View clinical trials related to Visual Impairment.
Filter by:To assess repeatability of electroretinogram and visual evoked potential in clinical practice
This project assesses the effect of bifocal cross-frequency transcranial alternating current stimulation (tACS) combined with visual training to improve visual recovery and orchestrated oscillatory activity in stroke patients suffering from visual field defects.
The use of tools is ubiquitous in our lives and allows us to expand the sensorimotor capacities of our body. Much research has been done on the subject in sighted people over the past decades. This work has mainly focused on the motor aspect of using the tool, neglecting the sensory aspect. However, any action involving a tool carries sensory information, for example in the use of the white cane by blind people. 26% (> 200,000) of blind people in France use a white cane to get around. By sweeping the cane on the ground, they use it as a sensorimotor extension of their body to extract information from the environment in order to locate a pedestrian crossing or possible obstacles. While it is well established that the tools increase the user's motor skills, we have only just begun to clarify how they also function as sensory extensions of the user's body and how this phenomenon is potentially dependent on constant use of the tool to compensate for a missing sense, as is the case with blind people using a cane. The aim of this study is to fill this important gap in our knowledge.
The trial will determine the impact of an information- and education-focused interventions on the anxiety levels, and patients' experiences as well as satisfaction of patients aged 10-14 and their caregivers during the MR examination.
This is a randomized, pilot interventional study in participants with visual field deficit (VFD) caused by cortical lesion. Damage to the primary visual cortex (V1) causes a contra-lesional, homonymous loss of conscious vision termed hemianopsia, the loss of one half of the visual field. The goal of this project is to elaborate and refine a rehabilitation protocol for VFD participants. It is hypothesized that visual restoration training using moving stimuli coupled with noninvasive current stimulation on the visual cortex will promote and speed up recovery of visual abilities within the blind field in VFD participants. Moreover, it is expected that visual recovery positively correlates with reduction of the blind field, as measured with traditional visual perimetry: the Humphrey visual field test. Finally, although results will vary among participants depending on the extension and severity of the cortical lesion, it is expected that a bigger increase in neural response to moving stimuli in the blind visual field in cortical motion area, for those participants who will show the largest behavioral improvement after training. The overarching goals for the study are as follows: Group 1 will test the basic effects of transcranial random noise stimulation (tRNS) coupled with visual training in stroke cohorts, including (i) both chronic and subacute VFD stroke participant, and (ii) longitudinal testing up to 6 months post-treatment. Group 2 will examine the effects of tRNS alone, without visual training, also including chronic and subacute VFD stroke participants and longitudinal testing.
This research is aimed to address one of the big gaps in the current vision rehabilitation protocols for people with profound visual impairment by evaluating a multisensory approach. There are a growing number of clinical trials that recruit people with end-stage eye diseases and the rehabilitation plan following various treatments is not clear. It is important to address this in order to maximize the efficacy of such treatments and to improve the quality of life in people with profound visual impairment.
This trial aims to assess the accuracy and test-retest variability of a new digital app which enables community visual acuity testing without requirement of an trained examiner.
This study is driven by the hypothesis that navigation for users of retinal prosthetics can be greatly improved by incorporating Spatial Localization and Mapping (SLAM) and object recognition technology conveying environmental information via a retinal prosthesis and auditory feedback. The investigators will study how effectively the SLAM technology enables the visual prosthesis system to construct a map of the user's environment and locate the user within that map. The technology will be tested both with normally sighted individuals donning a virtual reality headset and with retinal prosthesis users (Argus II).
The National Eye Institute estimated about 3 million people over age 40 in the US had low vision in 2010 and projects an increase to nearly 5 million in 2030 and 9 million in 2050. Current assistive technologies are a patchwork of mostly low-technology aids with limited capabilities that are often difficult to use, and are not widely adopted. This shortfall in capabilities of assistive technology often stems from lack of a user-centered design approach and is a critical barrier to improve the everyday activities of life (EDAL) and the quality of life (QOL) for individuals with low vision. An intuitive head mounted display (HMD) system on enhancing orientation and mobility (O&M) and crosswalk navigation, could improve independence, potentially decrease falls, and improve EDAL and QOL. The central hypothesis is that an electronic navigation system incorporating computer vision will enhance O&M for individuals with low vision. The goal is to develop and validate a smartHMD by incorporating advanced computer vision algorithms and flexible user interfaces that can be precisely tailored to an individual's O&M need. This project will address the specific question of mobility while the subject crosses a street at a signaled crosswalk. This is a dangerous and difficult task for visually impaired patients and a significant barrier to independent mobility.
In industrialized nations diabetic retinopathy(DR) is the most frequent microvascular complication of type 2 diabetes mellitus and the leading cause of visual impairment and blindness in the working-age population. The well-accepted strategy for prevention and treatment of diabetic eye complications focused on confirmed diabetic retinopathy, diabetic macular edema, cataract, etc, and there was no definitive therapy for preclinical central visual acuity (CVA) impairment, mainly because of its unknown pathogenesis. In our previous population-based study, the prevalence rate of early CVA impairment was as high as 9.1%, and that obviously limits the effects of diabetic eye diseases prevention and early-stage treatment strategy. Of note, the choriocapillaris is the only route for metabolic exchange in the retina within the foveal avascular zone, it was speculated that early CVA impairment is related to diabetic choroidopathy (DC). Recent research shows that the decreased macular choriocapillaris vessel density (MCVD) in diabetic eye ,which indicating early ischemia, is already present before diabetic macular edema can be observed; we have observed subfoveal choroidal thickness (SFCT) decreased significantly in the early CVA impairment patients. However, up til now, there was no epidemiology report on early CVA impairment in Chinese diabetes population. In the present study, we plan to conduct a 10-year perspective cohort observation of 2217 Chinese type 2 diabetic residents without diabetic retinopathy, diabetic macular edema, cataract and other vision impairing diseases, trying to find out related physical and biochemical risk factors. The results will facilitate discriminating high risk groups of early CVA impairment in diabetic patients. In the same time, a quantitative relationship between SFCT change, MCVD change and CVA change will be established. This study will demonstrate the role of DC in the occurrence of preclinical CVA impairment, and provide important theoretic evidence of blocking agents which target on DC.