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1.
Ophthalmol Sci ; 4(2): 100422, 2024.
Article in English | MEDLINE | ID: mdl-38187128

ABSTRACT

Purpose: Eccentric viewing training for macular disease has been performed for > 40 years, but no large studies including control groups have assessed the benefits of this training. The EFFECT (Eccentric Fixation From Enhanced Clinical Training) study is a large randomized controlled trial of 2 types of eccentric viewing training. Design: Randomized controlled trial. Participants: Two hundred adults with age-related macular disease. Methods: Participants were randomized to either of the following: (1) a control group; (2) a group receiving supervised reading support; (3) a group receiving 3 sessions of training to optimize the use of their own preferred retinal locus; or (4) a group receiving 3 sessions of biofeedback training of a theoretically optimal trained retinal locus. All participants received standard low-vision rehabilitation. Main Outcome Measures: The primary outcome was patient-reported visual task ability measured on the Activity Inventory instrument at goal level. Secondary outcomes included reading performance and fixation stability. Results: There was no difference between groups on change in task ability (F(3,174) = 1.48, P = 0.22) or on any of the secondary outcome measures. Visual acuity and contrast sensitivity fell in all groups, suggesting that disease progression outweighed any benefit of training. Conclusions: Eccentric viewing training did not systematically improve task ability, reading performance, or fixation stability in this study. Our results do not support the routine use of eccentric viewing training for people with progressing age-related macular disease, although this training may help people with end-stage disease. Rehabilitation of an inherently progressive condition is challenging. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

2.
Ophthalmic Physiol Opt ; 44(1): 5-16, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37728235

ABSTRACT

PURPOSE: To investigate the feasibility of children measuring their own contrast sensitivity using a range of tablet- and paper-based tests. METHODS: Forty children aged 5-15 years with amblyopia (N = 10), bilateral vision impairment (N = 10) or good vision (N = 20) measured their own vision on a screen-based optotype test (Manifold), a gamified vision test (PopCSF) and a paper-based test (Spotchecks) in a laboratory with minimal supervision. Completion rate, test-retest repeatability, test duration and participants' preferences were recorded for each test. RESULTS: Most participants (36/40) were able to perform all three tests. All tests were correlated with clinically measured visual acuity and contrast sensitivity (p < 0.001). The 95% coefficient of repeatability was 0.30 dB for Manifold, 0.29 dB for PopCSF and 0.13 dB for Spotchecks. All tests differentiated between children with reduced contrast sensitivity and control participants. PopCSF and Spotchecks were also able to differentiate between children with amblyopia and those with good vision. Median test time was 152, 130 and 202 s for Manifold, PopCSF and Spotchecks, respectively. Twenty-two participants preferred the PopCSF test, 10 preferred Spotchecks and 6 preferred Manifold. Thirty-nine out of the 40 children (98%) said they would measure their own vision at home using at least one of these tests every month. CONCLUSIONS: Children and young people can test their own contrast sensitivity with repeatable results. Of these three tests, the most repeatable was Spotchecks, the quickest was PopCSF and participants' favourite was PopCSF. Nearly all of the participants said they would be willing to use at least one of the three tests at home.


Subject(s)
Amblyopia , Child , Humans , Adolescent , Amblyopia/diagnosis , Contrast Sensitivity , Vision Tests , Vision, Ocular , Visual Acuity
3.
Disabil Rehabil ; : 1-10, 2023 Nov 06.
Article in English | MEDLINE | ID: mdl-37933205

ABSTRACT

PURPOSE: This study explores the initial views of people with age-related macular degeneration towards wearable electronic vision enhancement systems. METHODS: Ten adults with age-related macular degeneration participated in semi-structured interviews, which were analysed using reflexive thematic analysis. RESULTS: Four themes were identified. Firstly, participants spoke of the wide-ranging impact of sight loss and how current helpful coping strategies still had significant limitations, affecting their desire to seek new solutions. The second theme showed that "other people" offered welcomed support with existing electronic coping solutions and are needed to provide suitable advice and training. However, "other people" limited the acceptability of using new solutions in public places. The third theme captured participants' desire for a wearable aid providing image magnification and enhancement over a range of distances. The final theme covered the reality of some current wearable technology, perceived as heavy, enclosing, or strange in appearance. Appearance caused some to lose interest in use, although others reframed the devices' desired usefulness to solo and sedentary activities. CONCLUSION: This population are interested in the potential benefits of wearable electronic vision enhancement systems. More work is needed to understand the suitability of current solutions due to participant concerns about training, appearance and performance.


