Reading aids for adults with low vision

Gianni Virgili; Ruthy Acosta; Sharon A Bentley; Giovanni Giacomelli; Claire Allcock; Jennifer R Evans

doi:10.1002/14651858.CD003303.pub4

. 2018 Apr 17;2018(4):CD003303. doi: 10.1002/14651858.CD003303.pub4

Reading aids for adults with low vision

Gianni Virgili ^1,^✉, Ruthy Acosta ², Sharon A Bentley ³, Giovanni Giacomelli ¹, Claire Allcock ⁴, Jennifer R Evans ⁵

Editor: Cochrane Eyes and Vision Group

PMCID: PMC6494537 PMID: 29664159

Abstract

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.

Plain language summary

Reading aids for adults with low vision

What is the aim of this review?  The aim of this Cochrane Review was to compare different reading aids for people with low vision. Cochrane Review authors collected and analysed all relevant studies to answer this question and found 13 studies.

Key messages  There is insufficient evidence supporting the use of a specific type of electronic or optical reading aid. The review suggests that reading speeds improve with the use of stand‐mounted electronic devices. There is little evidence for a difference between head‐mounted or portable electronic devices versus optical or other electronic devices, although technology may have improved since these studies took place. There is no evidence to support the use of filters or prism spectacles.

What was studied in the review?  The number of people with low vision is increasing with the ageing population. Magnifying optical and electronic aids are commonly prescribed to help people maintain the ability to read when their vision starts to fade. Cochrane authors reviewed the evidence for the effect of reading aids on reading ability in people with low vision to find out whether there are differences in reading performance using conventional optical devices, such as hand‐held or stand‐based microscopic magnifiers, as compared to electronic devices such as stand‐based, closed circuit television and hand‐held electronic magnifiers.

Cochrane Review authors assessed how certain the evidence was for each review finding. They looked for factors that can make the evidence less certain, such as problems with the way the studies were done, very small studies, and inconsistent findings across studies. They also looked for factors that can make the evidence more certain, including very large effects. They graded each finding as being of very low, low, moderate or high certainty.

What are the main results of the review?  Cochrane Review authors found 13 relevant studies. Seven were from the USA, five from the UK and one from Canada. These studies compared the effect of different reading aids on reading performance, mainly reading speed. The participants were adults attending low vision services. Most of the people were affected by macular degeneration, which causes of loss of central vision and is often age‐related. Because most of the studies were small, the results were often imprecise, and it is difficult to know whether they apply to everyone with low vision.

The results were as follows.

• Reading speed may be faster with electronic devices than with optical magnifiers (moderate‐ and low‐certainty evidence).  • Provision of a closed circuit television (CCTV) at an initial rehabilitation consultation may increase reading speeds compared with standard low‐vision aids prescription alone (low‐certainty evidence).  • Reading speed with head‐mounted electronic devices showed inconsistent differences compared to optical devices (moderate or low‐certainty evidence).  • Reading speeds with a tablet computer compared with stand‐mounted CCTV were similar (low‐certainty evidence).  • Addition of an electronic portable device to a preferred optical device did not appear to increase reading speed (low‐certainty evidence).  • Coloured filters were no better and possibly worse than a clear filter for reading speed (low‐certainty evidence).  • Custom or standard prism spectacles did not appear to convey additional benefit compared with conventional reading spectacles for people with age‐related macular degeneration (low‐certainty evidence).

How up‐to‐date is this review?  Cochrane Review authors searched for studies that had been published up to 17 January 2018.

Summary of findings

Background

Description of the condition

There is no single, globally accepted definition of low vision (also known as partial sight, visual impairment and subnormal vision). However, there is general consensus that low vision is an uncorrectable loss of vision that interferes with daily activities. Definitions normally incorporate an estimate of visual loss in terms of impairment (e.g. measuring visual acuity or visual fields), or in terms of disability (measuring the ability to perform a certain task). One such definition states that low vision is the inability to read a newspaper at a normal reading distance (40 cm) with best refractive correction (Legge 1991).

The World Health Organization (WHO) has established criteria for low vision that are used in the International Classification of Diseases (WHO 2010). Low vision is defined as a best‐corrected visual acuity worse than 0.5 logMAR (Snellen 6/18 or 20/60) but equal to or better than 1.3 logMAR (3/60 or 20/400) in the better eye, or visual field loss corresponding to less than 20° in the better eye with best possible correction. Blindness is defined as a best‐corrected visual acuity worse than 1.3 logMAR or a visual field no greater than 10° around central fixation in the better eye with best possible correction. Visual impairment includes low vision as well as blindness. In the USA, legal blindness is defined as a visual acuity of 1.0 logMAR (6/60 or 20/200) or worse in the better eye.

Blindness is one of the most common disabilities (Congdon 2003): an estimated 39 million people were blind a decade ago, i.e. at the time of the last accurate assessment (Pascolini 2011). Among people older than 40 years in the USA, 937,000 were blind in 2002. Prevalence of blindness in the developing world (where 90% of total world blindness exists) and for the developed world is expected to increase significantly during the next decades as the world's population ages.

Causes of blindness are associated with race and ethnicity in the USA (Congdon 2004): age‐related macular degeneration (AMD) is the most common cause in white people, whereas cataract, glaucoma and diabetic retinopathy are the leading causes in Latinos and African Americans. Different treatable or preventable conditions are the most frequent causes of blindness in developing countries: infectious disease, nutritional causes, and especially cataract and refractive error (Congdon 2003; Pascolini 2011).

In industrialised countries, low vision is found principally in people aged 75 years or older (Margrain 1999; Tielsch 1990), and it has been ranked third (behind arthritis and heart disease) among conditions that cause people older than 70 years to need assistance in activities of daily living (Scott 1999). The ageing population, combined with the dramatic increase in visual impairment in the older age groups, explains the significant increase seen in the demand for low‐vision services.

Description of the intervention

The purpose of low‐vision rehabilitation is to allow the person to resume or to continue to perform daily living tasks. This is achieved by providing appropriate optical devices, environmental modifications and special training in the use of residual‐vision and low‐vision aids (Massof 1998). Without rehabilitation, people with decreased visual acuity often abandon reading and other tasks requiring detailed vision. For individuals with extensive loss of their visual field, orientation and mobility can become difficult.

For a person with low vision, reading is considered one of the most important tasks or goals to achieve (Leat 1994; Shuttleworth 1995). People using low‐vision aids have reported improvements in reading a specific letter size both during distance and near work, and they have found optical aids useful to perform tasks (Humphry 1986; Nilsson 1990; Virtanen 1991). A low‐vision aid (LVA) is any device that enables a person with low vision to improve visual performance.

Common optical LVAs include:

magnifiers – these sometimes have their own illumination and are either battery‐powered or rechargeable from mains electricity. They may be hand‐held or mounted on a stand or on spectacles;
telescopes – for work where the reading matter is distant, a telescope can be mounted on a spectacle frame. This gives a longer working distance, although less can be seen at one time because the field is necessarily restricted. Telescopes may also be hand‐held.

Electronic aids include primarily closed circuit television and other readers incorporating a monitor or a liquid‐crystal display (LCD) screen, which provide improved contrast and magnification.

How the intervention might work

Like many types of rehabilitation, low‐vision rehabilitation includes heterogeneous interventions, which may have several components. Moreover, people who are prescribed a low‐vision device usually receive training to use it. Several training techniques are employed, often using both office‐ and home‐based exercises with the device for a few hours in different sessions. Overall, multidisciplinary services tend to provide modern rehabilitation services (Langelaan 2007). Besides prescription of LVAs and training on their use, especially focused on reading tasks, services can provide psychological support, home environmental assessment, and – for people of working age – social worker support. Moreover, several types of professionals provide different types of follow‐up either in low‐vision clinics or at home.

As was intended, this review concentrates on reading aids that magnify text, sometimes also improving its contrast.

Why it is important to do this review

The most suitable device depends on the person's needs and the visual functioning they have. Rehabilitation should be tailored to correspond to the type of visual loss and may also be modified by the individual's choice or expectations or by more general cultural demands (Dickinson 1998; Margrain 1999). Besides the level of magnification, there are other factors that are important when choosing an optical device, such as ease of use and cosmetic appearance. Devices may be rejected if they have an unusual cosmetic appearance that calls attention to the person's disability.

Reading is an extremely complex visual task, which involves the integration of visual, cognitive and motor processes. In everyday reading, it is important for people to achieve their optimal reading rate (usually measured in words per minute), and, for people with low vision, a speed that is sufficient to complete the task within an acceptable amount of time. The effect of slow reading on comprehension is variable, as Dickinson 1998 found that low reading speed decreases comprehension but Legge 1989 did not.

