Can children measure their own vision? A comparison of three new contrast sensitivity tests.

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.

Are wearable electronic vision enhancement systems (wEVES) beneficial for people with age-related macular degeneration? A scoping review.

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.

Novel use of a Franklin split lens for cycling with hemianopia.

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.

Design considerations for the ideal low vision aid: insights from de-brief interviews following a real-world recording study.

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.

Lockdown low vision assessment: an audit of 500 telephone-based modified low vision consultations.

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.

Online Survey of Digital Reading by Adults with Low Vision.

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.

Everyday visual demands of people with low vision: A mixed methods real-life recording study.

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.

Benefit of an electronic head-mounted low vision aid.

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.

How People with Low Vision Achieve Magnification in Digital Reading.

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.

The Pulfrich Phenomenon: Practical Implications of the Assessment of Cases and Effectiveness of Treatment.

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.

Functional visual fields: relationship of visual field areas to self-reported function.

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.

Smartphone, tablet computer and e-reader use by people with vision impairment.

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.

Eccentric Viewing Training for Age-Related Macular Disease: Results of a Randomized Controlled Trial (the EFFECT Study).

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.

Relationship between fixation stability measured with MP-1 and reading performance.

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.

"I'm like something out of star wars": a qualitative investigation of the views of people with age-related macular degeneration regarding wearable electronic vision enhancement systems.

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.

Text accessibility by people with reduced contrast sensitivity.

PURPOSE: Contrast sensitivity is reduced in people with eye disease, and also in older adults without eye disease. In this article, we compare contrast of text presented in print and digital formats with contrast sensitivity values for a large cohort of subjects in a population-based study of older adults (the Salisbury Eye Evaluation). METHODS: Contrast sensitivity values were recorded for 2520 adults aged 65 to 84 years living in Salisbury, Maryland. The proportion of the sample likely to be unable to read text of different formats (electronic books, newsprint, paperback books, laser print, and LED computer monitors) was calculated using published contrast reserve levels required to perform spot reading, to read with fluency, high fluency, and under optimal conditions. RESULTS: One percent of this sample had contrast sensitivity less than that required to read newsprint fluently. Text presented on an LED computer monitor had the highest contrast. Ninety-eight percent of the sample had contrast sensitivity sufficient for high fluent reading of text (at least 160 words/min) on a monitor. However, 29.6% were still unlikely to be able to read this text with optimal fluency. CONCLUSIONS: Reduced contrast of print limits text accessibility for many people in the developed world. Presenting text in a high-contrast format, such as black laser print on a white page, would increase the number of people able to access such information. Additionally, making text available in a format that can be presented on an LED computer monitor will increase access to written documents.

The effect of low vision rehabilitation in diabetic eye disease: a randomised controlled trial protocol.

PURPOSE: Current research highlights a rising incidence of diabetes and its complications. Diabetic retinopathy is the leading cause of blindness within the working-age population of the United Kingdom. Increasing severity of retinopathy is associated with reduced visual function and participation in daily living. Only 8% of those referred to Moorfields Eye Hospital's low vision clinic have diabetic eye disease, a value less than prevalence figures for diabetes would predict. The lack of evidence for effectiveness of low vision intervention in this patient group could be responsible. Therefore, in line with CONSORT guidance, we present the methodology of the first randomised controlled trial to quantify the effect of low vision rehabilitation on people with diabetic eye disease. METHODS: One hundred participants were recruited into four retinopathy severity groups based on their diagnosis according to the English National Screening Programme Grading Protocol. Participants were randomised to either immediate intervention (1-2 weeks after enrollment) or delayed (control) intervention (3 months after enrollment). Intervention was a standard low vision assessment performed in a hospital clinic. The Activity Inventory (AI), was administered to all participants by telephone within 1 week of enrollment (before any intervention) and repeated at 3 and 6 months. RESULTS: One hundred participants (Type 1: 28, Type 2: 72; male: 62, female 38) have been recruited. Median habitual distance acuity was 0.19 logMAR (6/9, 20/30), with an interquartile range of 0.06-0.30 logMAR (6/7.5-6/12, 20/25-20/40). AI responses were scored by Rasch analysis, providing a measure of visual ability. Median baseline visual ability was 1.64 logits, with an interquartile range of 0.60-3.75 logits. Difference in mean change in visual ability between intervention groups will be assessed 3 months (primary outcome) and 6 months (secondary outcome) after enrollment. CONCLUSIONS: This is the first randomised controlled trial investigating the effectiveness of low vision rehabilitation for people with diabetic eye disease. With recruitment already complete, it is hoped this work will be the first step in guiding referral criteria for those with diabetic eye disease into the low vision service.