A device that offers image enhancement and variable magnification in a hands-free, wearable form is very desirable to people with age-related macular degeneration.Some potential users are not seeking new solutions to well-described problems, which may be a useful coping strategy but alternatively may be motivated by fear of the unknown, financial worries, or concerns about appropriate training.The weight and appearance of some of the current wearable electronic vision enhancement systems are not immediately appealing and would stop some from proceeding with a performance trial.After viewing the current devices, the desirable times to use a wearable electronic vision enhancement system may be reframed by users to focus predominately on sedentary tasks taking place in isolation at home.

4.
Ophthalmic Physiol Opt ; 43(4): 680-701, 2023 07.
Article in English | MEDLINE | ID: mdl-36876427

ABSTRACT

INTRODUCTION: Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the United Kingdom. It has a wide-ranging detrimental impact on daily living, including impairment of functional ability and quality of life. Assistive technology designed to overcome this impairment includes wearable electronic vision enhancement systems (wEVES). This scoping review assesses the usefulness of these systems for people with AMD. METHODS: Four databases (Cumulative Index to Nursing and Allied Health Literature, PubMed, Web of Science and Cochrane CENTRAL) were searched to identify papers that investigated image enhancement with a head-mounted electronic device on a sample population that included people with AMD. RESULTS: Thirty-two papers were included: 18 studied the clinical and functional benefits of wEVES, 11 investigated use and usability and 3 discussed sickness and adverse effects. CONCLUSIONS: Wearable electronic vision enhancement systems provide hands-free magnification and image enhancement producing significant improvements in acuity, contrast sensitivity and aspects of laboratory-simulated daily activity. Adverse effects were infrequent, minor and spontaneously resolved with the removal of the device. However, when symptoms arose, they sometimes persisted with continued device usage. There are multi-factorial influences and a diversity of user opinions on promotors to successful device use. These factors are not exclusively driven by visual improvement and incorporate other issues including device weight, ease of use and inconspicuous design. There is insufficient evidence of any cost-benefit analysis for wEVES. However, it has been shown that a user's decision to make a purchase evolves over time, with their estimates of cost falling below the retail price of the devices. Additional research is needed to understand the specific and distinct benefits of wEVES for people with AMD. Further patient-centred research should assess the benefits of wEVES in user-led activities when directly compared with alternative coping strategies, allowing professionals and users to make better prescribing and purchasing decisions.


Subject(s)
Macular Degeneration , Vision, Low , Wearable Electronic Devices , Humans , Quality of Life , Vision, Low/etiology , Macular Degeneration/therapy , Macular Degeneration/complications , Activities of Daily Living
5.
JAMA Ophthalmol ; 140(10): 1021-1022, 2022 10 01.
Article in English | MEDLINE | ID: mdl-35980620

ABSTRACT

This study compares visual acuity testing at home with visual acuity testing in a clinical setting.


Subject(s)
Ambulatory Care Facilities , Vision Tests , Humans , Visual Acuity
6.
Ophthalmic Physiol Opt ; 42(1): 218-223, 2022 01.
Article in English | MEDLINE | ID: mdl-34661913

ABSTRACT

PURPOSE: Optical rehabilitation for hemianopia includes the prescription of partial aperture prismatic lenses. Fresnel lenses for this purpose have poor optical quality, while bonded lenses have poor cosmesis and can only be made in glass, creating a potential hazard. Here we present an alternative lens type, which does not reduce contrast sensitivity and which can be made in plastic materials. METHODS: A rotated Franklin split lens was prescribed for the right eye only to provide a full aperture prismatic lens without using a Fresnel prism or bonded lenses. Using different refractive indices in each lens provided a minimal transition in thickness and an acceptable cosmetic appearance. This lens was prescribed to a 34-year-old woman with homonymous right hemianopia. Her contemporaneous comments are presented. RESULTS: The rotated Franklin split lens provided 18Δ over the temporal edge of the lens. The wearer noticed chromatic aberration with this lens, but was able to cycle comfortably when wearing the lens without any reduction in contrast. CONCLUSIONS: A rotated Franklin split lens can be used for the optical rehabilitation of hemianopia. In this case study, cycling was possible with this lens.


