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At least 1,675 records · Page 93Linked to original sources
PubMed1998

Perforating eye injuries from external rear vision mirrors.

PURPOSE: To highlight external rear vision mirrors as a cause of ocular injuries in motor vehicle accidents. METHODS: Three cases of perforating eye injuries due to shattered external rear vision mirrors in motor vehicle accidents are described. The relevant Australian design rules are reviewed. RESULTS/CONCLUSION: External rear vision mirrors can be responsible for serious ocular injuries in motor vehicle accidents. Further investigation of the incidence of such injuries is required to determine whether vehicle manufacturing methods and the design rules covering their production warrant revision.

Accidents, Traffic↗
PubMed2002

Efficacy of treatment for convergence insufficiency using vision therapy.

PURPOSE: The purpose of this study was to determine if vision therapy (VT), as practised within the constraints of UK optometric practice, employing graded routine eye exercises, is as an effective method for treatment of convergence insufficiency (CI) as previously published data suggest. The study also evaluates the associated symptoms before and after therapy. METHODS: As many optometrists diagnose CI solely on the basis of near point of convergence (NPC) and treat only when symptoms are present (Letourneau et al., 1979; Rouse et al., 1997), in this study CI was defined as NPC of 10 cm or greater (either with or without the presence of asthenopic symptoms for near work) accompanied by exophoria greater at near than at distance. The effect of treatment by optometric vision therapy (OVT) on the NPC and number of symptoms was investigated for 92 patients by retrospectively reviewing the clinical records. Success was defined as the restoration of NPC to normal values and significant reduction in the presenting symptoms. RESULTS: The effect of treatment on the NPC was shown to be highly significant (t = 14.61, p < 0.001). Although treatment times were slightly longer, the success rates were higher than reported by other authors. Post-treatment values for NPC were: <10 cm (98.9%), <8.5 cm (95.7%) and <6.5 cm (80.4%). Longer treatment times were noted for patients who complained that the text appeared to move (chi2, p = 0.007). CONCLUSION: Vision therapy is an effective method for treatment of CI.

Adolescent↗
PubMed2005

Effects of the removal of vision on body sway during different postures in elite gymnasts.

The aim of this study was to analyse the effects of the removal of vision on postural performance and postural control in function of the difficulty and specificity of the posture. Twelve elite gymnasts were instructed to be as stable as possible with eyes open and eyes closed in three postures: bipedal, unipedal, and handstand ranked from the less difficult and less specific to the more difficult and more specific. The ratios eyes closed on eyes open, computed on CP surface and CP mean velocity, which respectively represents postural performance and postural control, were similar in the bipedal and handstand postures. They were highly increased in the unipedal one. The effect of the removal of vision and so the role of vision on body sway was not directly linked to the difficulty or specificity of the posture; other tasks' characteristics like the segments configuration also played a role.

Adolescent↗
PubMed2006

Direct-vision stenting: the way forward for malignant oesophageal obstruction.

BACKGROUND AND STUDY AIMS: Self-expanding metallic stents now form the mainstay of treatment for palliation of dysphagia in oesophageal cancer. These stents are generally inserted under fluoroscopic guidance. However, both the internal and external marking of the tumour can be inaccurate and time-consuming, and access to fluoroscopic facilities is sometimes limited. We prospectively assessed the use of a method of stent insertion under direct vision without the aid of fluoroscopy. PATIENTS AND METHODS: A total of 50 consecutive patients presenting with obstructive symptoms secondary to inoperable oesophageal cancers were included in the study. We used either the 7-cm or the 11-cm covered Choo stent (MI-Tech Ltd., Seoul, South Korea). RESULTS: A total of 52 stents were inserted under direct vision. The procedure generally took less than 15 minutes and good palliation was achieved without complications. Fluoroscopic assistance was required in only one patient. CONCLUSIONS: Direct-vision stent insertion is simple, safe, effective, and only rarely requires fluoroscopic assistance. The technique may be of particular use in centres with limited access to fluoroscopy.

Adenocarcinoma↗
PubMed1999

[At home utilization of low-vision aids by the visually impaired].

