Visual Psychophysics / Physiological Optics - ARVO

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ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticslocated.Conclusions: The worse acuity found at the PRL than at otherlocations around the scotoma implies that the selection of the PRLlocation was unlikely to be based on optimizing acuity. Although ourmeasurements were made years after the development of the PRL,perceptual learning suggests that with continuous usage, acuity at thePRL should only get better and not worse, further affirming that theinitial selection of the PRL location was not based on optimizingacuity at a specific location.Commercial Relationships: Susana T. Chung, None; Jean-Baptiste Bernard, NoneSupport: NIH Grant R01-EY012810Program Number: 2184Presentation Time: 3:15 PM - 3:30 PMRetinal Fixation Locus in Patients with Bilateral CentralScotomas: Letter Targets are Better Suited for Visual Testingthan Targets that Fill inJoshua Pratt, Harold E. Bedell, Joy M. Ohara, Stanley Woo.University of Houston College of Optometry, Houston, TX.Purpose: Training eccentric viewing has been widely implementedas a regular part of low vision services for patients with centralscotomas. In this experiment we investigated whether target typeaffects the retinal fixation location and stability, and specificallywhether targets expected to perceptually fill in are imaged at thevestigial fovea. If targets expected to fill in are imaged at or near thevestigial fovea, then fixation on these targets would allow theprojected location of the vestigial fovea and the pathological scotomato be located accurately in visual space during eccentric viewingtraining, even without the use of a fundus imaging device.Methods: The retinal location and stability of fixation weremeasured using the Nidek MP-1 microperimter in twelve patientswith bilateral central scotomas for six types of fixation target, threeexpected to fill in and three that included letters. The approximateposition of the vestigial fovea was delineated either by using residualretinal landmarks or by locating the residual foveal pit in a densemacular scan, obtained with a Spectralis Optical CoherenceTomographer. Fixation location and stability were compared for thedifferent target types and referenced to the position of the vestigialfovea.Results: All of the subjects except one fixated consistently on targetsthat included a letter using peripheral retinal locations outside of thecentral scotoma. Eleven of the twelve subjects used a retinal locationcloser to the vestigial fovea to fixate targets expected to fill in,compared to letters. Although four of the subjects imaged the fill-intargets at or within a half degree of the vestigial fovea, six othersubjects imaged the fill-in targets at a retinal locus removed from thevestigial fovea. Target type produced no overall significant differencein fixation stability, specified in terms of bivariate contour ellipsearea. However, in some individual subjects fixation tended to bemore stable on letter targets than on fill-in targets.Conclusions: In patients with central field loss, letter targets generatemore consistent fixation behavior than fill-in targets and should beused for eccentric viewing training and perimetry.Commercial Relationships: Joshua Pratt, None; Harold E. Bedell,None; Joy M. Ohara, None; Stanley Woo, NoneSupport: NIH Core Grant P30 EY 07551, Beta Sigma KappaStudent Research GrantProgram Number: 2185Presentation Time: 3:30 PM - 3:45 PMQualitative and Quantitative Assessment of Metamorphopsia inRetinopathy PatientsEmily K. Wiecek 1, 2 , Kameran Lashkari 2, 3 , Steven C. Dakin 1, 4 , PeterBex 2, 3 . 1 Institute of Ophthalmology, University College London,London, United Kingdom; 2 Opthalmology, Harvard Medical, Boston,MA; 3 Opthalmology, Massachusetts Eye and Ear, Boston, MA;4 NIHR Biomedical Research Centre for Ophthalmology, MoorfieldsEye Hospital, London, United Kingdom.Purpose: Metamorphopsia (perceived distortion of visual space) iscommonly experienced by patients with retinal pathology. Althoughthis distortion is typically measured with Amsler charts, moreobjective and quantitative assessments are desirable for effectivemonitoring of the presence, progression, and remediation of visualimpairment. We compare qualitative assessments with novelquantitative methods across a range of retinal pathologies.Methods: An eleven-item questionnaire assessed metamorphopsiasymptoms in 80 patients with monocular distortion frommaculopathy. All patients completed an Amsler assessment(presented on a computer screen with fixation compliance monitoredby an eye tracker), and 35 patients additionally completed two novelobjective measures of metamorphopsia in the central five degrees ofvisual field. One task required participants to arrange dots in a square(combining spatial bisection and Vernier hyperacuities), and the otherused spatial alignment of dichoptically-presented targets. A dichoptictask was also used as a binary measure of inter-ocular suppression.Results: Monocular distortions were suppressed by undistortedvision in the better eye in 45% of patients. Questionnaire scores fromnon-suppressing patients positively correlated with distortionmeasures; however there was no relationship between subjective andquantitative assessments for patients who experienced suppression (p=.03). There was significant negative correlation in the overallvertical direction of distortion between the two novel quantitativedistortion assessments (p = .05), as well as a positive correlationbetween the directional displacement measured in the dichoptic taskand the gaze-contingent Amsler grid quantification (p = .01). Therewere no significant correlations between localized measures of visualdistortion across all three measures.Conclusions: The onset and progression of visual impairment maybe underreported in maculopathy due to the suppression of distortedvisual input from the more impaired eye. It is critical to assessmetamorphopsia monocularly, and we have introduced novel metricsto quantify such visual distortion in central vision.Commercial Relationships: Emily K. Wiecek, None; KameranLashkari, Circadian Technologies (F), Regeneron (R); Steven C.Dakin, None; Peter Bex, Adaptive Sensory Technology, LLC (S),Rapid Assessment of Visual Sensitivity (P)Support: R01EY019281, SCD is supported by NIHR BiomedicalResearch Centre for Ophthalmology at Moorfields Eye HospitalProgram Number: 2186Presentation Time: 3:45 PM - 4:00 PMThe effects of central and peripheral visual losses on reachingand graspingAachal Kotecha 1, 2 , Rachel T. Fahy 2 , Gary S. Rubin 2, 1 . 1 NIHR BRCfor Ophthalmology, UCL Institute of Ophthalmology & MoorfieldsEye Hospital, London, United Kingdom; 2 Visual Neuroscience, UCLInstitute of Ophthalmology, London, United Kingdom.Purpose: This study aims to evaluate the relative contributions ofcentral and peripheral vision to prehension in visually impairedadults.Methods: Reaching and grasping was quantified using motiondetection cameras (ProReflex, Qualisys AB, Sweden). Subjectsreached and grasped one of two cylindrical objects placed at 20cm or40cm from the hand. Measures were repeated 8 times under each testcondition and the median used in subsequent analysis. Indices of©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.
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.
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