Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vision, Low”

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 415 records · Page 23Linked to original sources
PubMed1994

Low-vision elders living arrangements, loneliness, and social support.

1. Loneliness was not found to be a significant problem in a study of low-vision older clients with various living arrangements. Different types of support networks did serve different functions depending on whether clients lived alone or with others. 2. Clients living alone were more satisfied with supporters who helped them when they were feeling down, whereas clients living with others were more satisfied with supporters who cared about them. 3. Clients living alone relied on friends and children as the most important sources of support; clients living with others relied most on children for the majority of their needs. 4. Supportive expectations should be shared with supporters in the network to prevent burnout of the support person and lack of support for the client in crises if the supportive person is not available.

Aged↗
PubMedDate not supplied

Comparison of low-vision reading with spectacle-mounted magnifiers.

Reading is the most common goal among persons with age-related macular degeneration and other retinal diseases that lead to macular loss, as well as the functional task most affected by the resulting central scotomas. This project determined whether reading ability is different when persons with macular loss read with a new hybrid-diffractive spectacle magnifier versus a refractive-aspheric spectacle magnifier and an aplanatic spectacle magnifier. After subjects completed a low-vision examination, we assigned them to groups that compared different types of spectacle magnifiers and assessed their reading acuity, speed, critical print size (print size large enough to provide a subject's best fluent reading), accuracy, and comprehension. Subjects completed visual analog scales to indicate their perceptions of satisfaction with reading, comfort with reading, and cosmesis (comfort with allowing others to see them read) and were asked which of the compared spectacle magnifiers they preferred for prescription. We subjected the data to paired t-tests to ascertain whether differences existed in subjects' reading ability and perceptions between the types of reading devices. Subjects' reading comprehension, perception of satisfaction, and perception of cosmesis were significantly better with the hybrid-diffractive lens than with the refractive-aspheric lens. Although subjects' critical print size was significantly better with the aplanatic lens than with the hybrid-diffractive lens, functional reading ability was not significantly different. More subjects preferred the hybrid-diffractive lenses for prescription. The hybrid-diffractive spectacle magnifiers are an important addition to the optical-device armamentarium for reading with low vision.

Aged↗
PubMed1986

Psychophysics of reading. IV. Wavelength effects in normal and low vision.

Does the color of text influence its legibility? There are reasons why it may do so for specific groups of low-vision observers. We used psychophysical methods to measure the effects of wavelength on the reading performance of four normal observers, two dichromats, and twenty-five low-vision observers. Reading rates were measured for text scanned across the face of a television (TV) monitor. We compared performance under four luminance-matched conditions in which sets of neutral-density and Wratten color filters were placed in front of the TV screen--blue (lambda max = 430 nm), green (lambda max = 550 nm), red (lambda max = 650 nm), and gray. Under photopic conditions, the reading rates of normal subjects were independent of wavelength, with the exception of characters near the acuity limit. At lower luminances, wavelength effects could be explained by the shift from photopic to scotopic vision. It was hypothesized that light scatter or absorption in eyes with cloudy ocular media would result in depressed performance in the blue. Only one of seven subjects demonstrated this effect, which we traced to wavelength-specific absorption. Observers with advanced photoreceptor disorders tended to read blue text faster than red text. This could not be explained on the basis of photopic spectral sensitivities alone. Finally, the presence of central or peripheral field loss was not predictive of wavelength-specific effects in reading. On the whole, wavelength only occasionally plays a significant role in reading. When it does, performance tends to be depressed either in the red or the blue and to be nearly optimal for green or gray.

Adult↗
PubMed1995

Using visual thresholds to establish low vision performance.

Table 6 gives an example of a similar task (N10 print of 75% contrast) but with different requirements of fluency showing how much extra visual performance (acuity threshold, contrast threshold and magnification) is needed to achieve fluent reading. After the clinical assessment of visual function, it should be possible to categorize clients into three different groups on the basis of their threshold visual performance, each needing a different approach depending on their goals and needs as shown in Table 7. These are: Group I: Limited or no survival reading potential. Group II: Survival reading potential but limited likelihood of fluency. Group III: Clear survival reading potential with fluent reading possible if motivated. The author believes that it is always best to start with what the client has to read in order to maintain their independence, rather than what they wish to read for leisure, education or employment. Therefore, it is more successful to concentrate initially on spot/survival reading even if the client seems to have potential for regaining fluency. It should, however, be made clear to the client that this is the approach to be adopted. It is futile for the practitioner, as well as frustrating and demoralizing to the client, to press ahead with complex devices or wasteful trial and error sessions if, at an early stage, it is clear that the client will never return to fluent reading. Instead, it is far better to begin the move to vision substitution (e.g. audio-tapes) for leisure reading at an earlier stage. The overriding influence in low vision management is clearly the motivation of the client.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrast Sensitivity↗
PubMedDate not supplied

Advanced low vision optics.