Given the availability of a wide range of aids from simple magnifiers to high‐power video magnifiers, all of which have advantages and disadvantages, an assessment of their effects on reading would be very useful.

Objectives

To assess the effects of different visual reading aids for adults with low vision.

Methods

Criteria for considering studies for this review

Types of studies

We included randomised and quasi‐randomised trials.

Types of participants

We included trials in participants aged 16 or over with low vision as defined by the study investigators. Where possible we grouped participants according to the type or cause of visual impairment. We included studies that enrolled people aged younger than 16 provided most participants were over that age.

Types of interventions

We included trials comparing any device or aid used for reading visually versus another device or aid. We considered reading aids that maximise the person's visual reading capacity, including non‐electronic aids, that is, optical devices such as magnifiers and telescopes, and electronic aids, such as several types of closed circuit television (CCTV). These devices are rated in terms of the equivalent power measured in dioptres, which allows comparison of devices to each other (Sloan 1971). We also considered consumer electronics such as smartphones and tablets.

We also considered other LVAs such as coloured filters and optical prisms, which are commonly prescribed in low‐vision rehabilitation as they are supposed to improve reading in some people.

We excluded trials in which the intervention is a device to read though hearing, such as screen readers or talking books, or through touch, such as Braille‐based devices and haptic devices. Finally, we did not consider rehabilitation strategies or complex low‐vision interventions.

Types of outcome measures

Using World Health Organization (WHO) language on functioning, disability and health (WHO 2002), maximum reading speed and reading acuity is the person's capacity under ideal conditions of text magnification and contrast, such as when using the Minnesota Low‐Vision Reading test (MNREAD). Capacity may be partly an individual trait (slow or fast reader) and can be limited by several visually and non‐visually impairing diseases. Vision‐based reading aids aim at maximising the person's performance by compensating their diminished visual function, especially by magnification. The choice of outcome measures in this review is driven by its emphasis on the vision‐related component of performance.

Research on psychophysics of reading has shown that reading speed is typically stable across a range of print sizes (maximum reading speed) that are larger than a certain threshold (critical print size), whereas at smaller print sizes, below the critical print size, the reading speed slows, and the reading acuity limit is reached (Ahn 1995a; Ahn 1995b; Legge 1985a; Legge 2007). Font size at critical print size is usually two or three times larger than reading acuity. A similar pattern is also present in most people with low vision (Legge 1985b; Legge 2007). A plot of reading speed against font size (adjusted by reading distance and expressed in logMAR) can be obtained using reading charts such as the MNREAD charts (Legge 2007). The updated version of this review adopts the following definitions developed by the authors of the MNREAD charts (Ahn 1995a).

Reading acuity: the smallest print that the person can read without making significant errors.
Critical print size: the smallest print that the person can read with maximum speed.
Maximum reading speed: the person's reading speed when reading is not limited by print size, i.e. for print size larger than the critical print size.

Rubin 2013 reviewed the issue of measuring reading performance in LVA research, finding that the methods for assessing reading performance and the algorithms for scoring reading tests need to be optimised to improve the reliability and responsiveness of reading tests. A systematic review on effectiveness of low vision service provision also affords a broader perspective on outcome measures, including quality of life measures (Binns 2012).

Primary outcomes

Reading speed in words per minute, recorded using typical font size (i.e. approximately 10 to 14 points), in books or newspapers.

We also accepted maximum reading speed recorded across a range of point sizes, using MNREAD or Bailey‐Lovie charts. However, it may be unclear, unless specified, whether maximum reading speed is achieved for common book text size with each reading aid. Thus, we rated studies reporting only maximum reading speed as providing indirect evidence regarding the primary outcome of this review.

Secondary outcomes

Reading duration in minutes, defined as the time the person could read without visual discomfort causing the need to take a pause.
Reading acuity in logMAR. Because this is mostly a function of magnification, we analyse this outcome only if devices are matched by magnification (e.g. a difference between unmatched electronic and optical aids needs no demonstration).
Ease and frequency of use as reported by the participants.
Quality of life as measured by any validated scale that aims to measure the impact of visual function loss on quality of life.
Reported adverse outcomes.

Search methods for identification of studies

Electronic searches

The Cochrane Eyes and Vision Information Specialist conducted systematic searches in the following databases for randomised controlled trials and controlled clinical trials. There were no language or publication year restrictions. The date of the search was 17 January 2018.

Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 12) (which contains the Cochrane Eyes and Vision Trials Register) in the Cochrane Library (searched 17 January 2018) (Appendix 1).
MEDLINE Ovid (1946 to 17 January 2018) (Appendix 2).
Embase Ovid (1980 to 17 January 2018) (Appendix 3).
LILACS (1982 to 17 January 2018) (Appendix 4).
OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu; searched 17 January 2018) (Appendix 5).
ISRCTN registry (www.isrctn.com/editAdvancedSearch; searched 17 January 2018) (Appendix 6).
US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov; searched 17 January 2018) (Appendix 7).
World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp; searched 17 January 2018) (Appendix 8).

Searching other resources

We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991 for relevant trials. We searched the reference lists of relevant articles to find additional trials. We used the Science Citation Index to find articles that cited relevant articles. We contacted investigators and manufacturers of low‐vision aids to identify other published and unpublished reports.

Data collection and analysis

Selection of studies

Two authors working independently assessed the titles and abstracts resulting from the electronic searches. We obtained the full copy of all relevant or potentially relevant trials and assessed these according to the 'Criteria for considering studies for this review'. We assessed only trials meeting these criteria for methodological quality. The authors were not masked to any trial details when making their assessments. We resolved disagreements about whether a trial should be included by discussion and consensus. We attempted to obtain additional information where necessary.

Data extraction and management

Two authors working independently extracted data using Covidence, resolving any discrepancies by discussion. We contacted investigators to obtain missing data where necessary.

For three studies, individual data were reported in tables of the publication. We used these for further analyses.

Assessment of risk of bias in included studies

Two authors working independently assessed risk of bias according to the methods set out in Chapters 8 and 10 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a; Sterne 2011). We considered the following parameters: method of allocation to treatment; allocation concealment (selection bias); documentation of exclusions and completeness of follow‐up (attrition bias); selective outcome reporting (reporting bias). We did not consider masking of participants, study personnel (performance bias) and outcome assessors (detection bias) since it is not possible with most LVAs. Moreover, masking is meaningless for some outcomes, such as participant's preference for each device. We graded each parameter of trial quality as being at low, high or unclear risk of bias. We contacted study authors for clarification on any item graded as unclear. Authors were not masked to any trial details during the assessment.

Evaluation of cross‐over‐like studies was an issue in this review. Assessing the performance of the same participant who tries different LVAs is a common study design used by researchers into low vision, which is also known as a 'within‐person' design. This is an efficient design since we do not need to allow for all variations that occur between arms of parallel‐group studies. In practice this means that, for the same number of participants, a cross‐over design is likely to be more powerful. However, cross‐over trials are not always appropriate. The most important consideration is whether the participants start the second period in a similar state as how they started the first period. If the characteristics of the participant have changed in some way by the time the second period starts, then the comparison of treatments is not fair, and there will be within‐participant variation. Based on the Cochrane Collaboration's Open Learning Additional Module 2, (Alderson 2002) and on Chapter 16 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011b), we addressed the following questions for cross‐over studies.

Is the condition of the participants chronic and stable?
Does the intervention provide temporary relief, and not permanent change?
Can the outcome be repeated in the second period if it occurs in the first?
Might the effect of the first intervention last into the second treatment period?
Does the trial go on long enough for the LVA to be properly used?

Assessment of randomisation procedures requires consideration of two components: sequence generation and allocation concealment. A discussion among the authors led to grading both components in cross‐over‐like studies included in this review as being at low risk of bias. In fact, in low‐vision studies adopting a cross‐over‐like design in this review, all participants used all devices and the order of presentation was randomised. We judged it necessary to address two questions when rating the quality of randomisation and allocation in this type of study.

Does knowledge of the first LVA selected affect recruitment into the trial?
Does the order in which the LVAs are used affect the results?

Regarding question 1, the answer should be no, since knowing the order of LVA presentation in the study should not affect recruitment into studies testing all devices in the same session. As to question 2, we considered two additional items: first, period effect (whether the condition can change during subsequent phases of testing of each device), and second, carry‐over effect or period‐by‐treatment interaction (whether the effect on performance of using a specific device affects the performance of the following device).

