Visual Psychophysics / Physiological Optics - ARVO

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ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsCommercial Relationships: Gregory R. Jackson, MacuLogix (F),MacuLogix (I), MacuLogix (E), Genentech (R); John G. Edwards,MacuLogix, Inc (I), MacuLogix, Inc (E), MacuLogix, Inc (P),MacuLogix, Inc (S)Support: NIH Grant EY019593Program Number: 5034 Poster Board Number: A0196Presentation Time: 2:45 PM - 4:30 PMHigh Angular Resolution Peripheral Refraction in Patients withAge Related Macular DegenerationBart Jaeken 2, 1 , Encarna Alcón 1, 3 , Jose María Marín 3 , Pablo Artal 1 .1 Laboratorio de Optica, Universidad de Murcia, Murcia, Spain;2 R&D, Voptica, Murcia, Spain; 3 Oftalmología, Hospital Virgen de laArrixaca, Murcia, Spain.Purpose: The Hartmann-Shack (HS) wavefront sensor was used todetermine the peripheral refraction (PR) at specific angles in subjectswith age related macular degeneration (AMD) (Lundström et al.,Optom Vis Sci 2007). The correction of the PR in those subjectscould improve their visual acuity at eccentric locations. However,instrumentation specifically designed for accurate and fast measuringPR was never tested in those patients. Easy determination of PRcould provide those patients with customized corrections.Methods: We adapted a fast scanning peripheral HS wavefrontsensor previously developed (Jaeken et al., Opt Exp 2011). Its designmakes it possible to measure fast (order of seconds) and with a highangular resolution (1 measurement/°) a large part of a horizontalmeridian of the visual field (50°). Two fixation methods were tested:placing the target in the patient’s preferred retinal location (PRL) andhaving the PRL aligned to the center of the measuring system. Forboth applications a red laser beacon was projected on a wall at 2meter from the patient. The stability of fixation while scanning wasdetermined looking at the position of the pupil in each frame of ascan. PR (sphere and cylinder) was determined from the series ofrecorded HS images. The repeatability of 4 consecutive scans wascompared with that in normal elderly eyes. The light distributionwithin the HS spots was evaluated intra-patient between the differentretinal areas.Results: No variation in the quality of the HS images was observedbetween the areas with and without retinal damage. Smalldisplacements of the centre of the pupil were registered, although thisdid not affect the refraction results. The repeatability of the 4 scans ineyes with AMD was not different from that in normal elderly eyes. Insome subjects anomalies were observed in the HS images which arepresumed to come from a plane close to the pupil plane. Since someof the patients did not undergo cataract surgery, it probably comesfrom crystalline lens opacities. The measured PR of PRL variedamong subjects.Conclusions: An adapted scanning peripheral wavefront sensor wasfound to be a functional tool for measuring fast and accurately the PRin AMD patients. This refractive information can be useful forcustomized corrections. For example, they could benefit from acustom designed intraocular lens adjusted to their exact PR at theirPRL.Commercial Relationships: Bart Jaeken, PCT/ES2011/070640 (P);Encarna Alcón, None; Jose María Marín, None; Pablo Artal,AMO (C), Voptica SL (P), Voptica SL (I), AMO (F), Calhoun Vision(F), Calhoun Vision (C), AcuFocus (C)Support: Ministerio de Ciencia e Innovación, Spain (grantsFIS2010-14926 and CSD2007-00013) and Fundación Séneca, Regionde Murcia, Spain (grant 4524/GERM/06)Program Number: 5035 Poster Board Number: A0197Presentation Time: 2:45 PM - 4:30 PMCompensation of fixational instability by the NIDEK MP-1micro-perimeterArunkumar Krishnan, Harold E. Bedell. University of Houston -College of Optometry, Houston, TX.Purpose: Micro-perimeters are used increasingly to assess patientswith central field loss, because of the reported capability of theseinstruments to compensate for fixational eye movements and presenttest stimuli repeatably at an intended retinal location. In this study weinvestigated the precision of eye-movement compensation by theNIDEK MP-1, when the fixation instability of normal subjects isincreased by changing the size of the fixation target.Methods: Retinal sensitivity for horizontal (H) and vertical (V)traverses across one edge of the optic disc were assessed in one eyeof 7 normal subjects, aged 25-35 years. Two fixation targets werechosen to promote ‘more’ and ‘less’ stable foveal fixation,respectively: a 1 deg cross and a 10 deg circle. A customized 15 x 2element array of Goldmann size II test stimuli, each separated by 0.1deg, was positioned horizontally across the temporal disc margin orvertically across the inferior or superior disc margin. An in-built 4-2-1 strategy determined the detection threshold for each stimuluselement in the array. The MP-1 recorded the distribution of fixationpositions during testing, from which the standard deviation (SD) offixation was computed in both the H and V directions. CumulativeGaussians were fit to the threshold profiles obtained during fixationon the cross and circle and the fitted SD for the circle fixation targetwas compared to the expected value based on an additive-variancemodel. Percent compensation during fixation on the circle target wasdefined as (expected SD - observed SD) / (expected SD).Results: Average fixational SDs increased from 0.20 to 0.65 deg (H)and 0.20 to 0.72 deg (V) for fixation on the cross and circle targets,respectively. Best-fit Gaussians to the perimetric profiles had SDsthat were not significantly shallower during fixation on the circlecompared to the cross (P = 0.11 [H]; P = 0.68 [V]). The averagepercent compensation for the increase in fixation instability on thecircle target, was 91.7% (H) and 86.6% (V), corresponding to anincrease in the SD of retinal image scatter of 2.2 (H) and 3.8 (V) minarc.Conclusions: The NIDEK MP-1 compensates well for an increase infixational instability in the horizontal and vertical directions. Thiscompensation ensures that, even in subjects with unstable fixation,perimetric test stimuli are presented close to the intended retinallocations.Commercial Relationships: Arunkumar Krishnan, None; HaroldE. Bedell, NoneSupport: Minnie flaura turner fund for impaired vision research,University of Houston sVGR.Program Number: 5036 Poster Board Number: A0198Presentation Time: 2:45 PM - 4:30 PMBCEA evaluation after pattern stimulation in wet AMD patientsEnzo M. Vingolo, Paolo G. Limoli, Serena Fragiotta, Vittoria DeRosa, Daniela Domanico. UOC Ophthal Hosp "SM Goretti" LT,University La Sapienza of Rome, Roma, Italy.Purpose: age related macular degeneration is one of the main causeof visual impairment in elderly people. We studied and compared theefficacy of rehabilitation by means of two different type ofbiofeedback techniques with MP-1 microperimeter in patients withevoluted AMD.Methods: We enrolled 30 patients, mean age 76,38yrs (8,77SD)bilaterally affected by wet AMD. Patients were randomly divided intwo groups: A was treated with an acoustic biofeedback, group B wastreated with a luminous biofeedback constituted by a black and whitecheckerboard flickering during the examination. All patients©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 Opticsunderwent 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 Visual 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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