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PubMed1994

Assessment of functional vision performance: a new test for low vision patients.

Measures of functional vision are needed to assess elderly low vision patients, their success in using devices, and their ability to manage outside the treatment setting. A new test devised to measure functional ability through the performance of everyday tasks was administered to 94 patients who had acuities of 20/100 or worse in their better eye. Consisting of three versions and four subtests: spot reading, short-term text reading, identifying paper currency and clock reading, the test used standardized items and was timed. In a multiple regression model predicting test performance higher scores were associated with better near acuity (P = .002), higher education (P = .022) and higher levels of self-reported visual skills (P = .072). These predictors plus distance acuity, age and sex only accounted for 35 percent of the variance in test scores. Repeated administration of the test to a different group of 21 patients showed the test to be reliable (intraclass correlation = .85, P < .01) and to have no practice or version effects or differences between raters. This new test may be useful for natural history studies and clinical trials involving low vision patients but further evaluation of its sensitivity to change over time is required.

Adolescent↗
PubMed1986

A hospital rental system for low vision aids.

Costly low vision aids are rented to patients by the Otago Hospital Board. Occupational therapists see the patients in the Low Vision Clinic and then as necessary in their homes. As a consequence accurate follow-up and analysis of the help provided by these aids is available. Patients with senile macular degeneration use telescopic reading aids for an average of 27 months after they are prescribed.

Adolescent↗
PubMed1991

Every optometrist's concern--patient's access to low vision services.

Persons with low vision are increasing in numbers and searching for access to quality low vision services. Working with these patients is an important part of all optometric service models. Issues that should be considered and services that should be provided to patients with low vision are discussed.

Aging↗
PubMed1985

Characteristics and low vision corrections in Stargardt's disease. Educational and vocational achievements enhanced by low vision corrections.

One hundred and sixteen patients with Stargardt's disease demonstrated the most useful optical aids that enabled them to obtain an education and employment. The most useful optical aid for distance was the 8X monocular focusable telescope. For near, high-add bifocals, tri-focals, half-eye binocular spectacle magnifiers, paperweight-type magnifiers and hand magnifiers were most useful. Optical aids were prescribed for 102 patients with a success rate of 96%. The progression of visual loss is generally gradual and symmetrical terminating within ten years after onset and not becoming worse than 20/800 (6/240). Academic success seems to be related more to intellectual ability than degree of visual impairment. Highly trained and educated individuals with Stargardt's disease were able to find employment and perform duties usually associated with normal vision.

Adolescent↗
PubMed1999

Clinical effect of low vision aids.

The number of patients with low vision is increasing as life expectancy increases. In addition, the interest and demand for low vision aids are also increasing with improved socioeconomic status and the development of mass media. Therefore, it is imperative to recognize the importance of low vision aids. We reviewed the clinical records of 118 patients who visited our low vision clinic more than twice. According to the data analyzed, optic nerve atrophy, retinal degeneration, diabetic retinopathy and age-related macular degeneration were the most common causes of low vision in these patients. The best corrected visual acuities without low vision aids were less than 0.3, but with the help of low vision aids, vision improved to more than 0.4 in 87% of the patients for near vision, and 56% for distant vision. The patients had complained that they could not read books, see a blackboard, recognize a person at a distance, and had other problems because of low vision. However, with the use of low vision aids their satisfaction with their vision rose to 70%. Hand magnifiers, high-powered spectacle lenses, and stand magnifiers were the low vision aids commonly used by people for near vision, while the Galilean telescope and Keplerian telescope were the most popular devices used for distant vision. In conclusion, low vision aids are very helpful devices to patients with low vision.

Adolescent↗
PubMed1990

The experience of a university-based low vision clinic.

An open low vision clinic has been in operation at University of Wales College of Cardiff, Department of Optometry for 5 years. This paper describes the demography and visual characteristics of 218 consecutively presenting patients. A detailed survey of the aids prescribed is conducted. A significant proportion of low vision patients required only simple aids (56.8%) and low magnification (71.6%). It is suggested that these patients could be assisted in an optometric practice. In addition, visual acuity, distance or near is not a good indicator of eventual visual performance with an LVA. Therefore, it was concluded that all patients having measurable form vision should receive a low vision assessment.

