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Background Previous research has established that some informal caregivers (relatives/friends) of people with visual impairment (PVI) may require support themselves. However, there is limited understanding of how healthcare services and sight charities in the UK currently support caregivers. This study was therefore conducted to explore what support, information, and advice healthcare and charity professionals (HCCPs) currently provide for caregivers, and which additional support HCCPs would recommend in order to benefit caregivers. Methods HCCPs filled out an online survey, distributed among UK-based professional bodies and charity partners. Of 104 individuals who consented to participate, 68 (65%) HCCPs completed the survey in September–November 2019. Participants responded to Likert-type questions about how they interact with and support caregivers of PVI. Thirty-eight (56%) participants provided responses to open-ended questions about improving support for caregivers; qualitative analysis was conducted using the Framework Method. Results The survey showed that caregiver support activities most commonly undertaken related to onward signposting (90% (95% CI: 82–97%) of participants), or providing information about low vision aids and adaptations (85% (95% CI: 77–94%)), compared to activities focused on broader caregiver wellbeing. In open-ended responses, HCCPs highlighted the difficulties caregivers face in navigating an under-resourced and complex system. They recommended improving coordination and accessibility of information, as well as provision of emotional support and tangible assistance such as respite care and financial support. Conclusions The study suggests that HCCPs perceive significant unmet needs among caregivers of PVI, and would welcome further resources, information, and training to support caregivers.

PURPOSE: Many of the UK's 2.5 million individuals living with vision loss receive support from relatives or friends (so-called 'informal caregivers'). However, there is limited understanding of how caregivers of people with visual impairment (PVI) are, or feel, supported by UK healthcare/statutory services and charities. This exploratory study was conducted to explore caregivers' experiences and their suggestions for enhancing support. \ud \ud METHODS: Participants self-identifying as UK-based caregivers of PVI (N = 100) volunteered to undertake an online survey, distributed through charity partners. The survey was comprised of the Client Satisfaction Questionnaire-8 (CSQ-8, a validated, self-report measure of satisfaction with support services), Likert-type questions and two open-ended, free-text questions. Interview participants (N = 22) were then selected from survey respondents, and semi-structured interviews were conducted to focus on caregivers' ideas for improving support. The Framework Method was used for inductive analysis of the free-text question responses and interview data. \ud \ud RESULTS: The mean (SD) CSQ-8 score was 21.60 (7.2), with no significant differences by demographic, relationship or vision-related factors, likely limited by the small subgroup sizes. Qualitative data demonstrated the heterogeneity of participating caregivers' experiences, highlighting the importance of personalised support for caregivers. Many participants advocated enhancing informational, practical, emotional and social support for caregivers, and stressed the importance of accessible services and consistent points of contact to turn to for support and advice. \ud \ud CONCLUSIONS: Although our sample was arguably better connected to support services than the general caregiver population, this study identified concrete suggestions to improve practical, emotional and peer support for caregivers of PVI.

Background Various instruments have been developed to measure aligning prism, the prism that eliminates a fixation disparity (associated heterophoria). This includes the established Mallett near vision unit and recently developed Thomson Vision Toolbox on the iPad. With no previous research investigating the agreement between these instruments, practitioners may question if they can be used interchangeably. Methods 80 participants underwent near vision testing with the Mallett unit and iPad fixation disparity test. Data were analysed in four ways to investigate the agreement of the two instruments. Results Many participants reported no fixation disparity (horizontally 46.25%, vertically 82.5%), or non-significant aligning prism (horizontally 70%, vertically 97.5%), on both instruments. The iPad revealed a larger range of aligning prism results horizontally, 6Δ base out to 15Δ base in; the Mallett unit produced a larger range of results vertically, 1Δ base up to 3.5Δ base down. More participants required a significant aligning prism on the Mallett unit horizontally and vertically. Wilcoxon signed rank analysis found that the difference in aligning prism was not statistically significant (p = 0.357 horizontally, p = 0.236 vertically), but 95% limits of agreement revealed clinically significant differences between the instruments. Conclusion Although the measured differences between the instruments are not significant in a Wilcoxon analysis, a Bland & Altman approach shows them to be in some cases clinically unacceptable, therefore the instruments should not be used interchangeably. Previous research indicates that the Mallett unit performs reasonably well at detecting symptomatic individuals and determining a prismatic correction that is likely to be helpful. Further research is required to determine the performance of the iPad test in these functions and to assess the reproducibility of both instruments.

