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PubMed2004

Reading errors made by children with low vision.

Previous research has shown that, on average, children with low vision lag their sighted peers in general reading development (in terms of speed, accuracy and comprehension). This study sought to examine this apparent lag by comparing the reading profiles of 25 normally sighted readers (mean age 8 years 8 months) with 25 low vision readers. The children were tested using a reading test (the Neale Analysis of Reading Ability, NARA) and were matched on the reading accuracy score produced by the test. Therefore in terms of the reading accuracy scores (and reading ages) derived from the NARA both groups were the same. The low vision readers were on average older than the normally sighted children (mean = 10 years, 5 months). When the reading profile (i.e. accuracy, comprehension and speed) was examined in the same analysis no significant effect was revealed [d.f. = 1, 48; F = 0.05; p > 0.1], but a general lag for these children is suggested (in keeping with previous research). However, a closer analysis of the reading error profile revealed the most common reading errors made by all readers in the analysis were either mispronunciations or substitutions. The low vision readers were more prone to making substitution errors than mispronunciations and the reverse was true for normally sighted readers [d.f. = 1, 48; F = 7.1; p < 0.05]. This indicates that the reading strategies adopted by low vision readers may differ from those of normally sighted readers of the same apparent reading ability.

Case-Control Studies↗
PubMed1987

Optometry residency in low vision rehabilitation: a cooperative program.

A cooperative Optometry Residency in Low Vision Rehabilitation has been established by the Optometry Sections at Hines Veterans Administration Hospital, Westside Veterans Administration Medical Center and the Illinois College of Optometry. The objective of this program is to train optometrists to function within, develop and direct clinical low vision programs in multidisciplinary settings. This optometry residency is unique in that it provides experience in delivering clinical low vision services in both inpatient and outpatient settings for patients of all ages during all stages of the clinical course of their disease, treatment and rehabilitation. Clinical rotations include the Optometry Section at the Central Blind Rehabilitation Center, the Chicago VICTORS Program, the Low Vision Clinic and affiliated Low Vision Clinics of the Illinois College of Optometry.

Blindness↗
PubMed1991

Low vision management of retinitis pigmentosa.

The low vision treatment of patients with retinitis pigmentosa (RP) has evolved through an understanding of the needs of the patient with extreme peripheral field constriction. Patient care involves four main areas: 1) best refraction and simple magnification, including the possibility of electronic type magnification for reading; 2) control of glare and determination of the proper illumination for reading and mobility; 3) use of field enhancement procedures for sighting and for mobility, including the understanding of cane travel and scanning techniques; 4) additional counseling and ancillary care. Through the methods described, patients who might have been poor prospects for low vision care 15 or 20 years ago, may now be able to function at much higher levels.

Eyeglasses↗
PubMed1998

The ophthalmic registered nurse's responsibility to the adult patient with low vision.

A key goal in the care of adult patients with low vision is to help them focus on their visual abilities rather than their disabilities. This article presents information that every ophthalmic nurse can use to teach patients with low vision some practical ways to change their personal environment to enhance visibility and safety. There are also some myths and misunderstandings about low vision that the nurse can dispel. Before referring patients to low-vision specialty clinics or organizations, every ophthalmic nurse can begin the visual rehabilitation for patients with low vision.

Activities of Daily Living↗
PubMed1999

The changing face of the visually impaired: the Kooyong low vision clinic's past, present, and future.

