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Low vision

Tanya Moutray, Jennifer R Evans, Noemi Lois, David J Armstrong, Tunde Peto, Augusto Azuara-Blanco
BACKGROUND: Diabetic retinopathy (DR) is a chronic progressive disease of the retinal microvasculature associated with prolonged hyperglycaemia. Proliferative DR (PDR) is a sight-threatening complication of DR and is characterised by the development of abnormal new vessels in the retina, optic nerve head or anterior segment of the eye. Argon laser photocoagulation has been the gold standard for the treatment of PDR for many years, using regimens evaluated by the Early Treatment of Diabetic Retinopathy Study (ETDRS)...
March 15, 2018: Cochrane Database of Systematic Reviews
M Austin Coker, Carrie E Huisingh, Gerald McGwin, Russell W Read, Mark W Swanson, Laura E Dreer, Dawn K DeCarlo, Lindsay Gregg, Cynthia Owsley
Importance: The prevalence of irreversible vision impairment in the United States is expected to increase by 2050. Vision rehabilitation is the primary treatment option. Clinical trials have established its efficacy in improving quality of life. Yet studies indicate that patients experience many barriers to accessing low-vision care. Objectives: To examine the rate of referral for low-vision rehabilitation services by resident and attending ophthalmologists for adults with irreversible vision impairment and to assess the knowledge, attitudes, and beliefs of patients about vision rehabilitation...
March 15, 2018: JAMA Ophthalmology
Mingfeng Ning, Shijie Zhang, Shiqiang Wang
The number of feature points on the surface of a non-cooperative target satellite used for monocular vision-based relative navigation affects the onboard computational load. A feature point selection method called the quasi-optimal method is proposed to select a subset of feature points with a good geometric distribution. This method, with the assumption that all of the feature points are in a plane and have the same variance, is based on the fact that the scattered feature points can provide higher accuracy than that of them grouped together...
March 14, 2018: Sensors
Mirna Pineda-Ortíz, Gustavo Pacheco-López, Moisés Rubio-Osornio, Carmen Rubio, Juan Valadez-Rodríguez
RATIONALE: Visual therapy, which includes a restorative and compensatory approach, seems to be a viable treatment option for homonymous defects of the visual field in patients with postgeniculate injury of the visual pathway, due to occipital arteriovenous malformation (AVM). Until now, the Mexican population suffering from homonymous hemianopia did not have health services that provided any type of visual therapy for their condition. PATIENT CONCERNS: A 31-year-old patient, who underwent a surgical procedure for resection of the AVM, was referred with posterior low vision on the left side...
March 2018: Medicine (Baltimore)
Xuefei Shao, Di Qiang, Yinhua Liu, Quan Yuan, Jin Tao, Bihua Ji
Cerebral syphilitic gumma is very rare and is often pathologically confirmed following surgery. This study reports three patients with cerebral syphilitic gumma. The first case was a 62-year-old man who was admitted to our hospital due to speech arrest for 10 hours. Head MRI showed a nodular signal shadow with a significant enhancement and a significant centerline shift. He subsequently received surgery, and cerebral syphilitic gumma was confirmed by postoperative pathology. The second patient was a 66-year-old man who was admitted to our hospital due to complaints of gradually decreasing right eye vision and headache for nearly 50 days...
2018: Frontiers in Neuroscience
Xavier Tchetnya, Calypse Asangbe Ngwasiri, Tiayah Munge, Leopold Ndemnge Aminde
BACKGROUND: Toxic epidermal necrolysis (TEN) is a rare life threatening dermatological disorder characterized by extensive epidermal detachment and erosion of mucous membranes. It is typically a side effect of some medications. Nevirapine, a nonnucleoside reverse transcriptase inhibitor (NNRTI) is one of the frequently used components of highly active antiretroviral therapy (HAART). Skin rash is its common adverse reaction, usually mild and rarely progressing to TEN. Ophthalmic involvement is common as well but rarely progresses to blindness especially in the pediatric population...
March 13, 2018: BMC Pediatrics
Anne M Menjivar, Marjean T Kulp, G Lynn Mitchell, Andrew J Toole, Kathleen Reuter
BACKGROUND: Convergence insufficiency (CI) is a common binocular vision disorder which often causes symptoms when doing near work. However, the best screening test for CI is unknown. The purpose of this study was to evaluate the ability of common tests of binocular and accommodative function to identify children with CI in a school screening setting. METHODS: Children aged nine to 14 were invited to participate. Positive fusional vergences, near point of convergence (NPC), accommodative amplitude, accommodative facility, Modified Thorington, and the Convergence Insufficiency Symptom Survey were evaluated...