Background: The number of individuals with a visual impairment in the UK was estimated a few years ago to be around 1.8 million People can be visually impaired from birth, childhood, early adulthood or later in life. Those with visual impairment are subject to health inequities and increased risk for patient safety incidents in comparison to the general population. They are also known to be at an increased risk of experiencing medication errors compared to those without visual impairment. In view of this, this review aims to understand the issues of medication safety for VI people. Methods/design: Four electronic bibliographic databases will be searched: MEDLINE, Embase, PsycInfo and CINAHL. Our search strategy will include search combinations of two key blocks of terms. Studies will not be excluded based on design. Included studies will be empirical studies. They will include studies that relate to both medication safety and visual impairment. Two reviewers (SG and LR) will screen all the titles and abstracts. SG, LR, RM, SCS and PL will perform study selection and data extraction using standard forms. Disagreements will be resolved through discussion or third party adjudication. Data to be collected include study characteristics (year, objective, research method, setting, country), participant characteristics (number, age, gender, diagnoses), medication safety incident type and characteristics. Discussion: The review will summarise the literature relating to medication safety and visual impairment.

Alongside difficulties with communication and social interaction, autism is often accompanied by unusual sensory and perceptual experiences including enhanced visual performance on tasks that involve separating local parts from global context. This superiority may be the result of atypical integrative processing, involving feedback and lateral connections between visual neurons. The current study investigated the integrity of these connections in autistic adults by examining two psychophysics tasks that rely on these processes - collinear facilitation and contour integration. The relative contribution of feedback and lateral connectivity was studied by altering the timing of the target relative to the flankers in the collinear facilitation task, in 16 autistic and 16 non-autistic adults. There were no significant differences in facilitation between the autistic and non-autistic groups, indicating that for this task and participant sample, lateral and feedback connectivity appear relatively intact in autistic individuals. Contour integration was examined in a different group of 20 autistic and 18 non-autistic individuals, for open and closed contours to assess the closure effect (improved detection of closed compared to open contours). Autistic individuals showed a reduced closure effect at both short (150 ms) and longer (500 ms) stimulus presentation durations that was driven by better performance of the autistic group for the open contours. These results suggest that reduced closure in a simple contour detection paradigm is unlikely to be due to slower global processing. Reduced closure has implications for understanding sensory overload by contributing to reduced figure-ground segregation of salient visual features.

Purpose: To compare the performance of near vision activities using additional portable electronic vision enhancement systems (p-EVES), to using optical magnifiers alone, by individuals with visual impairment. Methods: A total of 100 experienced optical aid users were recruited from low vision clinics at Manchester Royal Eye Hospital, Manchester, UK, to a prospective two-arm cross-over randomised controlled trial. Reading, performance of near vision activities, and device usage were evaluated at baseline; and at the end of each study arm (Intervention A: existing optical aids plus p-EVES; Intervention B: optical aids only) which was after 2 and 4 months. Results: A total of 82 participants completed the study. Overall, maximum reading speed for high contrast sentences was not statistically significantly different for optical aids and p-EVES, although the critical print size and threshold print size which could be accessed with p-EVES were statistically significantly smaller (p

Uncorrected refractive error is a major cause of vision impairment, and is indexed by visual acuity. Availability of vision assessment is limited in low/middle-income countries and in minority groups in high income countries. eHealth tools offer a solution; two-thirds of the globe own mobile devices. This is a scoping review of the number and quality of tools for self-testing visual acuity. Software applications intended for professional clinical use were excluded. Keyword searches were conducted on Google online, Google Play and iOS store. The first 100 hits in each search were screened against inclusion criteria. After screening, 42 tools were reviewed. Tools assessed near and distance vision. About half (

Purpose To determine the incremental cost-effectiveness of portable electronic vision enhancement system (p-EVES) devices compared with optical low vision aids (LVAs), for improving near vision visual function, quality of life and well-being of people with a visual impairment. Methods An AB/BA randomized crossover trial design was used. Eighty-two participants completed the study. Participants were current users of optical LVAs who had not tried a p-EVES device before and had a stable visual impairment. The trial intervention was the addition of a p-EVES device to the participant's existing optical LVA(s) for 2 months, and the control intervention was optical LVA use only, for 2 months. Cost-effectiveness and cost-utility analyses were conducted from a societal perspective. Results The mean cost of the p-EVES intervention was £448. Carer costs were £30 (4.46 hr) less for the p-EVES intervention compared with the LVA only control. The mean difference in total costs was £417. Bootstrapping gave an incremental cost-effectiveness ratio (ICER) of £736 (95% CI £481 to £1525) for a 7% improvement in near vision visual function. Cost per quality-adjusted life year (QALY) ranged from £56 991 (lower 95% CI = £19 801) to £66 490 (lower 95% CI = £23 055). Sensitivity analysis varying the commercial price of the p-EVES device reduced ICERs by up to 75%, with cost per QALYs falling below £30 000. Conclusion Portable electronic vision enhancement system (p-EVES) devices are likely to be a cost-effective use of healthcare resources for improving near vision visual function, but this does not translate into cost-effective improvements in quality of life, capability or well-being.