Subject(s)
Hemianopsia , Lenses , Adult , Contrast Sensitivity , Female , Humans , Prescriptions , Refractometry
7.
Ophthalmic Physiol Opt ; 41(2): 266-280, 2021 03.
Article in English | MEDLINE | ID: mdl-33533098

ABSTRACT

PURPOSE: Low Vision Aids (LVAs) can have a transformative impact on people living with sight loss, yet the everyday requirements for developing such devices remain poorly understood and defined. This study systematically explored LVA requirements through a structured de-brief interview following a real-world self-recording study. The purpose of this work was to define the actual needs of those living with sight loss so that low vision services can better address them in future. METHODS: Thirty-two visually impaired volunteers with varying levels of previous LVA experience participated in a de-brief interview centred around a structured questionnaire. The de-brief followed a one-week real-world study during which participants used recoding spectacles to capture and narrate all situations in which they would use a 'perfect sight aid'. Content and thematic analyses were used to analyse interviews which had the purpose of contextualising these recordings and exploring requirements around psychological, functional and design factors. RESULTS: Participants reported that 46% of tasks which they had recorded were most important to them. Of these tasks, 82% were encountered frequently. Few tasks emerged as very important across many participants, the remaining tasks reflecting individual lifestyles or circumstances. Every participant used at least one LVA in their everyday life and 72% identified further coping strategies. Current LVAs identified as consistently poor were distance LVAs, with all other devices receiving mixed or only positive feedback. Around two-thirds of participants would prefer LVA use on an ad-hoc / quick access basis rather than over long periods of time, and just over half would prefer to carry it rather than wearing it all day. Lack of consistency in these responses illustrated potentially different user clusters with divergent design needs. Two-thirds of participants emphasised the desire for a discreet LVA that does not attract attention. However, since half of all participants felt self-conscious in public or in front of other people when wearing the small recording spectacles, this may not be technically achievable. CONCLUSIONS: There is a substantial opportunity for new LVAs to address visual needs that traditional devices and coping strategies cannot support. Functional, psychological and design factors require careful consideration for future LVAs to be relevant and widely adopted.


Subject(s)
Adaptation, Psychological/physiology , Eyeglasses , Quality of Life , Sensory Aids/statistics & numerical data , Vision, Low/rehabilitation , Visual Acuity , Visually Impaired Persons/rehabilitation , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Reading , Vision, Low/physiopathology , Visually Impaired Persons/statistics & numerical data , Young Adult
8.
Ophthalmic Physiol Opt ; 41(2): 295-300, 2021 03.
Article in English | MEDLINE | ID: mdl-33529405

ABSTRACT

PURPOSE: Non-urgent face-to-face outpatient ophthalmology appointments were suspended in the United Kingdom in March 2020, due to the COVID-19 outbreak. In common with other centres, Moorfields Eye Hospital NHS Foundation Trust (London) offered modified telephone consultations to new and follow-up patients in the low vision clinic. Here we assess the success of this telephone service. METHODS: Data were collected for 500 consecutive telephone low vision appointments. Successful completion of the assessment and clinical outcomes (low vision aids prescribed, onward referral) were recorded. RESULTS: Telephone assessments were completed for 364 people (72.8%). The most common reasons for non-completion were either no answer to the telephone call (75 people, 15%), or the patient declining assessment (20 people, 4%). There was no association between age and the likelihood of an assessment being completed. 131 new low vision aids were dispensed, 77 internal referrals were made and 15 people were referred to outside services. More than 80% of the low vision aids prescribed were useful. CONCLUSIONS: Telephone low vision assessments were completed in about three-quarters of cases. About one-quarter of consultations resulted in new low vision aids being dispensed, which were generally found useful. Telephone low vision assessments can be used successfully in a large low vision clinic, but have many limitations when compared to face-to-face assessments.