Adolescent↗
PubMed1997

Improving stoma management in the low-vision patient.

Teaching the low-vision patient with an ostomy to manage a stoma independently provides a significant challenge for the WOC nurse. Although guide strips, lighted mirrors, and other handheld devices are available to patients with impaired eyesight, these products, when used alone, may be inadequate for the patient with an ostomy. In addition, there is a paucity of literature available to the WOC nurse describing specific interventions for the low-vision patient with an ostomy. Common visual problems encountered when managing people with an ostomy are reviewed. Specific interventions are discussed, including products designed to assist the low-vision patient with an ostomy with stoma care. A case study is provided that underscores the importance of consulting a low-vision specialist in the care of the patient with a new ostomy who has low vision as a result of albinism.

Adult↗
PubMed2003

Barriers to accessing low vision services.

AIM: To investigate barriers to accessing low vision services in Australia. METHODS: Adults with a vision impairment (<6/12 in the better eye and/or significant visual field defect), who were current patients at the Royal Victorian Eye and Ear Hospital (RVEEH), were interviewed. The questions investigated self-perceived vision difficulties, duration of vision loss and satisfaction with vision and also examined issues of awareness of low vision services and referral to services. Focus groups were also conducted with vision impaired (<6/12 in the better eye) patients from the RVEEH, listeners of the Radio for the Print Handicapped and peer workers at Vision Australia Foundation. The discussions were recorded and transcribed. RESULTS: The questionnaire revealed that referral to low vision services was associated with a greater degree of vision loss (p = 0.002) and a greater self-perception of low vision (p = 0.005) but that referral was not associated with satisfaction (p = 0.144) or difficulties related to vision (p = 0.169). Participants with mild and moderate vision impairment each reported similar levels of difficulties with daily activities and satisfaction with their vision (p > 0.05). However, there was a significant difference in the level of difficulties experienced with daily activities between those with mild-moderate and severe vision impairment (p < 0.05). The participants of the focus groups identified barriers to accessing low vision services related to awareness of services among the general public and eye care professionals, understanding of low vision and the services available, acceptance of low vision, the referral process, and transport. CONCLUSION: In addition to the expected difficulties with lack of awareness of services by people with low vision, many people do not understand what the services provide and do not identify themselves as having low vision. Knowledge of these barriers, from the perspective of people with low vision, can now be used to guide the development and content of future health-promotion campaigns.

Activities of Daily Living↗
PubMed1977

A multidiscipline approach in low vision rehabilitation.

The first low vision clinic was instituted at the Industrial Home for the Blind in 1953 in response to a growing demand that more effective use be made of the residual vision in blind persons. The technology was there. Eye practitioners certainly knew enough about vision problems to offer many of these people an opportunity to enter a new life. The problem was: how to put that knowledge to work through a sound service delivery system. By its twentieth anniversary in 1973 the clinic had seen almost 5,000 patients for low vision evaluation and had built a service which consistently provided substantial and useful improvement in vision through the use of optical aids to a majority of its patients. The low vision optometric staff works as an integral part of a rehabilitation team. That team consists of a number of professionals, including ophthalmologists, social workers, teachers, and a variety of rehabilitation instructors. All members work simultaneously to create a total program of rehabilitation for thepartially sighted. We feel this teamwork approach is of basic importance to effective rehabilitation.

Adolescent↗
PubMed1992

Challenges in applying autofocus technology to low vision telescopes.