Background Individuals with a restricted peripheral visual field or tunnel vision (TV) have problems moving about and avoiding obstacles. Some individuals adapt better than others and some use assistive optical aids, so measurement of the visual field is not sufficient to describe their performance. In the present study, we developed a new clinical test called the ‘Assessment of Visual Awareness (AVA)’, which can be used to measure detection of peripheral targets. Methods The participants were 20 patients with TV due to retinitis pigmentosa (PTV) and 50 normally sighted participants with simulated tunnel vision (STV) using goggles. In the AVA test, detection times were measured, when subjects searched for 24 individually presented, one degree targets, randomly positioned in a 60 degrees noise background. Head and eye movements were allowed and the presentation time was unlimited. The test validity was investigated by correlating the detection times with the ‘percentage of preferred walking speed’ (PPWS) and the ‘number of collisions’ on an indoor mobility course. Results In PTV and STV, the detection times had significant negative correlation with the field of view. The detection times had significant positive relations with target location. In the STV, the detection time was significantly negatively correlated with the PPWS and significantly positively correlated with the collisions score on the indoor mobility course. In the PTV, the relationship was not statistically significant. No significant difference in performance of STV was found when repeating the test one to two weeks later. Conclusion The proposed AVA test was sensitive to the field of view and target location. The test is unique in design, quick, simple to deliver and both repeatable and valid. It could be a valuable tool to test different rehabilitation strategies in patients with TV.

Purpose: This study evaluated the community-based eccentric viewing (EV) training offered across the United Kingdom by the Macular Society. Volunteer trainers deliver free one-to-one training, usually in learners' homes. They also share information about lighting, magnification, social support, and low-vision technology.\ud \ud Methods: The audio-recorded reading performance of learners was compared before and after training. Telephone questionnaires were used to assess life satisfaction, amount of reading performed, and health- and vision-related quality of life. Learners were also interviewed to obtain their subjective opinions.\ud \ud Results: A total of 121 learners completed all stages of the study. There was no significant change in maximum reading speed. A statistically significant (P < 0.001) but small improvement in both critical print size and threshold print size was found, but frequency and duration of reading did not increase. There was a borderline significant (P = 0.022) increase in “life satisfaction” for the learners, but a highly significant (P < 0.001) decrease in their “positive affect.” There was no change in health- or vision-related quality of life, or in the difficulty experienced in performing everyday tasks. However, according to learner interviews, 72% felt they had achieved a positive outcome from the training, and 75% felt they had received helpful advice in addition to the EV training.\ud \ud Conclusions: The lack of improvement of reading speed and modest improvement in threshold print size should be interpreted in the context of the unique features of this EV program, since many learners who would seem to have limited scope for improvement still undertake the training.

Aim: There are many colour vision tests available that detect, classify and grade colour deficiency for adults. Testing colour vision in older children is possible using the same tests but very young children may not yet be confident in identifying pictures and numerals, or may not understand tracing coloured pathways. This pilot study was designed to assess whether Lego1 bricks, which are available in many waiting areas, could be applied to detect colour vision deficiency. Methods: Two groups of 10 male subjects (age 18–32 years) were recruited. One group were colour normal (CVNorm) and 10 were aware of a colour defect (CVDef). Each group completed a standard colour vision assessment consisting of the anomaloscope, Ishihara pseudo-isochromatic plates and D-15 saturated caps. The CVNorm and CVDef groups were required to match Lego1 bricks of the same colour from a tray containing bricks of many colours within a light box using standard illuminant C. Different numbers of the test bricks (red, green, blue, yellow and beige) were randomly selected. Black, light green, white and orange bricks were added as distraction bricks. In a given time limit subjects had to select the bricks of a colour chosen by the assessor, and were scored for incorrectly chosen or missed bricks. The task was repeated under fluorescent and incandescent illumination. Results: CVNorm subjects had zero errors matching the bricks under all three illumination conditions. The CVDef group consisted of 9 dichromats (6 deuteranopes, 3 protanopes) and 1 deuteranomalous trichromat. Some CVDef subjects made one or two errors but in general many completed the task without making any errors. There was no statistical difference between the groups under any of the three illumination conditions. Conclusion: Conventional Lego1 bricks did not detect colour-matching problems in adults previously identified with severe colour deficiency and therefore cannot be recommended as a single test for paediatric colour vision examination.