1. The concepts of magnification rating, equivalent power, image location, enlargement ratio, and combined reading power confront the practitioner who uses magnification when working with low-vision patients. 2. The discussion of these advanced concepts gives the low-vision practitioner new insight into accurately recommending magnifiers. 3. These concepts should be integrated into the everyday work of professionals who optically rehabilitate patients with visual impairment.

Humans↗
PubMed1995

Low vision: physician screening helps to improve patient function.

Low vision is a common problem of older patients. As a primary care practitioner, you are not expected to treat most ocular problems, but you can play an important role by identifying patients with visual impairment. Familiarize yourself with the normal visual changes that occur with aging as well as the more common age-related ocular diseases, including glaucoma, cataracts, age-related macular degeneration, and diabetic retinopathy. You can identify patients with visual problems with a careful history and basic in-office tests of visual acuity. Refer patients found to have visual impairment to an eye care specialist for further evaluation.

Activities of Daily Living↗
PubMed1979

[The prism loupe spectacles used as low vision aid and in microsurgery (author's transl)].

In 1970 Biessels developed and constructed the new binocular prism loupe spectacles, mainly as improved low vision aids. They were derived from the Zeiss 8 x 20 prism binoculars, however, with different lenses and mechanical parts. They are quite different from the Galilean telescopic spectacles, hitherto available, with their lower mangifications, short working distances, chromatic aberration, and peripheral unsharpness. The Biessels prism loupes with variable magnification up to 12 times, and working distances of 18 to 30 cm, are mounted into spectacles. They provide for a comfortable stereoscopic vision with normal convergence. The visual field is virtually 20 cm at 25 cm distance, and sharp to the edges. The weight of a complete binocular prism loupe, including the frame, is from 100 to 110 grammes. In the past 7 years more than 500 of such visual aids have been delivered to low vision patients, half of them binocular, also 40 operating spectacles for microsurgery, all of them with great success. Here we report on the technical details and good results.

Eye Diseases↗
PubMed2002

Low vision rehabilitation in patients with age-related macular degeneration at a tertiary eye care centre in southern India.

PURPOSE: To evaluate the specific needs and types of low vision devices (LVDs) in patients with age-related macular degeneration (AMD) so as to use the residual vision effectively. METHODS: One hundred consecutive patients with diagnosis of AMD were evaluated to ascertain the degree of visual disability. Different LVDs were used to suit the specific needs of individual patients. The distribution of LVDs for distance and near and other rehabilitation measures were stratified for vision >or=6/18 and <6/18. Statistical analysis was performed using chi2 test/Fisher's exact test and paired t-test. RESULTS: The percentage of patients with visual acuity <6/18 reduced from 72.2% (26/36) to 47.2% (17/36) with the use of standard spectacles (P = 0.03). Similarly, the percentage of patients with visual acuity <6/18 reduced from 85.7% (6/7) to 14.3% (1/7) with the use of a telescope (P = 0.029). The optical devices for near tasks included spectacle magnifiers (n = 59), stand magnifiers (n = 19), and hand magnifiers (n = 18). With these LVDs, the near vision improved from 0.13 (decimal notations) to 0.39 (P < 0.001). Eighty-six patients were given at least one of the LVDs and 20% were prescribed more than one near device (bifocals, spectacle magnifiers, hand magnifiers, stand magnifiers). Additionally, patients also needed counselling (n = 89) and training on eccentric viewing (n = 39), coin identification (n = 45), and independent mobility (n = 41). CONCLUSION: The overall management of a patient with AMD must include counselling, prescription of appropriate LVDs and training to utilize the residual vision to its fullest advantage. This is expected to improve the patient's quality of life.

Aged↗
PubMed1981

A study of successful and unsuccessful low vision rehabilitation patients.

The needs of the visually handicapped are, at times neglected by our profession. This is partly due to the fact that inadequate guidelines exist to guide the occasional low vision practitioner. In an effort to shed more light on this problem, the characteristics of 84 low vision rehabilitants were studied. This group, as a whole, achieved a very high rate of success. Significant differences were found to exist between the successful and unsuccessful groups on measurements of amounts of money spent, number of devices prescribed, and best corrected visual acuity (conventional spectacles). A fourth variable, age, showed that substantial difference existed between the two groups. Possible explanations, implications, and the need for future research are discussed.

Adolescent↗
PubMedDate not supplied

Resources for the low-vision community.

1. The NAVH serves, exclusively, an otherwise overlooked group of disabled people--the visually impaired who are not totally blind. Although its numbers increase dramatically each year, the low vision community is largely unrecognized by the public. 2. Parent self-help discussion groups were initiated in the early 60s to help parents who expressed feelings of frustration that they could accept their offspring more readily if the child were totally blind. The first session supplied the vital information needed to prepare the first publications ever written about partially seeing children. 3. The agency has expanded to include all ages and to supply information about vision and vision throughout the world.