The preferred retinal locus in macular disease: toward a consensus definition.

BACKGROUND: Eccentric viewing in macular disease has been described for half a century. However, a clear definition of eccentric viewing and preferred retinal locus (PRL) does not exist. Here, we determine how the PRL in macular disease is defined by researchers active in this field and, based on the responses received, propose a standardized definition of the preferred retinal locus. METHOD: A literature review of articles describing the PRL or eccentric viewing was performed. The first and senior authors of all identified publications were contacted and were asked to define the preferred retinal locus. Themes of responses were identified using inductive qualitative research techniques. RESULTS: Frequently recurring themes related to the definition of the PRL included 1) it is a retinal area used for fixation, 2) it is task specific, 3) more than one PRL can be used, 4) it is a well-defined region of retina, and 5) the same PRL is used on repeated testing. CONCLUSION: Based on the responses received, a consensus definition of the PRL is proposed. It is suggested that researchers define the PRL carefully in experimental reports and an instrument that images the retina is used to define the location of the PRL.

Retinal specific measurement of dark-adapted visual function: validation of a modified microperimeter.

BACKGROUND: Scotopic function is an important marker of many retinal diseases and is increasingly used as an outcome measure in clinical trials, such as those investigating gene therapy for Lebers congenital amaurosis. Scotopic visual function has traditionally been measured using an adapted perimetry system such as the Humphrey field analyser (HFA). However this system does not control for fixation errors or poor fixation stability. Here we evaluate the use of an adapted microperimeter to measure visual function at defined retinal regions under scotopic conditions. METHODS: A MP-1 microperimeter (Nidek Technologies, Italy) was modified by adding a 1 log unit Neutral Density filter and a 530 nm shortpass filter within the optical path of the instrument. Stray light was shielded. Fine matrix mapping perimetry was performed on five younger (< 35 years) and five older (> 65 years) subjects with no eye disease and good vision. All subjects were fully dark adapted before testing and pupils were dilated with 1% tropicamide. Tests was performed once on the modified MP-1 microperimeter and once using a modified HFA, in a counterbalanced order. RESULTS: A foveal scotopic scotoma with a sensitivity reduction of >1 log unit was found using each instrument. In addition, the MP-1 system showed the retinal location of the foveal scotoma. Mean test time was 25 minutes for the MP-1 and 32 minutes for the HFA. DISCUSSION: A modified MP-1 microperimeter can be used to measure scotopic retinal function, creating results which are comparable to the modified Humphrey field analyser. Advantages of the MP-1 system include the ability to track the retina through testing, retinal localisation of the scotoma and a faster test time.

Objective visual assessment of antiangiogenic treatment for wet age-related macular degeneration.

PURPOSE: To assess cortical responses in patients undergoing antiangiogenic treatment for wet age-related macular degeneration (AMD) using functional magnetic resonance imaging (fMRI) as an objective, fixation-independent measure of topographic visual function. METHODS: A patient with bilateral neovascular AMD was scanned using fMRI before and at regular intervals while undergoing treatment with intravitreal antiangiogenic injections (ranibizumab). Blood oxygenation level-dependent signals were measured in the brain while the patient viewed a stimulus consisting of a full-field flickering (6 Hz) white light alternating with a uniform gray background (18 s on and 18 s off). Topographic distribution and magnitude of activation in visual cortex were compared longitudinally throughout the treatment period (<1 year) and with control patients not currently undergoing treatment. Clinical behavioral tests were also administered, including visual acuity, microperimetry, and reading skills. RESULTS: The area of visual cortex activated increased significantly after the first treatment to include more posterior cortex that normally receives inputs from lesioned parts of the retina. Subsequent treatments yielded no significant further increase in activation area. Behavioral measures all generally showed an improvement with treatment but did not always parallel one another. The untreated control patient showed a consistent lack of significant response in the cortex representing retinal lesions. CONCLUSIONS: Retinal treatments may not only improve vision but also result in a concomitant improvement in fixation stability. Current clinical behavioral measures (e.g., acuity and perimetry) are largely dependent on fixation stability and therefore cannot separate improvements of visual function from fixation improvements. fMRI, which provides an objective and sensitive measure of visual function independent of fixation, reveals a significant increase in visual cortical responses in patients with wet AMD after treatment with antiangiogenic injections. Despite recent evidence that visual cortex degenerates subsequent to retinal lesions, our results indicate that it can remain responsive as its inputs are restored.