High Tech Aids Low Vision: A Review of Image Processing for the Visually Impaired

Identifying causes of vision loss and assistive technology needs among patients attending rehabilitation clinic of a tertiary care center in North India

PURPOSE

Investigating the causes of visual loss and the best corrected visual acuity (BCVA) is crucial for identifying avoidable eye problems and planning appropriate rehabilitation and assistive technology (AT) services. The study aimed to identify various causes of vision loss and determine AT required for vision rehabilitation (VR).

METHODS

The electronic records of patients who attended the VR clinic at a tertiary eyecare for the past 2 years were reviewed. Information such as demographics, BCVA, and causes of visual impairment were retrieved from the records. BCVA was categorized into better than or equal to 1/60 and less than <1/60 for AT services.

RESULTS

In total, 1723 patients, mostly male (71.2%), visited the rehabilitation clinic from 2018 to 2019. Around 58.6% of patients belonged to the age group 16-49 years, whereas 25.6% were less than 15 years old. The most frequent eye problems were retinal disorders (63.5%), followed by retinitis pigmentosa (15.2%) and rod-cone dystrophy (4.7%). In contrast, congenital disorders were the most common cause of vision loss among younger groups. Approximately 36.0% of patients had <1/60 blindness and 16.6% had ≥1/60. Around 17.1% of patients would benefit from large prints (near vision acuity N18-N12).

CONCLUSION

Early detection and timely management will prevent a significant proportion of patients from developing irreversible vision loss. Around one-third of patients would benefit from visual substitution AT.

Low vision devices for age-related macular degeneration: a systematic review

PURPOSE

Age-related macular degeneration (AMD) is a degenerative condition impacting central vision. Evaluating the effectiveness of low vision devices provides empirical evidence on how devices can rehabilitate and overcome deficits caused by AMD. This evidence could help to facilitate discussion on necessary future improvements to vision enhancement technology.

METHODS

A systematic review of the literature was conducted on low vision device use in AMD populations. Relevant peer-reviewed research articles from six databases were screened.

RESULTS

The findings of thirty-five studies revealed a significant positive impact of low vision devices leading to improvements in visual acuity, reading performance, facial recognition, and more. While the studies were found to have moderate risks of bias, a GRADE assessment of the evidence suggested the certainty of the evidence was low-moderate.

DISCUSSION

Simple hand-held low vision devices (e.g., magnifiers) appear to currently have greater preferential support than newer visual enhancement technology (e.g., head mounted devices). Financial, comfort or usability reasons may influence preferences more than performance-based findings. However, there is a lack of studies examining newer technologies in AMD populations, which future research should address. Moreover, given the presence of bias across the studies and limited controlled experiments, confidence in the results may be low.

CONCLUSIONS

Most studies indicated that low vision devices have positive impacts on reading and visual performance. But, even though they are reported to be a valuable asset to AMD populations, more rigorous research is required to draw conclusive evidence. IMPLICATIONS FOR REHABILITATIONLow vision devices can improve patient outcomes (e.g., vision, reading ability) for age-related macular degeneration populations.A multidisciplinary combination of low vision devices and rehabilitative services (i.e., eccentric viewing training, counselling, education) may enhance quality of life.

Impact of Apps as Assistive Devices for Visually Impaired Persons

The pervasiveness of mobile devices and other associated technologies has affected all aspects of our daily lives. People with visual impairments are no exception, as they increasingly tend to rely on mobile apps for assistance with various visual tasks in daily life. Compared to dedicated visual aids, mobile apps offer advantages such as affordability, versatility, portability, and ubiquity. We have surveyed hundreds of mobile apps of potential interest to people with vision impairments, either released as special assistive apps claiming to help in tasks such as text or object recognition (n = 68), digital accessibility (n = 84), navigation (n = 44), and remote sighted service (n = 4), among others, or marketed as general camera magnification apps that can be used for visual assistance (n = 77). While assistive apps as a whole received positive feedback from visually impaired users, as reported in various studies, evaluations of the usability of every app were typically limited to user reviews, which are often not scientifically informative. Rigorous evaluation studies on the effect of vision assistance apps on daily task performance and quality of life are relatively rare. Moreover, evaluation criteria are difficult to establish, given the heterogeneity of the visual tasks and visual needs of the users. In addition to surveying literature on vision assistance apps, this review discusses the feasibility and necessity of conducting scientific research to understand visual needs and methods to evaluate real-world benefits.