Subject(s)
COVID-19/epidemiology , Disease Transmission, Infectious/prevention & control , Quarantine , Referral and Consultation/organization & administration , Telemedicine/methods , Telephone , Vision, Low/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Communicable Disease Control/methods , Comorbidity , Female , Humans , Male , Middle Aged , SARS-CoV-2 , United Kingdom/epidemiology , Vision, Low/diagnosis , Young Adult
9.
JAMA Ophthalmol ; 139(3): 271-277, 2021 03 01.
Article in English | MEDLINE | ID: mdl-33410910

ABSTRACT

Importance: Many ophthalmology appointments have been converted to telemedicine assessments. The use of a printed vision chart for ophthalmology telemedicine appointments that can be used by people who are excluded from digital testing has yet to be validated. Objectives: To evaluate the repeatability of visual acuity measured using the Home Acuity Test (HAT) and the agreement between the HAT and the last in-clinic visual acuity. Design, Setting, and Participants: This diagnostic study was conducted from May 11 to 22, 2020, among 50 control participants and 100 adult ophthalmology outpatients who reported subjectively stable vision and were attending routine telemedicine clinics. Bland-Altman analysis of corrected visual acuity measured with the HAT was compared with the last measured in-clinic visual acuity on a conventional Early Treatment Diabetic Retinopathy Study logMAR chart. Main Outcomes and Measures: For control participants, repeatability of the HAT and agreement with standard logMAR visual acuity measurement. For ophthalmology outpatients, agreement with the last recorded in-clinic visual acuity and with the International Classification of Diseases and Related Health Problems, 11th Revision visual impairment category. Results: A total of 50 control participants (33 [66%] women; mean [SD] age, 36.0 [10.8] years) and 100 ophthalmology patients with a wide range of diseases (65 [65%] women; mean [SD] age, 55.3 [22.2] years) were recruited. For control participants, mean (SD) test-retest difference in the HAT line score was -0.012 (0.06) logMAR, with limits of agreement (LOA) between -0.13 and 0.10 logMAR. The mean (SD) difference in visual acuity compared with conventional vision charts was -0.14 (0.14) logMAR (range, -0.4 to 0.18 log MAR) (-7 letters) in controls, with LOA of -0.41 to 0.12 logMAR (-20 to 6 letters). For ophthalmology outpatients, the mean (SD) difference in visual acuity was -0.10 (0.17) logMAR (range, -0.5 to 0.3 logMAR) (1 line on a conventional logMAR sight chart), with the HAT indicating poorer visual acuity than the previous in-clinic test, and LOA of -0.44 to 0.23 logMAR (-22 to 12 letters). There was good agreement in the visual impairment category for ophthalmology outpatients (Cohen κ = 0.77 [95% CI, 0.74-0.81]) and control participants (Cohen κ = 0.88 [95% CI, 0.88-0.88]). Conclusions and Relevance: This study suggests that the HAT can be used to measure visual acuity by telephone for a wide range of ophthalmology outpatients with diverse conditions. Test-retest repeatability is relatively high, and agreement in the visual impairment category is good for this sample, supporting the use of printed charts in this context.


Subject(s)
Outpatients , Printing/methods , Telemedicine/methods , Vision Disorders/diagnosis , Vision Screening/methods , Vision Tests/methods , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Young Adult
10.
J Vis ; 20(9): 3, 2020 09 02.
Article in English | MEDLINE | ID: mdl-32876678

ABSTRACT

Research has demonstrated that low vison aids (LVAs) can have a positive impact on the functional sight of those living with sight loss. Step changes in technology are now enabling new wearable LVAs with greater potential than those available previously. For these novel devices to receive increased acceptance and therefore adoption by those with sight loss, visual task demands have to be understood more clearly in order to enable better alignment between device design and user requirements. The aim of this study was to quantify these requirements. Thirty-two participants aged 18 to 87 wore a spectacle-mounted video camera to capture and narrate all everyday situations in which they would use a "perfect" sight aid during 1 week. Captured scenes were analyzed through categorization and computational image analysis. Results showed large variation in activities and lifestyles. Participants reported no available sight aid or coping strategy for 57% of the recorded activities. Reading made up 49% of all recorded tasks, the other half comprising non-textual information. Overall, 75% of captured activities were performed ad hoc (duration of 0-5 minutes), 78% occurred indoors, 58% occurred at home, 48% were lit by natural light, 68% included the object of interest within reach, and 69% required a single focus plane only. Around half of captured objects of interest had a size of 2 degrees visual angle (2.08 logarithm of the minimum angle of resolution [logMAR]) or smaller. This study highlights the need for a sight aid that can make both textual and non-textual scenes accessible while offering flexibility to accommodate individual lifestyles.