PURPOSE: Speech-reading is the ability to recognise certain sounds visually, using both the movements of the speaker's mouth, plus other sources of visual information, such as gestures and body language, facial expressions and situational clues. This study aimed to determine the effect of mild degrees of visual impairment on speech-reading ability. METHOD: A group of 15 normally-sighted subjects was assessed with different levels of simulated visual loss using occlusion foils, in the presence of constant background noise to simulate hearing loss. The visual impairments created ranged from 20 to 13 dB log contrast sensitivity (contrast thresholds 1-5%) (measured using the backlit Melbourne Edge Test) with acuity dropping from 6/6 to 6/24 (logMAR 0.0-0.6). The speech-reading ability with simulated impairment and noise was quantified as the number of words recognised correctly when watching a video of an actor speaking meaningful sentences. RESULTS: The introduction of the mildest simulated visual impairment (VA 6/6 logMAR 0.0; contrast sensitivity 20 dB, contrast threshold 1%) was sufficient to cause a statistically significant reduction in speech-reading ability (t-test, p < 0.001), and as the level of visual impairment was increased, the speech-reading ability became progressively worse throughout the range of impairments tested. CONCLUSIONS: This study shows that if hearing is compromised, then an observer's speech-reading ability is sensitive to changes in vision. It is likely that visual loss will have consequences for speech-reading ability. This will be particularly relevant to the elderly population who are often found to have a dual sensory loss that causes compromise to both visual and auditory sensory reception. Some of the difficulties in communication reported by the elderly with reduced hearing could be visual as opposed to auditory in origin.

(1) To explore the relation between performance on tasks of familiar face recognition (FFR) and face expression difference discrimination (FED) with both perceived disability in face recognition and clinical measures of visual function in subjects with age related macular degeneration (AMD). (2) To quantify the gain in performance for face recognition tasks when subjects use a bioptic telescopic low vision device.30 subjects with AMD (age range 66-90 years; visual acuity 0.4-1.4 logMAR) were recruited for the study. Perceived (self rated) disability in face recognition was assessed by an eight item questionnaire covering a range of issues relating to face recognition. Visual functions measured were distance visual acuity (ETDRS logMAR charts), continuous text reading acuity (MNRead charts), contrast sensitivity (Pelli-Robson chart), and colour vision (large panel D-15). In the FFR task, images of famous people had to be identified. FED was assessed by a forced choice test where subjects had to decide which one of four images showed a different facial expression. These tasks were repeated with subjects using a bioptic device.Overall perceived disability in face recognition did not correlate with performance on either task, although a specific item on difficulty recognising familiar faces did correlate with FFR (r = 0.49, p0.05). FFR performance was most closely related to distance acuity (r = -0.69, p0.001), while FED performance was most closely related to continuous text reading acuity (r = -0.79, p0.001). In multiple regression, neither contrast sensitivity nor colour vision significantly increased the explained variance. When using a bioptic telescope, FFR performance improved in 86% of subjects (median gain = 49%; p0.001), while FED performance increased in 79% of subjects (median gain = 50%; p0.01).Distance and reading visual acuity are closely associated with measured task performance in FFR and FED. A bioptic low vision device can offer a significant improvement in performance for face recognition tasks, and may be useful in reducing the handicap associated with this disability. There is, however, little evidence for a correlation between self rated difficulty in face recognition and measured performance for either task. Further work is needed to explore the complex relation between the perception of disability and measured performance.

Rachel Bambrick, Professor Christine Dickinson, John Taylor and Dr Robert Harper discuss the portable electronic vision enhancement systems study and explain its implications for those aiming to prescribe magnification for close work.

In the UK, low vision rehabilitation is delivered by a wide variety of providers with different strategies being used to integrate services from health, social care and the voluntary sector. In order to capture the current diversity of service provision the Low vision Service Model Evaluation (LOVSME) project aimed to profile selected low vision services using published standards for service delivery as a guide. Seven geographically and organizationally varied low-vision services across England were chosen for their diversity and all agreed to participate. A series of questionnaires and follow-up visits were undertaken to obtain a comprehensive description of each service, including the staff workloads and the cost of providing the service. In this paper the strengths of each model of delivery are discussed, and examples of good practice identified. As a result of the project, an Assessment Framework tool has been developed that aims to help other service providers evaluate different aspects of their own service to identify any gaps in existing service provision, and will act as a benchmark for future service development.