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.

Design of Smart Head–Mounted Display Technology: A Convergent Mixed-Methods Study

Introduction: The purpose of this study was to characterize functional impairments and human factor considerations that affect perceptions and preferences for head-mounted display (HMD) technology for adults with low vision and chronic eye disease. Methods: Through a convergent mixed-methods design, participants with visual impairments (age-related macular degeneration, diabetic retinopathy, glaucoma, or retinitis pigmentosa) were recruited. Participants completed the Impact of Vision Impairment (IVI) questionnaire, used commercially available HMDs (eSight, NuEyes, and Epson Moverio), and were interviewed. The IVI was used to identify groups with low, moderate, and high vision–related quality of life (VRQOL). Transcribed interviews were analyzed using a thematic approach. The survey and qualitative findings were integrated using mixed-methods joint display analysis. Results: Twenty-one participants were enrolled (mean age of 58.2 years, 57% male, median Snellen acuity of 20/40 [range: 20/20–hand movement]). An equal number ( n = 9) expressed a preference for eSight and NuEyes, while ( n = 3) preferred the Moverio. Participants emphasized ease of use, including HMD controls and screen, as common reasons for preference. Those with lower IVI well-being scores preferred eSight due to vision improvement. Those with moderate IVI well-being scores preferred NuEyes due to comfort and size. Those with high IVI well-being scores cited usability as the most important feature. Discussion: User preferences for HMD features were associated with VRQOL. A mixed-methods approach explained how varying degrees of visual impairment and HMD preferences were qualitatively related to usability at the individual level. Implications for Practitioners: To increase acceptance, new HMD development for low vision should focus on performance, usability, and human factors engineering. Although HMD technology can benefit individuals with low vision, device features and functions vary in meaningful ways based on vision parameters. Practitioners should be aware of how patient and device variations influence preferences when they recommend wearable systems and optimize training to harness these systems.

Characteristics of Visual Impairment and the Impact of Low Vision Assessment in a Tertiary Academic Hospital in Jordan

Purpose

This project aims to describe the characteristics of patients with visual impairment referred from a tertiary academic hospital in Jordan for a comprehensive low vision evaluation and to study its impact on their functional needs.

Methods

A retrospective analysis of the records of 108 patients from the ophthalmology clinic at Jordan University Hospital over the period from January 2014 to December 2018 was performed. Gathered information included age, gender, clinical diagnosis, family history of ocular disease, and type of low vision aid prescribed and its impact on patients' functional needs.

Results

The mean age was 44.64 years (range 4-88). Most participants were in the 19-60 years age group (50.0%). Fifty percent of the participants were the offspring of consanguineous marriages. The main cause of visual impairment in this cohort was retinitis pigmentosa, followed by diabetic retinopathy. The majority of low vision aids were prescribed for near distance tasks, and reading spectacles were the most prescribed visual aid. Eighty-nine percent of patients reported functional improvement and retained their visual aids upon follow-up.

Conclusion

Retinitis pigmentosa was the main cause of visual impairment in this cohort of patients referred from a tertiary academic hospital for low vision assessment. We report a consanguinity rate of 50%. The overwhelming majority of patients reported functional improvement and retained their visual aids upon follow-up. Awareness and integration of low vision services into a multidisciplinary approach and improving referral protocols is essential to better address the needs of patients with visual impairment. Familial counselling regarding consanguineous marriages and emerging research to treat inherited retinal diseases should be pursued.