March 13, 2018: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Yoshiyuki Henning, Nella Mladěnková, Hynek Burda, Karol Szafranski, Sabine Begall
Mammals usually possess a majority of medium-wavelength sensitive (M-) and a minority of short-wavelength sensitive (S-) opsins in the retina, enabling dichromatic vision. Unexpectedly, subterranean rodents from the genus Fukomys exhibit an S-opsin majority, which is exceptional among mammals, albeit with no apparent adaptive value. Because thyroid hormones (THs) are pivotal for M-opsin expression and metabolic rate regulation, we have, for the first time, manipulated TH levels in the Ansell's mole-rat (Fukomys anselli) using osmotic pumps...
March 12, 2018: Scientific Reports
Sobha Sivaprasad, Elizabeth Tschosik, Audrey Kapre, Rohit Varma, Neil M Bressler, Miriam Kimel, Chantal Dolan, David Silverman
PURPOSE: Geographic atrophy (GA) is an advanced form of age-related macular degeneration characterized by progressive, irreversible visual function loss. This analysis evaluates the psychometric properties of the 25-Item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) Composite, Near Activity, and Distance Activity scores in patients with GA. DESIGN: Reliability and validity study. METHODS: Reliability and validity were tested with NEI VFQ-25 data collected from 100 subjects with GA from United States' sites of the phase 2 Mahalo study of lampalizumab (NCT01229215)...
March 9, 2018: American Journal of Ophthalmology
F E Sahin, A R Tanguay
An imaging system design procedure for miniature wide-angle computational cameras with subsequent software correction of distortion is described. Such miniature wide-angle computational cameras have a broad range of applications, including eye-tracked extraocular cameras for retinal prostheses, and also wearable visual aids for the blind and those with low vision. As significant (typically barrel) distortion is commonplace in wide-field-of-view imaging systems, digital post-processing is often employed to generate rectilinear output images...
March 5, 2018: Optics Express
Shoaib Hassan, Anjana Haridas, Venki Sundaram
BACKGROUND: Strabismus, or squint, can be defined as a deviation from perfect ocular alignment and can be classified in many ways according to its aetiology and presentation. Treatment can be broadly divided into medical and surgical options, with a variety of surgical techniques being available, including the use of adjustable or non-adjustable sutures for the extraocular muscles. There exists an uncertainty as to which of these techniques produces a better surgical outcome, and an opinion that the adjustable suture technique may be of greater benefit in certain situations...
March 12, 2018: Cochrane Database of Systematic Reviews
Xiaokang Yu, Na Lei, Yalin Wang, Xianfeng Gu
3D dynamic surface tracking is an important research problem and plays a vital role in many computer vision and medical imaging applications. However, it is still challenging to efficiently register surface sequences which has large deformations and strong noise. In this paper, we propose a novel automatic method for non-rigid 3D dynamic surface tracking with surface Ricci flow and Teichmüller map methods. According to quasi-conformal Teichmüller theory, the Techmüller map minimizes the maximal dilation so that our method is able to automatically register surfaces with large deformations...
October 2017: Proceedings
Jonathan W Wallace, Brandon G Rasman, Brian H Dalton
Maintaining standing balance involves multisensory processing and integration to produce dynamic motor responses. Electrical vestibular stimulation (EVS) delivered over the mastoid processes can be used to explore the vestibular control of balance. The purpose of this study was to determine whether intrinsic foot muscles exhibit vestibular-evoked balance responses and to characterize the traits associated with these responses. Electromyography (EMG) of the abductor hallucis, abductor digiti minimi and medial gastrocnemius and anterior-posterior (AP) forces were sampled while quietly standing participants were subjected to a random continuous EVS signal (peak-to-peak amplitude = ±3 mA)...