Purpose: Vision and hearing impairments are known to increase in middle age. In this study we describe the prevalence of vision impairment and dual sensory impairment in UK adults aged 40-69 years in a very large and recently ascertained data set. The associations between vision impairment, age, sex, socioeconomic status, and ethnicity are reported. Methods: This research was conducted using the UK Biobank Resource, with subsets of UK Biobank data analysed with respect to self-report of eye problems and glasses use. Better-eye visual acuity with habitually worn refractive correction was assessed with a logMAR chart (n = 116 682). Better-ear speech reception threshold was measured with an adaptive speech in noise test, the Digit Triplet Test (n = 164 770). Prevalence estimates were weighted with respect to UK 2001 Census data. Results: Prevalence of mild visual impairment (VA >0.1 logMAR (6/7.5, 20/25) and ≥0.48 (6/18, 20/60)) and low vision (VA >0.48 (6/18, 20/60) and ≥1.3 (6/120, 20/400)) was estimated at 13.1% (95% CI 12.9-13.4) and 0.8% (95% CI 0.7-0.9), respectively. Use of glasses was 88.0% (95% CI 87.9-88.1). The prevalence of dual sensory impairment was 3.1% (95% CI 3.0-3.2) and there was a nine-fold increase in the prevalence of dual sensory problems between the youngest and oldest age groups. Older adults, those from low socioeconomic and ethnic minority backgrounds were most at risk for vision problems. Conclusions: Mild vision impairment is common in middle aged UK adults, despite widespread use of spectacles. Increased likelihood of vision impairment with older age and with ethnic minorities is of concern given ageing and more ethnically diverse populations. Possible barriers to optometric care for those from low socioeconomic and ethnic minority backgrounds may require attention. A higher than expected prevalence of dual impairment suggests that hearing and vision problems share common causes. Optometrists should consider screening for hearing problems, particularly among older adults. © 2014 The College of Optometrists.

For the reading task, contrast reserve is defined as the ratio of the letter contrast of the printed letters, to the reader's contrast threshold. Acuity reserve is the ratio of the print size used for the reading task, to the reader's visual acuity. The effects of low contrast reserve on reading performance were investigated at various magnifications, ranging from 3x to 7.5x, with the field of view systematically controlled. Eye movements were recorded whilst normally sighted subjects read using the magnifiers. It was shown that with adequate contrast reserve, increasing the field of view improved the reading rate because of the resulting increase in forward saccade length. Conversely, reducing the contrast reserve slowed the reading rate by decreasing the length of forward saccades and increasing the mean fixation duration, suggesting that the perceptual span is reduced at low contrast reserve. This study also shows that when the contrast reserve is low, providing magnification higher than that required for letter recognition (that is, increasing the acuity reserve) will not improve the reading performance. Furthermore, even when the contrast reserve was high, reading rates were lower for the magnifications of 5x and higher, because increases in saccade length do not match those of the retinal image size at these magnifications.

Introduction: The changes that occur in the reading eye movements of normally sighted readers were measured as they used hand magnifiers to identify how these devices contribute to the slow reading of visually-impaired patients. Methods: Subjects inexperienced in magnifier use read texts containing two sizes of print, using hand magnifiers of two different powers, held at two different eye-to-magnifier distances. The effect of magnification (up to 13.5x) and field-of-view (FOV) (2-45 characters) could be assessed independently. Results: Reading speed decreased with increasing magnification because the size of the saccades did not increase in proportion to the magnification: for a given level of magnification, decreasing the FOV and decreasing the viewing distance both reduce the size of the saccades even further. The overall reading speed is only slowed significantly when the FOV restriction is extreme (two characters' width). Conclusions: Two mechanisms seem to be used spontaneously by normally sighted readers to mitigate the limitation of reading speed created by the shortened saccades: head movement in the direction of reading and retinal image slip during fixation.

PURPOSE: To investigate the relationship between clinical impairment measures and reading performance in a large population with age-related macular degeneration. METHODS: The following clinical measures were evaluated on 243 patients with age-related macular degeneration: better eye distance visual acuity (ETDRS chart); threshold near word reading acuity (Bailey-Lovie Word Reading chart); maximum reading speed and critical print size (MNREAD chart); letter contrast sensitivity (Pelli-Robson); and kinetic perimetry (Bjerrum screen) to determine the nearest non-scotomatous point to fovea (NNPF; in degrees) and the central scotoma area (mm2). RESULTS: Distance acuity correlated well to threshold near word acuity (r = 0.71), but word acuity was usually poorer. Critical print size was strongly related (p < 0.001) to near visual acuity (r2 = 0.31 and beta = 0.47) and was poorer than threshold near word visual acuity by a mean difference of -0.41 (range, -1.10 to 0.34), which represents a mean acuity reserve of 2.5:1. On single regression, distance (p < 0.0001, r2 = 0.35, and beta = -102.37) and near acuities (p < 0.0001, r2 = 0.52, beta = -126.53), critical print size (p = 0.0001, r2 = 19, and beta = 0.002), contrast sensitivity (p < 0.0001, r2 = 19, and beta = 79.47), scotoma size (p = 0.006, r2 = 12, and beta = -0.04), and NNPF (p = 0.001, r2 = 12, and beta = -4.39) were all highly significantly related to reading speed although these predicted only a low percentage of variance. Best prediction of reading speed was obtained on multiple regression, where NNPF and near word acuity explained 60% of the variance (p < 0.0001). CONCLUSIONS: Optimal prediction of reading speed with clinical parameters appears to be based on the combination of near word acuity and scotoma area, explaining 60% of the variance. Other factors not measured in this study are likely to account for the rest of the prediction.