CLEAR - Contact lens technologies of the future

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses. This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases. The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.

A systematic review of emerging information technologies for sustainable data-centric health-care

BACKGROUND

Of the Sustainable Development Goals (SDGs), the third presents the opportunity for a predictive universal digital healthcare ecosystem, capable of informing early warning, assisting in risk reduction and guiding management of national and global health risks. However, in reality, the existing technology infrastructure of digital healthcare systems is insufficient, failing to satisfy current and future data needs.

OBJECTIVE

This paper systematically reviews emerging information technologies for data modelling and analytics that have potential to achieve Data-Centric Health-Care (DCHC) for the envisioned objective of sustainable healthcare. The goal of this review is to: 1) identify emerging information technologies with potential for data modelling and analytics, and 2) explore recent research of these technologies in DCHC.

FINDINGS

A total of 1619 relevant papers have been identified and analysed in this review. Of these, 69 were probed deeply. Our analysis found that the extant research focused on elder care, rehabilitation, chronic diseases, and healthcare service delivery. Use-cases of the emerging information technologies included providing assistance, monitoring, self-care and self-management, diagnosis, risk prediction, well-being awareness, personalized healthcare, and qualitative and/or quantitative service enhancement. Limitations identified in the studies included vendor hardware specificity, issues with user interface and usability, inadequate features, interoperability, scalability, and compatibility, unjustifiable costs and insufficient evaluation in terms of validation.

CONCLUSION

Achievement of a predictive universal digital healthcare ecosystem in the current context is a challenge. State-of-the-art technologies demand user centric design, data privacy and protection measures, transparency, interoperability, scalability, and compatibility to achieve the SDG objective of sustainable healthcare by 2030.

Glaucoma and Computer Use: Do Contrast and Color Enhancements Improve Visual Comfort in Patients?

PURPOSE

To estimate the impact of glaucoma on computer use and to assess specific adaptations of the graphical interface to this form of visual impairment.

DESIGN

Prospective, experimental cohort study.

PARTICIPANTS

Forty-nine participants were recruited: 16 patients with primary open-angle glaucoma (mean ± SD, 62.7 ± 5.6 years of age), 17 age-matched participants (mean ± SD, 59.1 ± 8.3 years of age), and 16 young control participants (mean ± SD, 23.3 ± 2.1 years of age).

METHODS

An ophthalmologic examination before the study evaluated the level of visual loss (mean deviation), visual acuity (logarithm of the minimum angle of resolution units), and contrast sensitivity (CS) of the primary open-angle glaucoma patients. Each participant underwent the following measurements: an information technology (IT) experience questionnaire, a preference task monitored by eye tracking, and a feedback session. The experimental task was based on ecological computer scenes with 3 enhancement levels (low, medium, and high), determined by gradual modulation of contrast, luminance, and color. Participants were asked to select the most readable and comfortable stimulus among 4 images displayed on the screen: the original computer scene and 3 enhanced versions.

MAIN OUTCOME MEASURES

Clinical, oculomotor, and subjective data were computed together in a multivariate model by using a principal component analysis (PCA).

RESULTS

The PCA revealed 3 principal components accounting for 72% of the total variance of the data and showed a greater need for enhanced computer scenes in glaucoma patients, an equal preference for low and medium enhancement within the 3 groups, and significantly longer oculomotor behavior in the patient groups. Subjective reports of difficulty using IT because of vision were correlated with visual impairment and high enhancement preference. Contrast sensitivity was critical to explaining the main variations of the data. A reduced CS had a significant effect on the preference for enhanced computer scenes (r = -0.43; P < 0.002) and a less effective exploration velocity (r = 0.43; P < 0.002).

CONCLUSIONS

Glaucoma alters the global exploration of computer scenes. High enhancement of the graphical interface could improve visual comfort during computer use. Subjective patients' reports underline the importance of including IT questions in visual-related quality-of-life questionnaires.

