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Visual Psychophysics / Physiological Optics - ARVO

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<strong>ARVO</strong> 2013 Annual Meeting Abstracts by Scientific Section/Group – <strong>Visual</strong> <strong>Psychophysics</strong> / <strong>Physiological</strong> <strong>Optics</strong>underwent a complete ophthalmological examination including: bestdistance and near visual acuity assessment, reading speed test, MP-1microperimetry evaluating BCEA. Low vision rehabilitationconsisted in 12 training sessions of 10 minutes for each eyeperformed once a week with MP-1 for both groups. Statisticalanalysis was performed using Student’s t- test.Results: After training all patients displayed an improvement invisual acuity, fixation behaviuor, retinal sensitivity and readingspeed.Group A: visual acuity was not statistically improved (p=0.054),reading speed showed statistically significant improvement(p=0.031), and a statistically significant reduction in average BCEAfixation (p=0.0023) was evidenced and a mean single point retinalsensitivity value was also improved (p=0.044).Group B: visual acuity was statistically higher (p=0.048), readingspeed showed statistically significant improvement (p=0.024), astatistically significant high reduction in BCEA (p=0.0012) wasevidenced and a mean single point retinal sensitivity value was alsoimproved (p=0.027).Conclusions: Our results show that biofeedback techniques canimprove fixation stability. Audio feedback and pattern stimulusfacilites transmission between intraretinal neurons as well as betweenthe retina and the brain, thereby probably facilitating a remappingphenomenon.Furthermore, highly informative and contrast rich pattern stimulusshowed a statistically significant difference towards uninformativeplain exercise limited to train the PRL as obtained with oldersoftware, thus indicating that it is possible with more informativetasks to reach a wider involvement of cell populations and recruitmore and more efficient ganglion cell receptive fields so to betterutilize the residual retinal function.Commercial Relationships: Enzo M. Vingolo, None; Paolo G.Limoli, None; Serena Fragiotta, None; Vittoria De Rosa, None;Daniela Domanico, NoneSupport: Sapienza C26A10NRES/2010Program Number: 5037 Poster Board Number: A0199Presentation Time: 2:45 PM - 4:30 PMThe Influence of Fixation Stability on Balance in Patients with aCentral ScotomaCaitlin Murphy 1, 4 , Janette Chu 2 , Eoghan Landy 2 , Jean-ChristopheCampbell 2 , Amy Phan 2 , Olga Overbury 1, 3 . 1 School of Optometry,University of Montreal, Montreal, QC, Canada; 2 Physiotherapy,McGill University, Montreal, QC, Canada; 3 Ophthalmology, McGillUniversity, Montreal, QC, Canada; 4 Centre for InterdisciplinaryResearch in Rehabilitation (CRIR), Montreal, QC, Canada.Purpose: Vision is second only to the vestibular system in terms ofits contribution to balance. Research has shown that visually impairedpeople (VIPs) often have problems in this domain. Some major visualdisorders damage the central retina. To compensate for the loss of afunctioning fovea, those affected use their remaining peripheral retinato accomplish daily tasks. This sometimes results in the formation ofan unstable, non-central fixation point. The purpose of this study wasto determine if reduced balance in VIPs is related to unstable fixation.Methods: Individuals with a visual acuity of 20/200 or better and adiagnosis of a retinal disorder, were recruited for this study. Therewere 44 participants (23 M and 21 F) ranging in age from 47 to 89years. Fixation stability was determined using the Mirametrix EyeTracker and participants were then divided into two groups: stablefixation and poor fixation. Functional balance was measured usingthe Timed Get-Up-and-Go (TUG) and the Berg Balance Scale (BBS).Balance confidence was assessed using the Activities-SpecificBalance (ABC) Scale. The examiners conducting the balance testswere masked to the fixation status of the participants.Results: Performance on the TUG test was significantly differentbetween the groups, with the poor-fixation group having a slowerTUG time than the stable-fixation group, t (42) = 1.7263, p < .05.Clinically, taking more than 13.5 seconds to complete the taskindicates an increased risk of falls. The poor fixation stability grouphad a mean score of 14.3 seconds. There was no significantdifference in functional balance between the stable- and unstablefixationgroups as determined by the BBS. Subjects with poorfixation stability scored lower on the ABC scale compared to thestable fixation group, t (42) = -1.856, p < .05. However, their scoreswere not low enough to have any clinical significance.Conclusions: Based on the TUG, VIPs with unstable fixation are at ahigher risk of falls compared to those with stable fixation. Althoughthere is a statistically significant difference between the two groupson the ABC scale, it is not great enough to conclude that those withpoor fixation are at risk of falls.Commercial Relationships: Caitlin Murphy, None; Janette Chu,None; Eoghan Landy, None; Jean-Christophe Campbell, None;Amy Phan, None; Olga Overbury, NoneProgram Number: 5038 Poster Board Number: A0200Presentation Time: 2:45 PM - 4:30 PMImpact of <strong>Visual</strong> Motion Displayed in a Non-Immersive Head-Mounted Device on the Balance of Patients with Age-RelatedMacular DegenerationCaroline Chauvire 1 , Coen Cecilia 1 , Arnaud Koustanai 1 , Johan LeBrun 1 , Samuel Pineau 1 , Thierry Villette 2 , Philippe Chaumet-Riffaud 1,3 , Saddek Mohand-Said 1 , Jose A. Sahel 1 , Avinoam B. Safran 1 .1 INSERM, U968; UPMC Univ Paris 06, UMR_S 968, Institut de laVision; CNRS, UMR_7210; CHNO des Quinze-Vingts, INSERM-DHOS CIC 503, Paris, France; 2 Essilor R&D International, Paris,France; 3 Univ Paris Sud, AP-HP, CHU Bicêtre, Paris, France.Purpose: Age-related Macular Degeneration (AMD) results in areduced visual acuity (VA). Head-Mounted Displays (HMD) may beuseful for affected individuals, by magnifying, freezing and draggingthe view, vertically or horizontally, to relieve from reduced field ofvision due to magnification. However, changes in image (size andmovements) are susceptible to disturb visuomotor coordination andthus to disrupt postural control. The aim of this study was to evaluatethe impact of changes in image on the balance of AMD patients,when using a non-immersive HMD.Methods: Three groups were included: 12 patients with atrophicAMD (AMDs: age between 62 and 81 years, mean 70; VA between+1.22 and +0.28 logMAR , mean +0.62), 6 older healthy subjects(OH: age between 65 and 75 years, mean 70; VA between 0 and -0.2logMAR, mean -0.04), and 5 young healthy subjects (YH: agebetween 30 and 48 years, mean 37 ; VA between +0 and -0.1logMAR, mean -0,01).Subjects stood in the dark on a stable force plate. A virtual street wasprojected onto a wall-screen. For comparison, subjects were testedwithout HMD eyes closed (EC) and eyes open (EO). When testedwith HMD, subjects wore a non-immersive binocular opto-electronicdevice, displaying an image through transparent lenses. They viewedthe scene moving successively in vertical and horizontal directionsand from one size to another. In non-immersive mode, subjectsviewed the scene both onto the wall-screen and in-motion through theHMD. In immersive mode, they only viewed the scene in-motionthrough HMD.Average velocity of center of pressure (V) was recorded. Each triallasted 51.2 s and was repeated 3 consecutive times.Results: Difference between EO and EC was greater in OH than inAMDs and YH (p

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