PURPOSE: To compare "single letter" (SL) acuity, "crowded letter" (CL) acuity, and "repeated letter" (RL) acuity for patients with age-related macular degeneration (AMD) and investigate if differences between these visual acuities are associated with fixation characteristics. METHODS: A total of 243 patients with AMD had their best-corrected visual acuity measured on an ETDRS chart. SL, CL, and RL acuities were measured using Landolt C targets on a monitor. Fifty-degree-field red-free fundus photographs were taken and a static target was used to calculate the Preferred Retinal Locus (PRL) distance and direction from the fovea. Quality of fixation (consistency and oculomotor response) was also assessed using a fundus camera and a dynamic target. RESULTS: RL acuity was almost always better than CL acuity and SL acuity was almost always better than CL acuity. The mean (+/-SD) RL-CL and SL-CL acuity differences were -0.13 (+/-0.15) logMAR and -0.11 (+/-0.13) logMAR respectively. The median PRL distance was 3.73 degrees and the preferred retinal areas for the location of the PRL were the left (left quadrant of visual field; 39.5% of cases) and superior (inferior quadrant of visual field; 25.4%). Visual acuity was significantly associated with PRL distance but PRL distance only explained 10% of the variation in visual acuity. PRL distance was found to be a significant but weak predictor of the SL-CL acuity difference but fixation quality was not a good predictor of the RL-CL acuity difference. CONCLUSIONS: Although the acuity measured under different stimulus conditions varies, the absolute differences are small. This suggests that these techniques would not be helpful in determining fixation characteristics, or predicting the outcome of rehabilitation in individual patients with AMD.

OBJECTIVE: To determine the effectiveness of prism spectacles in people with age-related macular degeneration by relocating the retinal image. METHODS: We implemented a randomized, placebo-controlled, double-masked trial. Participants with age-related macular degeneration received a standard low-vision assessment and the prescription of conventional low-vision aids 6 weeks before the study intervention. Participants were randomized to receive 1 of the following, including the optimal refractive correction: (1) custom, incorporating bilateral prisms to match participants' preferred power and base direction; (2) standard, incorporating standard bilateral prisms (6 prism diopters [Delta] base up for logMAR [logarithm of the minimum angle of resolution] visual acuity (VA) of 0.48-1.00 and 10Delta base up for logMAR VA of 1.02-1.68); or (3) placebo, consisting of spectacles matched in weight and thickness to prism spectacles but without prism. MAIN OUTCOME MEASURES: Outcomes measured binocularly at baseline and 3-month follow-up included distance logMAR VA, reading speed, critical print size, visual functioning questionnaires, and observed visual task performance. Scores on the 25-item National Eye Institute Visual Functioning Questionnaire and the Melbourne Low-Vision ADL (Activities of Daily Living) Index were converted to linear estimates using Rasch analysis. The Manchester Low Vision Questionnaire was used to collect descriptive data. RESULTS: A total of 225 participants completed the trial (median age, 81 years). We found no significant effect of treatment group on any of the outcome measures, including VA, the primary outcome (adjusted for baseline) (P = .63). Participants' responses to the Manchester Low Vision Questionnaire suggested that the prism spectacles added to their problems. CONCLUSIONS: Prism spectacles are no more effective than conventional spectacles for people with age-related macular degeneration.

Size judgements are usually based on size constancy. However, as the number of visual cues decreases, such as by decreasing the field of view, size judgements gradually change from those based on size constancy to those based on the visual angle. The present study investigated whether visually impaired (VI) individuals, most of whom do not have measurable stereoacuity and have visual field defects, might therefore make judgements based on visual angle rather than size constancy. Size constancy was measured on 42 VI and 20 normally sighted subjects. Results indicated that size judgements are similar for both VI and normally sighted individuals at 0.50 m, 1 and 2 m. Statistically significant differences were found at 3 m. Despite this it would appear that VI individuals are able to make judgements based on size constancy rather than the visual angle.