Subject(s)
Optical Devices/standards , Vision, Low/physiopathology , Visual Acuity , Wearable Electronic Devices/standards , Activities of Daily Living , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Visually Impaired Persons , Young Adult
11.
Optom Vis Sci ; 97(4): 249-256, 2020 04.
Article in English | MEDLINE | ID: mdl-32304534

ABSTRACT

SIGNIFICANCE: Access to digital text is increasingly widespread, but its impact on low-vision reading is not well understood. PURPOSE: We conducted an online survey of people with low vision to determine what assistive technologies they use for visual reading, their preferred text characteristics, and the time they devote to reading digital and hard-copy text. METHODS: One hundred thirty-three low-vision participants completed an online survey. Participants reported the nature and history of their low vision, their usage of different assistive technologies, and time devoted to five visual reading activities. RESULTS: The three largest diagnostic categories were albinism (n = 36), retinitis pigmentosa (n = 20), and glaucoma (n = 15). Mean self-reported acuity was 0.93 logMAR (range, 0.1 to 1.6 logMAR). Mean age was 46 years (range, 18 to 98 years). Participants reported on percentage time spent reading using vision, audio, or touch (braille). Seventy-five percent of our participants did more than 50% of their reading visually. Across five categories of reading activities-work or education, news, pleasure, spot reading, and social networking-participants reported more time spent on digital reading than hard-copy reading. Eighty-nine percent of our participants used at least one technology from each of our two major categories of assistive technologies (digital content magnifiers and hard-copy content magnifiers) for visual reading. CONCLUSIONS: Despite the growing availability of digital text in audio or braille formats, our findings from an online sample of people with low vision indicate the continuing importance of visual reading. Our participants continue to use technology to access both hard-copy and digital text, but more time is devoted to digital reading. Our findings highlight the need for continued research and development of technology to enhance visual reading accessibility.


Subject(s)
Reading , Self-Help Devices , Vision, Low/physiopathology , Adolescent , Adult , Aged , Aged, 80 and over , Communications Media , Diagnostic Tests, Routine , Eyeglasses , Female , Health Surveys , Humans , Male , Middle Aged , Mobile Applications , Visual Acuity/physiology , Young Adult
12.
Ophthalmic Physiol Opt ; 39(6): 422-431, 2019 11.
Article in English | MEDLINE | ID: mdl-31696539

ABSTRACT

PURPOSE: To evaluate the efficacy of electronic head-mounted low vision aid (e-LVA) SightPlus (GiveVision, UK, givevision.net) and to determine which people with low vision would see themselves likely using an e-LVA like this. METHODS: Sixty participants with low vision aged 18 to 93 used SightPlus during an in-clinic study session based on a mixed methods design. Visual acuity (ETDRS), contrast sensitivity (Pelli-Robson) and reading performance (MNREAD) were measured binocularly at baseline (no device), with the device in 'normal' mode (zoom only), and with preferred enhanced mode (zoom and one of four digital image enhancements). At the end of the session, a short questionnaire recorded willingness to use an e-LVA like SightPlus, potential use cases, positive/negative comments and adverse effects. RESULTS: Binocular distance visual acuity improved significantly by 0.63 logMAR on average (p < 0.0001) to 0.20 logMAR. Contrast sensitivity improved significantly by 0.22 log units (p < 0.0001) to 1.21 log units with zoom only and by 0.40 log units to 1.37 log units with zoom and preferred image enhancement. Reading performance improved significantly for near visual acuity and critical print size (p < 0.015), although reading speed significantly decreased (p < 0.0001). Nearly half (47%) of the participants indicated they would use an e-LVA like SightPlus, especially for television, reading and entertainment (e.g. theatre). Multivariate logistic regression showed that proportion of lifetime affected by sight loss, baseline contrast sensitivity and use of electronic LVAs explained 41% of the variation in willingness to use. CONCLUSIONS: SightPlus improves visual function in people with low vision and would be used in its current form by one half of the people who tried it. Adverse effects were infrequent and resolved when the device was removed. Future work should focus on comparing e-LVAs through repeatable real-world tasks and impact on quality of life.


