Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsimprovement in both reading acuity and critical print size with PRSprototype. Mean reading acuity without PRS prototype (1.00 ± 0.23logMAR) was statistically poorer (t=13.054, p≤0.001) than thatmeasured with it (-0.08 logMAR ± 0.25). The same trend was foundin mean critical print size, with 1.15 ± 0.18 logMAR without the PRSprototype and for values significantly better (t=16.694, p≤0.001) withprototype (0.13 ± 0.25 logMAR).Conclusions: Considerable improvement in both reading acuity andcritical print size was provided by PRS prototype use. However,reading speed results had no statistical differences with and withoutPRS prototype in this small cohort of patients. Further studies withlarge numbers of patients are recommendable to corroborate andextend the findings with this new promising technology.Commercial Relationships: Adriana Berezovsky, None; VagnerR. dos Santos, None; Nívea N. Cavascan, None; Solange R.Salomao, NoneProgram Number: 2751 Poster Board Number: B0005Presentation Time: 8:30 AM - 10:15 AMImproving reading speed in peripheral vision through a nontask-basedtrainingDeyue Yu. College of Optometry, The Ohio State University,Columbus, OH.Purpose: People with central vision loss rely on their peripheralvision for reading. Previous studies have shown that peripheralreading can be improved with practice on character-based tasks. Anoptimal training paradigm should require little effort from patients toallow self-administration while providing efficient learning andprominent improvements. Heretofore, such a paradigm has beenlacking. Here, we introduce a practical and effective training methodthat utilizes priming of stimulus identity to facilitate learning in theabsence of a task.Methods: Seven normally-sighted young adults were trained at 10°in the lower visual field in a pre/post design. In the pre-test, wemeasured reading speeds using Rapid Serial Visual Presentation,visual-span profile (letter-recognition accuracy as a function of letterposition) with trigrams (strings of three random letters), the spatialextent of crowding (letter separations yielding 80% recognitionaccuracy for the middle letters of trigrams), and isolated-letterrecognition performance. To assess transfer of learning across printsizes, reading speed was measured at two print sizes (2.5° (trained),1°). Training consisted of five sessions of viewing trigrams presentedat various letter positions, a total of 7150 trials. Each training sessionhad 26 blocks. Within each block, the middle letter of the trigram wasalways the same. The left and right letters were randomly selectedresulting in differences, across trials, in the perceived appearance ofthe middle letter. The observer had no task, but rather was asked toattend to each trial and learn the known target letter with the optionof repeating the same trigram stimulus for as many times as needed(averaged 0.4 times). The post-test was identical to the pre-test but inreversed order.Results: Averaged across observers, the five-day training reduced thespatial extent of crowding by 29% and enlarged the visual span by1.6 characters. The improvements transferred to the untrained readingtask for both the trained print size (reading speed increased from 132to 298wpm) and the untrained print size (from 68 to 171wpm), whichis beyond what is typically observed in traditional task-basedtraining.Conclusions: Our findings demonstrate the effectiveness of utilizingpriming and stimulus exposure in training to improve peripheralreading. Moreover, this non-task-based training is simple enough toallow self-training at home.Commercial Relationships: Deyue Yu, NoneProgram Number: 2752 Poster Board Number: B0006Presentation Time: 8:30 AM - 10:15 AMEffect of Decreased Lighting on Visual Acuity in NormalSubjects Donald C. Fletcher MD; California Pacific MedicalCenter Dept. of Ophthalmology and Smith-Kettlewell EyeResearch Institute. Laura Walker Renninger; Smith-KettlewellEye Research InstituteDavid T. Hamilton. 1 Low Vision Research, CPMC, San Francisco,CA; 2 Low Vision Research, Smith-Kettlewell Eye Research Institute,San Francisco, CA.Purpose: Central field loss patients anecdotally report that more lightimproves their vision. In a recent study (Fletcher, Renninger, andSchuchard, 2012), it was reported that indeed acuity declines withlower light levels. The purpose of this study is to determine the extentto which light conditions affect visual acuity in normally sightedsubjects.Methods: Binocular Visual acuity was assessed on 20 normallysighted volunteers using their habitual correction. Initially a Snellenletter chart was viewed at one meter under ambient room light.Participants were tested a second time while wearing 4%transmission gray filter glasses (NOIR U23) over their spectacles orcontact lenses. The acuity difference is reported as lines differencewith decreased light.Results: Participants ranged in age from 22-70 (with a mean of 44.85years). All patients displayed diminished visual acuity when 4%transmission glasses were worn. Lines difference ranged from 1 (31,F) to 7 (60, F) with the majority of patients falling in the 2-5 linerange (mean: 2.95 lines, median: 2.5 lines). In Dr. Fletcher's patients,he observes a mean drop of about two lines (ambient room light vs.4% transmission gray filter glasses.) My results are slightly moreexaggerated, with almost a full additional mean line drop (2 vs. 2.95lines.)Conclusions: A significant reduction in visual acuity was noted withreduced lighting in this population of normally sighted healthyindividuals. Providing adequate lighting conditions optimizes visualacuity for tasks such as reading. This is an inexpensive and easilyadministered test to evaluate visual performance under dim lightconditions. Pathological conditions are often felt to decreasefunctional performance in subdued lighting. This data can serve as abaseline for comparisons.Commercial Relationships: David T. Hamilton, NoneProgram Number: 2753 Poster Board Number: B0007Presentation Time: 8:30 AM - 10:15 AMLuminance in Acuity and Reading Performance of Low VisionPatientsDonald C. Fletcher 1, 2 , Laura Renninger 2 , Ronald A. Schuchard 3 .1 Ophthalmology, California Pacific Medical Center, San Francisco,CA; 2 Smith-Kettlewell Eye Research Institute, San Francisco, CA;3 VAPAHCS, Stanford University, Palo Alto, CA.Purpose: To assess the role of luminance in low vision patients forvisual function tests.Methods: 152 consecutive low vision patients had assessment ofvisual acuity (VA) with habitual correction and with a 4%transmission gray filter on the ETDRS chart at 1 meter. Readingacuity on the MN Read was performed in room light and then with125 (low) and 2070 Lux (high) additional lighting. Central visualfield (CCVFT) was also performed. All tests were done binocularly.Results: Patient age median (range) was 82 (13 - 101) years with63% female. All patients were referred for low vision rehabilitationwith 89% having the diagnosis of a maculopathy. Visual acuity withhabitual correction median (range) was 20/100 (20/20 - 20/1000).©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.