Ability of Head-Mounted Display Technology to Improve Mobility in People With Low Vision: A Systematic Review

Purpose

The purpose of this study was to undertake a systematic literature review on how vision enhancements, implemented using head-mounted displays (HMDs), can improve mobility, orientation, and associated aspects of visual function in people with low vision.

Methods

The databases Medline, Chinl, Scopus, and Web of Science were searched for potentially relevant studies. Publications from all years until November 2018 were identified based on predefined inclusion and exclusion criteria. The data were tabulated and synthesized to produce a systematic review.

Results

The search identified 28 relevant papers describing the performance of vision enhancement techniques on mobility and associated visual tasks. Simplifying visual scenes improved obstacle detection and object recognition but decreased walking speed. Minification techniques increased the size of the visual field by 3 to 5 times and improved visual search performance. However, the impact of minification on mobility has not been studied extensively. Clinical trials with commercially available devices recorded poor results relative to conventional aids.

Conclusions

The effects of current vision enhancements using HMDs are mixed. They appear to reduce mobility efficiency but improved obstacle detection and object recognition. The review highlights the lack of controlled studies with robust study designs. To support the evidence base, well-designed trials with larger sample sizes that represent different types of impairments and real-life scenarios are required. Future work should focus on identifying the needs of people with different types of vision impairment and providing targeted enhancements.

Translational Relevance

This literature review examines the evidence regarding the ability of HMD technology to improve mobility in people with sight loss.

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 16,000 people used a smartphone magnifier app in their daily lives

BACKGROUND

Smartphone video magnifier apps are being used by millions of people to assist their vision. To understand the behaviour of app users, an exploratory investigation was conducted based on 'big data' collected from their daily uses.

METHOD

A mobile magnification app was developed with embedded analytics data collection modules. Seven months after it was released to the public, 30 days of app use data were collected from 16,787 active users across 129 countries. App launches and function use were analysed.

RESULTS

The app was most commonly used for one to three minutes a day, while a very small portion of users (0.5 per cent) used it over 100 times within the month and over 30 minutes each time. Some of the focused objects (13 per cent with Apple iPhone and 21 per cent with Apple iPad) were further than two metres away. Two functions that can be used to address the image shaking problem - live image stabilisation and snapshot - were compared, and it was found the former was used more often than the latter in terms of event/launch ratio and event duration. The flash light function (daily mean 209 seconds per device) was used more than focus locking (47 seconds) and inverted colour (28 seconds).

CONCLUSIONS

The mobile magnification app was mostly used for brief spot reading, while long reading occurred as well. As versatile devices, smartphones were used for near and sometimes far vision reading. This study presents a novel methodology helpful for understanding the behaviour of users and evaluating the utility of specific functions.

Low Vision Enhancement with Head-mounted Video Display Systems: Are We There Yet?

SIGNIFICANCE

Head-mounted video display systems and image processing as a means of enhancing low vision are ideas that have been around for more than 20 years. Recent developments in virtual and augmented reality technology and software have opened up new research opportunities that will lead to benefits for low vision patients. Since the Visionics low vision enhancement system (LVES), the first head-mounted video display LVES, was engineered 20 years ago, various other devices have come and gone with a recent resurgence of the technology over the past few years. In this article, we discuss the history of the development of LVESs, describe the current state of available technology by outlining existing systems, and explore future innovation and research in this area. Although LVESs have now been around for more than two decades, there is still much that remains to be explored. With the growing popularity and availability of virtual reality and augmented reality technologies, we can now integrate these methods within low vision rehabilitation to conduct more research on customized contrast-enhancement strategies, image motion compensation, image-remapping strategies, and binocular disparity, all while incorporating eye-tracking capabilities. Future research should use this available technology and knowledge to learn more about the visual system in the low vision patient and extract this new information to create prescribable vision enhancement solutions for the visually impaired individual.