Subject(s)
Contrast Sensitivity/physiology , Quality of Life , Sensory Aids , Vision, Low/rehabilitation , Visual Acuity , Wearable Electronic Devices , Adolescent , Adult , Aged , Aged, 80 and over , Equipment Design , Female , Humans , Male , Middle Aged , Vision Tests , Vision, Low/physiopathology , Visually Impaired Persons/rehabilitation , Young Adult
13.
Neuroophthalmology ; 42(6): 349-355, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30524488

ABSTRACT

The Pulfrich phenomenon, originally described in normal observers, is a treatable disorder of the perception of movement in depth in cases of unilateral or asymmetric optic neuropathy. Treatment is highly bespoke and factors influencing treatment response and failure remain unclear. We assessed 25 adults with suspected Pulfrich phenomenon due to a range of conditions in two tertiary referral centres. Monocularly tinted spectacles were successful in reducing symptoms of the Pulfrich phenomenon under daylight conditions in nine subjects, eight of whom had optic neuritis. These spectacles were not effective at night and in patients with visual field defects due to ischaemic optic neuropathy, glaucoma, optic disc drusen or severe peripapillary retinal nerve fibre loss on optical coherence tomography.

14.
Optom Vis Sci ; 95(9): 711-719, 2018 09.
Article in English | MEDLINE | ID: mdl-30169350

ABSTRACT

SIGNIFICANCE: Digital reading displays provide opportunities for enhancing accessibility of text for low vision. How are these displays used by people in their daily lives? PURPOSE: Subjects responded to an online survey concerning their vision history, reading technology, display preferences, and reading habits. Here, we report on findings concerning acuity and magnification. METHODS: The survey asked subjects to arrange a text passage for typical reading and to report viewing distance, screen dimensions, and the number of characters per line. Seventy-five adult subjects (most with early-onset low vision, few with central field loss) completed all survey questions relevant to the analysis of acuity and magnification. Mean acuity was .92 logMAR (range, 0.1 to 1.6), and mean age was 44.8 years (range, 18 to 71 years). Twelve normally sighted controls reported the same information while viewing the passage on cell phones, tablets, and computers. RESULTS: The controls had a mean viewing distance of 38.7 cm and a mean x-height of 1.38 mm. For all three types of devices, angular x-height was 0.21° (close to laboratory estimates of the critical print size for reading). Low vision subjects showed decreasing viewing distance and increasing print size with larger values of logMAR acuity. Most of the low vision subjects achieved their desirable magnification by a combination of reduced viewing distance and increased physical letter size. The majority (54 of 75) relied more on letter-size magnification. Relative to the controls, regression analysis revealed that a typical low vision subject with logMAR acuity of 1.0 reduced viewing distance by a factor of 2.8 and enlarged physical print size by a factor of 6. CONCLUSIONS: Our survey shows that people with a wide range of acuities are engaged in digital reading. Our subjects achieved desirable magnification primarily by enlarging physical character size and to a lesser extent by reducing viewing distance.


Subject(s)
Audiovisual Aids , Reading , Vision, Low/physiopathology , Visual Acuity/physiology , Adolescent , Adult , Aged , Communications Media , Computers , Female , Humans , Male , Middle Aged , Physical Examination , Vision, Ocular/physiology , Young Adult
15.
BMJ Open ; 7(6): e015939, 2017 06 21.
Article in English | MEDLINE | ID: mdl-28637740

