Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsprehension planning [movement onset (MO ms); peak speed (Vmm/s), time to peak speed (ttV ms)], execution [movement duration(MD ms); path deviation ratio (PD)] grasping [peak grip aperture(PGA, angle), grip application time (GAT, ms)] and control[deceleration time (DT ms)] were quantified. Analyses wereperformed using repeated measures ANOVA.Results: The results of 9 control (C), 11 age related maculardegeneration (AMD) and 12 glaucoma (G) patients during binocularviewing are presented. There were significant group differences inmovement planning [MO: p < 0.01, V: p = 0.03, ttV: p < 0.01] andgrasping [GAT:p < 0.01] with aspects of execution and online controlapproaching significance [MD: p = 0.06; PD, p = 0.1].AMD and G patients had longer MO ('far,large' condition mean[standard error]: C = 274 [46] ms; G = 378 [87] ms; AMD = 439[104] ms), ttV (C = 594 [79] ms; G = 719 [103] ms; AMD = 766[100] ms) and GAT (C = 411 [74] ms; G = 544 [126] ms; AMD =644 [163] ms); however AMD reaching speed V was slower,suggesting a deficiency in some aspects of movement planning (C =1032 [122] mm/s; G = 918 [150] mm/s; AMD = 854 [94] mm/s). Incontrast, glaucoma patients displayed longer DT (C = 510 [109] ms;G = 552 [79] ms; AMD = 528 [74] ms) , MD (C = 935 [113] ms; G =1078 [192] ms; AMD = 1060 [156] ms) and higher PD (C = 1.14[0.04]; G = 1.16 [0.05]; AMD = 1.12 [0.04]) suggesting difficultieswith online control.Conclusions: This preliminary analysis suggests that whilstglaucoma and AMD patients have deficits in reach to graspmovements compared with controls, they display distinct differencesin movement planning and online control. Further work will explorehow these relate to their specific visual deficiency.Commercial Relationships: Aachal Kotecha, None; Rachel T.Fahy, None; Gary S. Rubin, NoneSupport: Special Trustees of Moorfields Eye HospitalProgram Number: 2187Presentation Time: 4:00 PM - 4:15 PMEffect of central vision loss on mutual gaze perceptionAlexandra R. Bowers 1 , Sarah S. Sheldon 1 , Jessilin Quint 2 , HeikoHecht 3 . 1 Schepens Eye Res Inst, Mass Eye and Ear, Ophthalmology,Harvard Med School, Boston, MA; 2 Indiana University School ofOptometry, Bloomington, IN; 3 Psychologisches Institut, JohannesGutenberg-Universitat, Mainz, Germany.Purpose: The ability to perceive mutual gaze (knowing whethersomebody else is looking at you) is an important nonverbal visual cuethat directs conversations and social interactions. Individuals withcentral vision loss (CVL) have limited access to such cues, whichmay cause difficulties in social situations. We evaluated perceiveddifficulties with gaze perception and examined the relationship withfunctional abilities quantified using a performance-based measure.Methods: 18 persons with CVL (visual acuity 20/60 to 20/250) and18 age-similar controls completed a battery of vision tests, a shortquestionnaire rating perceived difficulties with gaze perception, facerecognition and social interactions, and a gaze perception task. Theyadjusted the positions of the eyes of a life-size virtual head on amonitor at a 1-m distance until the eyes appeared either to be lookingstraight at them or were at the extreme lateral left or right position atwhich they still appeared to be looking toward them. For each trial (n= 48), the angular deviation of the final position of the virtual eyesfrom the straight ahead gaze position was computed. The gaze conewidth was the difference between the extreme left and right positions.Results: CVL participants reported moderate difficulty with knowingwhen somebody was looking at them; moderate difficulty with seeinghow other people reacted in social situations; and a variety of copingstrategies. Controls reported no difficulties. The median gaze conewidths were not significantly different for the two groups (CVL11.5°, controls 13.2°; p = 0.9) neither were the mean judgments ofthe straight ahead gaze direction (CVL 0.1 ± 0.9°, controls 0.2 ± 1.7°;p = 0.82). However, CVL participants had significantly morevariability in their judgments (6.9 ± 2.4° and 4.6 ± 1.8°; p < 0.01).Greater judgment variability correlated with higher levels ofperceived difficulties (r = 0.78, p < 0.001) but not with visual acuity(r = 0.44, p = 0.07) or contrast sensitivity (r = -0.37, p = 0.13).Conclusions: CVL increased the variability of mutual gazejudgments suggesting that CVL participants had more difficulty withthe task than controls; however, the average estimate of gazedirection was similar in the two groups. While traditional visionmeasures did not predict the extent to which CVL affected the morecomplex gaze judgment task, perceived difficulties were predictive ofincreased judgment variability.Commercial Relationships: Alexandra R. Bowers, None; Sarah S.Sheldon, None; Jessilin Quint, None; Heiko Hecht, NoneSupport: NIH grant T35EY007149Program Number: 2188Presentation Time: 4:15 PM - 4:30 PMAssociation of Self-Reported Task Difficulty with BinocularCentral Scotoma LocationsNicole C. Ross, Judith E. Goldstein, Robert W. Massof.Ophthalmology, Johns Hopkins Univeristy, School of Medicine,Baltimore, MD.Purpose: To determine if the location of binocular central scotomasrelative to fixation, predicts the difficulty that low vision patients arelikely to have with driving, reading, and mobility tasks.Methods: This study was conducted in accordance with the tenets ofthe Declaration of Helsinki and Johns Hopkins Institutional ReviewBoard.Perimetry: Central scotomas were mapped with a video haploscopetangent screen in 284 patients. The haploscope consisted of 2 flatpanel displays, one per eye, imaged at infinity through 9mm diameterexit pupils centered on the patient’s pupils. The patient’s refractiveerror corrections were incorporated into the optical paths. Infraredvideo cameras where used to monitor ocular alignment and fixationstability. The patient fused the two 50 o h x 40 o v displays and thefixation cross was imaged at the center of both displays, therebyproviding binocular fixation, while test stimuli were presentedmonocularly at 43 locations in a 25 o square grid around fixation.Self Reported Difficulty Ratings: Patients rated difficulty of a subsetof 120 reading, 50 mobility and 22 driving tasks in the ActivityInventory on a five point scale. Rasch analysis was used to estimateself-perceived ability for driving, reading and mobility for eachpatient.Analysis: Unpaired, two tailed t-tests were performed on distributionsof each ability measure for each test location in the central fieldcomparing patients who detected the stimulus to those who did not.Results: Driving: Scotomas below and to the lower right of fixationand a single point 10 o above and to the right of fixation wereassociated with significant decreases in self-perceived driving ability.Reading: Scotomas from 7.5 o left of fixation to 12.5 o right of fixationand scotomas below and to the lower right of fixation were associatedwith significant decreases in self-perceived reading ability.Mobility: Scotomas below and to the upper right of fixation weremost strongly associated with decreases in self-perceived mobilityfunction.Conclusions: Driving difficulty is associated with scotomas that fallon the instrument panel and rear view mirror when gazing straightahead. Reading difficulty is associated with scotomas that could©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permissionto reproduce any abstract, contact the ARVO Office at arvo@arvo.org.