MyVisionTest News Archive
Oct 17, 2009
Improving peripheral vision reading performance
Because age-related macular degeneration (AMD) frequently causes scotomas in central vision, afflicted patients must rely on their peripheral vision to read, making reading slow and difficult. Reading difficulty is the most common complaint in low vision clinics. Thus, developing suitable low-vision rehabilitation to enhance reading is vital for these low vision individuals.
To improve reading performance, patients with AMD can be trained to use assistive devices such as a magnifier, to improve eye-movement control, and to read with an optimal retinal location outside of their scotoma. In addition, perceptual learning tasks may have potential for improving the reading performance of AMD patients. Perceptual learning is defined as the long-term modification of perception and behavior following practice or sensory experience. It takes advantage of brain plasticity, which is the lifelong modifiability of functional and anatomical organization in the brain.
Methods and Results
The size of the visual span, the number of adjacent letters that can be recognized reliably without moving the eyes, imposes a limitation on reading speed. Slower reading speed observed in peripheral vision is associated with a smaller peripheral visual span. Perceptual training using a trigram letter-recognition task participants has been demonstrated to increase peripheral reading speed. This task involves identifying the letters of random 3-letter strings that are briefly exposed at differing distances to the left or right of the midline.
The lexical-decision task, like the trigram letter-recognition task, uses strings of three letters. Subjects indicate with a button press whether the string is a word or a non-word. Like the trigram-recognition task, the strings are presented at a range of positions left and right of the midline.
The RSVP (Rapid Serial Visual Presentation) reading task involved sequential presentation of the words of a sentence at a fixed location on a display screen. Subjects were instructed to fixate on a horizontal line while reading aloud a sentence presented in the superior or inferior peripheral visual field. Only horizontal eye movements along the fixation line were permitted during testing.
The present study compared the results of training using each of these three methods on peripheral reading speed. Twenty-eight normally sighted young adults were trained at 10 degrees in the lower visual field in a pre/post design.
All three training methods produced significant improvements in reading speed.
Using RSVP training, there was a mean improvement in reading speed of 72% at the trained retinal location. With trigram letter-recognition training, the subjects showed a mean improvement in reading speed of 54%. Using the lexical-decision training method, subjects improved by 39%, which is significantly lower than the improvement in the RSVP training group.
From these results, RSVP training appears to be more effective at increasing reading speed than either trigram letter-recognition or lexical-decision training. The RSVP training advantage is also found when the effects of training are tested at an untrained visual-field location and print size.
Discussion and Conclusions
The results of the present study showed that practice on any one of three perceptual learning tasks (RSVP reading, trigram letter recognition, or lexical decision) improved reading speed in the peripheral vision of normally-sighted young adults. Given these findings, the RSVP training method is likely to yield the greatest improvement in reading speed for low-vision subjects with central-field loss.
Although the RSVP training was most effective, the lexical-decision task has the advantage of easy self administration making it more practical for home-based training.
Read more...
Vision Res. 2009 Oct 8. [Epub ahead of print]
Tags: low vision, reading skills, eccentric viewing
Because age-related macular degeneration (AMD) frequently causes scotomas in central vision, afflicted patients must rely on their peripheral vision to read, making reading slow and difficult. Reading difficulty is the most common complaint in low vision clinics. Thus, developing suitable low-vision rehabilitation to enhance reading is vital for these low vision individuals.
To improve reading performance, patients with AMD can be trained to use assistive devices such as a magnifier, to improve eye-movement control, and to read with an optimal retinal location outside of their scotoma. In addition, perceptual learning tasks may have potential for improving the reading performance of AMD patients. Perceptual learning is defined as the long-term modification of perception and behavior following practice or sensory experience. It takes advantage of brain plasticity, which is the lifelong modifiability of functional and anatomical organization in the brain.
Methods and Results
The size of the visual span, the number of adjacent letters that can be recognized reliably without moving the eyes, imposes a limitation on reading speed. Slower reading speed observed in peripheral vision is associated with a smaller peripheral visual span. Perceptual training using a trigram letter-recognition task participants has been demonstrated to increase peripheral reading speed. This task involves identifying the letters of random 3-letter strings that are briefly exposed at differing distances to the left or right of the midline.
The lexical-decision task, like the trigram letter-recognition task, uses strings of three letters. Subjects indicate with a button press whether the string is a word or a non-word. Like the trigram-recognition task, the strings are presented at a range of positions left and right of the midline.
The RSVP (Rapid Serial Visual Presentation) reading task involved sequential presentation of the words of a sentence at a fixed location on a display screen. Subjects were instructed to fixate on a horizontal line while reading aloud a sentence presented in the superior or inferior peripheral visual field. Only horizontal eye movements along the fixation line were permitted during testing.
The present study compared the results of training using each of these three methods on peripheral reading speed. Twenty-eight normally sighted young adults were trained at 10 degrees in the lower visual field in a pre/post design.
All three training methods produced significant improvements in reading speed.
Using RSVP training, there was a mean improvement in reading speed of 72% at the trained retinal location. With trigram letter-recognition training, the subjects showed a mean improvement in reading speed of 54%. Using the lexical-decision training method, subjects improved by 39%, which is significantly lower than the improvement in the RSVP training group. From these results, RSVP training appears to be more effective at increasing reading speed than either trigram letter-recognition or lexical-decision training. The RSVP training advantage is also found when the effects of training are tested at an untrained visual-field location and print size.
Discussion and Conclusions
The results of the present study showed that practice on any one of three perceptual learning tasks (RSVP reading, trigram letter recognition, or lexical decision) improved reading speed in the peripheral vision of normally-sighted young adults. Given these findings, the RSVP training method is likely to yield the greatest improvement in reading speed for low-vision subjects with central-field loss.
Although the RSVP training was most effective, the lexical-decision task has the advantage of easy self administration making it more practical for home-based training.
Read more...
Vision Res. 2009 Oct 8. [Epub ahead of print]