PURPOSE: To demonstrate the changes that have occurred in a developed world low vision population over the past three decades and to examine the present rehabilitation of the visually impaired attending a multi-disciplinary low vision clinic. METHODS: A retrospective examination of the 22,860 patients attending the low vision clinic at Kooyong since its inauguration in 1972 to 1996 allowed the extraction of information on their age, gender, living status, and primary condition causing low vision. A prospective unified study of 590 patients attending the clinic over a 6-month period in 1998 examined the demographics of the present low vision population and what rehabilitation they received. RESULTS: The average age of patients attending the low vision clinic has steadily increased, with 87% over the age of 60 years in the mid-1990s compared to 71% in the mid-1970s. The percentage of female patients attending the clinic has also steadily risen over the past three decades (from 59 to 66%), as has the percentage of patients living alone (from 23 to 41%). The main change in the conditions causing visual impairment in the clinic's low vision population has been the increase in age-related macular degeneration (ARMD). The average presenting distance acuity was 6/38, improving to 6/30(-1) with refraction. One-third of the patients could manage N5 print with the aid of +4.00 near addition lenses or less. Over one-half were prescribed magnification aids, with 19% having need for 2 or more to accomplish their desired visual tasks. Two-thirds of the patients made use of staff from multiple disciplines during their visual rehabilitation. CONCLUSIONS: The low vision population has changed over the past three decades. Major changes that have implications on low vision rehabilitation services are the increasing age of the patients and the preponderance of ARMD.

Adult↗
PubMedDate not supplied

Managing low vision patients.

1. The ophthalmologist and staff are ultimately responsible for identifying low vision patients. 2. Most low vision patients who have a professional low vision evaluation are able to use vision enhancing devices. 3. In addition to optical magnifyers, new computer and television technology enhances use of residual vision.

Communication Devices for People with Disabilities↗
PubMedDate not supplied

Causes of low vision and blindness in children in a blind school in Lagos, Nigeria.

A descriptive study to determine the causes of low vision and blindness in children attending the Pacelli School for the Blind in Lagos State, Nigeria. A standardised methodology was used with structured and semi-structured questioinaires. Twenty-six children aged below 16 years who were identified as having low vision and blindness were examined to determine the causes of the low vision and blindness. The anatomical sites of diseases leading to low vision and blindness in these children were retina (30.8%), lens (23.1%), glaucoma (19.2%), cornea (11.5%) and optic nerve (7.7%). Aetiologically, 38.5% of low vision was due to hereditary factors, 23.1% intra-uterine, 15.4% others and unknown in 23%. Retinal dystrophy was the most common cause of low vision and blindness, while congenital cataract and glaucoma were the major causes of avoidable blindness. Very few cases of corneal scar (Measles/Vitamin A deficiency) were seen. The causes of low vision appeared to be different from those of blindness as hereditary and intra-uterine factors were mainly responsible for low vision. It is recommended that these children be identified early, through low vision care programmes and those with avoidable causes treated accordingly.

Adolescent↗
PubMed1995

Long-term results of low vision rehabilitation in age-related macular degeneration.

One to five years after successful low vision rehabilitation, 199 patients with age-related macular degeneration were asked by means of a questionnaire whether they still used their low vision aids and whether they were satisfied with the low vision counseling. We received feedback from 66% of the patients. 20 patients had already passed away. 74% of the 112 answering patients still use a low vision aid today. Three-quarters of them still use the originally prescribed low vision aid. Interestingly enough, the daily reading time was rather short, only 16% of the patients read more than 1 hour per day, 42% read somewhat more and 13% somewhat less than 10 minutes per day. Retrospectively, 81% of all responding patients found their low vision counseling at least a little, more of them quite or very helpful. These numbers suggest, that the initial labor of patiently examining and training older, visually handicapped patients is worthwhile.

Aged↗
PubMed2006

Low-vision reading speed: influences of linguistic inference and aging.

PURPOSE: Reading is a dynamic task involving both linguistic and visual analysis. In this study, we asked how two types of linguistic information--characters used in segmenting words from one another, and sentence context--differ in their usefulness for people with normal and low vision. Given evidence for age-related differences in some forms of cognitive processing, we also investigated the effect of age. METHODS: There were four groups of 10 participants: vision status (normal, low) crossed with age (young, <35 years; old, >65 years). Reading speeds were compared for regularly spaced text and text in which the spaces were removed, a manipulation intended to eliminate local cues for text segmentation and force attention to clusters of letters or whole words. We also evaluated the effect of sentence context by comparing reading speeds for regular sentences and sentences in which word order was scrambled. RESULTS: Removal of spaces had a greater impact on low vision than normal vision, reducing average speeds to 45% and 66% of speeds for regularly spaced text, respectively. We interpret this to mean that people with low vision have less access to spatially distributed linguistic regularities of text such as prefixes, suffixes, or word length. Removal of sentence context through scrambling had a greater impact on normal vision than low vision, reducing mean reading speed to 53% and 66%, respectively. Finally, comparison of our young and old readers showed no major differences in the use of sentence context or in the impact of removing spaces between words. CONCLUSIONS: People with low vision appear to rely more on spacing information in sentences, whereas people with normal vision appear to make better use of sentence context, irrespective of age.