Autofocus (AF) low vision telescopes offer the potential to increase the acceptance and utilization of such low vision aids (LVA) by the visually impaired. Many patients resist conventional manual focus telescopes for a variety of reasons including appearance, field of view, weight, and utility. The elderly who comprise the significant part of the target population may also resist telescopes due to an avoidance of the technical challenge of its use. Although an AF telescope is technically advanced, it may allow for less manipulation by the wearer and hence enable its more effective application to visual tasks, especially in the near- to mid-range where depths of field narrow and the demands for focusing increase. There are many challenges involved in the application of AF technology to LVA including modification of the focusing range, signal processing for physiologically acceptable performance, and power and weight considerations. A preliminary infrared (IR) AF prototype based upon our recent work with the Ocutech Vision Enhancing System (VES) has been produced. Initial findings are presented which address the requirements of a subsequent version as well as the challenges that will be faced to optimize such a device.

Audiovisual Aids↗
PubMed2004

Vision-specific health-related quality of life in age-related maculopathy patients presenting for low vision services.

Few studies have examined the effectiveness of low vision rehabilitation for age-related maculopathy (ARM) patients and its impact on vision-specific health-related quality of life (HRQoL). However, before a multi-site clinical trial can be conducted, appropriate outcome measures need to be identified for ARM patients who seek out low vision rehabilitation, including a vision-specific HR QoL instrument. The 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was developed to assess vision-specific HRQoL for low vision patients, including those with ARM. This study examines the performance of the NEI VFQ-25 among ARM patients who seek out low vision services and examines its relationship with visual acuity and self-reported use of low vision aids. One hundred and twenty-seven patients were recruited from a University-affiliated low vision clinic. During two telephone interviews, subjects completed the NEI VFQ-25 and a short cognitive test and provided information on general health and use of low vision aids. Additional information on visual acuity and eye health were collected from the medical record. Our results indicate that ARM patients who seek out low vision services report significant impairment in their vision-specific HRQoL. Their NEI VFQ-25 scores were lower compared to other ARM and low vision rehabilitation samples previously studied. The VFQ subscales with the largest deficits were near and distance visual acuities and psychosocial issues (near vision, distance vision, role difficulties, dependency, social functioning, mental health). These subscale scores were lower for those with greater visual acuity impairment. The VFQ subscale scores most impacted by the disease had wide variability and were higher for those who used low vision aids, suggesting that the NEI VFQ-25 is suitable for measuring further decline and treatment-related improvements. Thus, it should be strongly considered for a multi-site clinical trial on the effectiveness of low vision rehabilitation.

Aged↗
PubMed1996

Referral to low vision services by ophthalmologists.

PURPOSE: People in need of low vision rehabilitation services often experience delays in referral to services. This study investigates referral criteria of Australian ophthalmologists, the frequency of referral of their patients with low vision and their perceptions of low vision services. METHODS: A survey was sent to a representative, random sample of 200 ophthalmologists. They were asked about criteria used for the referral of their patients with low vision. The survey included questions on the frequency with which they prescribed low vision devices (LVD) and referral of their patients to low vision and rehabilitation services and peer support groups. Perceptions of the quality and availability of low vision services were also investigated. RESULTS: The response rate was 82%. Approximately 11% of ophthalmologists' patients have low vision. It is uncommon for ophthalmologists to prescribe LVD but 67% refer most of their patients with low vision. It is less common for them to refer to rehabilitation services (29%) or peer support services (18%). The perceived local availability of services influences the rate of referral. Ophthalmologists who used the criteria of moderate low vision (< 6/21 to < 6/60) are more likely to refer more of their patients than those who use the criteria of severe low vision. CONCLUSIONS: Australian ophthalmologists refer most of their visually impaired patients to low vision services, but infrequently to rehabilitation services or peer support groups. Differences in perceived need for low vision services indicated by the criteria used for referral, and the perceived availability, influence the rate at which ophthalmologists refer their patients for services. Ophthalmologists are encouraged to refer patients with permanent visual loss to low vision services earlier.

Australia↗
PubMed1994

Clinical low vision resource usage prediction.