Humans↗
PubMed2002

The National Blindness and Low Vision Prevalence Survey of Bangladesh: research design, eye examination methodology and results of the pilot study.

PURPOSE To describe the research design and eye examination protocol of The National Blindness and Low Vision Prevalence Survey of Bangladesh and to present the main results of the rural pilot study. METHODS A thorough description of the sampling strategy, eye examination protocol and operational definitions are presented. Multi-stage stratified (rural/urban) cluster random sampling, with probability proportional-to-size procedures, will be used for selection of a cross-sectional, nationally representative sample (12,900 subjects) of the population aged > or = l30 years. Each subject will be tested for visual acuity, auto-refracted and undergo optic disc examination. Those with <6/12 visual acuity in either eye will be re-tested with their refractive correction, dilated and examined for anterior and posterior segment disease. A preliminary, separate rural pilot survey sample was conducted according to the eye examination procedures, with results reported herein. RESULTS Two-hundred-and-four (73.1%) of 279 eligible subjects were examined for the rural pilot. Forty-eight persons had presenting visual acuity worse than 6/12 in either eye. The presenting visual acuity of the better eye was used to group the subjects into the following WHO categories (brackets enclose the number of subjects after refractive correction): Blind: 4 [4]; Visually impaired: 29 [14]; Sighted: 171 [186], of whom 3 [3] were unilaterally blind. Cataract was the main cause of visual acuity of less than 6/12, followed by refractive error, and age-related macular degeneration. CONCLUSIONS The pilot survey demonstrated that the proposed examination process for the main survey was both feasible and appropriate for the purposes of this study. Particular strengths of the pilot and subsequent main survey include the use of logMAR visual acuity testing and auto-refraction of all subjects. The pilot study reveals the burden of cataract and refractive error, which are two of the five diseases specifically targeted by the WHO global blindness initiative 'Vision 2020'.

Adult↗
PubMed1985

Visual improvement with low vision aids in Stargardt's disease.

We studied 71 patients with Stargardt's disease or fundus flavimaculatus to evaluate their potential for improvement in visual acuity with the use of low vision aids. The median visual acuity was 10/77 without an aid and 10/32 with a telescopic system. In 54 patients the best corrected reading acuity obtained was 4.0 point print. In all cases low vision aids improved visual acuity for both distance and reading.

Adolescent↗
PubMedDate not supplied

Rehabilitation options for patients with low vision.

Loss of vision has a profound effect on an individual's life. Reduced visual function, whether present at birth or appearing later in life, greatly affects one's perception of useful existence. When medical intervention can no longer restore or maintain a person's functional vision, rehabilitative measures are necessary to enable that person to adjust both physically and psychologically to his or her sensory loss. Rehabilitation for low vision offers visually impaired individuals a renewed independence and productivity that will enable them to rejoin society as active participants. Often patients and healthcare providers are unaware of the rehabilitation options that are available to them. Low-vision devices such as magnifiers and telescopes, as well as counseling and vocational training, are among the available options. Rehabilitation nurses are particularly qualified to identify patients with reduced functional ability and to recommend an appropriate visual assessment that can lead to maximized residual vision.

Ambulatory Care↗
PubMed1989

National survey of blindness and low vision in The Gambia: results.

A population based survey of blindness and eye disease has been conducted throughout the whole country of The Gambia, and 8174 people were examined. The prevalence of blindness (best acuity less than 3/60) was 0.7% and low vision (6/24-3/60) 1.4%. The causes of blindness were cataract (55%), non-trachomatous corneal opacity/phthisis (20%), and trachoma (17%). An estimated 5500 people in The Gambia require cataract surgery, 4600 eyelid surgery for entropion, and 4600 people spectacles to correct a refractive error which causes a visual acuity of less than 6/18. More than half the current burden of blindness in The Gambia is potentially remediable through the provision of cataract surgery and aphakic spectacles.

Adolescent↗
PubMed1990

Low vision and aging.

As people age they are more susceptible to various problems in the visual system. The optometrist is in the position to take care of many of the functional losses that result from age-related problems and diseases. With increased awareness of basic low vision and rehabilitation services, the practitioner can continue to care for the visual needs of the older patient.

Aged↗
PubMed1996

Prevalence and causes of low vision and blindness in the Extreme North Province of Cameroon, West Africa.

A survey to determine the prevalence and causes of blindness and visual impairment in the Extreme North Province of Cameroon was conducted in the Spring of 1992. A total of 10,647 people age 6 years and older was selected from a multi-stage, clustered sample stratified by ecological zone. The subjects were examined by ophthalmologist-led teams for visual acuity and ocular diseases. Approximately 1.2% of the sample was bilaterally blind by the World Health Organization classification (Category 3) of vision less than the ability to count fingers at 3 meters. Similarly to results found in other developing countries, senile cataract was the most common diagnosis encountered and the most frequent principal cause of low vision and blindness.

Adolescent↗