Adult↗
PubMed2001

Characteristics of the pediatric/adolescent low-vision population at the Illinois School for the Visually Impaired.

BACKGROUND: There are few descriptive studies of children and adolescents with low vision in the United States. Our study describes a pediatric/adolescent population at the Illinois School for the Visually Impaired (ISVI), detailing the etiologies of low vision and the devices prescribed. METHODS: A retrospective record review was conducted of 260 consecutive students who had been examined at the twice-yearly Lions of Illinois Low Vision Clinic at ISVI between the years 1991 and 1999. Data collected included age, race, sex, best-corrected visual acuity, ocular diagnoses, the etiology of low vision (if known), and low-vision devices prescribed. RESULTS: The population was 60% male. Ages ranged from less than 1 year to 20 years of age. The mean best-corrected distance visual acuity was approximately 20/200. Optic atrophy, cataracts, and retinopathy of prematurity were significant etiologies of low vision; however, the largest group of patients had a diagnosis classified as "other." Hand-held telescopes, bifocals/high adds, and tinted lenses were the major low-vision devices prescribed. CONCLUSIONS: While optic atrophy, cataracts, and retinopathy of prematurity were common causes of vision impairment among students at ISVI, the largest group of students had an etiology from a wide range of disorders. Information on the causes of low vision can help with decisions on the allocation of research funds and resources for low-vision devices.

Adolescent↗
PubMed1986

Evaluation of reading speed with four low vision aids.

Four commonly prescribed low vision aids of equivalent power were evaluated to determine maximum reading speed of normally sighted young adults. Subjects tested were fully sighted and of similar educational backgrounds. Presentation of the four aids was designed to duplicate common clinical methods of evaluating these categories of aids. Limitations imposed under these conditions on reading speed by the optics of the four systems were determined. Maximum reading speed was attained with microscopes, followed by (in order) hand magnifiers, focusable telescopes, and stand magnifiers. Results have implications on clinicians' initial performance expectations for these categories of optical aids for patients having low vision.

Adult↗
PubMed2001

A weighted version of the Melbourne Low-Vision ADL Index: a measure of disability impact.

OBJECTIVE: To develop a version of the Melbourne Low-Vision ADL Index that measures the personal impact of disability in activities of daily living (ADL's). Also, to determine the relationship between clinical measures of vision impairment and disability impact. METHODS: The Melbourne Low-Vision ADL Index (MLVAI) is a desk-based clinical assessment of disability in ADL's. Ability to perform each item is rated on a five-level descriptive scale from zero to four. In this study, the original version of the MLVAI was modified to measure disability impact. The simple modification involved weighting each item by the importance of that item to the person being tested. Importance was also rated on a five-level scale from zero to four. The validity and reliability of the Weighted Melbourne Low-Vision ADL Index (MLVAI(W)) was determined for 97 vision-impaired subjects in a cross-sectional study. RESULTS: Cronbach's alpha coefficient indicated an internal reliability of 0.94, and an intraclass correlation coefficient indicated an overall reliability of 0.88. The standard error of measurement was 24.7 points (out of a possible score of 400). There was a statistically significant difference in test scores between normal subjects and vision-impaired subjects. All vision measures had a high, statistically significant correlation with MLVAI(W) score. Near-word acuity had the strongest correlation (r(s) = 0.78, p < 0.001), followed by Melbourne Edge Test contrast sensitivity (r(s) = -0.72, p < 0.001). Visual field had the weakest correlation (r(s) = -0.52, p < 0.001). The best predictive model of MLVAI(W) score incorporated the variables age, near-word acuity, and visual field. Together, these variables accounted for 65.1% of the variance in MLVAI(W) score. CONCLUSIONS: The MLVAI is highly valid and reliable when weighted by a scale that reflects the personal importance of ADL's. The MLVAI(W) can provide information over and above that obtained with the usual clinical vision measures and may be used to assess low-vision patients and to measure low-vision rehabilitation outcomes. It is suggested that the assessment of disability using the original MLVAI and the assessment of the impact of disability using the MLVAI(W) should be kept separate to facilitate the clear interpretation of the outcomes of low-vision rehabilitation.