In an era of increased demands and constrained budgets, it is necessary to make the best use of all available resources. This is difficult when specialized vision care, such as low vision clinical assessment, is involved because of the heterogeneity of the patient populations seen by such clinics. PURPOSE. This research attempts to discover if these diverse patient populations can be identified and clustered into groups based upon similarity of clinical resources use. Specifically, the inquiry examines the potential for a low vision patient resource utilization classification scheme at the Low Vision Clinic (LVC) in the Centre for Sight Enhancement (CSE), University of Waterloo. METHODS. From a sample of 99 patients consulting the LVC in a 3-month period, retrospective data collection involved abstracting and coding medical records containing information detailing each patient's demographic, diagnostic, therapeutic, and resource utilization characteristics. Cluster analysis using Hartigan's block clustering algorithm was then applied to the data. A replication study was completed using a sample of 99 patients visiting the LVC 1 year later. RESULTS. Patients can be classified into five iso-resource groups, hereby termed low vision patient resource groups (LVPRGs). The clusters represent a resource consistent and clinically coherent scheme for classifying low vision patients based upon resource requirements. As a measure of repeatability, the groups reemerged in the replication study. CONCLUSIONS. If the groupings demonstrate robustness in a field test, clustering algorithms in general, and LVPRGs in specific, may offer useful tools to enhance resource utilization in the LVC setting.

Adult↗
PubMed2006

Prevalence and causes of blindness and low vision in southern Sudan.

BACKGROUND: Blindness and low vision are thought to be common in southern Sudan. However, the magnitude and geographical distribution are largely unknown. We aimed to estimate the prevalence of blindness and low vision, identify the main causes of blindness and low vision, and estimate targets for blindness prevention programs in Mankien payam (district), southern Sudan. METHODS AND FINDINGS: A cross-sectional survey of the population aged 5 y and above was conducted in May 2005 using a two-stage cluster random sampling with probability proportional to size. The Snellen E chart was used to test visual acuity, and participants also underwent basic eye examination. Vision status was defined using World Health Organization categories of visual impairment based on presenting visual acuity (VA). A total of 2,954 persons were enumerated and 2,499 (84.6%) examined. Prevalence of blindness (presenting VA of less than 3/60 in the better eye) was 4.1% (95% confidence interval [CI], 3.4-4.8); prevalence of low vision (presenting VA of at least 3/60 but less than 6/18 [corrected] in the better eye) was 7.7% (95% CI, 6.7-8.7); whereas prevalence of monocular visual impairment (presenting VA of at least 6/18 [corrected] in better eye and VA of less than 6/18 [corrected] in other eye) was 4.4% (95% CI, 3.6-5.3). The main causes of blindness were considered to be cataract (41.2%) and trachoma (35.3%), whereas low vision was mainly caused by trachoma (58.1%) and cataract (29.3%). It is estimated that in Mankien payam 1,154 persons aged 5 y and above (lower and upper bounds = 782-1,799) are blind, and 2,291 persons (lower and upper bounds = 1,820-2,898) have low vision. CONCLUSIONS: Blindness is a serious public health problem in Mankien, and there is urgent need to implement comprehensive blindness prevention programs. Further surveys are essential to confirm these tragic findings and estimate prevalence of blindness and low vision in the entire region of southern Sudan in order to facilitate planning of VISION 2020 objectives.

Adolescent↗
PubMed2000

Helping blind and partially sighted people to read: the effectiveness of low vision aids.

AIMS: To substantiate the claim that low vision aids reduce the degree of disability associated with visual impairment. METHODS: An observational study of vision, ocular pathology, age, sex, and reading ability in new referrals to a low vision clinic. Reading ability was assessed both with the patients' own spectacles and with an appropriate low vision aid. RESULTS: The reading performance and biographical characteristics of new referrals to a low vision clinic were recorded. Data were collected for 168 people over a 6 month period. Upon arrival at the clinic the mean functional visual acuity equated to 6/36 and 77% of patients were unable to read newsprint (N8). After a low vision assessment and provision of a suitable low vision aid 88% of new patients were able to read N8 or smaller text. CONCLUSIONS: The degree of visual impairment observed in new referrals to a low vision clinic is sufficient to prevent the majority from performing many daily tasks. Low vision aids are an effective means of providing visual rehabilitation, helping almost nine out of 10 patients with impaired vision to read.