March 7, 2018: Neuroscience
Scinob Kuroki, Shin'ya Nishida
When we touch an object, the skin copies its surface shape/texture, and this deformation pattern shifts according to the objects movement. This shift pattern directly encodes spatio-temporal "motion" information of the event, and has been detected in other modalities (e.g., inter-aural time differences for audition and first-order motion for vision). Since previous studies suggested that mechanoreceptor-afferent channels with small receptive field and slow temporal characteristics contribute to tactile motion perception, we tried to tap the spatio-temporal processor using low-frequency sine-waves as primitive probes in our previous study...
March 9, 2018: Scientific Reports
Enrique Barragán-Garza, Douglas D Koch, Luis G Vargas, Alan Lang, Adam Roy
PURPOSE: To assess the clinically acceptable range of inlay decentration with respect to the light-constricted pupil center and the coaxially sighted corneal light reflex (CSCLR) for an inlay (Raindrop Near Vision Inlay; ReVision Optics, Inc., Lake Forest, CA) that reshapes the anterior corneal surface. METHODS: In this retrospective, observational cohort study of 115 patients with emmetropic or low hyperopic presbyopia who were implanted with a shape-changing corneal inlay, visual acuity, task performance (in good and dim light), reports of halos and glare, and satisfaction data were collected from the preoperative and 3-month postoperative examinations...
March 1, 2018: Journal of Refractive Surgery
Xiaojun Wu, Guangming Gao
In machine vision, illumination is very critical to determine the complexity of the inspection algorithms. Proper lights can obtain clear and sharp images with the highest contrast and low noise between the interested object and the background, which is conducive to the target being located, measured, or inspected. Contrary to the empirically based trial-and-error convention to select the off-the-shelf LED light in machine vision, an optimization algorithm for LED light design is proposed in this paper. It is composed of the contrast optimization modeling and the uniform illumination technology for non-normal incidence (UINI)...
March 1, 2018: Applied Optics
B González-García, S García-Isidoro, J Contreras-Alcántara, J A Martínez-Gil, M A Díaz Y Orea, V O Castellanos-Sánchez
The most frequent diabetes-related complications are diabetic foot and glaucoma, which lead to amputation and loss of vision, respectively. Current scientific and technologic developments have permitted the design and implementation of prosthetic systems that are optimal for these patients, as the latter adapt themselves to them and can resume activities of daily living. The lack of economic resources compromises the quality of the prostheses patients can afford, as they resort to «artisanal» or «rustic» systems that hamper their adaptation process...
September 2017: Acta Ortopédica Mexicana
Michael E Ward, Jeffrey M Gelfand, Li-Yung Lui, Yvonne Ou, Ari J Green, Katie Stone, Kathryn L Pedula, Steven R Cummings, Kristine Yaffe
OBJECTIVE: Several cross-sectional studies have reported an association between visual contrast sensitivity (a functional measure of low contrast vision) and poor cognitive performance or dementia, but no studies have investigated this association prospectively in a population based cohort with final adjudication of mild cognitive impairment (MCI)/dementia. METHODS: In a prospective, community-based study of aging women (Study of Osteoporotic Fractures), we analyzed whether visual contrast sensitivity was associated with increased risk of MCI or dementia and/or worse performance on various cognitive tests assessed 10 years later...
March 8, 2018: Annals of Neurology
Andreas Brocher, Raphael Harbecke, Tim Graf, Daniel Memmert, Stefanie Hüttermann
We tested the link between pupil size and the task effort involved in covert shifts of visual attention. The goal of this study was to establish pupil size as a marker of attentional shifting in the absence of luminance manipulations. In three experiments, participants evaluated two stimuli that were presented peripherally, appearing equidistant from and on opposite sides of eye fixation. The angle between eye fixation and the peripherally presented target stimuli varied from 12.5° to 42.5°. The evaluation of more distant stimuli led to poorer performance than did the evaluation of more proximal stimuli throughout our study, confirming that the former required more effort than the latter...
March 7, 2018: Behavior Research Methods
Abigail L M Webb, Paul B Hibbard, Rick O'Gorman
Evidence suggests that females experience adaptive shifts in facial preferences across the menstrual cycle. However, recent discussions and meta-analyses suggest that these findings are equivocal. A previously unexplored question is the extent to which shifts in female preferences are modulated by hormone-dependent changes occurring in low-level vision, such as visual sensitivity. This mechanistic approach has been a novel method for investigating the extent to which complex perceptual phenomena are driven by low-level versus higher-level perceptual processes...
February 2018: Royal Society Open Science
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