Activities of Daily Living↗
PubMedDate not supplied

Prevalence of remediable disability due to low vision among institutionalised elderly people.

BACKGROUND: Prevalence of remediable visual disability among institutionalised elderly people, resulting from inappropriate use or non-use of low-vision aids, is reported to be high, but largely rests on anecdotal evidence. OBJECTIVE: To estimate the prevalence of binocular low vision and underlying eye diseases among institutionalised elderly people in a Dutch urban population and the size of remediable visual disability as the result of inappropriately corrected low vision. METHODS: The design was a cross-sectional survey of 284 subjects with low vision (corrected binocular vision <0.4) in nursing homes and homes for the elderly in the Netherlands. RESULTS: 284 of 610 eligible residents were examined. The prevalence of binocular low vision was 31.3%. Among elderly residents with low vision, prevalence of cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy was 77.9, 37.7, 5.2 and 5.2%, respectively. In 32 residents (41.6%), (non)-use of low-vision aids was considered inappropriate. In 50 residents (64.9%), visual disability was considered at least partially remediable, either through better use of low-vision aids, or through cataract extraction. Residents who were not optimally corrected for low vision were significantly more functionally impaired compared with their peers who were optimally corrected. CONCLUSION: Low vision is likely to be highly prevalent among institutionalised elderly. A significant amount of the associated visual disability may be remediable.

Aged↗
PubMed1995

Older Alabamians System of Information and Services (OASIS): a model Title VII chapter 2 low vision rehabilitation program.

BACKGROUND: Little attention has been paid in the ophthalmic literature to programmatic issues of low vision rehabilitation services delivery. The Older Alabamians System of Information and Services (Project OASIS) is a model low vision rehabilitation program functioning within the state of Alabama. This program is funded through Title VII, chapter 2 of the Rehabilitation Act, Independent Living Services for Older Blind Individuals. The program provides a comprehensive array of independent living services, including optometric low vision evaluation and low vision devices, to persons who are older and blind. Through intergency agreements between various state agencies and private entities, OASIS is able to maximize limited resources and reduce service redundancies. METHODS: Components of the OASIS consortium are reviewed along with outcomes of participants in fiscal year 1993-94. RESULTS: In fiscal year 1993-94 1,114 persons were entered into Project OASIS. Over half (569/1,114) of individuals accepted into the program received traditional optometric low vision rehabilitation services. More than 80% (586/717) of persons were able to achieve their independent living goals. CONCLUSIONS: Through a consortium effort between aging and rehabilitative services, minimal resources have been maximized to allow older visually impaired adults to benefit from comprehensive low vision rehabilitation services.

Activities of Daily Living↗
PubMed2003

Causes of low vision and blindness in rural Indonesia.

AIM: To determine the prevalence rates and major contributing causes of low vision and blindness in adults in a rural setting in Indonesia METHODS: A population based prevalence survey of adults 21 years or older (n=989) was conducted in five rural villages and one provincial town in Sumatra, Indonesia. One stage household cluster sampling procedure was employed where 100 households were randomly selected from each village or town. Bilateral low vision was defined as habitual VA (measured using tumbling "E" logMAR charts) in the better eye worse than 6/18 and 3/60 or better, based on the WHO criteria. Bilateral blindness was defined as habitual VA worse than 3/60 in the better eye. The anterior segment and lens of subjects with low vision or blindness (both unilateral and bilateral) (n=66) were examined using a portable slit lamp and fundus examination was performed using indirect ophthalmoscopy. RESULTS: The overall age adjusted (adjusted to the 1990 Indonesia census population) prevalence rate of bilateral low vision was 5.8% (95% confidence interval (CI) 4.2 to 7.4) and bilateral blindness was 2.2% (95% CI 1.1 to 3.2). The rates of low vision and blindness increased with age. The major contributing causes for bilateral low vision were cataract (61.3%), uncorrected refractive error (12.9%), and amblyopia (12.9%), and the major cause of bilateral blindness was cataract (62.5%). The major causes of unilateral low vision were cataract (48.0%) and uncorrected refractive error (12.0%), and major causes of unilateral blindness were amblyopia (50.0%) and trauma (50.0%). CONCLUSIONS: The rates of habitual low vision and blindness in provincial Sumatra, Indonesia, are similar to other developing rural countries in Asia. Blindness is largely preventable, as the major contributing causes (cataract and uncorrected refractive error) are amenable to treatment.

