Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsSupport: NEI Grant: R41EY022545-01Program Number: 2764 Poster Board Number: B0018Presentation Time: 8:30 AM - 10:15 AMFeedback measures for a wearable visual aid designed for thevisually impairedAminat Adebiyi 1 , James D. Weiland 1, 2 , Carey Zhang 1, 3 , KaveriThakoor 4 . 1 Biomedical Engineering, University of SouthernCalifornia, Los Angeles, CA; 2 Ophthalmology, University ofSouthern California, Los Angeles, CA; 3 Electrical Engineering,University of Southern California, Los Angeles, CA; 4 NeuroscienceGraduate Program, University of Southern California, Los Angeles,CA.Purpose: To test the viability of a voice-driven feedback system toassist low-vision subjects with mobility.Methods: The audible feedback system consists of audio boneconductionheadphones worn by the user behind the ear and a customAndroid application, which delivers commands to the user when aresearcher presses a button corresponding to that command on theprogram. Two low-vision subjects were recruited from the BrailleInstitute, Los Angeles. Wearing the audible feedback system,subjects were steered around a three minute randomized course fivetimes by a researcher, who gave commands that were randomized bytrial. Commands included ‘forward’, ‘veer left’, ‘turn left’, ‘veerright’, turn right’ and ‘stop’. The course measured 17ft X17ft andwas interspersed with one foot cones every five feet. Appropriateresponse to commands, angle of turns and reaction time weremeasured. Subjects were also given an exit survey that measured theusability of the feedback system. The Android application recorded atime stamp for each command and video footage was recorded foreach trial.Results: Subject one had an average of 71.80% responses consistentwith commands, whereas subject two had an average of 53.18%responses consistent with commands; although subject two showed ahigher range in improvement over the course of the trials. Bothsubjects had an average of 95% positive compliance to the ‘forward’and ‘stop’ commands, and less than 5% compliance to the ‘veer left’and ‘veer right’ commands. Subject one had an average reaction timeof 1.5 seconds, whereas subject two had an average reaction time of2.5 seconds. Both subjects had an average turning radius ofapproximately 70 degrees for the ‘turn right and ‘turn left’commands. Based on the system usability scale, the system wasdetermined to be 90% useable in its current condition.Conclusions: Judging by the reactions times and the system usabilityscale, the audible feedback system seems to be an intuitive solutionthat will create a balanced connection between the user and thefeedback controller. However, significant training is needed tomaximize appropriate responses by its users to the commandsprovidedCommercial Relationships: Aminat Adebiyi, None; James D.Weiland, Second Sight Medical Products, Inc. (F); Carey Zhang,None; Kaveri Thakoor, NoneSupport: Research to Prevent Blindness, W.M. Keck Foundation,USAMRMC-W81XWH-10-2-0076Program Number: 2765 Poster Board Number: B0019Presentation Time: 8:30 AM - 10:15 AMLOCOMOTION IN LOW LUMINANCE WITH NONIMMERSIVE HEAD MOUNTED DEVICE FOR PATIENTSWITH NIGHT BLINDNESSCoen Cecilia 1 , Caroline Chauvire 1 , Guillaume Le Gall 2 , ArnaudKoustanai 1 , Marion Swital 2 , Laurence Bernardini 1 , PhilippeChaumet-Riffaud 1, 3 , Saddek Mohand-Said 1 , Jose A. Sahel 1 , AvinoamB. Safran 1 . 1 INSERM, U968; UPMC Univ Paris 06, UMR_S 968,Institut de la Vision; CNRS, UMR_7210; CHNO des Quinze-Vingts,INSERM-DHOS CIC 503, Paris, France; 2 Essilor R&DInternationnal, Paris, France; 3 Univ Paris Sud, AP-HP, CHU Bicêtre,EA 4046, Paris, France.Purpose: Retinitis pigmentosa (RP) is characteristically associatedwith reduced dark adaptation, which may lead to difficulties forlocomotion in dim light specially when lighting abruptly decreases.We tested a non immersive Head Mounted Display (HMD) providinga luminance-enhanced video image to determine its value for affectedindividuals in dim light condition.Methods: Nine RP patients were enrolled (age from 23 to 81 years,mean 43). All patients complained of altered dark adaptation. Weevaluted visual acuity (VA), horizontal binocular visual field (VF)and dark adaptometry (Goldmann-Weekers - GW). We tested a nonimmersiveHMD (Essilor Int., Institut de la Vision, Paris, France;Lumus, Rehovot, Israel), which provides a processed video imagedisplayed on transparent lenses. Image was a luminance-enhancedview of the surrounding environment. Patients were asked to walkalong a straight corridor (white walls and floor, 30 meters long).Five conditions were explored as follows: (1) in a clear corridor inphotopic condition (700 lux), and (2) in dim light (5 lux); (3) in acorridor with 6 obstacles (white boxes 30x35x55cm) laid out on thefloor in photopic, (4) and dim light. The last condition (5) in acorridor with 6 obstacles, in dim light, was tested using the HMD.The walking speed was measured 3 times in each condition. Spatialdisposition of obstacles was modified between consecutive trials.Patients were exposed to photopic lighting during 5 min before eachtrial to prevent dark adaptation.Results: Four of nine patients performed better using the HMD thanwithout: between-groups comparison showed that these four patientsincreased their walking speed when obstacles were laid out in dimlight (mean walking speed without HMD = 0.35 m/s; SD = 0.07,mean walking speed with HMD = 0.47 m/s; SD = 0.06) ;( F (4,152)=12.1; p