Measures of treatment effect

We obtained the mean difference (MD) and its standard error (SE), referred to as 'SE(MD)', when continuous data were available. We then used the generic inverse variance method when dealing with cross‐over studies (Higgins 2011b); see also Appendix 9 for details and additional methods used.

Unit of analysis issues

Participants, rather than eyes, are the unit of analysis in this review. We encountered specific unit of analysis issues in studies comparing several devices on the same participant, which we dealt with as described in other sections of this review and as shown in Appendix 9. We included studies measuring outcomes in the better eye but excluded studies adopting eyes rather than individuals as the unit of analysis.

Dealing with missing data

There were only two parallel‐arm trials in this review. We enumerate missing data for each treatment arm in these studies in the Characteristics of included studies table. The concept of missing data is more complex when several devices are tested on the same participant, since the participant may be able to read with some devices but not with others. These issues are related to study inclusion criteria and are discussed in the Results and Discussion sections.

Assessment of heterogeneity

We assessed heterogeneity considering the study characteristics (including type of intervention and participants). We inspected the forest plot to see the range of effects. We also considered the Chi² test for heterogeneity and the I² statistic (which gives an estimate of the extent to which the observed variation can be attributed to true variation rather than random error); these statistics may have low power with few studies (Deeks 2011b).

Assessment of reporting biases

We considered reporting biases only for reading speed as the primary outcome, since we found it difficult to consider other outcomes not reported in the absence of standard measurements tools, relative to the specific aim of this review.

Data synthesis

We conducted data analysis following guidance from Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2011b). We pooled data using a fixed‐effect model, as the number of studies contributing data to each analysis was three or fewer. Since a cross‐over design was common in research on the effectiveness of LVAs, we included these studies in the review provided that the order of presentation of the devices was randomised or quasi‐randomised and specific methods were used to deal with them. A number of minor statistical and data extraction issues arose from the inclusion of these cross‐over studies, e.g. methods to handle within‐person correlation and multiplicity of testing. Other items were small sample size issues, data skewness, and the availability of individual patient data in small studies. We dealt with these issues using methods suggested in Elbourne 2002 and in Chapter 16 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011b), as summarised in Appendix 9.

Subgroup and sensitivity analyses

We did not do any subgroup or sensitivity analyses, as the number of studies was low for any analysis.

Summary of findings tables

We summarised the results in 'Summary of findings' tables as recommended in Chapter 11 of the Cochrane Handbook for Systematic Reviews of Interventions (Schünemann 2011). We graded the certainty of the evidence by consensus using the GRADE approach, which considers five parameters: imprecision, risk of bias, inconsistency, indirectness and publication bias (GRADEpro 2014).

Results

Description of studies

Results of the search

The electronic searches run in July 2006 yielded 488 reports. We screened the titles and abstracts and identified 20 studies that appeared relevant. We obtained full‐text copies of these reports and after further assessment, we included nine studies and excluded the remaining 11 studies.

An update search run in January 2013 yielded 528 references. The Trials Search Co‐ordinator removed 150 duplicates, scanned 378 references and removed 64 records that were not relevant to the scope of the review. We screened 314 references and obtained full‐text reports of eight studies, which we excluded after assessment. While this review was being updated, we retrieved studies in low‐vision research reported as conference abstracts. Currently we are unable to identify six full‐text reports of studies or make contact with the trialists. Relevant sections from the conference abstracts are shown in the Characteristics of studies awaiting classification. If we are able to collect sufficient data we will assess these studies for potential inclusion in further updates. In addition, handsearching references of other reports used for this review yielded two studies published in 2005, of which Watson 2005 is now included and Kaida 2005 is awaiting classification.

Updated searches conducted in January 2018 identified 1349 new records (Figure 1). After removing 345 duplicates, the Cochrane Information Specialist (CIS) screened the remaining 1004 records and removed 388 references that were not relevant to the scope of the review. We screened the remaining 616 records and obtained six full‐text reports and one conference abstract for further assessment. We excluded two studies (Alabdulkader 2012; Bailie 2013), and we identified five reports of three new studies (Jackson 2017; Morrice 2017; Taylor 2017); see Characteristics of included studies for details. We did not identify any ongoing studies from our searches of the clinical trials' registries.

Included studies

We included 13 studies in the review (see Characteristics of included studies). These studies took place in the USA (7 studies), UK (5 studies) and Canada (1 study). We provide summary descriptions for each, along with details of their 'Risk of bias' assessment, which is presented graphically in Figure 2. Interventions, outcome measures and their measurement tools were very variable and are summarised in Table 8.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

1. Interventions and outcomes in the included studies.

Study	LVAs compared	RS measurement	Reading acuity	Reading duration	Subjective preference for specific devices	Quality of life	Other outcomes reported but not included in this review
Culham 2004	4 electronic head‐mounted versus participant's aids or spectacles	Small (N 5), typical medium (N1 0) and large (N 20) print size	Bailey‐Lovie charts	—	—	—	Reading accuracy, contrast sensitivity (Pelli Robson), daily living tasks: grocery identification (seconds), writing cheques (seconds)
Eperjesi 2004	Coloured versus clear filter overlays	Rate of reading test (print size 4‐ to 18‐point)	Not available, but not relevant for filters which do not magnify text	—	—	—	—
Goodrich 2001	Hand‐held CCTV, stand‐mounted CCTV versus prescribed optical aid	1 M text (typical print size at 40 cm)	—	Cumulative time spent reading	Questions on subjective preference	—	Reading comprehension
Jackson 2017	Standard visual rehabilitation, provision of a free CCTV	IReST	IReST	—	—	Rasch‐scaled IVI	—
Kleweno 2001	Head‐mounted display versus standard CCTV	Next largest size close to near acuity (MNREAD electronic version)	MNREAD charts	—	Single question on preference in terms of brightness and clarity	—	Different contrast/colour condition for cathode ray tube or virtual retinal display
Morrice 2017	CCTV, tablet	IReST	IReST	—	Frequency of device use on a 0‐4 scale.	—	—
Ortiz 1999	Head‐mounted display (LVES) versus CCTV	News articles MNREAD	MNREAD charts	—	—	—	Reading comprehension
Peterson 2003	Head‐mounted display, hand‐held CCTV, standard CCTV versus the participant's optimum conventional optical magnifier	MNREAD reading speed across several print sizes available in figure	MNREAD‐like charts	—	Single question on subjective ease of use of each magnifier on a 5‐step scale	—	Ability to read specific print sizes (0.2‐1.0 logMAR); navigate a text, follow a route on a map, reading medicine bottle label
Spitzberg 1995	Mirror, prism or zoom optical magnifiers versus conventional magnifier (same magnification)	1M or 1.5M print (ordinary print size at 40 cm)	—	—	Preference for a specific device	—	Note: magnification was standardised at 3× for all devices
Smith 2005	Custom or standard bilateral prism spectacles versus conventional spectacles	MNREAD reading speed "at the critical print size"	MNREAD charts	—	MLVQ measuring helpfulness and use	NEI‐VFQ 25, MLVAI	—
Stelmack 1991	CCTV, illuminated stand magnifier, spectacles	Readers Digest (silent reading)	—	Reading time without visual discomfort	—	—	Reading comprehension
Taylor 2017	Portable electronic devices, optical device in use	IReST, MNREAD	IReST, MNREAD	—	—	—	—
Watson 2005	Hybrid‐diffractive spectacle magnifier compared with a refractive spectacle magnifier and an aplanatic spectacle magnifier (2 separate experiments)	MNREAD maximum RS with each reading aid; Pepper Visual skills for Reading Test	MNREAD charts	—	Self‐report of satisfaction with reading using a visual analogue scale	—	Reading accuracy, Morgan Low Vision reading Comprehension Assessment

Study	Number of participants	Principal cause of low vision
Culham 2004	20	AMD (n = 10), early onset macular disease (n = 10)
Eperjesi 2004	12	AMD (n = 12)
Goodrich 2001	22	AMD (n = 16), CRVO (n = 2), diabetic retinopathy (n = 2), macular hole (n = 1), cone dystrophy (1)
Jackson 2017	37	AMD or juvenile onset macular degeneration (n = 27), optic nerve disease (n = 6), macular dystrophy or other maculopathy (n = 4)
Kleweno 2001	13	Retinal (n = 7), optical (n = 3), amblyopic (n = 2), unknown (n = 1). No AMD cases
Morrice 2017	100	AMD (n = 57), diabetic retinopathy (n = 6), glaucoma (n = 6), other (n = 25), unknown (n = 6)
Ortiz 1999	10	Uveitis (n = 1), corneal opacity (n = 1), glaucoma (n = 1), optic neuritis (n = 1), macular degeneration (n = 2), other retinal diseases (n = 4)
Peterson 2003	70	AMD (n = 40), vascular retinopathy (n = 11), diabetic retinopathy (n = 9), corneal condition (n = 6), glaucoma (n = 4)
Smith 2005	243	AMD (n = 243)
Spitzberg 1995	39	Not known
Stelmack 1991	37	AMD or ocular histoplasmosis (n = 37)
Taylor 2017	82	AMD (n = 47), Stargardt (n = 3), retinitis pigmentosa (n = 3) myopic degeneration (n = 5), glaucoma (n = 6), diabetic retinopathy (n = 2), nystagmus (n = 5), other (n = 11)
Watson 2005	30	AMD or juvenile macular degeneration or diabetic retinopathy (number of participants unclear)