BACKGROUND: The increase of life expectancy causes a rising number of partially sighted. Therefore our Department of Ophthalmology has founded a laboratory for partially sighted 7 years ago. To optimize patient care, the results were now reinvestigated. MATERIALS AND METHODS: For the present study, 125 patients were selected by geographical aspects (home nearby clinic) from the lab's pool. After a 3 month minimum period of using the low-vision aid (LVA) patients were visited at their homes. Near visual acuity, distance visual acuity, magnification, and contrast sensitivity were studied under domestic and optimized conditions of illumination. Patients were interviewed in detail to investigate their habits of LVA use. RESULTS: An overall number of 94 patients (66 females and 28 males) could be evaluated. The most patients were between 80 and 84 years old. Vision impairment was attributable mostly to macular degeneration (55%) and diabetic retinopathy (21%). Visual acuity and contrast sensitivity decreased during the period of investigation. 79% of the patients had a unsatisfactory domestic illumination (< 1000 lx). Only 23% of the patients used their LVA at a fixed location. Main field of using LVA was reading (68%). The LVA were rarely used for writing and other fields of practice. 76% of LVA were used daily, more than 50% for a maximal duration of 1 h/d. Magnifiers were preferably used for short-time activities. Closed circuit television systems (CCTV) had a very good acceptance. Telescopes were characterized by a very high rate of rejection. The number of non-used LVA was approximately a fifth. Reasons were decreased visual acuity, impractical handling, missing introduction by delivering optician (54%) as well as unsatisfactory illumination. CONCLUSIONS: Improved patient care can be obtained by regular check-up visits (6 months), enhanced illumination, low-vision training, home visits, multi-disciplinary care and modified prescription of LVA.

Aged↗
PubMed1990

[Should the ophthalmologist provide low vision counseling?].

The experience gained at the low-vision center of St. Gallen Eye Hospital shows that there is a real need for this service, particularly among the elderly, and that this kind of counseling is very time-consuming. Until now, low-vision counseling in Switzerland has been provided mainly by opticians and other paramedical personnel. In view of these facts the question arises as to whether such services should not also--and primarily--be provided by ophthalmologists and their orthoptists. For more complicated cases it is suggested that low-vision counseling should also be offered at the ophthalmology departments of major hospitals.

Aged↗
PubMed1978

A possible explanation as to why the newly sighted commonly perform well on pseudoisochromatic colour vision tests.

Patients whose vision has been restored after long periods of blindness commonly experience difficulty in perceiving. Parodoxically, such patients often perform well on pseudoisochromatic colour-vision tests. A well-known example is Gregory and Wallace's subject, S.B. who performance on the Ishihara test was perfect. It is suggested that restoration of vision may be associated with relatively poor visual acuity and that this, by filtering higher spatial frequencies, enhances the legibility of pseudoisochromatic test patterns. Two experiments confirm that the Ishihara plates are more legible when seen as defocused images.

Blindness↗
PubMed1980

Vision, visibility, and perception in driving.

Recent research is reviewed and its implications discussed. "On-the-Spot" accident investigations have confirmed that errors of perception by the driver are a major contributory factor to accidents. However, the available evidence suggests that few of these are attributable to reduced or defective vision, since at best only a weak relationship has been found between a driver's level of vision (or visual performance) and his accident rate. A number of reasons for this general finding are considered, including driver compensation. For all drivers, the rapid fall in visual acuity with angular distance from the centre of vision presents particular problems, giving special significance to eye-movement patterns and the problems of visual search. Numerous physical and psychophysical restrictions on visibility could lead to the "looked, but failed to see" type of accident, but their relative importance requires evaluation. There is now much evidence that the driver is quite often operating beyond his visual or perceptual capabilities in a number of key driving situations, including overtaking, joining or crossing a high-speed road, and a number of nighttime situations. It is concluded that "expectancy", based on experience in both the long and the short term, has a profound influence on driver perception and assessment of risk. For all drivers, serious errors of judgment from time to time would seem inevitable. In general, these do not lead to accidents because of, among other things, the safety margins added by the driver and adjustments made by other road users. Thus, despite his limitations and fallibilities, the average driver is involved in surprisingly few serious incidents, particularly in view of the rapid rate of decisionmaking that is required. However, the present accident rate should not be accepted as inevitable and various countermeasures are discussed.

Accidents, Traffic↗
PubMed1987

Inheritance of color vision in a New World monkey (Saimiri sciureus).

Squirrel monkeys (Saimiri sciureus) have a striking color-vision polymorphism; each animal has one of six different types of color vision. These arise from individual variation in the presence of three different middle- to long-wavelength cone pigments. The distribution of cone phenotypes was established for a large sample of squirrel monkeys, including several families, through analysis of a retinal gross potential. The results indicate that the inheritance of color vision in the squirrel monkey can be explained by assuming that the three middle- to long-wavelength cone pigments are specified by three alleles at a single locus on the X chromosome. This arrangement is discretely different from that found in Old World monkeys and humans.

Animals↗
PubMed1999

Causes and prevalence of non-vision impairing ocular conditions among a rural adult population in sw Uganda.

