Low vision

The Virtual Retinal Display (VRD) is a new technology for creating visual images. It was developed at the Human Interface Technology Laboratory (HIT Lab) by Dr. Thomas A. Furness III. The VRD creates images by scanning low power laser light directly onto the retina. This special method results in images that are bright, high contrast and high resolution. In this paper, we describe how the VRD functions, the special consequences of its mechanism of action and potential medical applications of the VRD, including surgical displays and displays for people with low vision. A description of its safety analysis will also be included. In one set of tests we had a number of patients with partial loss of vision view images with the VRD. There were two groups of subjects: patients with macular degeneration, a degenerative disease of the retina and patients with keratoconus. Typical VRD images are on the order of 300 nanowatts. VRD images are also readily viewed superimposed on ambient room lig...

Address: Department of Psychology, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK Email: Jan Mitchell* - j.mitchell@rhul.ac.uk; Clare Bradley - c.bradley@rhul.ac.uk * Corresponding author ... Abstract Background: The Age-related Macular Degeneration Alliance ...

This is a case report of Acanthamoeba as a causative agent of keratitis at the Department of Ophthalmology, University Hospital Rijeka. Delay in treatment led to an advanced stage of the disease with multiple complications. Initially, presented symptoms were similar to those of herpetic keratitis. In the mean time progression of the disease led to a cloudy cornea with a stromal ring infiltrate, poor vision, elevated intraocular pressure, a mature cataract and finally corneal melt. Corneal scrapings were obtained from a 28 years old female patient, wearing soft contact lenses and with poor lens hygiene. Acanthamoeba cysts were identified by the cytological examination. Culture of the corneal scraping had confirmed Acanthamoeba as the etiological agent. Making the diagnosis of Acanthamoeba is difficult. We presented this case of delayed diagnosis and unfavorable outcome as a reminder that clinical suspicion remains the most important diagnostic tool. Contact lens wears with a new diag...

Horizontal peripheral prisms for hemianopia provide field expansion above and below the horizontal meridian; however, there is a vertical gap leaving the central area (important for driving) without expansion. In the oblique design, tilting the bases of both prism segments toward the horizontal meridian moves the field expansion area vertically and centrally (closing the central gap) while the prisms remain in the peripheral location. However, tilting the prisms results also in a reduction of the lateral field expansion. Higher prism powers are needed to counter this effect. We developed, implemented, and tested a series of designs aimed at increasing the prism power to reduce the central gap while maintaining wide lateral expansion. The designs included inserting the peripheral prisms into carrier lenses that included yoked prism in the opposite direction, combination of two Fresnel segments attached at the base and angled to each other (bi-part prisms), and creating Fresnel prism-...

Refractive errors are a major cause of visual impairment in the population. To find the pattern of refractive errors among patients evaluated in a tertiary care hospital in the western region of Nepal. The present hospital-based retrospective study was conducted in the Department of Ophthalmology of the Manipal Teaching Hospital, situated in Pokhara, Nepal. Patients who had refractive error of at least 0.5 D (dioptre) were included for the study. During the study period, 15,410 patients attended the outpatient department and 10.8% of the patients were identified as having refractive error. The age of the patients in the present study ranged between 5 - 90 years. Myopia was the commonest refractive error followed by hypermetropia. There was no difference in the frequency of the type of refractive errors when they were defined using right the eye, the left eye or both the eyes. Males predominated among myopics and females predominated among hypermetropics. The majority of spherical er...

It is a widely accepted belief in clinical practice that children with a visual impairment can profit from the use of a low vision aid (LVA). However, we found a considerable gap in our scientific understanding of LVA use, particularly in young children. This is the reason for the analysis presented in this paper. A selected overview of LVA use in adults is given, from which valuable insights are taken. Additionally, an action perspective for analysing LVA use is discussed as well as the results of tool-use studies in children. Mainly based on these three ingredients, we developed a conceptual framework for LVA use. The framework consists of three interacting relations between LVA, child and task. Performance of a particular child on a specific task with a certain LVA is constrained by the following three reciprocal and dynamic relations: the Child-to-Task relation (related to goal-information), the Child-to-LVA relation (related to control-information), and the LVA-to-Task relation (related to topology information).► Both definition and performance of a task change critically when using a LVA. ► LVAs change properties and possibilities of attached perception and action systems. ► Performance with LVA is shaped by the relations between LVA, user, and task. ► Research on the developing interrelations in the LVA-Child-Task system is needed.