Study	Optical device(s)	Electronic device(s)	Comment
Culham 2004	Participants's optical device	Head‐mounted; 4 types: Jordy, Flipperport, Maxport and NuVision	Maximum field of view (i.e. at minimum magnification) was 30° horizontal by 22.5° vertical for all the four electronic devices. There were differences in field of view with optical devices.
Eperjesi 2004	10 different coloured light filter overlays (Intuitive Overlays) Clear filter	No electronic device	—
Goodrich 2001	Participant's optical device	Stand‐mounted CCTV (Optelec Clearview or TSI Genie) Hand‐held mouse‐based, plus 27" TV monitor (Innoventions Magni‐Cam)	—
Jackson 2017	No optical device	Stand‐mounted CCTV (Clearview, Optelec)	Vision rehabilitation consultation (all participants) during which patients were educated about rehabilitation strategies, given information about remaining visual function, and shown a range of optical and electronic devices that they could purchase.
Kleweno 2001	No optical device	Head‐mounted (Virtual Retinal Display) Stand‐mounted CCTV (EIZO Flexscan TX‐C7, Nanao Corp)	—
Morrice 2017	No optical device	Tablet computer (Apple iPad Air) Stand‐mounted CCTV (Clearview+, Optelec)	—
1999	No optical device	Head‐mounted electronic device (Low Vision Enhancement System, Visionics Corp) Stand‐mounted CCTV (VTEK Voyager XL)	Unclear whether these were matched by field of view
Peterson 2003	Participant's own optical magnifier	Hand‐held mouse‐based, plus 14" TV monitor (TVi Zoom, Concept Systems, Nottingham, UK) Hand‐held mouse‐based, plus head‐mounted display (Virtual I/Om Escom, Heppenheim, Germany) Stand‐mounted CCTV (Spectrum, Clearview, Tieman, Notthingham, UK)	Magnification and field‐of‐view matched. There were clear differences in field of view among these devices.
Smith 2005	Custom prism spectacles Standard bilateral prism spectacles Conventional spectacles with near prescription	No electronic device	Differences in field of view among these devices should be small.
Spitzberg 1995	Spherical mirror magnifier covering one whole column width of newsprint A cylindrical mirror magnifier covering one whole page width A reflecting prism magnifier with a 45 degree viewing angle Zoom magnifier	No electronic device	4 devices with the same nominal magnification (3×). There were clear differences in the field of view and working distance between each of these devices, with measurements given in the paper.
Stelmack 1991	Illuminated stand magnifier in conjunction with a bifocal or reading prescription to compensate for accommodative demand Spectacle reading lenses, either prism half eyes or Aolite microscopes, which were optimised for reading standard point size.	Stand‐mounted CCTV (VTEK Voyager)	Although not specified, there were clear differences in the field of view and working distance between each of these devices.
Taylor 2017	Participant's existing optical device	Hand‐held (not mouse‐based) electronic device (Optelec Compact+, Optelec Compact 4HD, Schweizer eMAG 43, Eschenbach Mobilux Digital)	Differences in field of view among these devices should be small.
Watson 2005	Hybrid diffractive spectacle magnifier (Eschenbach Optik Noves) Refractive aspheric spectacle magnifier (American Optical Aolite) Aplanatic spectacle magnifier (Designs for Vision Clear Image2)	No electronic device	Differences in field of view among these devices should be small.

