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Indian Journal of Ophthalmology Jan 2021To identify children with low vision from two local schools for the blind, to provide low vision devices (LVD) to those who may benefit from it, and to encourage them to... (Review)
Review
PURPOSE
To identify children with low vision from two local schools for the blind, to provide low vision devices (LVD) to those who may benefit from it, and to encourage them to learn print.
METHODS
A prospective study was conducted among children from two local schools for the blind. Best-corrected visual acuity (BCVA) was done using the Snellen chart. Children with BCVA of counting finger (CF) 1/2 meter or more in the better eye underwent low vision assessment. Distant vision was assessed using the Feinbloom chart and near vision was assessed using the Lea symbol chart. Low vision devices (LVD) were prescribed as required.
RESULTS
Among 185 children enrolled, 31 children had BCVA of >CF ½ meter. Using a telescope, distant vision was better than 3/36 in 48.4%, 3/36-3/12 in 16.2%, and 3/9.5 to 3/3 in 35.4%. Among 23 children who read 1M at <10 cm, 22.6% could read 0.6-0.8M, and 25.8% could read 1M using LVD.
CONCLUSION
Regular screening of children in schools for the blind could identify children who might benefit from LVD. A review of protocols for the entry of children in schools for the blind by screening these children by a specialist team prior to admission should be made mandatory.
Topics: Child; Humans; India; Prospective Studies; Schools; Vision Screening; Vision, Low; Visual Acuity
PubMed: 33323596
DOI: 10.4103/ijo.IJO_142_20 -
Optometry and Vision Science : Official... Apr 2021This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in individuals with vision impairment. Assessment for and identification of... (Review)
Review
This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in individuals with vision impairment. Assessment for and identification of binocular vision dysfunctions can detect individuals experiencing difficulties in activities including reading, object placement tasks, and mobility.Comprehensive vision assessment in low vision populations is necessary to identify the extent of remaining vision and to enable directed rehabilitation efforts. In patients with vision impairment, little attention is typically paid to assessments of binocular vision, including ocular vergence, stereopsis, and binocular summation characteristics. In addition, binocular measurements of threshold automated visual fields are not routinely performed in clinical practice, leading to an incomplete understanding of individuals' binocular visual field and may affect rehabilitation outcomes.First, this review summarizes the prevalence of dysfunctions in ocular vergence, stereopsis, and binocular summation characteristics across a variety of ocular pathologies causing vision impairment. Second, this review examines the links between clinical measurements of binocular visual functions and outcome measures including quality of life and performance in functional tasks. There is an increased prevalence of dysfunctions in ocular alignment, stereopsis, and binocular summation across low vision cohorts compared with those with normal vision. The identification of binocular vision dysfunctions during routine low vision assessments is especially important in patients experiencing difficulties in activities of daily living, including but not limited to reading, object placement tasks, and mobility. However, further research is required to determine whether addressing the identified deficits in binocular vision in low vision rehabilitative efforts directly impacts patient outcomes.
Topics: Activities of Daily Living; Depth Perception; Humans; Quality of Life; Reading; Vision, Binocular; Vision, Low; Visual Fields; Visual Perception; Visually Impaired Persons
PubMed: 33828038
DOI: 10.1097/OPX.0000000000001672 -
Middle East African Journal of... 2014Childhood blindness and visual impairment (CBVI) are major disabilities that compromise the normal development of children. Health resources and practices to prevent... (Review)
Review
Childhood blindness and visual impairment (CBVI) are major disabilities that compromise the normal development of children. Health resources and practices to prevent CBVI are suboptimal in most countries in the Eastern Mediterranean Region (EMR). We reviewed the magnitude and the etiologies of childhood visual disabilities based on the estimates using socioeconomic proxy indicators such as gross domestic product (GDP) per capita and <5-year mortality rates. The result of these findings will facilitate novel concepts in addressing and developing services to effectively reduce CBVI in this region. The current study determined the rates of bilateral blindness (defined as Best corrected visual acuity(BCVA)) less than 3/60 in the better eye or a visual field of 10° surrounding central fixation) and functional low vision (FLV) (visual impairment for which no treatment or refractive correction can improve the vision up to >6/18 in a better eye) in children <15 years old. We used the 2011 population projections, <5-year mortality rates and GDP per capita of 23 countries (collectively grouped as EMR). Based on the GDP, we divided the countries into three groups; high, middle- and low-income nations. By applying the bilateral blindness and FLV rates to high, middle- and low-income countries from the global literature to the population of children <15 years, we estimated that there could be 238,500 children with bilateral blindness (rate 1.2/1,000) in the region. In addition, there could be approximately 417,725 children with FLV (rate of 2.1/1,000) in the region. The causes of visual disability in the three groups are also discussed based on the available data. As our estimates are based on hospital and blind school studies in the past, they could have serious limitations for projecting the present magnitude and causes of visual disabilities in children of EMR. An effective approach to eye health care and screening for children within primary health care and with the available resources are discussed. The objectives, strategies, and operating procedures for child eye-care are presented. Variables impacting proper screening are discussed. To reach the targets, we recommend urgent implementation of new approaches to low vision and rehabilitation of children.