Background. The goal of occupational therapy education is to train generalists who can refine their knowledge after graduation according to the requirements of the professional environment. However, it is currently unclear to what extent sensory screening should be included in the educational curricula. Purpose. The purpose of this study was to examine the sensory screening education for and practice by occupational therapists working with older adults. Method. A cross-sectional survey was used to collect data from members of the Quebec Order of Occupational Therapists. Descriptive statistics were used in the analysis. Findings. Data from 102 respondents indicated that training on sensory impairment–related topics was minimal and in stark contrast to the proportion who reported serving clients with a visual (92%), hearing (84%), or combined impairment (53%). Implications. Occupational therapy considers numerous aspects of physical, cognitive, and emotional well-being. The
question remains as to what extent vision and hearing health should take their place among these priorities.

Introduction: The Virtual Retinal Display (VRD) is a new technology for creating visual images. It was developed at the Human Interface Technology Laboratory (HIT Lab) by Dr. Thomas A. Furness III. The VRD creates images by scanning low power laser light directly onto the retina. This special method results in images that are bright, high contrast and high resolution. In

The purpose of this thesis is to investigate potential key determinants of the success, or otherwise, of endeavours to address avoidable Visual Impairment (VI) by addressing Uncorrected Refractive Error (URE) in Mozambique and the wider region of sub-Saharan Africa by providing optometric services. It includes a Cost Benefit Analysis (CBA) of a higher education optometry training programme, barriers that might prevent the realisation of overarching goals despite a successful training programme, and a Willingness to Pay (WTP) analysis to inform the pricing structure and to determine the financial sustainability of the system. Methods A standard CBA methodology was applied to ascertain societal net benefit. Costs including those associated with establishing an optometry service. Benefits were calculated by considering how addressing URE could increase productivity. Disability weighting (DW) for VI was applied …

Visually impaired people is a big community all over the world. They usually seek help to perform their daily activities such as reading the expired date of food cans or medicine, reading out PIN of a certain ATM Visa, identifying the color of clothes or differentiate between the money notes and other objects with the same shape. A number of IT-based solutions have been proposed to help and assist blind and/or visually impaired people. Generally speaking, these solutions, however, do not support Arabic languages nor protect blind users' privacy. In this paper, Trusted Blind Society (TBS) mobile application is proposed. It is an android application which allows blind users to recognize their unknown surroundings by utilizing two concepts: social networks sites and friendsourcing. These two concepts were employed by allowing family members and the trusted friends, who are registered on Twitter, to answer blind users' questions on a real time. The solution is also bilingual, supports (Arabic/English) and allows screen reader using Android talk-back service. The performance of the TBS system was evaluated using loader.io to check its stability under the heavy load and it was tested by a number of blind volunteers and the results showed good performance comparing to most related work.

This article presents a pilot study conducted in Barcelona with blind and visually-impaired people. The aim was to analyze the use and efficacy of tactile maps produced by means of 3D printing. For this purpose, structured interviews were used, along with direct observation, the creation of cognitive maps and tasks with prototypes. The aim has been to examine the instrumental and communicative value of these products in terms of interpreting, memorizing and understanding a certain urban route, comparing this with experience in situ, focusing on the difficulties faced by the visually disabled when visiting new places. Findings show the utility of this type of technique in aiding visually disabled users to memorize routes. As a limitation, this study shows that tactile maps are not wholly efficient since they require verbal support, which makes it hard for them to be used autonomously.

Structured abstract: Purpose: Previous studies have guided the development of deafblindness rehabilitation by reporting on the priorities of researchers and of deafblind individuals; however, service and care providers may be able to bring a different and important perspective to shaping the development of this clinical field and its research. The present study aims to give them a voice in this process. Methods: We conducted a qualitative survey in which 68 stakeholders in deaf-blind rehabilitation from 6 countries described their perceived research and rehabilitation priorities for the coming decade. Verbatim transcripts were analyzed using thematic analysis through open coding, creating categories, and abstraction. Results: Three categories of priorities emerged: those common to rehabilitation and research (such as assistive technology, communication services , and interdisciplinarity), those unique to rehabilitation (such as augmented service provision), and those unique to research (such as recruitment databases and measurement tools). Conclusions: When viewing the findings from within the context of the existing research literature, the overlap indicated that research and rehabilitation efforts are moving in a congruent direction for researchers, service providers, and persons with deafblindness. Future efforts should focus on information exchange in order to improve evidence-based rehabilitation practice.