The Effect of a Head-mounted Low Vision Device on Visual Function

SIGNIFICANCE

Head-mounted low vision devices have received considerable attention in recent years owing to rapidly developing technology, facilitating ease of use and functionality. Systematic clinical evaluations of such devices remain rare but are needed to steer future device development.

PURPOSE

The purpose of this study was to investigate, in a multicenter prospective trial, the short- and medium-term effects of a head-worn vision enhancement device (eSight Eyewear).

METHODS

Participants aged 13 to 75 years with stable vision (distance acuity, 20/60 to 20/400; visual field diameter >20°) were recruited across six sites. Data were collected at baseline (no device), at fitting (with device), and after 3 months of everyday use. Outcome measures were visual ability measured by the Veterans Affairs Low Vision Visual Functioning Questionnaire 48, distance acuity (Early Treatment Diabetic Retinopathy Study), reading performance (MNREAD chart), contrast sensitivity (MARS chart), face recognition, and a modified version of the Melbourne Low Vision Activities of Daily Living (ADL) Index.

RESULTS

Among the 51 participants, eSight introduction immediately improved distance acuity (0.74 ± 0.28 logMAR), contrast sensitivity (0.57 ± 0.53 log units), and critical print size (0.52 ± 0.43 logMAR), all P < .001, without any further change after 3 months; reading acuity improved at fitting (0.56 ± 0.35 logMAR) and by one additional line after 3 months, whereas reading speed only slightly increased across all three time points. The Melbourne ADL score and face recognition improved at fitting (P < .01) with trends toward further improvement at 3 months. After 3 months of use, Veterans Affairs Low Vision Visual Functioning Questionnaire 48 person measures (in logits) improved: overall, 0.84, P < .001; reading, 2.75, P < .001; mobility, 0.04, not statistically significant; visual information, 1.08, P < .001; and visual motor, 0.48, P = .02.

CONCLUSIONS

eSight introduction yields immediate improvements in visual ability, with face recognition and ADLs showing a tentative benefit of further use. Overall, visual ability, reading, and visual information showed greatest benefit with device use. Further studies need to examine benefits of practice and training and possible differential effects of underlying pathology or baseline vision.

Using an Augmented Reality Device as a Distance-based Vision Aid-Promise and Limitations

SIGNIFICANCE

For people with limited vision, wearable displays hold the potential to digitally enhance visual function. As these display technologies advance, it is important to understand their promise and limitations as vision aids.

PURPOSE

The aim of this study was to test the potential of a consumer augmented reality (AR) device for improving the functional vision of people with near-complete vision loss.

METHODS

An AR application that translates spatial information into high-contrast visual patterns was developed. Two experiments assessed the efficacy of the application to improve vision: an exploratory study with four visually impaired participants and a main controlled study with participants with simulated vision loss (n = 48). In both studies, performance was tested on a range of visual tasks (identifying the location, pose and gesture of a person, identifying objects, and moving around in an unfamiliar space). Participants' accuracy and confidence were compared on these tasks with and without augmented vision, as well as their subjective responses about ease of mobility.

RESULTS

In the main study, the AR application was associated with substantially improved accuracy and confidence in object recognition (all P < .001) and to a lesser degree in gesture recognition (P < .05). There was no significant change in performance on identifying body poses or in subjective assessments of mobility, as compared with a control group.

CONCLUSIONS

Consumer AR devices may soon be able to support applications that improve the functional vision of users for some tasks. In our study, both artificially impaired participants and participants with near-complete vision loss performed tasks that they could not do without the AR system. Current limitations in system performance and form factor, as well as the risk of overconfidence, will need to be overcome.