Topics: Adolescent; Age Distribution; Blindness; Child; Child, Preschool; Female; Humans; Infant; Male; Mediterranean Region; Prevalence; Vision, Low; Visual Acuity; Visually Impaired Persons
PubMed: 25371641
DOI: 10.4103/0974-9233.142273 -
Indian Journal of Ophthalmology May 2020The objective of this study was to estimate the level of visual impairment in patients diagnosed to have age-related macular degeneration (ARMD) who presented to...
PURPOSE
The objective of this study was to estimate the level of visual impairment in patients diagnosed to have age-related macular degeneration (ARMD) who presented to low-vision care (LVC) clinic at a tertiary eye care center in India, to analyze the type of distant and near devices prescribed to them and to compare the visual benefit in different age groups among patients with ARMD.
METHODS
A retrospective review was done for 91 patients with low-vision secondary to ARMD who were referred to the LVC clinic from 2016 to 2017. Demographic profile: age, gender, occupation, ocular history, visual acuity status, and type of low-vision device (LVD) preferred were documented. The details of LVDs and subsequent improvements were noted.
RESULT
Of the 91 patients, 64 (70.3%) were men and 27 (29.7%) were women. Of the cases which were referred, 36.26% had a severe visual impairment (VI), 32.96% had moderate VI, 28.57% had mild VI, and 5.49% had profound VI. The majority of the patients had myopia 57 (62.63%), followed by hyperopia in 25 (27.47%) subjects. The subjects were divided into three groups based on age 40-65 years, 66-75 years, and above 75 years for the analysis of VI. There was a statistically significant improvement (P < 0.01) in near vision with the help of LVDs in all three groups. SEE TV binocular telescope was the most commonly prescribed LVD for viewing distant objects. The most commonly preferred magnifier for near work was half-eye spectacle (56%) followed by stand magnifier (9.9%) and portable video magnifier (9.9%).
CONCLUSION
The use of LVDs can help these patients with ARMD in cases where medical and surgical treatment have no or a limited role in restoring useful vision.
Topics: Adult; Aged; Female; Humans; India; Macular Degeneration; Male; Middle Aged; Retrospective Studies; Vision, Low; Visual Acuity
PubMed: 32317472
DOI: 10.4103/ijo.IJO_1093_19 -
Eye (London, England) Oct 2022To assess the main causes leading to childhood visual impairment/blindness in a center for low vision in Israel and to analyze the literature on pediatric blinding... (Review)
Review
BACKGROUND
To assess the main causes leading to childhood visual impairment/blindness in a center for low vision in Israel and to analyze the literature on pediatric blinding diseases in developed countries.
METHODS
Retrospective study based on observational case series. Data were obtained from medical records of visually impaired children, seen at a national referral low vision center. Children were divided into two groups: moderate visual impairment (6/18 to 6/60) and severe visual impairment (SVI)/blindness (<6/60). Inherited eye diseases (IED) were grouped together for analysis. Data from the Israeli blind registry from the same period of time were analyzed for comparison. A review of literature on childhood blindness in developed countries since 2000 was conducted.
RESULTS
A total of 1393 children aged 0-18 years were included in the study. Moderate visual impairment was seen in 1025 (73.6%) and SVI/blindness in 368 (26.4%) of the studied children. Among blind children, IED accounted for at least 51% of all diagnoses, including mainly albinism and retinal dystrophies. IED prevalence was equally high in both main ethnic groups (Jewish and Arab Muslims). Non-IED (22.6%) included mainly patients with cerebral visual impairment and retinopathy of prematurity.
CONCLUSIONS
The leading cause of childhood visual impairment and blindness in our patient cohort was IED. Analyses of the literature from the last two decades show that IED are a major cause for SVI/childhood blindness in other developed countries as well. Updated patterns of global childhood blindness may suggest a need for new approach for screening programs and modern tactics for prevention.
Topics: Blindness; Child; Eye Diseases, Hereditary; Humans; Infant, Newborn; Israel; Retrospective Studies; Vision Disorders; Vision, Low; Visual Acuity; Visually Impaired Persons
PubMed: 34426656
DOI: 10.1038/s41433-021-01743-3 -
Journal of Rehabilitation Research and... 2016Vision impairments are highly prevalent after acquired brain injury (ABI). Conceptual models that focus on constructing intellectual frameworks greatly facilitate... (Review)
Review
Vision impairments are highly prevalent after acquired brain injury (ABI). Conceptual models that focus on constructing intellectual frameworks greatly facilitate comprehension and implementation of practice guidelines in an interprofessional setting. The purpose of this article is to provide a review of the vision literature in ABI, describe a conceptual model for vision rehabilitation, explain its potential clinical inferences, and discuss its translation into rehabilitation across multiple practice settings and disciplines.