Low Vision Rehabilitation: Caring for the Whole Person . Ophthalmology Monograph 12. Ed by D C Fletcher. Pp 162. £75. San Francisco: American Academy of Ophthalmology, 1999. ISBN1-56055-170-4. This book is one component of the Lifelong Education for the Ophthalmologist (LEO) framework, produced by the American Academy of Ophthalmology. Those not claiming credits can still benefit from the multiple choice questions (with answers and explanations). The preface sets out a comprehensive range of educational objectives which are largely met by the text, but one has the impression that its primary (and most challenging goal) is persuading ophthalmologists that something can be done for the low vision patient. Ophthalmologists, more than any other group, apparently see vision loss as the “arch enemy”, and usually encounter visually impaired patients in the upsetting early stages of the condition, rather than when …

Clinical Optics and Refraction . Ed by O J Lehmann, D H Verity, A G A Coombes, F G Ah-Fat, P J Francis, A C W Ionides. Pp 160, £19.99. Oxford: Butterworth-Heinemann, 1998. ISBN0-7506-2188-5. This book is aimed at the ophthalmologist, orthoptist, or optometrist, especially in their student or trainee days. It has an unaccustomed layout: each chapter is divided into (approximately) page sized chunks, with each page headed with a question asking which of the five statements about “topic X” is/are correct. There are then a few paragraphs summarising the topic, and at the bottom of the page are listed the answers as to whether the statements were true or false. The use of questions promises well as a learning tool, providing the well known pitfalls can be avoided: the statements must be well chosen to tap into the essentials of the subject rather than irrelevant …

Purpose Quality of life (QoL) questionnaires have been suggested as the most appropriate way to measure the effectiveness of low vision rehabilitation. This study investigated the relative contribution of visual and psychosocial factors to different aspects of QoL in people with low vision. Methods A total of 448 consecutive patients between the ages of 18 and 96 years, with best-corrected binocular visual acuity≤6/18 and attending a low vision clinic, were recruited. Telephone delivery of previously validated questionnaires was used. The Low Vision Quality of Life (LVQOL), the Adaptation to Age-Related Vision Loss (AVL)-12, and the Keele Participation Restriction Questionnaire (KAP) questionnaires were considered as outcome measures for functional vision, adaptation to vision loss, and participation restriction, respectively. Personality (BFI-10), religious beliefs (SBI-15), social support (MOS), the mental and physical components of general health (the MCS and PCS of SF-12), well-being (WHO-5), use of magnifiers (MLVQ), understanding of their eye condition and satisfaction with the eye clinic (MLVQ), level of education, and financial status were all considered as predictive of QoL. Results Regression analysis found the PCS and MCS from SF-12 to be major predictors of LVQOL, AVL-12, and KAP scores. Although distance visual acuity and contrast sensitivity were predictors of LVQOL scores, "use of magnifiers" did not contribute to any of the QoL measures. Conclusions Nonvisual factors, such as physical and mental health, were found to be stronger predictors of QoL in people with low vision than visual factors such as contrast sensitivity and visual acuity, or the use of magnifiers. Researchers need to be aware when measuring QoL in a population with low vision that even vision-related QoL is strongly influenced by nonvisual variables.

PURPOSE: To investigate self-reported difficulties experienced by visually impaired subjects in real-world tasks requiring judgment of space and distance and to determine whether laboratory measures of spatial localization predict self-reported difficulty with spatial tasks better than traditional measures of visual function, such as visual acuity and contrast sensitivity. METHODS: Forty-two subjects with visual impairment participated. The Spatial Localization Questionnaire (SLQ) was developed to investigate self-reported spatial localization difficulties, and subjects answered the questionnaire as part of the study. Subjects also completed a variety of clinical vision tests (visual acuity, contrast sensitivity, stereo acuity, and reading speed) and laboratory vision tests (vernier acuity, bisection acuity, and visual direction). RESULTS: The SLQ was found to have good validity. Several significant correlations were found between the Rasch analysis ability scores for the questionnaire and the clinical and laboratory vision tests. Using stepwise regression analysis, we found that vernier acuity and contrast sensitivity accounted for 42% of the variance in the Rasch scores (P < 0.001). CONCLUSIONS: The findings indicate that certain subjects with visual impairment have difficulty with real-world spatial tasks, as indicated by the SLQ. Of note, these difficulties were better predicted by vernier acuity (a resolution test) and contrast sensitivity, rather than vernier or bisection bias, which measure localization.

Using infra-red oculography, electro-oculography and fundus video-recordings, waveform characteristics (amplitude, frequency, waveform shape and foveation) were examined in over 150 individuals with congenital nystagmus. For many of the subjects the nystagmus exhibited marked variability in both space and time. The sources of this variability were explored and the state of attention of the observer was found to be a dominant factor. The waveform and precision of foveation were not found to be related to any one classification group (eg. albino or idiopathic).