ABSTRACT

INTRODUCTION: Low vision and blindness adversely affect education and independence of children and young people. New 'assistive' technologies such as tablet computers can display text in enlarged font, read text out to the user, allow speech input and conversion into typed text, offer document and spreadsheet processing and give access to wide sources of information such as the internet. Research on these devices in low vision has been limited to case series. METHODS AND ANALYSIS: We will carry out a pilot randomised controlled trial (RCT) to assess the feasibility of a full RCT of assistive technologies for children/young people with low vision. We will recruit 40 students age 10-18 years in India and the UK, whom we will randomise 1:1 into two parallel groups. The active intervention will be Apple iPads; the control arm will be the local standard low-vision aid care. Primary outcomes will be acceptance/usage, accessibility of the device and trial feasibility measures (time to recruit children, lost to follow-up). Exploratory outcomes will be validated measures of vision-related quality of life for children/young people as well as validated measures of reading and educational outcomes. In addition, we will carry out semistructured interviews with the participants and their teachers. ETHICS AND DISSEMINATION: NRES reference 15/NS/0068; dissemination is planned via healthcare and education sector conferences and publications, as well as via patient support organisations. TRIAL REGISTRATION NUMBER: NCT02798848; IRAS ID 179658, UCL reference 15/0570.


Subject(s)
Audiovisual Aids , Computers, Handheld , Education/methods , Research Design , Vision, Low , Adolescent , Child , Feasibility Studies , Humans , Learning , Pilot Projects , Quality of Life , Reading , Self-Help Devices
16.
Ophthalmic Physiol Opt ; 37(4): 399-408, 2017 07.
Article in English | MEDLINE | ID: mdl-28281282

ABSTRACT

PURPOSE: The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss. METHODS: Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory. RESULTS: Greater visual field loss (0-60°) was associated with worse self-reported function both overall (R2 = 0.50; p < 0.0001), and for mobility (R2 = 0.64; p < 0.0001). Central (0-30°) and peripheral (30-60°) visual field areas were similarly related to mobility function (R2 = 0.61, p < 0.0001 and R2 = 0.63, p < 0.0001 respectively), although the peripheral (30-60°) visual field was the best predictor of mobility self-reported function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R2 = 0.56, p < 0.0001 and R2 = 0.67, p < 0.0001 respectively). The inferior field was found to be the best predictor of mobility function in multiple regression analysis. CONCLUSION: Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0-30°) and peripheral (30-60°) mean threshold are good predictors of self-reported function, but the peripheral (30-0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field.


Subject(s)
Self Report , Sensory Thresholds/physiology , Vision, Binocular/physiology , Vision, Low/physiopathology , Visual Acuity , Visual Fields/physiology , Aged , Contrast Sensitivity , Female , Humans , Male , Middle Aged , Quality of Life , Reading , Surveys and Questionnaires , Vision, Low/diagnosis , Visual Field Tests
17.
Br J Ophthalmol ; 99(4): 540-4, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25351679

ABSTRACT

BACKGROUND/AIMS: The National Institute for Health and Care Excellence (NICE) has recommended the use of ranibizumab for neovascular age-related macular degeneration (AMD) and for diabetic macular oedema (DMO) as part of its health technology appraisal process. In the economic evaluations of both interventions, utility values were derived from members of the general public wearing contact lenses with a central opacity that was meant to simulate the blind spot experienced by many patients with advanced retinal disease. This paper tests the validity of the contact lens simulation, and finding it to be invalid, explores the impact on prior economic evaluations. METHODS: Visual acuity, contrast sensitivity and visual fields were assessed with and without simulation lenses in five healthy subjects with normal vision. RESULTS: We identified important differences between the contact lens simulation and vision loss experienced by patients with AMD. The contact lens simulator did not cause the central scotoma which is characteristic of late-stage AMD and which leads to severe difficulty with everyday activities such as reading or recognising faces and objects. The contact lens instead caused a reduction in retinal illumination experienced by the subjects as a general dimming across the retina. CONCLUSIONS: A contact lens with a central opacity does not simulate a central scotoma. The clinical differences between simulated and actual AMD suggest there has been an underestimation of the severity of AMD health states. This brings into question the validity of the economic evaluations of treatments for AMD and DMO used by NICE.