Adolescent↗
PubMed2006

Measuring outcomes of vision rehabilitation with the Veterans Affairs Low Vision Visual Functioning Questionnaire.

PURPOSE: To evaluate the sensitivity to change, in patients who undergo vision rehabilitation, of the Veteran Affairs (VA) Low Vision Visual Functioning Questionnaire (LV VFQ-48), which was designed to measure the difficulty visually impaired persons have in performing daily activities and to evaluate vision rehabilitation outcomes. METHODS: Before and after rehabilitation, the VA LV VFQ-48 was administered by telephone interview to subjects from five sites in the VA and private sector. Visual acuity of these subjects ranged from near normal to total blindness. RESULTS: The VA LV VFQ exhibited significant differential item functioning (DIF) for 7 of 48 items (two mobility tasks, four reading tasks, and one distance-vision task). However, the DIF was small relative to baseline changes in item difficulty for all items. Therefore, the data were reanalyzed with the constraint that item difficulties do not change with rehabilitation, which assigns all changes to the person measure. Subjects in the inpatient Blind Rehabilitation Center (BRC) program showed the largest changes in person measures after vision rehabilitation (effect size = 1.9; t-test P < 0.0001). The subjects in the outpatient programs exhibited smaller changes in person measures after rehabilitation (effect size = 0.29; t-test P < 0.01). There was no significant change in person measures for the control group (test-retest before rehabilitation). CONCLUSIONS: In addition to being a valid and reliable measure of visual ability, the VA LV VFQ-48 is a sensitive measure of changes that occur in visual ability as a result of vision rehabilitation. Patients' self-reports of the difficulty they experience performing daily activities measured with this instrument can be used to compute a single number, the person measure that can serve as an outcome measure in clinical studies. The VA LV VFQ-48 can be used to compare programs that offer different levels of intervention and serve patients across the continuum of vision loss.

Activities of Daily Living↗
PubMed1993

Establishment of comprehensive low vision services in Michigan.

The AOA Low Vision Section presented its distinguished service award to the Michigan Commission for the Blind during the Section's 10th anniversary celebration at the 95th AOA Congress in Montreal. A progressive low vision service delivery system has evolved in Michigan over the past 22 years with optometry identified as the provider of clinical low vision care. The development of this system is described as the relationship between the Michigan Optometric Association, Michigan Commission for the Blind, and other multidisciplinary agencies is explained. Strategies for serving the visually impaired pediatric, career/vocationally aged, elderly and multiply handicapped populations in Michigan are highlighted. This historical review offers ideas for future planning as optometric low vision services are integrated into other state programs.

Humans↗
PubMed1995

Psychophysics of reading--XIII. Predictors of magnifier-aided reading speed in low vision.

A key clinical problem in low-vision assessment is finding simple measures that are predictive of real-world performance. Our purpose was to determine whether a set of clinical variables could predict how well low-vision subjects read with their magnifiers. The variables were Snellen acuity, presence/absence of central scotomas, clear/cloudy ocular media, age, magnifier type, and score on a standardized test of reading speed (Minnesota Low-vision Reading Test). Forty low-vision subjects identified the magnifier they most "preferred" to use, based on the frequency and length of time used, ease of use, or any other factor considered important by each subject. All subjects were highly experienced with their magnifier (3 months to 21 yr of use). We classified the magnifiers into five categories: (1) standard correction only; (2) hand-held magnifier; (3) spectacle-mounted magnifier; (4) closed-circuit TV; and (5) stand magnifier. Subjects used their preferred magnifiers to read aloud printed paragraphs of about 150 words from which their reading speeds were calculated. By far the best predictor of the magnifier-aided reading speed was the score on the standardized reading test which accounted for 79.7% of the variance. 43.7% of the variance was accounted for by age, and 42.3% by magnifier type. Snellen acuity, central visual field status, and ocular media status were not significantly correlated with magnifier-aided reading speed. We conclude that a standardized clinical reading test can give a valid prediction of the reading speed a low-vision patient is likely to achieve with a magnifier.

Adult↗