Information is scanty about the extent of ocular morbidity in developing countries, particularly for non-vision impairing conditions (NVIC), although these constitute the majority of consultations in eye clinics. We have conducted a survey to determine the prevalence and causes of NVIC in a Ugandan adult population and compared our findings with the work pattern of the district hospital. Adults were screened using Snellen's illiterate E chart and those found with visual impairment (acuity less than 6/18) in either eye were referred to a low-vision clinic, and those with obvious ocular disease or symptoms, but without visual impairment, to an outreach clinic. A total of 2886 (53%) out of 5479 adults were screened. Of these, 257 (8.9%) were referred to the outreach clinic, of whom 173 (67%) attended. Of those attending the low-vision clinic 83% had visual impairment confirmed, and 92% of those attending the outreach clinic were confirmed not to have visual impairment. The four commonest NVIC observed at the outreach clinic were: presbyopia (48%), allergic conjunctivitis (20%), early cataract (9%) and infective conjunctivitis (8%), the same conditions as those most commonly seen at the district hospital. In this community, over 80% of NVIC are caused by four conditions which are potentially either correctable, operable or treatable. Training health workers to recognise and treat these conditions would serve the great majority of eye patients. Hospital activity data can be used cautiously to assess the relative frequency of NVIC in the community.

Adolescent↗
PubMed1987

Neuromuscular control of posture in the infant and child: is vision dominant?

This study explored the effects of vision and maturation on the characteristics of neuromuscular responses underlying balance control in both seated and standing children of five age groups (3 1/2-5 months, 8-14 months, 2-3 years, 4-6 years, and 7-10 years). A platform was used to unexpectedly disturb the child's balance in the anterior or posterior direction. Responses of the leg, trunk, and neck muscles were recorded using surface electromyograms. Vision was not required for the activation of these responses in any of the age groups tested. However, comparison of the muscle response latencies of standing children to posterior platform translation in the two visual conditions showed a significant reduction in latency for neck flexors in the 2- to 3-year-olds with vision removed and ann increase in the total number of monosynaptic reflexes. No reduction in latency was found in the older age groups. The hypothesis of a shift from an early long latency visual dominance to a shorter latency proprioceptive one during childhood is discussed. Postural control showed a cephalo-caudal developmental gradient with postural responses appearing first in the neck, then trunk, and finally, legs, as children developed from 3 to 14 months of age. A wide variety of response patterns was seen in the 3- to 5-month-olds, indicating that postural responses are not functional prior to experience with stabilizing the center of mass.

Journal Article↗
PubMed1988

Developmental differences in the use of peripheral vision during catching performance.

Recently, it has been argued that peripheral vision may control adequate orientation of catching limbs, although questions have been raised of whether this remains the case as skill develops. The aim of the present study was to remediate previous methodological deficiencies to verify whether developmental differences exist in the extent of the functional visual field. A further aim included examining the importance of peripheral vision as a control process for effector orientation during catching without recourse to an occlusion technique. Previous arguments that peripheral vision may be necessary in controlling one-handed catching performance were extended to a two-handed catching task. Male subjects (n = 80) were required to perform a two-handed catch and simultaneously process a peripheral visual signal presented either early in, in the middle of, or late in flight. Developmental differences were noted between the age groups (mean ages = 10, 12, 16, and 20 years) in the ability to divide visual attention between the ball in flight, location of hands, and the peripheral cue acting as a probe. Evidently, the ability to allocate control of effects to the articular proprioceptive system develops with age because there was an obvious improvement in peripheral visual processing performance during the late segment of flight. Specifically, it appears that between the ages of 12 and 15 years catchers develop the capacity to increase the functional control of the articular proprioceptive system, as indicated by a significant decrease in peripheral visual errors during the late segment made by the latter age group. Limited evidence is also presented suggesting that the successful allocation of greater control to the articular proprioceptive system changes as a function of practice and experience with the specific central task, thus overcoming initial reliance on sight of the catching hands.

Journal Article↗
PubMed2002

Age-related differences in vision and proprioception in a lower limb interceptive task: the effects of skill level and practice.

This study examined age-related differences in the role of visual proprioception during a lower limb interceptive action and how this varies as a function of skill and practice. In Experiment 1, skilled and less-skilled 8-, 10-, and 12-year-old boys controlled a soccer ball using their preferred foot under full vision and when sight of the effector was occluded. With the exception of the high-skilled 12-year-olds and low-skilled 8-year-olds, participants showed a decrement in peformance when denied access to visual proprioception. In Experiment 2, the effect of practicing under different informational constraints was examined for 12 year-old boys. Children performed varying amounts of practice under full vision, or in a condition where sight of the foot was occluded, before being transferred to the alternative viewing condition. Participants who practiced under occluded viewing conditions showed greater relative improvement in performance over practice and transfer sessions compared with a full vision control group. Some support is provided for the manipulation of visual informational constraints as an effective pedagogical approach to motor learning.