Adult↗
PubMed1995

Functional considerations in evaluation and treatment of the client with low vision.

In evaluating and treating clients who have low vision, the occupational therapist must consider factors in addition to typical measures of the client's visual acuity, field loss, and oculomotor control. It is important to consider the functional implications of the client's ocular pathology, including illumination needs, contrast sensitivity, sensitivity to glare, and need for magnification as well as environmental factors such as the amount of pattern in a visual task, the amount of lighting and contrast available, and the conditions under which the task is performed. These factors are all relevant to occupational therapy low vision rehabilitation because each may influence the way in which a client uses his or her residual vision and achieves successful adaptation. This article provides an overview of these factors and presents a suggested protocol for evaluation of the client with low vision.

Activities of Daily Living↗
PubMed2000

A retrospective study of low-vision cases in an Indian tertiary eye-care hospital.

PURPOSE: To obtain data on the characteristics of low-vision patients seen at a tertiary eye care hospital in India. METHODS: Records of 410 patients were retrospectively reviewed at the Centre for Sight Enhancement, L.V. Prasad Eye Institute, Hyderabad, India. Patient underwent a comprehensive clinical low-vision examination. Data obtained included age, gender, consanguinity, visual acuity, visual fields, ocular conditions causing low vision and types of low-vision devices and methods prescribed. RESULTS: Two hundred and ninety seven (72%) of 450 patients were male. One-fifth were in the 11-20 years age group (21%). Visual acuity in the better eye was < 6/18-6/60 in almost half these patients (49.3%). One hundred and twenty two patients (29.9%) referred with a visual acuity of > or = 6/18, either had difficulty in reading normal print or had restricted visual fields. The main causes for low vision were: retinitis pigmentosa (19%), diabetic retinopathy (13%), Macular diseases (17.7%), and degenerative myopia (9%). Visual rehabilitation was achieved using accurate correction of ametropia (174 patients), approach magnification (74 patients) and telescopes (45 patients) for recognising faces, watching television and board work. Spectacle magnifiers (187 patients), hand/stand magnifiers (9 patients), closed-circuit television (3 patients), overhead illumination lamp (143 patients) and reading stand (24 patients) were prescribed for reading tasks. Light control devices (146 patients) were used for glare control, and cane (128 patients) and flashlight (50 patients) for mobility. Patients were trained in activities to improve their daily living skills, (54 patients); counselled in environmental modification (144 patients) and ancillary care (63 patients) for educational and vocational needs. CONCLUSION: Data obtained from this study elucidates the characteristics of low-vision patients. This information is likely to help in the development of appropriate low vision services.

Adolescent↗
PubMed1991

Specialization in low vision rehabilitation and visual therapy.

A questionnaire was mailed to members of the Low Vision Section (LVS) of the American Optometric Association (AOA) and the Council on Visual Development (COVD) to determine the practice patterns of low vision clinicians, amount and source of specialty training and the extent of dual specialization in both low vision rehabilitation and visual training by members of COVD. Results indicate that 61.1 percent of AOA/LVS members and 20.9 percent of COVD members examine more than four patients per month who require low vision services. Yet, only 2.1 percent of COVD respondents and 32.2 percent of AOA/LVS respondents spend more than 20 percent of their practice time providing low vision services.

Humans↗