Topics: Brain Injuries; Humans; Models, Theoretical; Vision, Low
PubMed: 27997671
DOI: 10.1682/JRRD.2015.06.0113 -
Indian Journal of Ophthalmology 2012Two-thirds of the world's population with low vision resides in the Asia-Pacific region. Provision of comprehensive low vision services is important to improve... (Review)
Review
Two-thirds of the world's population with low vision resides in the Asia-Pacific region. Provision of comprehensive low vision services is important to improve vision-related quality of life (QoL) for people with this condition. This review outlines the critical issues and challenges facing the provision of low vision services in the Asia-Pacific region. The review offers possible strategies to tackle these issues and challenges facing service providers and policy makers in lieu of Vision 2020 strategies in this area. Pertinent findings from the global survey of low vision services and extensive ground work conducted in the region are used; in addition, a discussion on the availability of services, human resources and training, and funding and the future sustainability of low vision care will be covered. In summary, current issues and challenges facing the region are the lack of specific evidence-based data, access, appropriate equipment and facilities, human resources, funding, and sustainability. These issues are inextricably interlinked and thus cannot be addressed in isolation. The solutions proposed cover all areas of the VISION 2020 strategy that include service delivery, human resources, infrastructure and equipment, advocacy and partnership; and include provision of comprehensive care via vertical and horizontal integration; strengthening primary level care in the community; providing formal and informal training to enable task shifting and capacity building; and promoting strong government and private sector partnership to achieve long-term service financial sustainability.
Topics: Asia; Health Policy; Health Services Needs and Demand; Humans; Prevalence; Primary Health Care; Vision, Low
PubMed: 22944759
DOI: 10.4103/0301-4738.100549 -
Indian Journal of Ophthalmology Jan 2023The present study was a population-based study to determine the prevalence and causes of low vision in children less than 16 years in North India.
PURPOSE
The present study was a population-based study to determine the prevalence and causes of low vision in children less than 16 years in North India.
METHODS
This cross-sectional study was conducted in 40 clusters of urban Delhi. Children aged less than 16 years underwent visual acuity screening using age-appropriate visual acuity charts. All children with visual acuity of <6/12 in any eye in the age group between 3 and 15 years and inability to follow the light in age less than 3 years were referred for detailed ophthalmic examination in a centrally based clinic. Cycloplegic examination and best-corrected visual acuity (BCVA) were assessed. They were examined by an ophthalmologist to determine the prevalence and causes of functional low vision (FLV). The prevalence of FLV was compared with other population-based studies across India and other parts of the world.
RESULTS
Amongst 20,955 children examined for visual acuity, 789 children were referred to the central clinic for detailed ophthalmic examination. The overall prevalence of low vision was 0.62 per 1,000 children (95% confidence interval [CI] 0.12-1.90). The main anatomical cause of low vision was retinal abnormalities.
CONCLUSION
Although the prevalence of children with low vision decreased as compared to previous population-based studies. There is an important need to create awareness among parents on appropriate and timely usage of low-vision devices (LVDs) at an affordable cost to improve the visual quality in children with low vision.
Topics: Humans; Child; Vision, Low; Prevalence; Cross-Sectional Studies; Vision Disorders; India; Blindness
PubMed: 36588238
DOI: 10.4103/ijo.IJO_1078_22 -
The Cochrane Database of Systematic... Apr 2018The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual-vision and low-vision aids, which range from simple optical magnifiers to high-magnification video magnifiers.
OBJECTIVES
To assess the effects of different visual reading aids for adults with low vision.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 12); MEDLINE Ovid; Embase Ovid; BIREME LILACS, OpenGrey, the ISRCTN registry; ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). The date of the search was 17 January 2018.
SELECTION CRITERIA
This review includes randomised and quasi-randomised trials that compared any device or aid used for reading to another device or aid in people aged 16 or over with low vision as defined by the study investigators. We did not compare low-vision aids with no low-vision aid since it is obviously not possible to measure reading speed, our primary outcome, in people that cannot read ordinary print. We considered reading aids that maximise the person's visual reading capacity, for example by increasing image magnification (optical and electronic magnifiers), augmenting text contrast (coloured filters) or trying to optimise the viewing angle or gaze position (such as prisms). We have not included studies investigating reading aids that allow reading through hearing, such as talking books or screen readers, or through touch, such as Braille-based devices and we did not consider rehabilitation strategies or complex low-vision interventions.