Age Factors↗
PubMed2005

Access to vision care in an urban low-income multiethnic population.

OBJECTIVE: This study applied a well-known, recently revised theoretical model of healthcare access and utilization, the Behavioral Model for Vulnerable Populations, to examine the relationship between access to care and utilization of eye care services among a multiethnic, predominately minority sample of residents from low-income public housing. DESIGN: Population-based, cross-sectional survey of community sample. SETTING: Urban Public Housing Communities in Los Angeles County, California. PARTICIPANTS: A geographically defined stratified random sample of 152 residents (86% Latino or African American) 40 years of age and older from three urban public housing communities. RESULTS: Only 62% of our sample of persons 40 years and older had received an eye examination within the past 2 years. Sixty-one percent of participants reported having vision care coverage. Yet, one out of four respondents claimed that no health care provider had ever told them that they needed an eye-examination. Applying multiple logistic regression and controlling for a number of predisposing, enabling, and need-for-care characteristics, the variables 1) receiving advice from health care providers for eye examination (OR = 3.9, p < 0.01), 2) possessing coverage for eye-care (OR = 3.2, p < 0.01), and 3) having regular and continuity of medical care (OR = 2.4, p < 0.01) remained significant predictors of eye-examination within the past 2 years. CONCLUSION: This study documents significantly diminished utilization of eye care services relative to recommended guidelines for a low-income, predominately minority sample of residents from public housing communities. We documented no association between presence of diabetes or hypertension and recency of eye examination. Affordability, continuity, and regular sources of care, as well as receiving physician advice, remain the core factors significantly associated with receiving vision care. These results underscore the need for continued efforts to ensure that the medically underserved minority have access to vision care services. These findings also point toward the urgent need for educational and motivational interventions that encourage health care providers serving underserved communities to promote eye examination, particularly among diabetic patients, hypertensive patients, and other individuals at risk for eye-related disease and complications.

Adult↗
PubMed2006

The Refractive Status and Vision Profile (RSVP): Translation into Persian, reliability and validity.

PURPOSE: To translate and test the reliability and validity of a Persian translation of the Refractive Status and Vision Profile (RSVP), a vision-related quality of life questionnaire, in Iran. METHODS: Forward & backward translation, committee review and pilot testing were performed to develop a final Iranian version of the RSVP. Seventy-three consecutive patients with refractive error before or after refractive surgery at the LASIK ward of Farabi Eye Hospital completed the questionnaire. A convenience sample of 14 patients completed the questionnaire twice within one week. Reliability was measured by internal consistency (Cronbach's alpha) and the intraclass correlation coefficient for test-retest reliability. Validity was evaluated by correlation between the different RSVP subscales, known groups comparison analysis, and correlation between the subscales versus global items and traditional clinical measures. RESULTS: Internal consistency was high (Cronbach's alpha : 0.71-0.92; except for the subscale expectations, alpha : 0.6). Test-retest reliability of subscales and the overall RSVP scale, as estimated by the intraclass correlation coefficient, was high except for optical problems and glare. Comparisons between pre- and post-operative groups of patients showed significantly higher (worse) scores for concern, physical/social functioning, and the overall score in the pre-operative group. Almost all subscales showed desirable inter-scale correlations. CONCLUSION: The Iranian version of the RSVP is a reliable and valid measure of vision-related quality of life in patients with refractive error.

Adult↗
PubMed2004

Signatures of selection and gene conversion associated with human color vision variation.

Trichromatic color vision in humans results from the combination of red, green, and blue photopigment opsins. Although color vision genes have been the targets of active molecular and psychophysical research on color vision abnormalities, little is known about patterns of normal genetic variation in these genes among global human populations. The current study presents nucleotide sequence analyses and tests of neutrality for a 5.5-kb region of the X-linked long-wave "red" opsin gene (OPN1LW) in 236 individuals from ethnically diverse human populations. Our analysis of the recombination landscape across OPN1LW reveals an unusual haplotype structure associated with amino acid replacement variation in exon 3 that is consistent with gene conversion. Compared with the absence of OPN1LW amino acid replacement fixation since divergence from chimpanzee, the human population exhibits a significant excess of high-frequency OPN1LW replacements. Our results suggest that subtle changes in L-cone opsin wavelength absorption may have been adaptive during human evolution.

