ability of the users of the masks to perform their essential job functions still needs to be researched.

Adult↗

PubMed2005

Factors related to vision care in an older adult cohort.

PURPOSE: This study provides cross-sectional data on eye care utilization in a community-based adult population. METHODS: Data are from a questionnaire administered during the 7-year follow-up of the Epidemiology of Hearing Loss Study in 2000 to 2002. Participants in the population-based Beaver Dam Eye Study were eligible for the Epidemiology of Hearing Loss Study, which began in 1997. The primary outcome was self-reported vision testing within the past year. RESULTS: Subject ages ranged from 55 to 99 years (n = 2433), and 60.4% were female. Fifty-three percent of subjects reported they had their vision tested in the past year. Diabetes was self-reported by 11.5% of subjects, and 70.9% of diabetic participants had their vision tested in the past year. A current hospitalization or health insurance plan was reported by 98.6% of subjects. In multivariate analyses, self-reported factors significantly associated with having a vision test in the past year were female gender (odds ratio [OR] = 1.27; 95% confidence interval [CI] 1.06-1.52), current use of refractive correction for distance (OR = 1.98; 95% CI 1.56-2.52), glaucoma (OR = 3.52; 95% CI 2.37-5.24), cataract surgery (OR = 1.57; 95% CI 1.21-2.03), age-related macular degeneration (ARMD) (OR = 1.74; 95% CI 1.22-2.47), diabetes (OR = 2.46; 95% CI 1.83-3.31), visiting a primary care practitioner for any reason in the past year (OR = 1.72; 95% CI 1.32-2.25), having a hearing test in the past year (OR = 1.79; 95% CI 1.40-2.28), and the cessation of driving because of poor vision (OR = 1.64; 95% CI 1.16-2.52). In participants 65 years of age or older, having private insurance was associated with increased odds (OR = 3.39, 95% CI 1.82-6.31) of vision testing in the past year. CONCLUSION: This study suggests that chronic ocular conditions, diabetes, health insurance beyond government entitlements, and the use of other healthcare services are associated with increased eye care utilization.

Aged↗