Artificial Intelligence and Big Data in Public Health

Artificial intelligence and automation are topics dominating global discussions on the future of professional employment, societal change, and economic performance. In this paper, we describe fundamental concepts underlying AI and Big Data and their significance to public health. We highlight issues involved and describe the potential impacts and challenges to medical professionals and diagnosticians. The possible benefits of advanced data analytics and machine learning are described in the context of recently reported research. Problems are identified and discussed with respect to ethical issues and the future roles of professionals and specialists in the age of artificial intelligence.

Clinical characteristics and causes of visual impairment in a low vision clinic in northern Jordan

Aim

The aim of the study was to identify causes of visual impairment among patients attending a low vision clinic in the north of Jordan and to study the relevant demographic characteristics of these patients.

Subjects and methods

The retrospective study was conducted through a review of clinical records of 135 patients who attended a low vision clinic in Irbid. Clinical characteristics of the patients were collected, including age, gender, primary cause of low vision, best corrected visual acuity, and current prescribed low vision aids. Descriptive statistics analysis using numbers and percentages were calculated to summarize categorical and nominal data.

Results

A total of 135 patients (61 [45.2%] females and 74 [54.8%] males) were recruited in the study. Mean age ± standard deviation for the study population was 24.53 ± 16.245 years; age range was 5–90 years. Of the study population, 26 patients (19.3%) had mild visual impairment, 61 patients (45.2%) had moderate visual impairment, 27 patients (20.0%) had severe visual impairment, and 21 patients (15.6%) were blind. The leading causes of visual impairment across all age groups were albinism (31.9%) and retinitis pigmentosa (RP) (18.5%). Albinism also accounted for the leading cause of visual impairment among the pediatric age group (0–15 years) while albinism, RP, and keratoconus were the primary causes of visual impairment for older patients. A total of 59 patients (43.7%) were given low vision aids either for near or distance. The only prescribed low vision aids for distances were telescopes. For near, spectacle-type low vision aid was the most commonly prescribed low vision aids.

Conclusion

Low vision services in Jordan are still very limited. A national strategy programme to increase awareness of low vision services should be implemented, and health care policies should be enforced to cover low vision aids through the national medical insurance.

Age-related macular degeneration changes the processing of visual scenes in the brain

In age-related macular degeneration (AMD), the processing of fine details in a visual scene, based on a high spatial frequency processing, is impaired, while the processing of global shapes, based on a low spatial frequency processing, is relatively well preserved. The present fMRI study aimed to investigate the residual abilities and functional brain changes of spatial frequency processing in visual scenes in AMD patients. AMD patients and normally sighted elderly participants performed a categorization task using large black and white photographs of scenes (indoors vs. outdoors) filtered in low and high spatial frequencies, and nonfiltered. The study also explored the effect of luminance contrast on the processing of high spatial frequencies. The contrast across scenes was either unmodified or equalized using a root-mean-square contrast normalization in order to increase contrast in high-pass filtered scenes. Performance was lower for high-pass filtered scenes than for low-pass and nonfiltered scenes, for both AMD patients and controls. The deficit for processing high spatial frequencies was more pronounced in AMD patients than in controls and was associated with lower activity for patients than controls not only in the occipital areas dedicated to central and peripheral visual fields but also in a distant cerebral region specialized for scene perception, the parahippocampal place area. Increasing the contrast improved the processing of high spatial frequency content and spurred activation of the occipital cortex for AMD patients. These findings may lead to new perspectives for rehabilitation procedures for AMD patients.

Wearable Improved Vision System for Color Vision Deficiency Correction

Color vision deficiency (CVD) is an extremely frequent vision impairment that compromises the ability to recognize colors. In order to improve color vision in a subject with CVD, we designed and developed a wearable improved vision system based on an augmented reality device. The system was validated in a clinical pilot study on 24 subjects with CVD (18 males and 6 females, aged 37.4 ± 14.2 years). The primary outcome was the improvement in the Ishihara Vision Test score with the correction proposed by our system. The Ishihara test score significantly improved ([Formula: see text]) from 5.8 ± 3.0 without correction to 14.8 ± 5.0 with correction. Almost all patients showed an improvement in color vision, as shown by the increased test scores. Moreover, with our system, 12 subjects (50%) passed the vision color test as normal vision subjects. The development and preliminary validation of the proposed platform confirm that a wearable augmented-reality device could be an effective aid to improve color vision in subjects with CVD.

