There are more than 3.3 million Americans with low vision, most of whom have reading difficulties. Many suffer from macular degeneration and associated loss of central vision. The primary purpose of this proposal is to develop principled training methods to enhance low-vision reading, particularly for those with macular degeneration Our research indicates that decrease in the size of the visual span is a key factor explaining reduced reading speed in low vision. The visual span for reading refers to the number of letters, arranged side-by-side as in text that can be recognized accurately without moving the eyes. Structure of the retina and cortical magnification of the central visual field produce a small visual span, even for normal vision. This small visual span is further diminished as a consequence of eye disease. In a series of psychophysical studies, we will build on our prior research on the visual span to develop principled training methods to enhance low-vision reading. The three forms of training to be evaluated include: 1) Vertical reading in cases where the vertical visual span exceeds the horizontal visual span;2) Oculomotor training of eye fixations to maximize the information transfer rate through the visual span;and 3) Perceptual Learning which is focused on enlarging the size of the visual span. The applications to reading rehabilitation will benefit from our exploration of the sensory factors determining the size of the visual span and its role in reading. We will examine spatial factors (crowding, positional uncertainty) and temporal factors determining the size of the visual span in central and peripheral vision. We will use fMRI to localize the neural site of word and letter recognition within the visual span and the influence of perceptual learning on its size. These studies will inform our psychophysical exploration of the visual- processing capacity of the preferred retinal locus (PRL), the region of peripheral retina used for reading by many people with macular degeneration.

Public Health Relevance

There are more than 3.3 million Americans with low vision, most of whom have reading difficulties. Our broad goal is to use findings from vision science to understand the reading difficulties of people with low vision. A major goal of the current proposal is to develop principled training methods to enhance low-vision reading, particularly for people with macular degeneration.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY002934-32
Application #
8312612
Study Section
Central Visual Processing Study Section (CVP)
Program Officer
Wiggs, Cheri
Project Start
1979-09-01
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2014-08-31
Support Year
32
Fiscal Year
2012
Total Cost
$358,776
Indirect Cost
$121,176
Name
University of Minnesota Twin Cities
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Legge, Gordon E (2014) Prentice medal lecture 2013: visual accessibility: a challenge for low-vision research. Optom Vis Sci 91:696-706
Subramanian, Ahalya; Legge, Gordon E; Wagoner, Gunther Harrison et al. (2014) Learning to read vertical text in peripheral vision. Optom Vis Sci 91:1097-105
Liu, Haicheng; Jiang, Yi; Zhang, Bo et al. (2013) The orthographic sensitivity to written Chinese in the occipital-temporal cortex. Exp Brain Res 227:387-96
He, Yingchen; Legge, Gordon E; Yu, Deyue (2013) Sensory and cognitive influences on the training-related improvement of reading speed in peripheral vision. J Vis 13:14
Kwon, MiYoung; Legge, Gordon E (2013) Higher-contrast requirements for recognizing low-pass-filtered letters. J Vis 13:13
Kwon, MiYoung; Legge, Gordon E (2012) Spatial-frequency requirements for reading revisited. Vision Res 62:139-47
Ma, Lifei; Jiang, Yi; Bai, Jian'e et al. (2011) Robust and task-independent spatial profile of the visual word form activation in fusiform cortex. PLoS One 6:e26310
Kwon, Miyoung; Legge, Gordon E (2011) Spatial-frequency cutoff requirements for pattern recognition in central and peripheral vision. Vision Res 51:1995-2007
Legge, Gordon E; Bigelow, Charles A (2011) Does print size matter for reading? A review of findings from vision science and typography. J Vis 11:
Bai, Jian'e; Shi, Jinfu; Jiang, Yi et al. (2011) Chinese and Korean characters engage the same visual word form area in proficient early Chinese-Korean bilinguals. PLoS One 6:e22765

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