Stand‐mounted CCTV versus optical device for adults with low vision
Patient or population: adults with low vision  Settings: low vision services  Intervention: stand mounted CCTV  Comparison: optical device
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants (studies)	Certainty of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	Optical device	Stand‐mounted CCTV
Reading speed (words per minute) Follow‐up: at time of assessment	The mean reading speed using an optical device was  65.8 words per minute	The mean reading speed using a stand‐mounted CCTV was 45.5 words per minute more  (26.0 fewer to 65.0 more)	70  (1 study)	⊕⊕⊝⊝  Low^a,b	Optical device was participant's own. In a different study of 22 participants the comparator was best prescribed optical device. The mean reading speed using a stand‐mounted CCTV was 12 words per minute more (2.5 fewer to 26.5 more) than with best prescribed optical device.
Reading duration (minutes) Follow‐up: at time of assessment	The mean reading duration using an optical device was  23 minutes	The mean reading duration using a stand‐mounted CCTV was was 13.7 minutes more (7.9 more to 19.5 more)	22  (1 study)	⊕⊕⊕⊝  Moderate^c	In another study of 37 people people using a CCTV reported a longer duration (29 minutes) than with optical aids (13 minutes) but no analyses could be performed due to marked skewness problems.
Reading acuity	Not reported
Ease and frequency of use Task difficulty score (0 = very easy to use 5 = extremely difficult) Follow‐up: at time of assessment	The mean task difficulty score with the optical device was 3.3	The mean task difficulty score with the stand‐mounted CCTV was 2.0 lower (easier) (2.52 lower to 1.48 lower)	70  (1 study)	⊕⊕⊕⊝  Moderate^b	—
Quality of life	Not reported
Adverse outcomes	Not reported
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CI: confidence interval.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Hand‐held mouse‐based electronic device versus optical device for adults with low vision
Patient or population: adults with low vision  Settings: low vision services  Intervention: hand‐held mouse‐based electronic device  Comparison: optical device
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants  (studies)	Certainty of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	Optical device	Hand‐held mouse‐based electronic device
Reading speed (words per minute) Follow‐up: at time of assessment	The mean reading speed using an optical device was  65.8 words per minute	The mean reading speed using a mouse‐based device (with 14'' monitor) was 40.5 words per minute more (23.7 more to 57.3 more)	70  (1 study)	⊕⊕⊕⊝  Moderate^a	In a different study of 22 participants the mean reading speed using a mouse‐based device with a 27" monitor was 15.8 words per minute more (0.42 to 31.2 more) compared with best prescribed optical device (64 words per minute).
Reading duration (minutes) Follow‐up: at time of assessment	The mean reading duration using an optical device was  23 minutes	The mean reading duration with the mouse‐based electronic device was 12.8 minutes more (9.3 more to 16.3 more)	22  (1 study)	⊕⊕⊕⊝  Moderate^b	—
Reading acuity	Not reported
Ease and frequency of use Task difficulty score (0=very easy to use 5=extremely difficult) Follow‐up: at time of assessment	The mean task difficulty score with the optical device was 3.3	The mean task difficulty score with the stand‐mounted CCTV was 1.3 lower (easier) (1.30 lower to 0.95 lower).	70  (1 study)	⊕⊕⊕⊝  Moderate^a	—
Quality of life	Not reported
Adverse outcomes	Not reported
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CI: confidence interval.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Hand‐held (not mouse‐based) electronic device in addition to optical device versus optical device
Patient or population: adults with low vision  Settings: low vision services  Intervention: hand‐held electronic device in addition to optical device  Comparison: optical device
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants (studies)	Certainty of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	Optical device	Hand‐held electronic device in addition to optical device
Reading speed (words per minute) using the IReST test Follow‐up: two months	The mean reading speed using optical device in the control groups ranged from 37 to 57 words per minutes	The mean reading speed with a hand‐held electronic device was 1.7 words per minute fewer (7.2 fewer to 3.8 more)	100 participants (1 study)	⊕⊕⊕⊝  Moderate^a	—
Reading duration	Not reported
Reading acuity	Not reported
Ease and frequency of use Frequency of use (0 = never to 4 = several times a day) Follow‐up: 2 months	The mean frequency of use of the optical device was about 3.4	The mean frequency of use of a hand‐held electronic device was −0.9 worse (−1.3 worse to −0.6 worse)	100 participants (1 study)	⊕⊕⊝⊝  Low^a,b	—
Quality of life estimating perceived difficulty using the NV‐VFQ‐15 questionnaire Follow‐up: 2 months	The mean perceived difficulty ranged in the control group was about 2 (SD: 1.3)	The mean perceived difficulty in the intervention groups was  0.57 less difficult (0.33 less to 0.81 less)	100 participants (1 study)	⊕⊕⊕⊝  Moderate^a	NV‐VFQ‐15 questionnaire developed with near vision items of the VFQ‐48 questionnaire (Rasch analysis)
Adverse outcomes	Not reported
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CI: confidence interval; IReST: International Reading Speed Texts; NV‐VFQ: Near Vision Visual Function Questionnaire.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Stand‐mounted CCTV with visual rehabilitation vs visual rehabilitation alone
Patient or population: adults with low vision  Settings: low vision services  Intervention: stand‐mounted CCTV after visual rehabilitation consultation  Comparison: visual rehabilitation consultation
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants (studies)	Certainty of the evidence  (GRADE)
	Assumed risk	Corresponding risk
	visual rehabilitation only	stand‐mounted CCTV with visual rehabilitation
Reading speed (maximum reading speed words per minute) Follow‐up: 1 month after visual rehabilitation consultation	The mean reading speed with visual rehabilitation only was 34 words per minute	The mean reading speed in the intervention groups was 33.7 words per minute more (4.3 more to 63.1 more)	31 (1 study)	⊕⊕⊝⊝  Low^a,b
Reading duration	Not reported
Reading acuity	Not reported
Ease and frequency of use	Not reported
Quality of life Follow‐up: 1 month after visual rehabilitation consultation	The authors provided additional analysis results which showed no statistically significant difference between the 2 groups for the Rasch‐scaled person‐measures for any domain (emotional, mobility, reading); however, an overall quality of life measure could not be extracted for use in this review.		31 (1 study)	⊕⊕⊝⊝  Low^a,b
Adverse outcomes	Not reported
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CCTV: closed circuit television; CI: confidence interval.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Stand‐mounted closed circuit television (CCTV) versus head‐mounted electronic device (HMD) for adults with low vision
Patient or population: adults with low vision  Settings: low vision services  Intervention: stand‐mounted CCTV  Comparison: HMD
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants (studies)	Certainty of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	HMD	Stand‐mounted CCTV
Reading speed (words per minute)  MNREAD Charts Follow‐up: at time of assessment	The mean reading speed using HMD was 66 words per minute	The mean reading speed using stand‐mounted CCTV 3.1 words per minute more (3.5 fewer to 9.7 more)	93  (3 studies)	⊕⊕⊝⊝  Low^a,b	—
Reading duration	Not reported
Reading acuity (logMAR)  MNREAD charts. Higher score is worse acuity. Follow‐up: at time of assessment	The mean reading acuity with HMD was 0.92 logMAR	The mean reading acuity with stand‐mounted CCTV was 0.05 logMAR higher (i.e. same) (0.06 lower to 0.15 higher)	13  (1 study)	⊕⊝⊝⊝  Low^a,c	—
Ease and frequency of use Task difficulty score (0 = very easy to use 5 = extremely difficult) Follow‐up: at time of assessment	The mean task difficulty score with the optical device was 3.3	The mean task difficulty score with the stand‐mounted CCTV was 0 lower (same difficulty) (0.37 lower to 0.37 higher)	70 (1 study)	⊕⊕⊝⊝  Low^a,b	One study with 13 participants collected data on perceived brightness and clarity of images. 10/13 people found the head‐mounted device to be brighter and 9/13 felt the head‐mounted device was clearer compared with the CCTV.
Quality of life	Not reported
Adverse outcomes	Not reported
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CCTV: closed circuit television; CI: confidence interval; HMD: head‐mounted device.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Prism spectacles versus conventional spectacles for adults with low vision
Patient or population: adults with low vision (people with AMD)  Settings: low vision services  Intervention: prism spectacles  Comparison: conventional spectacles
Outcomes	*Illustrative comparative risks (95% CI)**		No of participants (studies)	Certainty of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	Conventional spectacles	Custom prism spectacles
Reading speed (words per minute) Follow‐up: 3 months	The mean reading speed using conventional spectacles was 67 words per minute	The mean reading speed using custom prism spectacles was  6 fewer words per minute (25.4 fewer to 13.4 more)	150  (1 study)	⊕⊕⊝⊝  Low^a	In the same study, the mean reading speed using standard prism spectacles was  7 fewer words per minute (25.9 fewer to 11.9 more) compared with conventional spectacles
Reading duration	Not reported
Reading acuity in logMAR Follow‐up: 3 months	The mean reading acuity using conventional spectacles was  1.50 logMAR	The mean reading acuity using custom prism spectacles was  0.07 logMAR higher  (0.05 lower to 0.19 higher)	150  (1 study)	⊕⊕⊝⊝  Low^a	In the same study, the mean reading acuity using standard prism spectacles was  0.06 logMAR higher (0.06 lower to 0.18 higher) compared with conventional spectacles
Ease and frequency of use	Not reported
Quality of life (NEI‐VFQ score) Scale from: 0‐100. Higher scores are better Follow‐up: 3 months	The mean quality of life score using conventional spectacles was 53	The mean quality of life score using custom prism spectacles was  0 higher (same)  (5.62 lower to 5.62 higher)	153  (1 study)	⊕⊕⊕⊝  Moderate^b	In the same study, the mean quality of life score using standard prism spectacles was 1 higher (4.75 lower to 6.75 higher) compared with conventional spectacles.
Adverse outcomes	Not reported
The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CI: confidence interval; NEI‐VFQ: National Eye Institute Visual Functioning Questionnaire.
GRADE Working Group grades of evidence  High‐certainty: we are very confident that the true effect lies close to that of the estimate of the effect.  Moderate‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Low‐certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.  Very low‐certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

Head‐mounted CCTV	Mean difference in reading speed (words per minute) compared with reading speed of 95 words per minute using optical device (95% CI)
Flipperport (table stand camera)	−24.6 (−40.88 to −8.32)
Jordy	−33.7 (−50.34 to −17.06)
Maxport	−29.4 (−45.74 to −13.06)
NuVision	−40 (−56 to −23.3)

Type of filter (% transmission)	Mean difference in reading speed (words per minute) compared with reading speed of 84 words per minute in the control (clear overlay 100% transmission, reading speed 83.7 wpm) group (95% confidence interval)
Rose (78)	−9 (−24 to 6)
Pink (78)	−9 (−15 to −3)
Yellow (93)	−7 (−20 to 6)
Orange (83)	−13 (−29 to 2)
Mint‐green (85)	8 (−17 to 2)
Lime‐green (86)	−6 (−24 to 6)
Grey (71)	−4 (−25 to 17)
Blue (74)	−12 (−24 to 1)
Aqua (81)	−9 (−15 to −3)
Purple (67)	−14 (−25 to −3)

Outcome or subgroup title	No. of studies	Statistical method	Effect size
1 Reading speed (words per minute)	1	Mean Difference (Fixed, 95% CI)	Totals not selected
2 Frequency of use (0‐4 scale)	1	Mean Difference (Fixed, 95% CI)	Totals not selected
3 Quality of life	1	Mean Difference (Fixed, 95% CI)	Totals not selected

Outcome or subgroup title	No. of studies	Statistical method	Effect size
1 MNREAD maximum reading speed (words per minute)	1	Mean Difference (Fixed, 95% CI)	Totals not selected
1.1 Diffractive versus refractive‐aspheric spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.2 Diffractive versus aplanatic spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
2 MNREAD critical print size (M print size)	1	Mean Difference (Fixed, 95% CI)	Totals not selected
2.1 Diffractive versus refractive‐aspheric spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
2.2 Diffractive versus aplanatic spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
3 Morgan Low Vision Reading Comprehension Assessment	1	Mean Difference (Fixed, 95% CI)	Totals not selected
3.1 Diffractive versus refractive‐aspheric spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
3.2 Diffractive versus aplanatic spectacle magnifier	1	Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]

Outcome or subgroup title	No. of studies	Statistical method	Effect size
1 Reading speed (words per minute)	1	Mean difference (Fixed, 95% CI)	Totals not selected
1.1 Rose filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.2 Pink filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.3 Yellow filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.4 Orange filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.5 Mint filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.6 Lime filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.7 Grey filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.8 Blue filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.9 Aqua filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
1.10 Purple filter	1	Mean difference (Fixed, 95% CI)	0.0 [0.0, 0.0]

Date	Event	Description
12 January 2018	New search has been performed	Electronic searches updated
12 January 2018	New citation required but conclusions have not changed	This update includes three new studies (Jackson 2017; Morrice 2017; Taylor 2017).