It has frequently been reported that the spontaneous ocular oscillation in congenital nystagmats is less intense for near viewing than during distance fixation. The reason for this effect was sought, and the influences of monocular adduction, convergence and accommodation acting separately and synergistically were assessed. The frequent assumption that nystagmus intensity (amplitude and frequency) is determined by convergence angle (either symmetrical or asymmetrical) was confirmed, and it was found that binocular viewing was not necessary. An identical effect on nystagmus intensity could be created for distance fixation by the use of base-out prisms, and these were prescribed for constant wear in two congenital idiopathic nystagmats. Although nystagmus intensity was constantly reduced, no concomitant increase in binocular contrast sensitivity or Snellen visual acuity occurred.

Introduction: Hearing, vision, and cognitive impairment commonly co-occur in older people. However, the rate of recognition and appropriate management of combined hearing and vision impairment in people with dementia impairment is low. The aim of this work was to codevelop internationally relevant, multidisciplinary practice recommendations for professionals involved in the diagnosis, care, and management of older people with these concurrent conditions. Methods: We applied consensus methods with professional and lay expert stakeholders, using an adapted version of the World Health Organization Handbook for Guideline Development. The development involved 4 phases and included: (1) collating existing evidence, (2) filling the gaps in evidence, (3) prioritising evidence, and (4) refining the final list of recommendations. Each phase encompassed various methodologies including a review of existing guidelines within the 3 clinical domains, systematic reviews, qualitative studies, a clinical professional consortium, surveys, and consensus meetings with interdisciplinary domain experts. Results: The task force evaluated an initial list of 26 recommendations, ranking them in the order of priority. A consensus was reached on 15 recommendations, which are classified into 6 domains of “awareness and knowledge,” “recognition and detection,” “evaluation,” “management,” “support,” and “services and policies.” Pragmatic options for implementation for each domain were then developed. Conclusion: This is the first set of international, interdisciplinary practice recommendations that will guide the development of multidisciplinary services and policy to improve the lives of people with dementia and hearing and vision impairment.

Normal observers subjected to retinal image motion equivalent to that experienced by congenital nystagmats were found to display a contrast sensitivity function with characteristics similar to those shown by nystagmat observers. The amplitude, frequency and waveform (and hence foveation time) of nystagmic oscillation were varied, with alteration of the waveform producing the most significant effect on the contrast sensitivity function. The pseudocycloid waveform with the longest percentage foveation time per cycle was commensurate with the best visual resolution of medium-to-high spatial frequency targets. For all waveforms the length of the foveation period showed good correlation with visual resolution of the targets.

The clinical diagnosis of albinism can often be uncertain, particularly when one is confronted with blond patients with congenital nystagmus. Monochromatic fundus photography was carried out on 31 patients with congenital nystagmus to examine three retinal features: the macular pigment, foveal vasculature, and the retinal pigment epithelium. All subjects who were later classified as albinos did not exhibit any signs of macular pigmentation. Our results imply that monochromatic fundus photography can be a useful aid in the diagnosis of albinism.

Patients with low vision typically have reduced visual acuity and a significant loss of contrast sensitivity, often in combination with visual field loss. These impairments cause a number of disabilities including difficulty with reading, writing, recognising faces, watching television, orientation and mobility, and completing activities of daily living. In a recent large scale survey of providers of low vision services, Elliott et al 1found that for elderly patients with low vision, the primary objectives identified at low vision assessment were to obtain help with reading and with vision oriented performance of daily living activities. Secondary objectives commonly include obtaining help with watching television, mobility and independent travel, and hobbies. In many cases, these objectives can be met by the prescription and use of conventional low vision aids (LVAs)—that is, optical devices providing magnification in order to compensate for reduced visual acuity, while contrast is maximised with local task lighting. LVAs are, unfortunately, highly task specific, and the patient may need several different aids to deal with a variety of identified requirements. Recently, however, alternative devices have been introduced which offer a number of distinct advantages over conventional LVAs in low vision rehabilitation. The purpose of this review is to describe these devices and to discuss both their current and future potential in comparison with existing technology. Contrary to early work suggesting that LVAs are often limited in their effectiveness,2 3 more recent studies indicate that low vision rehabilitation and the prescription of LVAs can offer considerable benefit to the visually impaired, with at least one device being used by between 80% and 91% of patients provided with an LVA.4-8 It is recognised, however, that some patients do not continue to use LVAs following their dispensing. While some users discontinue with an LVA because of a change …