Subject(s)
Contact Lenses, Hydrophilic , Contrast Sensitivity/physiology , Macular Degeneration/physiopathology , Models, Biological , Vision Disorders/physiopathology , Visual Acuity/physiology , Visual Fields/physiology , Health Status Indicators , Healthy Volunteers , Humans , Quality of Life , Retina/physiology , State Medicine , Visual Field Tests
18.
Ophthalmic Physiol Opt ; 34(5): 552-7, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25070703

ABSTRACT

PURPOSE: Consumer electronic devices such as smartphones, tablet computers, and e-book readers have become far more widely used in recent years. Many of these devices contain accessibility features such as large print and speech. Anecdotal experience suggests people with vision impairment frequently make use of these systems. Here we survey people with self-identified vision impairment to determine their use of this equipment. METHOD: An internet-based survey was advertised to people with vision impairment by word of mouth, social media, and online. Respondents were asked demographic information, what devices they owned, what they used these devices for, and what accessibility features they used. RESULTS: One hundred and thirty-two complete responses were received. Twenty-six percent of the sample reported that they had no vision and the remainder reported they had low vision. One hundred and seven people (81%) reported using a smartphone. Those with no vision were as likely to use a smartphone or tablet as those with low vision. Speech was found useful by 59% of smartphone users. Fifty-one percent of smartphone owners used the camera and screen as a magnifier. Forty-eight percent of the sample used a tablet computer, and 17% used an e-book reader. The most frequently cited reason for not using these devices included cost and lack of interest. CONCLUSIONS: Smartphones, tablet computers, and e-book readers can be used by people with vision impairment. Speech is used by people with low vision as well as those with no vision. Many of our (self-selected) group used their smartphone camera and screen as a magnifier, and others used the camera flash as a spotlight.


Subject(s)
Attitude to Computers , Cell Phone/statistics & numerical data , Computers, Handheld/statistics & numerical data , Vision Disorders , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Surveys and Questionnaires , Young Adult
19.
Ophthalmic Physiol Opt ; 33(5): 611-7, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23489240

ABSTRACT

BACKGROUND: People with visual impairment have reduced reading performance, which is thought to be related to unstable or eccentric fixation. New microperimeters such as the MP-1 offer straightforward analysis of fixation stability. The aim of this study was to investigate the relationship between fixation stability and reading speed in a large cohort of people with diverse causes of visual impairment and to verify the correlation between reading speed and different methods for the quantification of fixation. METHODS: The better eye of one hundred and twenty subjects was assessed. Fixation values were obtained from the MP-1 microperimeter. Reading speed was evaluated using newspaper text with magnifiers if required. RESULTS: The poorest fixation stability and reading performance was found in people with age-related macular degeneration while the best fixation was in retinitis pigmentosa subjects. A linear relationship was found between reading speed and the proportion of fixations within 2° (r² = 0.51, p < 0.001) and 4° (r² = 0.36, p < 0.001). A negative correlation was found between reading speed and all three bivariate contour ellipse areas (BCEA; for log transformation of 1-S.D., 2-S.D. and 3-S.D.: r² = 0.39, p < 0.001). In a multiple regression model, proportion of points falling within 2° and 4° circle was significantly related to reading speed (r² = 0.55, p < 0.01; r² = 0.43 p < 0.01); also BCEAs values were strongly related to reading ability only in patients with central vision loss (r² = 0.62, p < 0.01 for LogBCEA 68.2%; r² = 0.61, p < 0.01 for LogBCEA 95.4% and 99.6%) and peripheral defect (r² = 0.52, p < 0.01 for LogBCEA 68.2%; r² = 0.50, p < 0.01 for LogBCEA 95.4%; r² = 0.49, p < 0.01 for LogBCEA 99.6%) but not in combined defect subjects. CONCLUSIONS: The study confirms that in people with visual impairment the reduced reading performance is correlated with fixation instability. Moreover, there is a strong relationship between reading speed and both the proportion of fixations falling within 2° and 4° and bivariate contour ellipse area values.


Subject(s)
Fixation, Ocular/physiology , Reading , Vision Disorders/physiopathology , Visual Field Tests/methods , Visual Fields/physiology , Adult , Aged , Aged, 80 and over , Cohort Studies , Female , Humans , Male , Middle Aged , Visual Field Tests/instrumentation
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