Date	Event	Description
9 October 2013	New search has been performed	2013, Issue 10: Searches updated: one additional trial (Watson 2005) has been included in the review; risk of bias tables have been completed for all trials and the text of the review has been updated.
3 October 2013	New citation required but conclusions have not changed	2013, Issue 10: Two new authors, Lori Grover and Sharon Bentley, have joined the review team for this update.
27 October 2008	Amended	Converted to new review format.
14 July 2006	New citation required and conclusions have changed	Substantive amendment

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Reading speed (words per minute)	3		Mean difference (Fixed, 95% CI)	3.13 [‐3.47, 9.73]
2 Reading acuity (logMAR)	1		Mean difference (Fixed, 95% CI)	Totals not selected

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Reading speed (words per minute)	2		Mean difference (Fixed, 95% CI)	9.54 [‐0.27, 19.36]
2 Reading duration in minutes	1		Mean difference (Fixed, 95% CI)	Totals not selected

Methods	Study design: cross‐over randomised controlled trial  Randomised presentation of devices. First, the clinician determined as many unique combinations of the order of showing each device and listed them. Second, an independent non‐clinician was then asked to randomly rearrange the order of the possible combinations on the list. On completion of the clinical evaluation, participants were loaned 2 of the electronic devices, each for a period of 1 week, for use at home.  Masking: participant ‐ masking issues are not described but the study participants, providers and outcome assessors were likely to be unmasked given the use of recognisable devices  Exclusions after randomisation: none reported  Losses to follow‐up: none reported  Unusual study design: within‐person design, i.e. a cross‐over study in which all participants try all 4 devices. After training the use is restricted to 2 devices per participant
Participants	Country: UK  Number randomised: 20 people recruited from the low‐vision clinic and specialist medical clinics at Moorfields Eye Hospital  Cause of low vision: AMD (n = 10), early onset macular disease (n = 10)  Age: estimated average age 58 years, range 21 to 82  Sex: 9 men, 11 women, 55% women  Inclusion criteria: English‐speaking and prepared to attend 5 appointments; visual acuity between 6/18 and 1/60 in the better eye and stable vision for at least 3 months; to be experienced in the use of optical LVAs (i.e. for 1 year or more); prior to recruitment all participants had to have received standard hospital care and any medical intervention required had been completed.  Exclusion criteria: any co‐existing conditions which may have affected the handling of devices or performance with them
Interventions	Intervention: 4 types of head‐mounted electronic devices (HMDs): Flipperport, Jordy, Maxport, and NuVision. Participants' own spectacles were used with the HMDs when appropriate Comparator: Habitual spectacle correction for distance with a +1.50 addition for intermediate distance and a +4.00 addition for near, as required, depending on accommodative ability Previously prescribed low‐vision device Duration: 1 week
Outcomes	Use of the devices for a range of clinical and practical visual tasks. Assessment was based on clinical and practical visual tasks measured in the laboratory. On completion of the clinical evaluation, devices were also loaned to participants for use in their habitual environments for a period of 1 week, on a random basis. Reading speed and accuracy using passages of text. Three print sizes were used: N 5 (i.e. comparable with medicine bottle labels), N 10 (standard newsprint) and N 20 (small newspaper headlines) Performance on 2 intermediate distance visual tasks: time to complete, sign and date a cheque; time to locate and touch 2 grocery items from an assembled collection of 15 products on a shelf
Notes	Date study conducted: not reported  Funding: supported by the Macular Disease Society  Declaration of interest: the authors had no financial interest in any device used in the study.  Trial registration number: not reported
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised presentation of devices; although no further detail was given on how randomisation sequence was generated, selection bias should be avoided since all participants used all devices (cross‐over study design)
Allocation concealment (selection bias)	Low risk	Randomised presentation of devices; although no further detail was given on how randomisation sequence was concealed, selection bias should be avoided since all participants used all devices (cross‐over study design)
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No loss to follow‐up reported
Selective reporting (reporting bias)	Low risk	No protocol available, but primary outcome reported
Period effect	Low risk	Stable vision required during the last 3 months to include participants
Carry‐over effect and period‐by‐treatment interaction	Unclear risk	No details reported

Methods	Study design: quasi‐randomised cross‐over trial  Masking: masking issues are not described, but study participants, providers and outcome assessors were likely to be unmasked given the use of recognisable devices  Exclusions after randomisation: none reported  Losses to follow‐up: none reported  Unusual study design: within‐person design, i.e. a cross‐over study in which all participants try the devices consecutively
Participants	Country: USA  Number randomised: 22 veterans enrolled in the residential rehabilitation programme of the Western Blind Rehabilitation Center (none with previous reading training)  Cause of low vision: AMD (n = 16), CRVO (n = 2), diabetic retinopathy (n = 2), macular hole (n = 1), cone dystrophy (n = 1)  Age: mean age 73 years, range 53 to 87 years  Sex: 20 men, 2 women, 9% women  Inclusion criteria: legal blindness; central scotoma with a intact peripheral field; stated desire for reading rehabilitation  Exclusion criteria: cognitive deficits or current use of medication that would impair reading ability; illiteracy
Interventions	Intervention: Stand‐mounted CCTV, hand‐held CCTV using a 27" television. Comparator: Prescribed optical device (stand magnifier n = 19; microscopic lenses n = 3). 5 days "hands‐on" training with each of the 3 types of devices (the prescribed optical device considered as control). Eccentric viewing training preceded reading training. Duration: 15 training sessions plus sessions needed for evaluation
Outcomes	Reading speed using paragraphs of 250 words in Times New Roman (1 M font) with 5th‐grade difficulty reading comprehension assessed with 5 question for each paragraph; Reading duration during each training session; Participants' preferences for a specific device with forced and open‐ended questions
Notes	Date study conducted: not reported  Funding: supported by a grant from Innovations Inc and the Veteran Afffairs Palo Alto HEalth Care System  Declaration of interest: not reported  Trial registration number: not reported
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quasi‐randomised study: the order of presentation of the devices was rotated for consecutive participants; despite this, selection bias should be avoided since all participants used all devices (cross‐over nature of the study design)
Allocation concealment (selection bias)	Low risk	Order of randomisation can be foreseen because rotation was used; despite this, selection bias should be avoided since all participants used all devices (cross‐over nature of the study design)
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No loss to follow‐up or exclusion after randomisation reported
Selective reporting (reporting bias)	Low risk	No protocol available, but primary outcome reported
Period effect	Low risk	No details reported, but same‐session, short duration testing made this type of bias unlikely
Carry‐over effect and period‐by‐treatment interaction	Unclear risk	No details reported

Methods	Study design: parallel group randomised controlled trial  Masking: not reported, but not possible for these interventions  Losses to follow‐up: 7 withdrawals, 2 in intervention group and 5 in comparator (4 in comparator group at 1 month)  Unusual study design: no
Participants	Country: USA  Number randomised: 37 people with central field loss recruited at the multidisciplinary outpatient vision rehabilitation clinic at the Massachusetts Eye and Ear Hospital  Cause of low vision: AMD or juvenile onset macular degeneration (n = 27), optic nerve disease (n = 6), macular dystrophy or other maculopathy (n = 4)  Age: mean age 73 years, range 40 to 91 years  Sex: 19 men, 18 women, 49% women  Inclusion criteria: age ≥ 40 years, central visual field loss, visual acuity worse than 20/40 in each eye and better than 20/400 in the better seeing eye, cumulative score of > 20 (of 30) on the 6‐question modified Mini Mental State Examination (MMSE) questionnaire for visually impaired, sufficient hearing to participate in interviews, and no previous experience with vision rehabilitation or video camera magnifiers.  Exclusion criteria: none
Interventions	Intervention: Electronic video magnifier plus standard comprehensive vision rehabilitation with optical aid prescription Comparator: Standard comprehensive vision rehabilitation with optical or electronic aid prescription (see below) All participants underwent an initial vision rehabilitation consultation, during which patients were educated about rehabilitation strategies, given information about remaining visual function, and shown a range of optical and electronic devices, which they could purchase. Patients in the video magnifier group received a free desk video magnifier when they presented for initial consultation. Patients in the visual rehabilitation group were free to purchase devices at any time, and they were advised that they would also receive a free video magnifier after the completion of rehabilitation training with an occupational therapist. Everyone returned after 1 month to begin an occupational therapy evaluation and subsequent training. Duration: 1 month
Outcomes	Reading speed assessed in words per minute (wpm) using the International Reading Speed Texts (IReST); quality of life and self‐perceived visual functioning using the Impact of Vision Impairment questionnaire (IVI) and 10 reading questions from the Activity Inventor. Results were evaluated at enrolment, when all participants used pre‐rehabilitation  devices, and at 1 month after enrolment, when participants who had had access to a video magnifier completed reading assessment using the video magnifier. Planned 1 year follow‐up not reported.
Notes	Date study conducted: February 2010 to May 2011  Funding: devices provided by Optelec USA  Declaration of interest: not reported  Trial registration number: NCT01670643
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated numerical series
Allocation concealment (selection bias)	Low risk	Randomisation "was assigned at the initial consultation when the subject signed consent" (author's information)
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	6 out of 36 participants were lost to follow‐up at one month due to withdrawals, of which 2 in the intervention group and 4 in the comparator group, with causes of withdrawal not reported
Selective reporting (reporting bias)	Low risk	Pre‐specified outcomes on Clinical Trials registry entry include objective and subjective reading tests and standard international tool was used (IReST)