Scharioth Macula Lens: A new intraocular implant for low-vision patients with stabilized maculopathy- first experience

AIMS

To present the initial results of Scharioth Macula Lens (SML) implantation. The SML is a new add-on intraocular lens designed to increase uncorrected near visual acuity (UCVA) in patients with stabilized maculopathy.

METHODS

Eight patients were included in the study. All met the indication criteria before SML implantation. An SML was implanted in the better seeing eye. Near and distance visual acuity were tested. Possible complications and patient complaints were recorded and patients were asked about their quality of vision after SML implantation. The examination was carried out on day 1, 1 week, 1, 3 and 6 months after surgery.

RESULTS

Six-month-results are presented. Apart from one, all patients with the SML had good near visual acuity at a recommended reading distance of 15 cm. Preoperatively, the mean (min-max) near UCVA was J13 (J8-J16), mean distance BCVA was 0.27. Postoperatively, the best results were after 1 month - near UCVA was J2.5 (J1-J7), distance BCVA was 0.26. Three months after surgery, this decreased to J4.5 (J1-J8); distance VA remained 0.25. Six months postoperatively - near vision was J4 (J1-J8) and distance VA was unchanged. Patients reported problems with reading speed and reading distance. Daily exercise improved their reading ability. One patient converted to wet AMD 3 months post-implantation.

CONCLUSION

The SML is a new hope for low-vision patients. It acts as a magnifier in the eye. It is a suitable method for increasing near visual acuity in patients with inactive maculopathy.

Scene perception in age-related macular degeneration: Effect of spatial frequencies and contrast in residual vision

Age-related macular degeneration (AMD) is characterized by a central vision loss. Here, we investigated the ability of AMD patients to process the spatial frequency content of scenes in their residual vision, depending of the luminance contrast level. AMD patients and normally-sighted elderly participants (controls) performed a categorization task involving large scenes (outdoors vs. indoors) filtered in low spatial frequencies (LSF), high spatial frequencies (HSF), and non-filtered scenes (NF). Luminance contrast of scenes was equalized between stimuli using a root-mean square (RMS) contrast normalization. In Experiment 1, we applied an RMS contrast of 0.1 (for luminance values between 0 and 1), a value situated between the mean contrast of LSF and HSF scenes in natural conditions. In Experiment 2, we applied an RMS contrast of 0.3, corresponding to the mean contrast of HSF scenes in natural conditions. In Experiment 3, we manipulated four levels of linearly-increasing RMS contrasts (0.05, 0.10, 0.15, and 0.20) for HSF scenes only. Compared to controls, AMD patients gave more non-responses in the categorization of HSF than NF or LSF scenes, irrespective of the contrast level of scenes. Performances improved as contrast increased in HSF scenes. Controls were not differentially affected by the spatial frequency content of scenes. Overall, results suggest that LSF processing is well preserved in AMD patients and allows efficient scene categorization in their parafoveal residual vision. The HSF processing deficit could be partially restored by enhancing luminance contrast.

Reading Digital with Low Vision

Reading difficulty is a major consequence of vision loss for more than four million Americans with low vision. Difficulty in accessing print imposes obstacles to education, employment, social interaction and recreation. In recent years, research in vision science has made major strides in understanding the impact of low vision on reading, and the dependence of reading performance on text properties. The ongoing transition to the production and distribution of digital documents brings about new opportunities for people with visual impairment. Digital documents on computers and mobile devices permit customization of print size, spacing, font style, contrast polarity and page layout to optimize reading displays for people with low vision. As a result, we now have unprecedented opportunities to adapt text format to meet the needs of visually impaired readers.