DATA COLLECTION AND ANALYSIS
We used standard methods expected by Cochrane. At least two authors independently assessed trial quality and extracted data. The primary outcome of the review was reading speed in words per minute. Secondary outcomes included reading duration and acuity, ease and frequency of use, quality of life and adverse outcomes. We graded the certainty of the evidence using GRADE.
MAIN RESULTS
We included 11 small studies with a cross-over design (435 people overall), one study with two parallel arms (37 participants) and one study with three parallel arms (243 participants). These studies took place in the USA (7 studies), the UK (5 studies) and Canada (1 study). Age-related macular degeneration (AMD) was the most frequent cause of low vision, with 10 studies reporting 50% or more participants with the condition. Participants were aged 9 to 97 years in these studies, but most were older (the median average age across studies was 71 years). None of the studies were masked; otherwise we largely judged the studies to be at low risk of bias. All studies reported the primary outcome: results for reading speed. None of the studies measured or reported adverse outcomes.Reading speed may be higher with stand-mounted closed circuit television (CCTV) than with optical devices (stand or hand magnifiers) (low-certainty evidence, 2 studies, 92 participants). There was moderate-certainty evidence that reading duration was longer with the electronic devices and that they were easier to use. Similar results were seen for electronic devices with the camera mounted in a 'mouse'. Mixed results were seen for head-mounted devices with one study of 70 participants finding a mouse-based head-mounted device to be better than an optical device and another study of 20 participants finding optical devices better (low-certainty evidence). Low-certainty evidence from three studies (93 participants) suggested no important differences in reading speed, acuity or ease of use between stand-mounted and head-mounted electronic devices. Similarly, low-certainty evidence from one study of 100 participants suggested no important differences between a 9.7'' tablet computer and stand-mounted CCTV in reading speed, with imprecise estimates (other outcomes not reported).Low-certainty evidence showed little difference in reading speed in one study with 100 participants that added electronic portable devices to preferred optical devices. One parallel-arm study in 37 participants found low-certainty evidence of higher reading speed at one month if participants received a CCTV at the initial rehabilitation consultation instead of a standard low-vision aids prescription alone.A parallel-arm study including 243 participants with AMD found no important differences in reading speed, reading acuity and quality of life between prism spectacles and conventional spectacles. One study in 10 people with AMD found that reading speed with several overlay coloured filters was no better and possibly worse than with a clear filter (low-certainty evidence, other outcomes not reported).
AUTHORS' CONCLUSIONS
There is insufficient evidence supporting the use of a specific type of electronic or optical device for the most common profiles of low-vision aid users. However, there is some evidence that stand-mounted electronic devices may improve reading speeds compared with optical devices. There is less evidence to support the use of head-mounted or portable electronic devices; however, the technology of electronic devices may have improved since the studies included in this review took place, and modern portable electronic devices have desirable properties such as flexible use of magnification. There is no good evidence to support the use of filters or prism spectacles. Future research should focus on assessing sustained long-term use of each device and the effect of different training programmes on its use, combined with investigation of which patient characteristics predict performance with different devices, including some of the more costly electronic devices.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Eyeglasses; Humans; Lenses; Macular Degeneration; Middle Aged; Optical Devices; Randomized Controlled Trials as Topic; Reading; Sensory Aids; Vision, Low; Visual Acuity; Visually Impaired Persons
PubMed: 29664159
DOI: 10.1002/14651858.CD003303.pub4 -
Proceedings of the National Academy of... Dec 2020Two fundamental constraints limit the number of characters in text that can be displayed at one time-print size and display size. These dual constraints conflict in two...
Two fundamental constraints limit the number of characters in text that can be displayed at one time-print size and display size. These dual constraints conflict in two important situations-when people with normal vision read text on small digital displays, and when people with low vision read magnified text. Here, we describe a unified framework for evaluating the joint impact of these constraints on reading performance. We measured reading speed as a function of print size for three digital formats (laptop, tablet, and cellphone) for 30 normally sighted and 10 low-vision participants. Our results showed that a minimum number of characters per line is required to achieve a criterion of 80% of maximum reading speed: 13 characters for normally sighted and eight characters for low-vision readers. This critical number of characters is nearly constant across font and display format. Possible reasons for this required number of characters are discussed. Combining these character count constraints with the requirements for adequate print size reveals that an individual's use of a small digital display or the need for magnified print can shrink or entirely eliminate the range of print size necessary for achieving maximum reading speed.
Topics: Humans; Middle Aged; Photic Stimulation; Printing; Reading; Vision, Low; Vision, Ocular; Visual Acuity; Young Adult
PubMed: 33168745
DOI: 10.1073/pnas.2007514117