Methods	Study design: quasi randomised cross‐over trial  Masking: masking issues are not described, but study participants, providers and outcome assessors were likely to be unmasked given the use of recognisable devices  Exclusions after randomisation: none reported  Losses to follow‐up: none reported  Unusual study design: within‐person design, i.e. a cross‐over study in which all participants try the devices consecutively
Participants	Country: Canada  Number randomised: 100 participants from low‐vision services who were literate and cognitively capable  Cause of low vision: AMD (n = 57), diabetic retinopathy (n = 6), glaucoma (n = 6), other (n = 25), unknown (n = 6)  Age: estimated mean age 75 years, range 24 to 97 years  Sex: 39 men, 161 women, 81% women  Inclusion criteria: visual acuity better than 6/90, but worse than 6/24 in the better eye with best standard correction, as measured by the ETDRS chart, or qualify for low‐vision rehabilitation in the province of Quebec  Exclusion criteria: mild cognitive impairment
Interventions	Intervention: Tablet computer (Apple iPad Air, 2013 model, 16 GB) with a 9.7" (diagonal) backlit LED rectangular screen Comparator: Closed circuit television: ClearView+model (Optelec, Longueuil, QC, Canada), which has a 22" thin film transistor screen (flicker‐free panel) Home magnification not considered since not optimised Duration: single test session
Outcomes	Reading speed, measured with the International Reading Speed Texts (IReST)  Quality of life: visual function index (VF‐14)
Notes	Date study conducted: not reported  Funding:Quote "This work was supported in part by the Vision Research Network, the Fonds de recherche du Québéc ‐ Santé (#28881, #30620, and #32643), the Antoine Turmel Foundation and the MAB‐Mackay Foundation."  Declaration of interest: reported no conflict of interest  Trial registration number: not reported
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Order of presentation of the devices was reported to be pseudo‐randomised to reduce practice or fatigue effects (quasi‐random assignment). Although no further detail was given on how randomisation sequence was generated, selection bias should be avoided since all participants used all devices (cross‐over study design)
Allocation concealment (selection bias)	Low risk	Randomised presentation of devices; although no further detail was given on how randomisation sequence was concealed, selection bias should be avoided since all participants used all devices (cross‐over study design)
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No loss to follow‐up or exclusion reported
Selective reporting (reporting bias)	Low risk	No protocol available, but primary outcome reported
Period effect	Low risk	No details reported, but same‐session, short duration testing made this type of bias unlikely
Carry‐over effect and period‐by‐treatment interaction	Unclear risk	No details provided

Study	Reason for exclusion
Alabdulkader 2012	Only one device type was adopted
Bailie 2013	Not a randomised or quasi‐randomised controlled trial
Blaskey 1990	Assessment of Irlen filters in people with reading difficulty not due to low vision
Bonatti 2008	Stand magnifier compared to hand magnifier regarding subjective preference, but reading speed or reading acuity data not assessed
Cheong 2005	Large‐print reading training effect and not LVA effect studied
Cheong 2009	Reading performance of 29 participants with AMD assessed using their habitual stand magnifier with and without a temporary line guide attached; no comparison of different LVAs
Cohen 1991	LVAs compared in normal observers
Culham 2009	The study aims to elicit the users' responses to 4 electronic HMDs and to correlate users' opinion with performance, but reading speed or acuity data for each device were not assessed
Goodrich 1977	Participants assigned to 2 groups but no randomisation used (information obtained by the first author)
Goodrich 2004	Within‐person or cross‐over study but all participants underwent training and testing with the 3 devices in the same order
Jacobs 1990	Evaluated whether the colour of the screen altered performance of CCTV
Kuyk 1990	Comparison of motorised and manual focus Keplerian telescopes, but target spotting and not reading performance assessed
Lawton 1989	Before‐and‐after study on compensation filters boosting the amplitudes of the intermediate spatial frequencies more than the amplitude of the lower spatial frequencies. No control group
LOVIT 2008	Multicentre randomised study comparing the effectiveness of a low‐vision rehabilitation programme with control (waiting list); outcome measure was change in participants' visual reading ability estimated from participant responses to the Veterans Affairs Low‐Vision Visual Functioning Questionnaire (LV VFQ–48) reading items completed at baseline compared with 4 months after enrolment for the treatment and control groups. No comparison of different reading aids
Margrain 2000	No comparisons between LVAs
Parodi 2004	RCT including 28 participants comparing the effect of prisms (5 to 7 prismatic dioptres) in the better eye versus control. Excluded because the aim was to improve visual acuity
Rees 2006	Comparison of low‐cost and high‐cost hand‐held magnifiers, but no comparison of different LVAs
Reeves 2004	The effectiveness of 3 models of low‐vision rehabilitation for people with AMD compared rather than the efficacy of specific types of LVAs
Rohrschneider 1998	Assessed reading speed in CCTV with different image refresh rates (50 Hz, 60 Hz and 70 Hz of frequency)
Rosenberg 1989	Quasi‐randomised study comparing prismatic correction in 19 participants versus 11 controls. Excluded because the aim of the study was to improve visual acuity not reading acuity
Rossi 1990	Effect on walking and transfer assessed in stroke patients with hemianopsia or visual neglect using Fresnel prisms vs control. No reading speed data
Scott 2002	Evaluation of performance in icon identification tasks while the screen features of the graphical user interface were varied
Wolffshon 2002	Coloured lenses compared with no filter in 10 AMD people and 5 healthy controls, but reading speed not assessed

Methods	Quote: "Twenty‐nine adults (distance visual acuity 20/80‐20/320) from the Vision Rehabilitation Center read short paragraphs (41‐44 words) using three 10× devices (a portable electronic magnification system (EMS), a hand held magnifier (MAG) and table top CCTV). Subjects read three font sizes (18, 12, and 8 pt, san serif) with each device. We defined a weighted words per minute reading rate from the time taken to read and approximate number of words read from each paragraph. We also recorded age (19‐91), diagnosis (41% ARMD) and previous use of each device. "
Participants	29 adults
Interventions	A portable electronic magnification system (EMS), a hand held magnifier (MAG) and table top CCTV
Outcomes	Quote: "The group as a whole read faster with the CCTV, then magnifier, then portable EMS (P<0.0001). To our surprise, with each device, reading was slowest with 18 pt and fastest with 8 pt. There was no effect of familiarity with device. For subjects with ARMD, again, reading was fastest with CCTV but there was no difference between MAG and EMS. Unlike the group as a whole, reading rate was the same for all font sizes except with CCTV, where reading was fastest with 8 pt type. Conclusions: the portable EMS provides no benefit for low vision patients. The increase in reading performance with decreasing font size may be due to increased field of view. Further research is required. "
Notes	ARVO abstract only

PERMALINK

Reading aids for adults with low vision

Gianni Virgili

Ruthy Acosta

Sharon A Bentley

Giovanni Giacomelli

Claire Allcock

Jennifer R Evans

Abstract

Background

Objectives

Search methods

Selection criteria

Data collection and analysis

Main results

Authors' conclusions

Plain language summary

Summary of findings

Background

Description of the condition

Description of the intervention

How the intervention might work

Why it is important to do this review

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Types of participants

Types of interventions

Types of outcome measures

Primary outcomes

Secondary outcomes

Search methods for identification of studies

Electronic searches

Searching other resources

Data collection and analysis

Selection of studies

Data extraction and management

Assessment of risk of bias in included studies

Measures of treatment effect

Unit of analysis issues

Dealing with missing data

Assessment of heterogeneity

Assessment of reporting biases

Data synthesis

Subgroup and sensitivity analyses

Summary of findings tables

Results

Description of studies

Results of the search

1.