Africa↗
PubMed2005

The future of patient-centered care: scenarios, visions, and audacious goals.

The U.S. health care system is transforming. It must. Patient-centered care (PCC) is a core quality that the system should include. This article presents the highlights of a project on the future of PCC created for the Picker Institute. As an example of futures work, this project developed four images or stories of what might happen, as well as a vision and audacious goals for what should happen to PCC. The first and most likely scenario is an increase in patient-centeredness as a function of current trends. However, in the second scenario, health care could become even more stressed and leave PCC behind as it seeks to lower cost without focusing on quality. The third scenario envisions more excellent systems that integrate PCC seamlessly into their work. The fourth scenario sees collaboration and shared responsibility, in association with advanced information tools, thereby enabling PCC to contribute to preventing illness and lowering health care costs. The scenarios indicate that the patient-centeredness of health care could improve slightly, stall, or advance significantly. The PCC Vision calls for each of us to be in charge of our health, and to get the care we need (not less and not more) in timely, effective, and personal ways consistent with our values. The audacious goals set an agenda with priorities from the PCC community. These include shared decision making by consumers, ensuring health care professionals are trained in supporting active patients, anticipating health and long-term care needs for individuals, adopting the Institute of Medicine's (IOM) simple rules for health care, and making the patient perspective a priority in policy and planning. Each of us and our organizations are confronted with the challenge of this vision and audacious goals. Health care professionals and provider systems, whether conventional or alternative in nature, face these issues. While complementary and alternative medicine (CAM) providers often get higher marks from consumers for their attention, many CAM modalities are largely provider-determined. Patient-centered care will require more empowerment and activation of patients and consumers.

Chronic Disease↗
PubMed1999

Vision rehabilitation for age-related macular degeneration.

Though the numbers of patients with ARMD are high, associated referrals for vision rehabilitation are not. Practitioners need to refer patients with age-related maculopathy when medical and surgical treatment are no longer possible, and patients need to be educated to that fact. The impact of improving activities of daily living may be monumental and benefits society as a whole. People who are visually impaired are often ill-prepared to deal with the substantial adjustment involved, further stressing their entire support system. It may not be safe for visual and systemic reasons for older adults to cook, clean, and maintain their home. Poor vision contributes to the already increased risk of falls and subsequent fractures in these patients. Individuals who may have already been told they can no longer drive now face the possibility of being unable to live in their houses. Their independence may be threatened dramatically and abruptly. All these circumstances contribute to anxiety and depression. Patients with ARMD need to be educated about their disease process (teaching that can never be assumed to have been initiated). They need to be educated that they will not go completely blind and that, with assistance, they can accomplish a great deal. With today's technology, it is not difficult to help visually impaired individuals with ARMD, unless they are not referred or lack motivation. The primary complaint of an individual with ARMD is recognition of central detail. This affects all activities of daily living, and patient performance is subject to the duration and severity of the disease (including the size, density, and location of the central scotoma) and to their understanding of the disease. Rubin and coworkers, found that slow reading performance of patients with a dense central scotoma might reflect inherent limitations of peripheral retina for complex visual tasks. ARMD in most cases lends itself to magnification that enlarges the object beyond the blind spot for visual recognition. Visual devices for distance, intermediate, and near tasks are usually helpful after patient education regarding their predicament and education for adaptation. Eccentric fixation techniques should be one of the first exercises mastered prior to further visual rehabilitation. Activities of daily living should be addressed with every individual, and appropriate assessment of existing problems and modifications to those problems should be implemented. Orientation and mobility should be offered to any individual who is legally blind or has difficulty with safe travel. A great deal of empathy is required on the part of the vision rehabilitation team. However, when patients lack of motivation, feel despair, or exhibit psychosocial overtones of reliance on others, they needs to be confronted, and appropriate action must be taken. Social work consultation and access to a support group can go a long way in mental strengthening and socialization. The author conducted a support group that, over a 10-year period, had a negligible dropout rate owing to the positive socialization obtained from attending the meetings. Older adults who are still working should be referred to an agency for vocational and financial resources if so desired. There is the issue of driving. In the United States, maintaining a driver's license is an important part of the quality of life. Older adults are the most rapidly growing segment of the driving population in the United States. The percentage of drivers older than 65 is expected to increase 17% by the year 2020. The rate of traffic fatalities among older adults has increased substantially, although the overall rate of fatalities is declining. The elderly drive fewer miles but have the highest rate of crashes per miles driven. Many important issues regard the older adult driver. (ABSTRACT TRUNCATED)

Eyeglasses↗