Included studies

2.

1. Interventions and outcomes in the included studies.

Design

Participants

Interventions

Outcome measures

Reading speed (primary outcome in this review)

Reading acuity

Quality of life

Reading duration

Preference for each device

Outcomes not used in this review

Excluded studies

Risk of bias in included studies

Allocation

Blinding

Incomplete outcome data

Selective reporting

Other potential sources of bias

Period effect: stability of disease during cross‐over phases

Carry‐over effect and period‐by‐treatment interaction: the potential risk of learning effect or fatigue during repeated testing

Effects of interventions

Summary of findings for the main comparison. Stand‐mounted closed circuit television (CCTV) versus optical device for adults with low vision.

Summary of findings 2. Hand‐held mouse‐based electronic device versus optical device for adults with low vision.

Summary of findings 3. Hand‐held (not mouse‐based) electronic device plus optical device versus optical device for adult with low vision.

Summary of findings 4. Stand‐mounted closed circuit television (CCTV) plus visual rehabilitation versus visual rehabilitation alone.

Summary of findings 5. Stand‐mounted closed circuit television (CCTV) versus head‐mounted electronic device (HMD) for adults with low vision.

Summary of findings 6. Stand‐mounted closed circuit television (CCTV) versus hand‐held mouse‐based electronic device (HHD) for adults with low vision.

Methods	Quote: "In this study we explored the effect reading training and device type (optical aid closed circuit television (CCTV)) on reading performance of individuals with central field loss. While a central field loss reduces reading performance, rehabilitation can restore function, but the question of how much rehabilitative training is necessary to optimize reading has not been addressed. Reading performance with low vision aids has similarly been shown to be effective, but the value of optics aids versus CCTV has not been extensively explored. METHOD: 50 subjects with central field loss who participated in the rehabilitation program of the Western Blind Rehabilitation Center volunteered to participate in the study; which used a randomised, counter‐balances design. All subjects received comprehensive optometric examinations, were prescribed an optimum near vision optical aid and CCTV. The training group received ten days of instructor training with their optical aid and fifteen days of instructor training with their CCTV. The other group received five days of instructor training with the optical aid followed by five days of independent practice and seven days of training with the CCTV and eight days of independent practice. The variables of acuity, contrast sensitivity, reading speed and reading duration were measured."
Participants	50 people with central loss
Interventions	Optimum near vision optical aid and CCTV
Outcomes	Quote: "Short term instructor training combined with independent practice was as effective in optimizing reading speed and duration as was the longer term instructor training. CCTVs provided greater reading speed and duration than did optical aids. Reading performance with an optical aid was only moderately correlated with reading performance with a CCTV. CONCLUSION. Instructor training combined with independent practice is an effective method of rehabilitating reading skills. CCTVs offer advantages in terms of reading speed and duration. Reading training is a variable which, if taken into account, can improve both low vision clinical practice and research"
Notes	American Academy of Optometry abstract only

Methods	Quote: "Reading aids are arguably the most frequently prescribed low vision device, yet there is little comparative information on the performance to be expected for different low vision devices prescribed for patients having different characteristics. PURPOSE. This study sought to provide comparative information for clinicians to assist in prescribing low vision reading devices, and for patients in selecting which device will best meet their needs in relation to its cost. METHOD. Subjects were 133 patients (mean age = 68.5 yrs) of the Western Blind Rehabilitation Center. Subjects were assigned to one of three groups based upon field loss: central (N = 90); peripheral (N = 28); or mixed central and peripheral field loss (N = 15). The study used a within‐person, counterbalanced design with all subjects trained in reading with an optical aid (primarily stand magnifiers or microscopic lenses) and CCTV. Reading speeds and durations were recorded."
Participants	132 low‐vision participants
Interventions	Optical aid (primarily stand magnifiers or microscopic lenses) and CCTV
Outcomes	Quote: "Central loss subjects read 20% faster and 34% longer with the CCTV than their best optical aid. Peripheral loss subjects read only 12% faster and 23% longer with CCTV than their best optical aid, and mixed loss subjects read only 9% faster and 34% longer. CONCLUSIONS. CCTVs, as a low vision reading device, provided all subjects in this study with an average of 23% to 34% longer reading durations. Reading speeds averaged between 9% and 20% greater. Central loss subjects appear to gain the greatest benefit from CCTV, while mixed and peripheral loss subjects gain a greater reading duration with the CCTV. The relative benefits of devices for each patient group will be discussed in the context of information that may assist the clinician in prescribing low vision reading devices. Prescribing information should encompass the patient's reading needs and the cost of the devices, as well as, information about the performance patient's can expect from the device."
Notes	American Academy of Optometry abstract only

Methods	Quote: "Low power lasers have been used for purposes ranging from scanning laser ophthalmoscopes to heads‐up displays for aircraft pilots. In this study we have begun a formal examination of one possible application as a reading display for low vision patients. The prototype device, called Nomad, is a monocular, head‐mounted display that uses a red laser to display text onto the retina. A CCTV camera and XY table provided input. METHODS: 20 subjects read with the prescribed optical device, CCTV, and Nomad. Data was collected on subject visual acuity, pathology, contrast sensitivity, duration of visual disability, and reading speed and reading duration with each device. In addition subjective impressions of the Nomad were gathered using both forced choice and open‐ended questions."
Participants	20 low vision participants
Interventions	Prescribed optical device, CCTV, and Nomad
Outcomes	"Subject reading speeds with the Nomad were faster than optical devices, but slower than CCTV. Reading durations with the Nomad were similar to that with CCTV; both of which were about 3X longer than optical devices. Subjective data indicated that subjects would prefer another color, or full‐color laser for the Nomad and would like a more comfortable head‐mount. Most subjects preferred the brightness and sharpness of the Nomad display to the displays of the optical devices and CCTVs. The brightness and high contrast may allow patients with extremely low vision to maintain, the ability to read visually even when conventional devices are no longer effective. CONCLUSIONS: the Nomad is a prototype display with potential as both a distance and near vision aid. At present it is a useful research tool to begin examining the potential benefits of new visual display technology. We will discuss our findings in relation to this potential."
Notes	American Academy of Optometry abstract only

Methods	Within‐person study (2 low‐vision aids tested on the same participant); order of presentation randomised (coin toss, as notified by the authors)
Participants	13 low‐vision persons participated in the study. Their ages ranged from 57‐82 years, average 70 years. Their best corrected visual acuity ranged from 0.01‐0.30, average 0.04. They were asked to read characters with these 2 devices for 20 seconds text of decreasing print size
Interventions	A hand‐held retinal projection system was compared with a face‐mounted video display using a CCTV system
Outcomes	Reading speed, critical print size
Notes	Article in Japanese; authors have been contacted to collect data and there was no answer

Methods	Quote: "Portability and ease of text and spot reading is a challenge for low vision patients needing high levels of magnification. 'Powervision,' a new, head‐mounted electronic magnification system, offers portable high magnification for reading. This pilot study compared the speed and accuracy of text and spot reading by low vision patients using 'Powervision' (P), traditional CCTV (C) and a comparable hand held magnifier (H). METHODS. Twenty patients from the Vision Rehabilitation Center of the Mass. Eye and Ear Infirmary best corrected to < or = 20/80, could read English, and consented to participate were included. Patients were scored on time and accuracy of reading three short paragraphs of text (8, 12, 18 pt print) and spot reading of a hospital bill. Patients reported ease of reading with each of the three devices. "
Participants	20 low‐vision participants
Interventions	Powervision, traditional CCTV and a comparable hand held magnifier
Outcomes	Quote: "Ages ranged 22‐92 (mean 58.3), with acuities of 20/80‐20/800 (mean 20/267), and primary diagnoses of ARMD (23%) and other etiologies of visual loss. Text reading mean scores (360s maximum) were P: 313s, C: 180s, H: 248s, and accuracy (12.0=whole paragraph correct, 0=could not read) was P: 8.4, C: 11.3, H: 8.9. Spot reading mean times were P: 95s, C: 60s, H: 83s and accuracy (4.0= all correct, 8.0= all incorrect) measured P: 5.4, C: 4.2, H: 5.1. Mean patient reports of ease of use (1=Very Easy, 5=Very Difficult) were P: 3.5, C: 1.9, H: 3.1 for text reading and P: 3.6, C: 1.7, H: 2.8 for spot reading. DISCUSSION. In this pilot population, despite its portability, Powervision scored less well on speed and accuracy of spot and test reading and for patient report of ease of use. Planned redesign and training in use may improve patient performance."
Notes	ARVO abstract only